Full Set

Integrated Services Digital Network (ISDN) BRI

.ISDN BRI divides the regular copper telephone line into three channels: 2 64-Kbps bearer (B) channels can transfer data up to 128 Kbps (data compression increases the data transfer rate). Only one B channel is used during phone use reducing maximum speed to 64 Kbps. 1 16-Kbps delta (D) channel for connection control.

1000BaseSX (short)

1,000 Mbps (half-duplex) 2,000 Mbps (full-duplex) Fiber optic 220 to 550 meters depending on cable quality

1000BaseLX (long)

1,000 Mbps (half-duplex) 2,000 Mbps (full-duplex) Fiber optic 550 meters (multimode) 10 kilometers (single-mode)

1000BaseCX (short copper)

1,000 Mbps (half-duplex) 2,000 Mbps (full-duplex) Special copper (150 ohm) 25 meters, used within wiring closets

1000BaseT

1,000 Mbps (half-duplex) 2,000 Mbps (full-duplex) Twisted pair (Cat5 or higher) 100 meters

10GBaseSR/10GBaseSW

10 Gbps (full-duplex only) Multimode fiber optic 300 meters

10GBaseLR/10GBaseLW

10 Gbps (full-duplex only) Single-mode fiber optic 10 kilometers

10GBaseER/10GBaseEW

10 Gbps (full-duplex only) Single-mode fiber optic 40 kilometers

10GBaseT

10 Gbps (full-duplex only) Twisted pair (Cat6, or 7) 100 meters

Cat 6a

10 Gbps speeds are limited to cable lengths less than 100 meters. Provides additional shielding and tighter cable twists than standard Cat 6, which reduces (alien) crosstalk and makes it less susceptible to EMI.

Cat 6

10 Gbps speeds are limited to cable lengths less than 55 meters.

10BaseT

10 Mbps (half-duplex) 20 Mbps (full-duplex) Twisted pair (Cat 4 or 5) 100 meters

10BaseFL

10 Mbps (multimode cable) Fiber optic 1,000 to 2,000 meters

100BaseTX

100 Mbps (half-duplex) 200 Mbps (full-duplex) Twisted pair (Cat5 or higher) Uses 2 pairs of wires 100 meters

100BaseFX

100 Mbps (multimode cable) Fiber optic 412 meters

2G

2G (second generation) networks were the first to offer digital data services. 2G data speeds are slow (14.4 Kbps) and are used mainly for text messaging, not internet connectivity. 2.5G supports speeds up to 144 Kbps. EDGE (also called 2.75G) networks are an intermediary, between 2G and 3G networks. EDGE is the first cellular technology to be truly internet-compatible, with speeds of 400-1,000 Kbps.

celluar voice and data

2G (second generation) networks were the first to offer digital data services. 2G data speeds are slow (14.4 Kbps) and were used mainly for text messaging and not internet connectivity. 2.5G was an evolution that supported speeds up to 144 Kbps. EDGE (also called 2.75G) networks are an intermediary between 2G and 3G networks. EDGE is the first cellular technology to be truly internet compatible, with speeds between 400 and 1,000 Kbps. 3G (third generation) offers simultaneous voice and data. The minimum speed for stationary users is quoted at 2 Mbps or higher. 4G (fourth generation) offers minimum speeds of around 38 Mbps, with up to 100 Mbps possible.

3G

3G offers simultaneous voice and data. Minimum speeds for stationary users are quoted at 2 Mbps or higher. The following extensions enhance 3G networks: HSPA+ (also known as smart antenna) uses multiple-input and multiple-output (MIMO). It significantly increases data throughput and link range without additional bandwidth or increased transmit power. Long Term Evolution (LTE) and LTE-Advanced increase downlink/uplink speeds to 100/50 Mbps and 1Gbps/500Mbps, respectively

4G

4G is available with minimum speeds around 3-8 Mbps, with over 100 Mbps possible. 4G: Uses MIMO. Is not compatible with 3G; 4G requires a complete retrofit on the part of service providers and new equipment for the consumer. Utilizes Worldwide Interoperability for Microwave Access (WiMAX). WiMAX delivers high-speed internet service (up to 1 Gbps for stationary users) to large geographical areas.

hard disk speeds

5400 RPM (not desired) 7200 RPM (minimum) 10,000 RPM 15,000 RPM

5G

5G is able to achieve speeds twenty times faster that 4G; its peak speed is 20Gb per second. Uses MIMO. Includes lower frequencies than previous generations, down to 600 MHz. Uses Long-Term Evolution (LTE) for wireless connections.

802.1x

802.1x authentication uses usernames and passwords, certificates, or devices such as smart cards to authenticate wireless clients. Originally designed for Ethernet networks, the 802.1x standards have been adapted for use in wireless networks to provide secure authentication. 802.1x authentication requires the following components: A RADIUS or TACACS+ server to centralize user account and authentication information. A centralized database for user authentication is required to allow wireless clients to roam between cells but authenticate using the same account information A PKI for issuing certificates. At a minimum, the RADIUS server must have a server certificate. To support mutual authentication, each client must also have a certificate Use 802.1x authentication on large, private networks. Users authenticate with unique usernames and passwords.

hyper-threading

Hyper-threading is a feature of some Intel processors that allows a single processor to run threads (instructions) in parallel, as opposed to processing threads linearly. Hyper-threading enables a processor to execute two threads at the same time. For example, on a quad-core Intel system that supports hyper-threading, the processor can execute 8 threads at a time (2 on each core). Hyper-threading is not the same as multithreading. Multithreading is a feature of an application that allows it to send multiple threads at the same time. Applications are typically written to support multithreading to take advantage of multiple cores (executing threads on two or more processors at the same time) or hyper-threading features.

I/O Connectors

I/O connectors for onboard components are located on the back of the motherboard. These connectors typically include the following: PS/2 mouse and keyboard ports USB ports Serial ports (COM 1, 2, 3, and 4) Parallel port Audio jacks Ethernet port An I/O shield fits over the connectors to secure them and protect the inside of the computer from dust and debris.

Internet Message Access Protocol (IMAP) 143

IMAP is an email retrieval protocol designed to enable users to access their email from various locations without the need to transfer messages or files back and forth between computers. Messages remain on the remote mail server and are not automatically downloaded to a client system.

IMEI vs. IMSI

IMEI stands for International Mobile Equipment Identity. It is a unique number given to every single mobile phone. It is typically located behind the battery. IMEI numbers of cellular phones connected to a GSM network are stored in the Equipment Identity Register database containing all valid mobile phone equipment. When a phone is reported stolen or is not type approved, the number is marked invalid. IMSI stands for International Mobile Subscriber Identity. This is a unique identifier that defines a subscriber in the wireless world, including the country and mobile network to which the subscriber belongs. The IMSI is one of the pieces of information stored on a SIM card.

IP version 6 (IPv6)

IP version 6 (IPv6) was developed to address the fact that IPv4 addresses have been exhausted. The IPv6 address is a 128-bit binary number.

LCD IPS panels

IPS (In-plane switching) panels have the best color reproduction quality and viewing angles among LCDs, making them well suited for graphic artists, designers, and photographers. IPS panels have relatively slow response times (5-16 ms) and refresh rates (60 Hz) and have a slight purple tint when viewed from a wide angle. High-end IPS LCDs are very expensive (over $1000).

Integrated Services Digital Network (ISDN) PRI

ISDN PRI requires different cables to be installed rather than the regular phone lines. The cable is divided into 24 channels: 23 B channels (each at 64 Kbps) for data transmission. 1 D channel (at 64 Kbps) for connection control.

Integrated Services Digital Network (ISDN)

ISDN is a digital service, running over a switched network.ISDN is not available in all areas; subscribers are required to be within a certain proximity of telephone company equipment. ISDN is more common in Europe than in the United States.

Automatic Private IP Addressing (APIPA)

If a Windows client is configured to receive an IP address from a DHCP server, but cannot contact a DHCP server, it will automatically assign itself an IP address within the following range: 169.254.0.1 to 169.254.255.254 with the subnet mask 255.255.0.0 With APIPA: The host is configured to obtain IP information from a DHCP server (this is the default configuration). If a DHCP server cannot be contacted, the host uses APIPA to assign itself an IP address. The host configures only the IP address and mask. It does not assign itself the default gateway and DNS server addresses. For this reason, APIPA can be used only on a single subnet. You can use APIPA instead of a DHCP server, but it should be used only on a small network that does not need default gateway or DNS server settings configured. APIPA is the term used by Microsoft Windows. On other systems (e.g., Linux), this functionality is known as link-local addressing.

application crash

If an application you are using crashes, an error has occurred that gives you no choice except to exit the application. Sometimes you can fix the problem by rebooting the computer. You may need to debug your system. Check log files for errors that provide clues about what might have caused the crash.

poor print quality laser printer

If faint images from previous printouts appear on subsequent pages, the fluorescent lamp and rubber scraper might not be removing remaining toner from the drum prior to starting a new print job. A dirty primary corona wire can cause a vertical stripe down the print job because that part of the OPC drum is not being charged by the charge corona. A dirty secondary corona wire could cause the same problem because the charge is not being applied to part of the paper. A dirty drum or roller can create lines or splotches at regular intervals on the print job. If toner is not sticking to the paper, check the transfer (fuser) rollers. A faulty static eliminator strip might cause paper jams because the paper will stick to the components inside the printer.

Install the Printer Drivers

Each network host that wants to use the printer must have the corresponding printer driver installed. When you share a printer in Windows, the current printer driver is automatically delivered to clients that connect to the shared printer. If the client computers run a different version of Windows, you can add the necessary printer drivers to the printer object. To add drivers for network users: Edit the printer properties and use the Advanced tab Edit the print server properties and use the Sharing tab

rail

Each separate voltage output circuit is referred to as a rail and can power multiple devices. To avoid overloading one circuit, many newer power supplies have two or more +12 volt rails. These are known as dual rail power supplies. Separate rails balance the power load between multiple circuits, preventing any one circuit from becoming overloaded

EL-WLED

Edge-Lit White LED (EL-WLED or WLED) displays use white LEDs along one edge (usually the top) of the LCD and a light diffuser to backlight the screen. EL-WLED LCDs are the least expensive, thinnest, and most widely used type of LCD.

Smoke or Burning Smell

If smoke or a burning smell is observed coming from a computer, it indicates that electricity is not flowing in the correct manner within the system. If smoke is observed, shut the system off immediately. This issue could be caused by: A connector that isn't seated properly and electricity is arcing between leads. A short circuit in the printed circuit board of the motherboard itself or on an expansion board. An improperly installed component. Unfortunately, a component that is smoking has probably already been damaged to some degree. It's unlikely that it will ever function properly again. Replacement components are usually required.

Printer Properties

Edit the properties of the printer object in order to: Print a test page Share the printer Change the driver used by the printer object Add drivers for network users Change the port used by the printer Match the colors on the screen to the colors that are printed by loading color management profiles Assign permissions to control what users can do Configure a time range during which the printer will be available Configure custom settings for the specific print device Users with the Print permission can print using the printer; users with the Manage printers permission can edit the printer properties and pause the printer, but cannot manage any documents waiting to be printed.

vi

Edits the contents of a text file. The vi uses four different operating modes: Command mode Command-line mode Insert mode Replace mode For example, to edit the contents of the widget.txt file, you would enter vi widget.txt at the shell prompt. You would then press the i key to enter Insert mode and make the necessary changes to the file. When done editing the file, you would press the Esc key to enter Command mode. Then you would press the : key to enter command-line mode where you would enter exit to save your changes and exit the vi editor.

Failing CPU Symptoms

If the computer boots, but the processor is running at less than its rated speed, check for incorrectly set motherboard settings or use the BIOS/UEFI to set the appropriate CPU speed. If you cannot set the correct speed, try updating the BIOS with the latest version.

The system boots, but the display remains blank

Either a card or memory module is not seated, or the system includes unsupported memory. Non-parity RAM is incompatible with ECC memory and SDRAM is incompatible with EDO memory.

The system boot fails and sounds a beep code

Either no memory is installed or the memory was not detected.

32-bit or 64-bit Processor

A 32-bit processor can process 32-bits of information at a time; a 64-bit processor can process 64-bits of information. The biggest advantage of 64-bit processors over 32-bit processors is in the amount of memory they can use. 32-bit processors have a limit of 4GB. 64-bit processors have a theoretical limit of 16 EB, although operating system and current hardware limitations impose a much lower practical limit. The operating system and applications must be written for 64-bits to take full advantage of 64-bit processing. The processor instruction set identifies all instructions (operations) that a processor can perform. 32-bit processors use the IA-32 instruction set (also referred to as x86). Itanium processors from Intel use the IA-64 instruction set. AMD64 and Intel 64 processors use the x86-64 instruction set (also referred to as x64). 32-bit applications can run on 64-bit processors using the following methods: Itanium processors use a software layer to translate between IA-32 and IA-64. x64 processors execute both 32-bit and 64-bit instructions in the hardware. You can run a 32-bit operating system on a computer with a 64-bit processor. Applications typically perform better on 64-bit systems. 64-bit applications typically perform better than 32-bit applications. In some cases, 32-bit applications might perform better on 64-bit systems.

3D Printer

A 3D Printer creates a physical object by taking a digital model and manufacturing the object layer by layer. There are many different 3D printing technologies and materials that can be used depending on the object to be created. The materials that 3D printers use to create objects are called filaments. The most popular filaments are ABS (Acrylonitrile Butadiene Styrene) and PLA (Polylactic Acid). 3D printing can be done using many different kinds of filaments such as PVA, PET, PETT, HIPS, nylon, wood, sand stone, metal, magnetic iron, conductive PLA, carbon fiber PLA, flexible/TPE 3D printer filament, glow in the dark, and amphora 3D printer filament.

DIMM

A DIMM (dual in-line memory module) has pins on both sides of the module, with each pin being unique. DIMMs have a 64-bit data path that matches the system bus width. RDRAM and DDR/2/3/4 are packaged into DIMMs, with each specification having a unique number of pins and notch position. DDR4 allows for DIMMs of up to 512 GB in capacity.

DVD-DL

A DVD-RW DL employs two recordable dye layers, each capable of storing about 4.7 GB; the total disk capacity is 8.5 GB. Some DVDs can store data in two different layers on the same side. The outer layer is semi-transparent, allowing the laser to read data from the inner layer. Dual-layer discs can hold up to 8.5 GB of data. Dual-layer recordable discs cost more than single layer discs. Dual-layer DVDs are recorded using Opposite Track Path (OTP). Most newer drives can read both single and dual layer discs. However, older drives might not support dual layer discs.

Foreign

A Foreign disk is a dynamic disk that was created in one system and moved to another system. When you first add the disk to a different system, the partition information for the disk must be updated to reflect all dynamic disks in the current system. Import the disk to make it available in the new system.

JBOD Facts

A JBOD configuration creates a single volume using space from two or more disks. Spanning is another term for JBOD because the volume spans multiple physical disks. Data is not striped between disks, but saved to one or more disks (depending on how the operating system decides to save each file). On a new JBOD configuration, data is typically saved to the first disk until it is full. Then additional data is saved to the second disk and so on. Disks used within the spanned volume can be of different sizes. JBOD uses the entire space available on all disks for data storage (no overhead). There are no performance or fault tolerance benefits with JBOD. If one drive fails, you might be able to use disk recovery tools to recover data from the remaining disks.

KVM switch

A KVM (keyboard, video, mouse) switch allows multiple computers to use a single keyboard, mouse, and monitor. KVM switches have multiple input groups, with each group accepting keyboard, video, and mouse connections from one computer. A single output group connects to the shared peripheral devices. Buttons on the KVM switch are used to toggle between each connected computer. Rackmount KVM switches can support up to 16 computers and are typically used in data centers to manage servers from a central console. Desktop KVM switches typically support two or three computers, which must be within about 5 meters. Networked or remote KVM switches use special hardware devices that send keyboard, mouse, and video content through a network connection.

Network-Attached Storage (NAS)

A NAS is a device that is optimized to provide a single service: file sharing. NAS devices range in price from several hundred to several thousand dollars. A NAS can be connected to a network and configured very easily. This makes them a great choice for most networks needing a file sharing service.

PCI Extended (PCI-X)

A PCI design that overcomes PCI bandwidth limitations.

RAID 10 (Stripe of Mirrors)

A RAID 10 volume stripes data across mirrored pairs and across multiple disks for data redundancy. If a single disk fails, its data can be recovered using the mirrored information stored on the remaining disks. If two disks in the same mirrored pair fail, all data will be lost because there is no redundancy in the striped sets. Provides fault tolerance for a single disk failure. Provides redundancy and performance. Uses 50% of the total raw capacity of the drives is due to mirroring. Requires a minimum of four disks.

RAID 5 (Striping with Distributed Parity)

A RAID 5 volume combines disk striping across multiple disks with parity for data redundancy. Parity information is stored on each disk. If a single disk fails, its data can be recovered using the parity information stored on the remaining disks. Striping with distributed parity: Provides fault tolerance for a single disk failure. Provides an increase in performance for read operations. Write operations are slower with RAID 5 than with other RAID configurations because of the time required to compute and write the parity information. Requires a minimum of three disks. Has an overhead of one disk in the set for parity information. (1 / n - 1). A set with 3 disks has 33% overhead. A set with 4 disks has 25% overhead. A set with 5 disks has 20% overhead.

SODIMM

A SODIMM (small outline dual in-line memory module) is a smaller DIMM used in laptops. SODIMMs are much smaller than other memory, perfect for notebook computers. Notice the notch slightly off center in the 144-pin SODIMM. 144-pin SODIMMs are used by SDRAM, DDR, and DDR2 memory. On the 200-pin SODIMM, notice that the notch is farther off center than the 144-pin SODIMM. You might also be able to notice the higher pin density. 200-pin SODIMMs are used by DDR2 and DDR3 memory.

TOSLINK

A TOSLINK (or optical audio cable) connector is used with digital optical I/O for S/PDIF audio.

taskbar

A bar normally located at the bottom of the Windows desktop, displaying information about open programs and providing quick access to others.

barcode reader

A barcode reader is a device that can scan barcodes. Barcodes are most commonly used in retail environments at checkout stands. Shipping companies, hospitals, and other organizations use barcodes to track or inventory items. Most bar code readers use a laser to scan the barcode. Some use cameras or optical scanners. Barcode readers include software that interprets the meaning of the barcode. By installing a special app, smart phones are able to function as a barcode reader by using the phone's built-in camera.

bridge

A bridge connects two segments within the same subnet that use different media types. For example, you can use a bridge to connect wireless clients to wired clients on the same network.

Bridge

A bridge connects two segments within the same subnet. Bridges learn which side a host resides on by copying the MAC address of the source device and placing it into the MAC address table. The port number the frame entered is also recorded in the table and associated with the source MAC address. Another functionality of a bridge is to convert one type of transmission medium into another. A common example of this is a wireless bridge, which converts wired transmissions into wireless transmissions and vice versa.

Bus Topology

A bus topology consists of a trunk cable with nodes either inserted directly into the trunk or tapped into the trunk using offshoot cables called drop cables. A broken cable anywhere on the bus breaks the termination and prevents communications between any devices on the network.

card reader

A card that contains an embedded microchip or a magnetic strip is inserted into the reader. The reader then scans the chip or strip, verifies its contents, and authenticates the user. Card readers can be stand-alone devices or integrated with other peripherals (e.g., a keyboard or workstation).

Cell Tower Analyzer

A cell tower analyzer can be used to troubleshoot cellular network connectivity by displaying the following information: Signal strength/interference Number of cell towers in the area The location of each cell tower Mobile network information (e.g., network type, data activity, service provider, etc.)

system resources

A computer assigns system resources to hardware devices, and the computer uses these assignments to communicate with the device. You should be familiar with three categories of system resources:

Just a Bunch of Disks (JBOD)

A configuration that places multiple disks in a single logical storage unit.

Peripheral Component Interconnect (PCI)

A connection slot for a 32-bit computer bus.

Missing BIOS/UEFI Settings

A constant source of power is required to store the settings configured in the motherboard BIOS/UEFI chipset. The motherboard also needs constant power to keep the system clock running while the system is powered off. Most motherboards implement a small battery that provides this power. If this battery starts to fail, then the following may occur when the system is powered on: The system clock loses time. Settings configured in BIOS/UEFI are lost. If this happens, it's likely that the motherboard battery has failed and needs to be replaced.

Directory simple explanation

A container in a volume that holds files or other directories.

virtual reality headset

A device worn on the head that covers the eyes and provides separate images for each eye, stereo sound, and motion tracking sensors to create a virtual reality experience for the user. Some headsets also have eye tracking sensors and work with handheld gaming controllers. Virtual reality is widely used to train medical and military professionals. As it becomes more affordable, it is being widely adopted in many fields.

Dial-Up

A dial-up connection uses a modem connected to the phone line to connect to the internet. Dial-up connections use the public switched telephone network (PSTN). Phone lines are sometimes referred to as POTS (plain old telephone service). Multiple standards define how to send digital data over the analog phone lines at various speeds and compression ratios. Dial-up connections are available anywhere a telephone line exists. Data transfer rates include 28.8 Kbps, 33.3 Kbps, and 56 Kbps. Dial-up connections cannot be used for both voice (phone calls) and data at the same time.

directory

A directory (also called a folder) is a container in a volume that holds files or other directories. It is used to logically sort and organize data to keep related files grouped together. Most operating systems use a hierarchal filing structure.

Redundant Array of Independent Disks (RAID)

A disk sub-system that combines multiple physical disks into a single logical storage unit.

Dot Matrix

A dot matrix printer is an impact printer that transfers characters by striking a pattern (from a matrix) through an inked ribbon and onto paper. The most common number of pins on a dot matrix printer is 9, 18, or 24, with more pins providing a higher resolution. 24-pins create a near-letter quality print and anything with less than 24-pins provides a draft quality print. The overall print quality of a dot matrix printer is quite poor when compared to that of other types of printers. The speed of dot matrix printers is measured in characters per second (CPS). Common speeds for a dot matrix printer are 32 to 72 CPS. Dot matrix printers operate in either a font (letters, numbers and symbols) or dot-addressable (graphs and charts) mode. Dot matrix printers can use either a friction feed or a tractor feed system to move paper through the printing assembly. Because dot matrix printers strike the image onto paper, it is a good printer to use when carbon-copy documents are being printed. The print head can become dangerously hot due to pin friction. Dot matrix printers can be loud because printing takes place by pins physically striking the ink ribbon, paper, and the platen (a metal plate behind the paper).

drivers

A driver is program that enables the operating system to interact with hardware devices.

Dye Sublimation (Dye Diffusion Thermal Photo)

A dye sublimation printer is a non-impact printer that uses film-embedded dye. The print head heats and passes over the film, causing the dye to vaporize and soak into the film paper. Dye sublimation printing prints in transitioning colors rather than pixels. Produces photographic quality images.

failed to boot

A failure to boot with an error message that reads something to the effect of "OS Not Found" could be trivial or serious. Common causes include the following: You're booting from the wrong disk ; one that doesn't have an operating system installed. This is a very common issue. It frequently occurs when a CD or DVD is in your optical drive at system boot and the BIOS/UEFI is configured to boot from the optical drive first. The error message is displayed when an operating system can't be found on the optical disc. To fix this issue, simply remove the optical disc from the drive and reboot. This error could also be caused in situations where you have multiple hard disks in the system, but only one has an operating system installed. If the boot device setting gets inadvertently changed in the BIOS/UEFI, it will try to boot the system from the wrong hard disk.Your master boot record (MBR) has been overwritten or is corrupt. The MBR is the first sector of your hard drive that tells the BIOS where to look for the operating system on the disk. If the MBR is damaged or corrupt, then the operating system will fail to load.On Windows, you have to boot from the installation disc to enter the recovery environment and select the Automatic repair option. Alternatively, you can select the Command prompt option and run the bootrec command to rebuild the boot configuration data. You can also run the bootrec command with the following switches: /fixmbr: Repairs the master boot record /fixboot: Repairs the boot sector /rebuildbcd: Rebuilds the boot configuration data

file

A file is a one-dimensional stream of bits treated as a logical unit. They are the most basic component that a file system uses to organize raw bits of data on the storage device itself. The filename is made up of the directory path plus the file name. An extension can also be added to the filename to identify the file type and the program used to create, view, and modify the file.

Screen flickers or appears wavy, user reports headaches

A flickering screen can be caused by too low of a refresh rate or a loose video cable. Make sure the video cable is properly connected. Set the refresh rate to the maximum allowed by the monitor. If you cannot increase the refresh rate, try decreasing the resolution size and see if higher refresh rates become available. Maximum refresh rate is determined by the monitor, the video card, and the video cable. To achieve higher refresh rates, one (or all) of these components may need to be upgraded.

Fuel Cell

A growing technology that is still developing and is being implemented into the small electronic device market. Not truly a battery. Offers instant power and uses replaceable cartridges. Rather than being recharged (taking hours), when its charge becomes low, the fuel is merely replaced (taking seconds).

Gyroscope

A gyroscope measures the vertical and horizontal orientation of the device. This essentially creates a user input mechanism. The tablet can detect changes in vertical and horizontal acceleration and respond programmatically. For example, changes in vertical and horizontal acceleration detected by the gyroscope can be used as input for a gaming app.

hard disk drive (HDD)

A hard disk is a thick magnetic disk encased in a thicker protective shell. A hard disk consists of several aluminum platters, each of which requires a read/write head for each side. All of the read/write heads are attached to a single access arm to prevent them from moving independently. Each platter has circular tracks that cut through all of the platters in the drive to form cylinders. The spinning of the platters is referred to as revolutions per minute (RPM). The higher the revolutions per minute, the faster the data can be accessed

Hub

A hub provides a central connecting point for multiple media segments on the same subnet. When a hub receives a signal, it is sent out to all the ports on the hub. Hubs operate in half-duplex mode because the path between devices is shared, meaning that devices can only send when no other devices are sending data. Hubs are a legacy network device and are rarely used because they lack features and perform poorly.

hubs

A hub provides a central connection for multiple media segments on the same subnet. When a hub receives a signal, it is repeated out to all other ports. Hubs operate in half-duplex mode, meaning devices can either send or receive data at any given time.Hubs are rarely used in networking environments. You should avoid them if possible.

Exposing

A laser beam changes the charge on the surface of the drum in a pattern of the page's image.

Local Area Network (LAN)

A local area network is a network in a small geographic area, like an office. A LAN typically uses wires to connect systems together.

USB Type c

A long, thin oval connector designed to be a universal USB port that works with many devices and connectors.

Boot Errors

A malfunctioning motherboard may generate error codes when the system is powered on. Every time the PC boots, it runs a Power On Self-Test (POST) to make sure all of the basic hardware in the system is present and functioning correctly. If a problem is identified during POST, an error is generated. How the error message is reported to the end user depends upon the motherboard manufacturer. The following may be used: Audible beeps Numeric codes Error messages The actual codes and messages will vary by manufacturer. Check the motherboard documentation for specific details. For example, a numeric 201 error code may indicate a memory problem on some systems, while a 301 error indicates the keyboard did not respond correctly during POST. Sometimes, a computer system may experience problems (such as a malfunctioning video adapter) that can prevent error messages from being displayed during POST. If this is the case, use a POST card to access POST error codes. Most models use an LED display to report any error codes generated during POST. A POST card is commonly implemented as an expansion board that is inserted into an expansion slot in the motherboard. However, some POST cards also include a USB interface that allows them to be connected to computers that don't have expansion slots, such as a notebook system.

file system

A means for organizing and storing data and information on a storage device.

Non-Volatile Memory Express (NVMe)

A memory storage device designed to allow access to non-volatile storage media through a PCI express (PCIe) bus. NVM Express is designed to work well with low latency and internal parallelism of solid-state storage devices. By allowing host hardware and software to utilize the level of parallelism possible in modern SSDs, NVM Express reduces I/O overhead and improves functionality. NVM Express devices come in three forms. The most common are standard-sized PCI Express expansion cards and a 2.5-inch form-factor devices that provide a four-lane PCI Express interface through the U.2 connector. There are also storage devices that use SATA Express and the M.2 specification, which support NVM Express as the logical device interface.

Mesh Topology

A mesh topology exists when there are multiple paths between any two nodes on a network. Mesh topologies are created using point-to-point connections. This increases the network's fault tolerance because alternate paths can be used when one path fails. Two variations of mesh topologies exist, partial mesh and full mesh. In a partial mesh topology, some redundant paths exist. In a full mesh topology, every node has a point-to-point connection with every other node. Full mesh topologies are usually impractical in a standard LAN because the number of connections increases dramatically with every new node added to the network. A separate network interface and cable for each host on the network is required. However, a full mesh topology is commonly used to interconnect routers, providing alternate paths should one path go down or become overloaded. Mesh networks are also commonly used to create redundant paths between access points in a wireless network, providing alternate paths back to the wireless controller should one access point go down or become overloaded. With this topology, every access point can communicate directly with any other access point on the wireless network.

Metropolitan Area Network (MAN)

A metropolitan area network is a network that covers an area as small as a few city blocks to as large as an entire metropolitan city. MANs are typically owned and managed by a city as a public utility. Be aware that many IT professionals do not differentiate between a wide area network and a MAN, as they use essentially the same network technologies.

microphone

A microphone converts sound into an electrical signal. Some computers have a built-in microphone, and many headsets and camera systems that connect to computers include microphones.

miniUSB/microUSB

A mini-USB connector is a small USB cable connector that is often used by handheld electronic devices like mobile phones, MP3 players, and digital cameras. On mobile phones it is often used for both USB data connectivity and charging. The new connector, called micro-USB, is smaller than the mini-USB connector and allows for even thinner device designs.

RAID 1 (Mirroring)

A mirrored volume stores data to two duplicate disks simultaneously. If one disk fails, data is present on the other disk, and the system switches immediately from the failed disk to the functioning disk. Mirroring: Provides fault tolerance for a single disk failure. Does not increase performance. Requires two disks. Has a 50% overhead. Data is written twice, meaning that half of the disk space is used to store the second copy of the data. Overhead is 1 / n where n is the price of the second disk. RAID 1 is the most expensive fault tolerant system.

Drive not recognized by the BIOS/UEFI

A modern BIOS/UEFI automatically detects your drives and their geometry during POST. In older systems, you had to manually enter the disk geometry and it was very common for a wrong value to be entered. In modern systems, this rarely happens. If the BIOS can't detect your drive, it's usually caused by one of three things. The power connector is unplugged. The SATA cable is unplugged. The drive is malfunctioning.

Support manual

A motherboard's support manual is an excellent source of information. Support manuals contain technical specifications as well as diagrams that identify the motherboard's components. If you are missing a motherboard's support manual, check the manufacturer's website.

Mount point

A mount point is an empty folder on an existing volume that points to another partition. Data saved to the folder is physically saved on the referenced partition.

Mulitcore processor

A multiple core processor has multiple processors within a single processor package. Dual-core, triple-core, and quad-core processors are typical in desktop systems. Multi-core systems enable the operating system to run multiple applications simultaneously. Without multiple processors, applications appear to run at the same time, but must wait their turn for processing time from the single processor. Some applications can be written to execute on multiple processors at the same time. Some motherboards use two (or more) processor sockets to provide a multiple processor solution. Multi-core processors use a single motherboard socket to support multiple processors.

Network Adapter

A network adapter is responsible for creating and receiving transmission signals that are sent along the networking medium. A network interface card (NIC) uses a cable medium (such as twisted pair or fiber optic cables). A wireless network adapter transmits radio waves.

Network Interface Card

A network interface card (NIC) creates the signals that are sent along the networking medium. A transceiver built into the network adapter formats the binary data for transmission on the network medium. Ethernet devices are identified using the MAC address, which is burned into the network interface card.

Internetwork

A network with geographically dispersed WAN connections that connect multiple LANs is often called an internetwork. Additionally, connecting two networks under different management is a form of internetworking because data must travel between two networks.

Partition

A partition is a logical division of a storage device associated with a hard disk drive. Multiple partitions can be assigned to a single device, in which case a drive letter is assigned to represent each partition. Multiple letters do not always mean that there are multiple devices, just multiple partitions.

patch panel

A patch panel is a device that is commonly used to connect individual stranded wires into female RJ45 connectors. For example, you might connect four pairs of wires from a punchdown block to a port on the patch panel. On the patch panel, you then connect drop cables (cables with RJ45 connectors) to the patch panel on one end and a computer on the other end.

Personal Area Network (PAN)

A personal area network is a very small network used for communication between personal devices. For example, a PAN may include a notebook computer, a wireless headset, a wireless printer, and a smartphone. A PAN is limited to a few feet in range. A PAN is typically created using Bluetooth wireless technologies.

Stuck/dead pixels

A pixel that is stuck is in an always on state and displays white. A dead pixel is stuck in an off state and displays black. Stuck pixels can be fixed by playing special videos that display a series of colors. Sometimes the video needs to be played for several hours. Most of the time, dead pixels are caused by a malfunctioning pixel and cannot be fixed. If playing the video does not fix stuck or dead pixels, the only way to fix the problem is by replacing the monitor.

Port Replicator

A port replicator attaches to a laptop computer and allows you to connect multiple peripheral devices such as a printer or a second monitor.

Print Queue

A print queue is a location on the hard disk that holds print jobs that are waiting to be processed. Each printer object has its own print queue. Double-click the printer to open the print queue. By default, users can manage their own jobs in the print queue (pause/unpause or delete). Users who have the Manage documents permission can manage all documents in the queue (pause, resume, delete, or rearrange the order). Users can only pause individual documents (or all documents) in the queue; they cannot pause the printer.

Toner

A printer's reported toner level isn't based on how much toner is left in the cartridge, but on how many pages have been printed since the toner cartridge was installed. For this reason, it is important to check the actual toner level periodically. If the cartridge still has sufficient toner, but you are receiving prompts that say that toner level is low, you can reset the toner page counter by following the instructions in your owner's manual. The toner cartridge might include some of the components necessary in the printing process such as the developing roller, corona wire, and OPC drum in a single cartridge referred to as an electrophotographic (EP) cartridge. If this is the case, these components are replaced every time you change the toner. Excess toner can clog up the inner components of a printer over time. Toner has a magnetic charge, so it is important that it only be cleaned by an anti-static vacuum cleaner. The dust and toner on the inside of printers should be cleaned out on a regular basis.

USB Type A

A rectangular connector that generally plugs directly into the computer or a hub. Almost all USB cables have one Type-A connector on one of the ends.

Ring Topology

A ring topology connects neighboring nodes until they form a ring. Signals travel in one direction around the ring; each device on the network acts as a repeater to send the signal to the next device.

Router

A router connects two network segments that have different subnet addresses. A router has multiple network connections, and each connection is on a different subnet. Routers use the IP address within a packet to move packets between networks. Routers maintain a list of known networks and the next router in the path to reach the destination network.

router

A router connects two network segments that have different subnet addresses. A router has multiple network connections. Each connection is on a different subnet. Routers use the IP address within a packet to move packets between networks.

operating system

A set of programs that acts as an interface between the applications that are running on a computer and the computer's hardware.

Volume simple explanation

A single accessible storage area within a file system.

Mini PCI

A small form factor used by computers.

Door Lock

A smart lock is an electromechanical lock that can be locked and unlocked using a smart phone. It uses a wireless protocol and a cryptographic key to execute the authorization process. It can also monitor access and send alerts related to the status of the device.

Switch

A smart switch is a device that allows you to control hardwired lights, ceiling fans, certain fireplaces, small appliances, and even the garbage disposal with an app on your phone or with your voice using a virtual assistant. Smart switches give smart home features to anything you turn on or off with the flip of a switch.

Solid State Drive (SSD)

A solid state drive is a flash device with a storage capacity similar to a small hard drive. Solid state drives are used as replacements for hard disk drives for storing operating system, application, and data files.

HDMI

A sound card with an HDMI port is capable of sending HD audio to an HDMI device. Some sound cards are able to output video or combine a video signal from a video card and output the combined audio/video signal through the HDMI port.

Spanned volume

A spanned volume has unallocated disk space on a different disk.

Extended File Allocation Table (ExFAT or FAT32)

A special file system designed to support large flash drives.

USB Type B

A square connector with two beveled corners. Type-B connectors are mostly used with printers. Some networking devices, such as hubs and modems, also use this connector. Most USB cables that use this connector have a Type-A connector on one end that plugs into the computer.

star topology

A star topology uses a hub or switch to connect all network connections to a single physical location. Today, it is the most popular type of topology for a LAN.

RAID 0 (Striping)

A stripe set breaks data into units and stores the units across a series of disks by reading and writing to all disks simultaneously. Striping: Provides an increase in performance. Does not provide fault tolerance. A failure of one disk in the set means all data is lost. Requires a minimum of two disks. Has no overhead because all disk space is available for storing data.

Application

A subclass computer program that is designed for end users.

Subnet

A subnet is a portion of a network with a common network address. All devices on the subnet share the same network address, but they have unique host addresses. Each subnet in a larger network has a unique subnet address. Devices connected through hubs or switches are on the same subnet. Routers are used to connect multiple subnets.

Switch

A switch provides a central connection for multiple media segments on the same subnet. A switch receives a signal on one port and forwards that signal only to the port where the destination device is connected. Switches learn where a device is connected by copying the MAC address of the source device and placing it into the MAC address table. The port number the frame entered is also recorded in the table and associated with the source MAC address. If the switch doesn't know which port a destination device is connected to, it will send the frame in question to all ports.

switch

A switch provides a central connection for multiple media segments on the same subnet. When a switch receives a signal, it forwards that signal only to the port where the destination device is connected. Switches use the MAC address to send frames to the destination device. Switches operate in full-duplex mode, meaning devices can send and receive data at the same time because transmission paths are dedicated to only the communicating devices. When possible, use switches instead of hubs.

Thermal

A thermal printer is a non-impact printer that uses heat to cause a reaction on specially treated paper. Monochrome thermal paper is chemically treated to darken where heated (photosensitive). Many cash registers use this type of printer for creating receipts. Color thermal paper is chemically treated to absorb color from a ribbon where heated. Ink is applied using the ribbon in a similar manner to a solid ink printer. The color system used by thermal printers is CMYK (cyan, magenta, yellow, and black). The paper must make one pass for each application of a different color. The feed assembly takes the thermal paper off the roll and it sends it through the printer to the outside of the printer. Color thermal printers are very expensive, high quality, and operate quietly.

Printer

A virtual device (logical software entity) inside the print server that can be configured to send output to a print device. The printer is made up of the print driver, the printing device, and the spooler.

volume

A volume is a single accessible storage area within a file system. A volume can encompass a single partition or span across multiple partitions depending on how it is configured and what operating system you are using. Volumes are identified by drive letters.

Wide Area Network (WAN)

A wide area network is a group of LANs that are geographically isolated, but are connected to form a large internetwork.

Wireless Local Area Network (WLAN)

A wireless LAN covers an area that is roughly the same size as a standard LAN. It uses radio signals to connect systems instead of wires.

Devices on Wireless Networks

A wireless NIC for sending and receiving signals. A wireless access point (AP) is a lot like a hub. It receives wireless signals from several nodes and retransmits them to the rest of the network. A wireless bridge connects two wireless APs into a single network or connects your wireless AP to a wired network. Most APs today include bridging features.

Wireless Mesh Network (WMN)

A wireless mesh network (WMN) is a group of wireless mesh nodes that communicate with one another to share the network connection across a large area. They provide the ability to stream voice, data, and video between arbitrary pairs of devices. Each device in the WMN uses the others as relays to avoid the need for infrastructure.

Wireless Wide Area Network (WWAN)

A wireless wide area network (WWAN) covers a large geographical area by connecting separate areas wirelessly. WLAN and WWAN both connect to the internet wirelessly, but they use different technologies to do it. WWANs are often referred to as 3G, 4G, or LTE networks because they usually use cellular network technologies as connection types.

Apple Filing Protocol (AFP) 548

AFP is the protocol used by systems running Mac OS X or newer to support file sharing on the network. AFP replaced AppleTalk and has gone through several revisions.

ATX Full-Tower

ATX full-tower cases are the largest computer cases. Full-tower cases have a lot of space for external and internal components. ATX full-tower cases are compatible with the following form factors: Standard ATX EATX microATX

ATX Mid-Tower

ATX mid-tower cases are slightly smaller than full-tower cases. Mid-tower cases have fewer external and internal bays. ATX mid-tower cases are compatible with the following form factors: Standard ATX microATX Mini-ITX EATX (some)

powersupply

ATX power supplies aid in cooling by exhausting hot air out the back of the case.

Configure Encryption and Authentication

Add authentication to allow only authorized devices to connect. Use encryption to protect wireless communications from eavesdropping. Always use WPA2 when possible. If WPA2 isn't available, use WPA. Use pre-shared key (PSK) authentication with either AES (more secure) or TKIP (less secure) encryption for a SOHO network without a domain, Configure the shared secret (passphrase) value used with WPA2 or WPA. Each client needs to be configured with same secret value. Because WEP has several known security vulnerabilities and can be easily cracked, it should be used only as a last resort. When using WEP, never use shared key authentication; use only open authentication.

feature support

Additional features on sound cards provide higher quality sound or additional functionality. DirectSound 3D allows a computer to play audio in surround sound. EAX is a high-definition sound technology originally developed for video games. This technology provides such realistic nuances that audio can actually cue gamers. THX is a sound quality standard, originally created for film, now available on sound cards. This is a sound card feature that allows computers to present theater quality sound output. Dolby Digital is a technology that broadcasts sound at a frequency the human ear can hear and diminishes collateral sound. This is a sound card feature that allows computers to present higher quality sound output. DTS (Digital Theater Systems) Digital requires an optical reader to decode physical data and send it to a computer for processing. This is a sound card feature that allows computers to present theater quality sound output. SDDS (Sony Dynamic Digital Sound) was originally developed for theater sound. SDDS decoders provide error correction. MIDI (Musical Instrument Digital Interface) is a protocol for recording and playing audio created on digital synthesizers. This feature allows the computer to become an integrated component to a musical instrument.

PDF

Adobe created PDF as a successor to PostScript. PDF allows you to distribute documents on the web and have them displayed consistently in a wide variety of environments. Adobe has also provided Acrobat Reader free for multiple platforms and promoted PDF extensively, so it has become the de facto standard for page description languages.

PostScript

Adobe created a printer language called PostScript that easily handles scaling of certain fonts and images. Printers that understand PostScript are usually more expensive than other printers.

Client-Server advantages

Advantages of client-server networks include the following: Easy to expand (scalable) Easy to support Centralized services Easy to back up

Peer to Peer Advantages

Advantages of peer-to-peer networks include the following: Easy implementation Inexpensive

Airplane Mode

Airplane mode is a setting available on many smart phones, portable computers, and other electronic devices that suspends the device's radio-frequency signal transmitting functions, which disables telephone, Wi-Fi, and Bluetooth when activated.

thermal management

All ATX power supplies have a fan that cools the unit. The fan direction pulls cooler air from the front of the case and blows hot air out the back. Older ATX units use a reverse air flow that blows air directly over the CPU. This method is not as efficient.

star topology tips

All network connections are located in a single place, which makes it easy to troubleshoot and reconfigure. It is easy to add or remove nodes. Cabling problems usually only affect one node.

su

Allows you to switch user accounts. su - (su with a space and a hyphen) is used to switch to the root user with the home directory and environment variables assigned to the root user.

Secure the SOHO Network

Although the router should now be configured to connect hosts to the private network and provide internet access, the following steps should be taken to properly secure the network from external threats: Configure the firewall on the device. Enabling the basic firewall on the router provides an additional level of security for the private network. If necessary, configure exceptions on the firewall to allow specific traffic through the firewall. Configure content filtering and parental controls. Most SOHO routers provide content filtering and parental controls that prevent hosts from accessing specific websites or using a specific internet service, such as chat, torrent, or gaming applications. Physically secure the router. Anyone with physical access to the router can make configuration changes and gain access to the network. To prevent this, limit physical access to the router. For example, place the router and other networking equipment in a locked closet.

I/O address

An I/O address (also known as a port address) allows two devices in a computer to send information to each other. When a device wants to send information to another device, it addresses the data to the receiving I/O port number and sends it out on the system bus. Each device in a computer must have its own I/O address.

NFC

An NFC connector is used to emulate cryptographic smart card functionalities for RFID tags or memory cards.

RCA connector

An RCA connector on a sound card is used for coaxial digital I/O for S/PDIF audio. While RCA connectors can be used for analog audio, RCA connectors on a sound card are normally used for S/PDIF digital audio.

devices

An STA (station) is any device that is able to use the 802.11 protocol to communicate on a wireless network.Many wireless access points include ports (i.e., switches or routers) to connect the wireless network to the wired portion of the network.

Ad hoc

An ad hoc network works in peer-to-peer mode. The wireless NICs in each host communicate directly with one another. An ad hoc network is difficult to maintain for a large number of hosts because connections must be created between a host and every other host, and special configurations are required to reach wired networks. You will typically use an ad hoc network only to create a direct, temporary connection between two hosts.

Integrated Drive Electronics (IDE)

An electronic interface allows communication between a motherboard's data paths or bus and a computer's hard disks.

Emergency Notification

An emergency notification system is a method of facilitating one-way message broadcasts to one or many groups of people, alerting them to a pending or existing emergency.

Extended volume

An extended volume has unallocated disk space on the same disk.

Extranet

An extranet is a private network that uses internet technologies, but its resources are made available to external trusted users. For example, you might create a website on a private network that only users from a partner company can access.

IR

An infrared port is a port on a mobile device that enables devices to exchange data without using cables.

Infrastructure

An infrastructure wireless network employs an access point that functions like a hub on an Ethernet network. With an infrastructure network, you can easily add hosts without increasing administrative efforts (scalable), and the access point can be easily connected to a wired network, allowing clients to access both wired and wireless hosts. You should implement an infrastructure network for all but the smallest of wireless networks.

Internet Appliance

An internet appliance is a specialized device that performs a specific network role. The following are some common internet appliances: Web proxy Content filter Malware scanner Internet appliances are typically more expensive than configuring a server to perform the same task. However, internet appliances perform much better and have more features.

Intranet

An intranet is a private network that uses internet technologies. Services on an intranet are only available to hosts that are connected to the private network. For example, your company might have a website that only employees can access.

Legacy Bus

An old bus no longer supported by manufacturers.

Analog Input and Output

Analog output jacks allow you to play sound on your computer through external devices: The speaker out connector sends signal to external speakers. This signal is amplified and the computer controls the sound level that is sent. The line out connectors send audio to other sound devices. This signal is unamplified. Analog input jacks allow you to record audio through the sound card. The line-level (line-in) connector receives signals from CD players and musical instruments coming from the line out port of the other device. The mic-level (mic in) connector receives signals from a microphone.

CAS Latency

Another factor that affects the performance of memory is the latency associated with accessing data in RAM. With a read request, there is a delay between the time the data is requested and the time that the data is available on the module's output pins. This delay is called the CAS latency (CL). Older memory expressed the delay in nanoseconds, but DRAM uses a ratio based on the clock frequency to describe the delay. For memory modules of the same type and frequency, a lower CAS number indicates less delay (e.g., "faster" RAM). Because CL is related to the frequency, you cannot directly compare the CAS latency between modules with a different frequency. For example, a DDR2 module operating at 533 MHz with a CL of 6 has more delay than a DDR3 module at 667 MHz with a CL of 7. In addition to CL, there are other memory characteristics that describe the delay for performing other types of operations. Collectively, these values are referred to as the memory timings. For stable operations, the bus must take into account these latencies to keep the bus and the memory synchronized. Manufacturers test memory modules and rate them based on the operating frequency and the timing characteristics. Settings that produce stable performance are then encoded into the SPD module on the memory. The BIOS then reads this information to know how to configure memory settings on the motherboard. For many systems, you can manually modify the memory timings and frequency. Running RAM at a lower clock speed enables you to decrease the CAS latency setting; increasing the frequency must usually be compensated for by increasing the CL (and other) settings.

Apps

Applications must be written to run on mobile devices based on the operating system and system architecture. App distribution is provided online by platform: Google: Play Store iOS: AppStore MS: Windows Store

Partition (reasons)

Assigning the boot system to a different partition than application and data files can help many computers run more smoothly and minimize damage in a system crash. Storing the swap file on its own partition is sometimes necessary or useful. Creating a separate partition for your operating system can help it run properly. Some operating systems can't run on a large partition. Assigning log files to be stored on distinct partitions can help minimize the effects of a system crash due to excessively large log files. Assigning distinct operating systems to run on assigned partitions allows a dual boot system setup.

channels

Audio can be split into multiple channels, which increases the sound quality and makes it more realistic. Some standard channel configurations are as follows: 2 channel audio is stereo. Examples of 2 channel audio include standard TV and radio. 4 channel audio is quadraphonic audio and was an early attempt at surround sound. 5.1 channel audio, also known as surround sound, has 6 audio channels: five speakers and one low-frequency effects subwoofer (LFE) channel. 7.1 channel has 8 audio channels: 7 speakers and one LFE subwoofer channel. This is the first technology providing error correction.

Verify network communication

If the computer has a valid network connection and IP configuration values are correctly set, you can use the ping command to test connectivity with other network hosts. Ping sends out a request that is answered by the destination device. If the ping test succeeds, the destination device is working. If you are still having problems, check issues with logon, resource sharing, permissions, or services. If the ping test fails only to that device, then the device might not be properly configured. If a ping test fails to any network device, check routers and other devices. You can use the host name with the ping command. If you can ping the device by the IP address but not the host name, then the problem is likely with the DNS configuration. Be aware that many devices are now configured not to respond to ping requests. A failed ping test might not give you reliable information about the status of network devices.

error-correcting code (ECC)

Error Correcting Code (ECC) memory is a type of memory that detects and corrects the common kinds of internal data corruption. ECC memory is also called parity memory. Using ECC, a value is appended to the end of each byte so that the value of the data can be compared and recalculated if an error occurs. ECC is an improvement on parity techniques because errors in more than one bit can be detected and corrected. Keep in mind the following facts about error correcting memory: Memory modules with ECC have extra memory chips on the module (typically 9 modules instead of 8). If the number of chips is divisible by 3 or 5, the module is ECC memory. ECC or parity memory must be supported by the motherboard. Because it is more expensive than non-ECC, ECC memory is typically used only in servers. ECC memory is slower than non-ECC memory. Do not mix ECC and non-ECC memory in a system. Mixing ECC and non-ECC memory disables the error correction function. You might hear the terms parity and ECC being used interchangeably. However, parity RAM only checks for errors while ECC RAM checks and corrects errors.

Distance

Ethernet standards define the maximum distance for cable lengths between two devices. The maximum cable length for UTP Ethernet "T" implementations is 100 meters for all standards. The length for fiber optic cables varies depending on the cable type and specification, but typically ranges from 100 meters to 40 kilometers.

Standards

Ethernet standards identify the transmission speed and the cable type. Data transfer rates range from 10 Mbps (very old Ethernet networks) up to 10 Gbps. Between 100 and 1000 Mbps are the most common speeds for most networks.

Networking Media

Ethernet supports the following cable types: Unshielded twisted-pair cables (UTP) with RJ45 connectors. This is the most common transmission medium used for Ethernet. Fiber optic cables, which are used in high-speed applications (such as servers or streaming media). Coaxial cable with F-type connectors for cable internet services. Coaxial cable is also used for older Ethernet implementations ( which are often called thinnet or thicknet networks).

twisted pair tips

Even though different cable categories may look physically similar, they are electrically different. Higher cable categories use different wire gauges and have more wire twists per inch than lower cable categories, which allows for much faster transmission speeds. Some cables use plenum plastic as an insulator. Plenum wires are fire resistant and non-toxic when burned. These types of cables are rated to be run in the plenum (the space above a ceiling or below a floor) or a building. Each type of UTP cable can be substituted for any category below it, but never for a category above. For example, Cat 6 can be substituted for a task requiring Cat 5e; however, neither Cat 5 nor Cat 3 should be used for this particular task.

Drive Noise

Excessive or unusual drive noise is almost always indicative of a failing hard disk. For example, a clicking noise coming from the drive usually indicates one or more failing heads.

expansion slots

Expansion slots (also called expansion buses) allow you to expand the capabilities of your computer by installing expansion cards. There are a number of different expansion slot types: PCI (Peripheral Component Interconnect) PCI-X (Peripheral Component Interconnect Extended) PCIe (Peripheral Component Interconnect Express) Accelerated Graphics Port (AGP)

Coaxial Disadvantages

Expensive Not very flexible (difficult to bend around corners) Using splitters degrades signal quality

File Transfer Protocol (FTP) 21

FTP provides a generic method of transferring files. It can include file security through usernames and passwords, and it allows file transfer between dissimilar computer systems. FTP can transfer both binary and text files, including HTML, to another host. FTP URLs are preceded by ftp:// followed by the DNS name of the FTP server. To log into an FTP server, use: ftp://username@servername.

server types

File and Print Server - Provides file sharing and print sharing services. Application Server - Provides access to a shared network application (a database server that contains customer information). Directory Server - Handles user authentication. Also stores user credentials, permissions, and settings. Remote Access Server - Provides remote access to network resources. Web Server - Serves web pages and web content via HTTP. DNS Server - Uses the domain name service to map IP addresses to domain names. DHCP Server - Automatically configures network hosts with an IP address, subnet mask, DNS server, and default gateway.

file system examples

File systems take many forms. Some common ones beside exFAT, FAT32, and NTFS include: Compact Disk filing system (CDFS), a virtual file system used with Linux. Network File System (NFS), a distributed file system that allows client computers to access files over a computer network. Ext4, the default Linux file system (and its predecessor ext3, which is still in use).

flash devices

Flash memory cards store information using programmable, non-volatile flash memory.

Maintenance Kits

Following the manufacturer's recommendations for the installation of maintenance kits can greatly extend a printer's life. Most maintenance kits include replacements for the most commonly used components of a printer such as: Fuser wires Rollers Toner drum If these parts are replaced on a regular basis (usually after about 20,000 pages of printing), you can avoid a great deal of common printer problems. It is important to buy the maintenance kit for your exact make and model of printer.

Extend Volume

For basic volumes, you can only extend the volume onto the same drive using contiguous unallocated space. Many third-party partitioning tools can extend partitions regardless of the operating system. To extend the volume onto the same drive using non-contiguous unallocated space or to extend the volume onto another disk, convert the disk to a dynamic disk and then extend the volume. An extended volume uses disk space on the same disk. A spanned volume uses disk space on a different disk. The system volume can only be extended using contiguous free space on the same disk. This is the same for both basic and dynamic disks. Volumes must be unformatted or formatted with NTFS to be extended.

Check ribbon, ink, and toner levels.

For dot matrix printers, printer images become faint when the ribbon needs to be replaced. Also, ensure that there is not too much gap between the printer head and the paper. For inkjet printers, if pages have missing lines, use the printer's automatic cleaning feature. If this doesn't work, replace the printer cartridge. For missing or incorrect colors, verify ink levels. For laser printers with missing lines, try shaking the toner cartridge to distribute the toner evenly. If lines are still missing, or if extra characters appear, you might need to have the printer cleaned or some internal components replaced.

Printout Quality Issues

For newer laser and inkjet printers, calibrate the printer (perform a self-test). Often the printer uses the self-test to check the printed image and make minor adjustments automatically. Calibration fixes blurry text, misalignment (jagged lines), or incorrect colors. If the text appears garbled, make sure the proper printer driver is used. If necessary, upgrade to the latest version or reinstall the driver. If the page prints only part way through (and the rest of the page is blank), you might need to upgrade the memory on the printer or check the print server settings. Check the pickup rollers if paper is not being fed through the printer properly.

Fequency

For optimal performance, you should match the memory frequency (sometimes called the speed) with the frequency supported by the system bus/memory controller. You can install slower memory in the motherboard, but this will degrade performance. You can install faster memory in the motherboard, but it will operate only up to the maximum supported by the motherboard. When you mix memory with different frequencies, all memory will operate at the lowest frequency. Most memory modules include an EEPROM chip that identifies its frequency. The BIOS uses the information in this chip to set the frequency automatically. On many systems, you can edit the BIOS manually to change the frequency. If the BIOS does not configure memory to run at its highest rated speed, then do the following: Verify that the motherboard supports that speed. You might be able to update the BIOS to support faster memory. The serial presence detect (SPD) on the memory is often set below the maximum rating for the memory. To use the maximum speed settings, you might need to manually configure the speed and timing settings for the memory (if the motherboard allows you to do this).

Image does not display on a second monitor

For problems with dual-monitor systems: Make sure the video card supports dual display. Verify that the operating system supports and is configured for dual displays. In display settings, extend the desktop onto the second monitor.

Antenna Orientation

For radio frequency wireless devices, the antenna orientation might have a small effect on signal strength. There are two types of antennas that are commonly used in wireless networks. Directional antenna Creates a narrow, focused signal in a particular direction, which increases the signal strength and transmission distance Provides a stronger point-to-point connection; is better equipped to handle obstacles Omnidirectional antenna Disperses the RF wave in an equal 360-degree pattern Provides access to many clients in a radius For other devices, such as infrared or satellite, the orientation of the receiving device is critical. For these types of devices, make sure the receivers have a line-of-sight path to communicate.

force quit

Force Quit is used to stop non-responsive processes and applications. It can also be used to restart the Finder service. Force Quit can be accessed from the Apple menu or the keyboard shortcut Command+Option+Esc.

basic disk and partions

Basic disks use primary and extended partitions. Each physical disk can have up to four primary partitions or three primary partitions and one extended partition. Logical drives are defined within an extended partition. You can have up to 24 logical partitions on an extended partition. The extended partition can be divided into multiple logical drives. Basic disks store partition information in a portion of the master boot record (MBR) known as the partition table. The partition table has room for up to four partition entries. When an extended partition is used, one of the four entries points to an extended boot record (EBR). The EBR is located within the extended partition and contains information about the logical drives within the extended partition.

Video

Be aware of the following facts about screens and video cards: XGA screens have the normal 4:3 aspect ratio. WXGA screens use a widescreen aspect ratio. Some screens promise brighter display for crisper viewing or better viewing outdoors. The video controller is either integrated onto the motherboard or it might be a separate board that can be replaced. Video memory typically shares a portion of the system memory, although some notebooks have dedicated video memory. Most notebooks have an external video port that you can use to display the screen on a projector or a monitor. To show the display on the external monitor, change the display settings in the operating system or use the Fn keyboard combination. Some notebooks have special touchscreens that can rotate 180 degrees, allowing the notebook to close and the screen to still be visible. Some notebooks allow you to detach or remove the screen from the keyboard. This turns the notebook into a tablet. Some laptops have multiple display screens. You can always connect a second monitor to a laptop if you need dual display functionality.

802.11a specs

Frequency 5 GHz (U-NII) Maximum speed 54 Mbps Maximum distance 100 ft. Channels (non-overlapped) 23 (12) Modulation technique OFDM Backwards compatibility N/A

Mean Time Before Failure (MTBF)

Because of the way they are constructed, an SSD storage device has a lifespan called the mean time before failure, which is usually much shorter than standard hard disk drives. Each time a write/erase operation occurs, it consumes some of the finite lifetime of the flash memory chips within the SSD device. Be aware that some applications running on the system can overuse SSD storage devices. For example, audio, graphic, and especially video editing applications commonly require a very large number of write/erase operations and can cause SSD storage devices to fail prematurely. However, these applications also benefit greatly from the increased speed offered by SSD storage devices. Therefore, if you chose to use SSDs with these types of applications, you should consider configuring an automatic data backup process (such as Windows Backup and Restore or File History) to protect the data stored on the SSD drive on a traditional hard disk drive. Some system builders implement a mix of storage devices in high performance systems so that: Heavily used information is stored on a standard hard disk drive. For example, the Windows operating system and its applications may be installed on a less expensive but more durable standard hard disk drive. Only data that requires high performance is stored on SSD storage devices. Important data on the SSD is automatically backed up on the standard hard disk drive.

full array WLED

Full-array WLED displays have an array of white LEDs behind the screen. Full-array WLED LCDs are able to dim specific regions of the screen, resulting in a much higher contrast ratio than LCDs that use EL-WLED technology.

Configure the Router

Before setting up the network, some basic settings on the router need to be configured. Most important is to change the default administrator username and password. Default usernames and passwords are easily guessed or discovered by checking the device documentation. By changing the password, you protect the system from unauthorized access.

Configure the Internet Connection

Begin by connecting the router to the internet connection using the device's WAN port. For a DSL or ISDN router, connect the device directly to the DSL/ISDN line. For a cable, fiber optic, or satellite connection, connect the router to the Ethernet port on the modem or connection device. Many routers will automatically detect and configure the internet connection. If not, follow the ISP instructions for setting up the connection. This could include: Configuring the internet connection with a static IP address assigned by the ISP or configuring the device to use DHCP for addressing Configuring the protocol used for the connection. This will often be PPPoE for an always-on internet connection Configuring logon information (username and password) to access the internet Configuring a default gateway and DNS server addresses that the router will use in order to access the internet

biometric scanner

Biometric scanners are used as a form of authentication. They are able to scan users' unique physical features and use them to verify their identity. Common physical features used by biometric scanners include: Retina (eyes) Fingerprint Face Heart beat

Blu-ray Disc (BD)

Blu-ray Disc (BD) is a newer optical disc format that is capable of greater storage capacity than DVDs. Blu-ray was originally developed for high definition video (and expanded content on movie discs), but can also be used for data storage. Most Blu-ray drives include a second read laser for reading CDs and DVDs. Without this additional laser, Blu-ray drives would not be able to read CDs or DVDs. Blu-ray is intended to eventually replace DVD. Blu-ray has become the accepted HD video standard as the last movie studio stopped distributing HD DVD movies.

BD Facts

Blu-ray uses a blue laser instead of the red laser used with CDs and DVDs. The blue laser light has a shorter wavelength, which allows data to be packed more tightly on the disc. A single layer Blu-ray disc holds 25 GB; a double layer disc holds up to 50 GB. Experimental 20 layer discs can hold up to 500 GB. Blu-ray discs can be read-only (BD-ROM), recordable (BD-R), or rewritable (BD-RE). A 1x Blu-ray drive reads data at 4.5 MBps.

Bluetooth

Bluetooth uses radio waves in the 2.4 GHz frequency range for communication. Bluetooth uses ad hoc connections between devices to create personal area networks called piconets. A piconet can have up to 7 devices, and each device can participate in multiple piconets at the same time. By using adaptive frequency hopping (AFH), Bluetooth is able to automatically detect other devices in the area and avoid the frequencies used by those devices. It can switch between 79 channels to avoid interference. A 128-bit proprietary encryption mechanism is used to encrypt signals.

how windows works with drivers

Both legacy and plug and play devices need drivers to configure and use the device. Windows detects newly installed devices and tries to find and load the driver automatically. Many drivers are automatically included with the operating system. Some drivers are preinstalled during the operating system installation. Windows will automatically use preinstalled drivers when they match new devices. Windows can search the internet for some drivers. If Windows cannot find a suitable driver, you are prompted to identify alternate locations to search in order to find the correct driver.

Buffered (Registered)

Buffered (or registered) RAM has a buffer that holds memory addresses or data before it is transferred to the memory controller. Buffered RAM improves stability on systems with a lot of RAM (over 1 GB). Buffered RAM might slow system performance. ECC modules are typically buffered. Buffered RAM must be supported by the motherboard. Some motherboards require buffered memory. Unbuffered memory does not have a buffer to hold memory addresses or data before it is transferred to the memory controller. Unbuffered memory can be found in servers and high-end workstation.

Legacy buses

Buses that have been replaced by newer types are considered legacy buses. Legacy buses are rarely used and include the following: AGP (accelerated graphics port) was a dedicated bus type used by dedicated video cards. AMR (audio/modem riser) was a riser card that attached to the motherboard and allowed additional cards (called daughter cards) to be installed. CNR (communications network riser) was a riser card slot that allowed for installing network, sound, or modem functions.

Slow performance when drawing screens

By default, Windows automatically adjusts visual effects based on system performance. You can manually modify the types of effects used to optimize how Windows looks and performs. In general, the more visual effects that are enabled, the more CPU and graphics processing is required. If the system has a slow processor, low memory, or not enough video memory, using visual effects can make the system respond slowly. Use the advanced system settings to edit performance settings for visual effects. In File Explorer, right-click This PC and select Properties. Select Advanced system settings. On the Advanced tab under Performance, select Settings. Optimizing for appearance turns on all visual effects. Optimizing for performance turns off all effects. Effects can be enabled or disabled individually.

Enable MAC Address Filtering

By specifying which MAC addresses are allowed to connect to your network, you can prevent unauthorized devices from connecting to the access point. MAC address filtering can be implemented in one of two ways: All MAC addresses are allowed to connect to the network, except for those specified in the deny list. All MAC addresses are denied access, except for those specified in the allow list. MAC address filtering is considered a cumbersome and weak form of security. Permitted MAC addresses can be very easily captured and spoofed by even casual attackers.

GPT

GPT partitions are a new standard that are gradually replacing MBR partitions. GPT is associated with UEFI. GPT stands for GUID Partition Table. It's named for the fact that every partition on the drive has a globally unique identifier, or GUID. That means that each partition worldwide would have its own unique identifying number.

CD-ROM

CD-ROM stands for compact disc read-only memory. CD-ROMs are identical in appearance to audio CDs, and data is stored and retrieved in a very similar manner

CD-RW

CD-RW stands for Compact Disc-ReWritable. CD-RW can be written, read many times, erased, and rewritten. CD-RW has a capacity of about 650 MB. CD-RW drive speed rating includes three parameters: a write speed, a rewrite speed, and a CD-RW read speed. All of these are multiples of the original 150 KBps 1x speed defined by the first CD-ROM drives.

Compact Disc (CD)

CDs were first developed to store digital music. Later, the CD technology was adapted to store digital computer data. A CD: Can hold 74 to 80 minutes of audio Is 120 millimeters in diameter Is 1.2 millimeters thick

Complementary Metal-Oxide Semiconductor (CMOS)

CMOS is legacy computer chip technology that has become a general term used for the program that stores important system information related to the starting of a computer. It is often used synonymously with BIOS. Data held in CMOS includes the hard disk type and configuration, the order of boot devices, and other configurable settings related to the system hardware. The following are important things to know about CMOS: You changed the data stored in CMOS using a CMOS editor program that was part of the BIOS. CMOS used to refer to the real-time clock and the CMOS chip that stored system information. Both were powered by a CMOS battery. Now, the EEPROM chip stores the system information that used to be stored on the CMOS chip. EEPROM requires no power to maintain data storage. The CMOS battery is still used to keep the real-time system clock running when the computer is powered off. It can be a low-voltage dry cell, lithium mounted on the motherboard, or even AA batteries in a housing clipped on a wall inside of the case. The electric current is about 1 millionth of an amp and can provide effective power for years.

Cable

Cable networking uses a cable TV connection to create a wide area connection to the internet. A cable modem (router) connects the computer to the cable network for sending networking signals. The same cable line is used to carry networking and cable TV signals, although in some cases a separate line is installed for internet access. Cable networking requires the installation of a cable TV line to your location if one does not exist.

cache

Cache is memory that the processor can access directly without using the system RAM. There are four types of processor cache: Level 1 (L1) cache is integrated on the processor die itself and stores instructions for the processor. On multi-core systems, each processor typically has its own L1 cache. Some processors might have two L1 caches, one for instructions and one for data. Level 2 (L2) cache is additional cache used for both instructions and data. Depending on the processor, L2 cache might be shared between two or more cores, or exclusive to a single core. Level 3 (L3) cache is additional cache beyond the level 2 cache. For multi-core systems, L3 cache is shared between all cores. Level 4 (L4) cache is shared dynamically between the on-die graphics processor unit (GPU) and CPU. Be aware of the following regarding processor cache: The size of the cache increases as you move from L1 to L4, with L1 cache being the smallest. As a general rule, a processor with more cache performs better than a processor with less cache (all other things being equal). Originally, only L1 cache was on the processor die, with L2 cache being on the motherboard between the CPU and the RAM. As processor technology has advanced, L2 cache moved to the processor die, with L3 cache being on the motherboard. Today, all three cache levels are located on the processor. The L4 cache acts an overflow cache for the L3. Information evicted from L3 is dumped into L4.

GPT abilities

Can be basic or dynamic. Supports up to 128 partitions depending on space allocated for the partition table. There is no need for extended and logical partitions. Can support between 8 and 9.4 zettabytes depending on the sector size. Stores multiple copies of the partition table across the disk, so it's much more robust and can recover if the data is corrupted. Stores cyclic redundancy check (CRC) values to check that its data is intact. If the data is corrupted, GPT notices the problem and attempts to recover the damaged data from another location on the disk. MBR has no way of knowing if the data is corrupted. You would only see that there was a problem when the boot process failed or the partitions vanished. Includes a protective MBR. The protective MBR sees the GPT drive as a single partition that extends across the entire drive. If you try to manage a GPT disk with an old tool that can only read MBRs, it will see the GPT disk as a single partition that extends across the entire drive. The protective MBR makes sure that the old tools don't mistake the GPT drive for a non-partitioned drive and overwrite all your data.

case fans

Case fans create a pressurized system that allows air to flow through the case in a specific way. Intake fans (at the front) pull air inside the case to cool components. Outtake fans (at the back and top) exhaust warm air from inside the case. Some cases have intake fans on the side case cover. Fan filters can be installed to keep dust and debris inside the case to a minimum.

Cellular

Cellular networking uses the cellular phone infrastructure for internet access. Mobile phones with digital data plans use cellular signals to connect to the internet.Cellular networking is a truly mobile solution. You can often be moving and still have internet access without manually having to reconnect. Internet access is limited to areas with cell phone coverage. Coverage will be dictated by the service provider's network.

cd

Changes directories in the file system. For example, to change to the /home directory in the file system, you would enter cd /home at the shell prompt

Channel Bonding

Channel bonding combines two, non-overlapping 20 MHz channels into a single 40 MHz channel, resulting in slightly more than double the bandwidth. The 5 GHz range has a total of 23 channels, with 12 non-overlapping. This allows for a maximum of 6 non-overlapping bonded (combined) channels. The 2.4 GHz range has a total of 11 channels, with 3 non-overlapping. This allows for a maximum of 1 non-overlapping bonded channel. For this reason, channel bonding is typically not practical for the 2.4 GHz range.

Channel Bonding

Channel bonding is used to combine even more channels in the 5 GHz band, allowing for up to 160 MHz wide channels. Even though 160 MHz wide channels are supported, most 802.11ac networks use 80 MHz wide channels.

Check Disk (Chkdsk)

Check Disk is a utility that verifies the file system integrity of a hard disk. You can run Check Disk by typing Chkdsk at a command prompt.

input devices

Check the following when troubleshooting input devices: Make sure the device is plugged in securely. For stuck or malfunctioning keyboard keys, you might be able to pop the key off and clean the contact underneath. Be aware that replacing the keyboard might be cheaper than spending a lot of time cleaning it. Make sure that nothing is on the keyboard as the system boots. If a key is pressed during the boot up process, a 301 (keyboard) error can result. If this happens, then it is more than likely you will have to reboot. For wireless devices, check the battery level. Charge the device or change the batteries if necessary. If advanced features are not available for the device, update or install the correct device driver.

Printer Doesn't Print

Check to make sure that the printer is turned on and is online. Make sure that the printer is not paused. Verify that the cable is connected on both ends and that it is the correct cable for that printer. For network printers, make sure that the printer is configured with correct TCP/IP settings for the network. Ensure that there is paper in the feed tray and that the tray, feed, and rollers are all in their correct positions. Verify that the correct paper tray was selected when sending the print job. Look for a paper jam. If a jam is found, clear it and then check any feed and roller mechanisms nearby and confirm that they are clean and operating correctly. Check the ink and toner levels.Check the printer console or workstation for any error messages or error codes. Use the printer documentation or the manufacturer website to look up specific codes displayed on the printer. On the workstation, verify that the Print Spooler service is started. Check the print queue. Sometimes a large document might be first in the queue and is stalling or otherwise preventing other documents from printing. Move the document down in the queue, or delete the document from the queue if necessary. If a problem cannot be found, try restarting the printer and the computer.

Low Earth Orbit Satellite (LEO):

Closer to the Earth than GEOs Orbits at a distance of about 1200 miles above the Earth Simpler and cheaper to make than GEOs Fast, accurate communication and service Coverage area is limited; needs more satellites to cover a bigger area

Bluetooth Applications

Common applications for Bluetooth include the following: Connecting peripheral devices (e.g., keyboard and mouse) Wireless headphones and smart phone headsets Peer-to-Peer communications (e.g., sharing data between a smart phone, notebook, and tablet) Bluetooth is also able to transmit audio and video data signals

common flash devices

CompactFlash cards SD cards SSD cards MiniSD cards MicroSD cards xD cards Hybrid cards (combines SSD and HDD technology) Memory sticks

Impact

Complete the following to maintain impact printers: Replace the ribbon as needed. Avoid rewinding and reusing the print ribbon as it will dramatically decrease your print quality. Remove accumulated debris. Pay special attention to the tractor feeds as debris can cause them to jam. Calibrate the printer. Some dot matrix printers include a calibration utility that you can use to print out a calibration page. Follow the manufacturer's instructions for completing the calibration. Replace the print head if necessary. Heavily used printers may require replacement of the print head as it wears out. Follow the manufacturer's instructions for replacing the print head.

Inkjet

Complete the following to maintain inkjet printers: Replace the ink cartridge as needed. Avoid refilling and reusing the ink cartridge as it could decrease your print quality. In addition, many ink cartridge manufacturers include a small fuse or switch that is tripped when the cartridge runs out of ink. The switch has to be reset, or the fuse replaced, before the cartridge could be refilled and reused. Calibrate the printer after replacing the ink cartridge. Most inkjet printers include a calibration utility that you can use to align the new print head in the new cartridge. Remove accumulated debris. Pay special attention to the paper rollers as debris can cause them to jam. Check the carriage assembly and belt. The carriage is the assembly that holds the ink cartridges and slides back and forth using a belt drive to transfer ink onto the paper.On heavily-used printers, the carriage and the belt that drives it can wear out or sustain damage. If this happens, you may experience carriage jams. You may also hear a grinding noise as the printer attempts to move the carriage. In this situation, you can replace the carriage assembly and the belt. The steps for doing this will vary by printer manufacturer. Consult the appropriate documentation for your printer.

Thermal

Complete the following to maintain thermal printers: Clean the heating element. Clean the print head every time the ribbon is changed. Clean the head with isopropyl alcohol and a lint-free rag. Remove accumulated debris with compressed air. Clean the drive roller using an alcohol wipe.

Fiber Optics Advantages

Completely immune to EMI Highly resistant to eavesdropping Fastest available transmission rates Greater cable distances without a repeater

system does not boot

Computers require a functioning video card in order to boot. If the system does not boot and the monitor is blank, check the monitor's power and video connections. If the motherboard returns a POST error (either a code or a series of beeps), ensure the video card is seated properly and has the necessary power connections. If the motherboard still returns a POST error, the video card is bad and should be replaced.

ranndom SATA facts

Connect the boot drive to the lowest SATA channel number of the installed devices. The boot sequence will normally follow the channel order unless a boot priority is specified in the BIOS/UEFI. The cable length can be up to one meter (up to 2 meters for eSATA).

cp

Copies files and directories from one location in the file system to another. For example, to copy the widget.odt file to the /home/rtracy directory, you would enter cp widget.odt /home/rtracy at the shell prompt. To copy an entire directory structure, include the -R option, which specifies that the directory contents be recursively copied.

gestures

Gestures are specific finger motions that are used to perform a specific function on a Mac OS system. They are used by Apple systems that use an Apple Multi-Touch trackpad, a Magic Mouse, or a touchscreen. Below are just some of the gestures that are available on Mac OS:

High-bandwidth Digital Content Protection (HDCP)

HDCP is a method for protecting digital media. The purpose of HDCP is to prevent the interception and copying of protected data streams as they are sent from a playback device to a display device (e.g., from a DVD player to an HDTV). When playing protected content from a PC, the DVD player, video card, and display device must all support HDCP. If you plan on watching protected content on your PC, or playing content from your PC to an external TV, make sure the video card supports HDCP.

HDMI audio

HDMI cables are able to carry both video and audio signals; however, most video cards send only a video signal. The following techniques can be used to send an audio signal through the video card: With audio pass-through, an audio output cable is connected to the video card. The video card combines the audio signal with the video signal for HDMI output. This option is often called HDTV out. A graphics card with an onboard audio processor can decode and process audio and send it out the HDMI port. This option is often referred to as onboard sound.

Hypertext Transfer Protocol (HTTP) 80

HTTP is used by web browsers and web servers to exchange files (such as web pages) through the World Wide Web and intranets. HTTP can be described as an information requesting and responding protocol. It is typically used to request and send web documents, but is also used as the protocol for communication between agents using different IP protocols.

Hypertext Transfer Protocol over Secure Socket Layer or HTTP over SSL (HTTPS) 443

HTTPS is a secure form of HTTP that uses SSL as a sublayer for security. SSL secures messages being transmitted on the internet. It uses RSA for authentication and encryption. Web browsers use SSL (Secure Sockets Layer) to ensure safe web transactions. URLs that begin with https:// trigger your web browser to use SSL.

DDR

DDR (Double-Data Rate Synchronous Dynamic RAM) is a variation of the original synchronous DRAM (SDRAM). All variations of DDR are synchronized with the system clock and accept 64-bit words. DDR accepts a single command and two consecutive data sets per bus clock cycle. Operating at the same frequency, DDR has twice the bandwidth of SDRAM. DDR operates at 2.5 volts at bus frequencies between 100-200 MHz. DDR memory has a single notch, slightly off center. DDR memory has 184 pins.

DDR2

DDR2 doubles the data transfer rate of DDR, for four times the bandwidth of SDRAM. DDR2 accepts four consecutive 64-bit words per bus clock cycle. DDR2 includes a buffer between the data bus and the memory. DDR2 operates at 1.8 volts at bus frequencies between 200-533 MHz. The internal memory frequency is half that of the bus frequency (100-266 MHz). DDR2 memory differs from DDR memory as follows: The notch is slightly closer to the middle. It has 240 pins. While you don't need to count the pins, you should notice that the pins are smaller because they have to fit in the same space as the DDR memory.

DDR3

DDR3 doubles the data transfer rate of DDR2, for eight times the bandwidth of SDRAM (twice that of DDR2). DDR3 accepts eight consecutive 64-bit words per bus clock cycle. DDR3 operates at 1.5 volts at bus frequencies between 400-1000 MHz. The internal memory frequency is one-fourth that of the bus frequency (100-266 MHz). DDR3 memory has a single notch more left of center than the notch for DDR or DDR2. Like DDR2, DDR3 has 240 pins.

DDR4

DDR4 doubles the data transfer rate of DDR3 for ten times the bandwidth of SDRAM. DDR4 accepts eight consecutive 64-bit words per bus clock cycle. DDR4 operates at 1.2 volts at bus frequencies between 1066-2133 MHz. The internal memory frequency is about one-tenth that of the bus frequency (100-266 MHz). DDR4 reduces the demand for power. DDR4 is not compatible with earlier types of random access memory (RAM) because of the different signaling voltages, physical interface, and other factors. DDR4 theoretically allows for DIMMs of up to 512 GB in capacity, compared to the DDR3's theoretical maximum of 128 GB per DIMM. DDR4 memory has a single notch slightly right of center. DDR4 has 288 pins.

Dynamic Host Configuration Protocol (DHCP) 67, 68

DHCP is used to dynamically assign IP addressing information to network hosts when they come online. The client system, when it connects to the network, broadcasts a DHCPDISCOVER message on the network, looking for a DHCP server. The DHCP server responds with a DHCPOFFER message containing proposed IP addressing configuration information. The client then responds with a DHCPREQUEST message to the DHCP server indicating it wants to use the proposed configuration. The DHCP server makes the assignment with a DHCPACK message.

DMA

DMA (Direct Memory Access) channels are conduits high-speed devices use to bypass the CPU and communicate with RAM directly. Devices such as hard drives, sound cards, and FireWire cards use DMA channels to increase the speed of data transfers. Devices must have a unique DMA channel.

Domain Name System (DNS) 53

DNS is a system that is distributed throughout the internetwork to provide address/name resolution. For example, the name www.mydomain.com would be identified with a specific IP address.

Dynamic RAM (DRAM)

DRAM stores data using a single transistor for every bit of data (a 0 or a 1). To maintain the state of the transistor, DRAM must continually supply power to the transistor; when the power is turned off, the data is lost. DRAM is simple to implement. DRAM can have a very high density (e.g., high storage capacity). Because of the simplicity, DRAM is relatively inexpensive. DRAM is used in the main system memory on a computer.

Digital Subscriber Line (DSL)

DSL provides broadband digital data transmission over existing telephone lines. DSL divides the telephone line into multiple channels. One channel is used for analog voice, while the remaining channels are used for digital data. Filters are used to separate the analog voice data from digital data. Several DSL standards exist, including ADSL, SDSL, and HDSL (collectively referred to as xDSL). Depending on the type of DSL used, you can use the same line for simultaneous voice and data. DSL is not available in all areas; the service location must be within a fixed distance of telephone switching equipment.

Digital Versatile Disc (DVD)

DVD (Digital Versatile Disc) is an optical media standard that can be used to store large amounts of different types of data (computer data, video, audio). Most DVD drives can read and write. Older drives or older DVD players might only support DVD-R. A DVD with a single side of data can hold about 4.7 GB. A DVD-ROM is read-only memory. DVD-RW is a rewritable DVD format. DVD-RW uses a crystal encoding on the bottom of the DVD disc. DVD speeds use a multiple of 1.35 MBps or 11 MBps

Input

Data that is entered into the computer system via an input or storage device.

memory

Dedicated video cards use high-speed memory to store graphic data. The amount of memory on the card affects performance as well as other characteristics. The amount of memory on a card can be as low as 1 GB or as high as 12 GB. Dedicated video cards use the following types of memory: DDR, DDR2, and DDR3 memory are similar to system memory. This type of memory is cheaper, but provides less performance features than special graphics memory. GDDR2, GDDR3, and GDDR5 are DDR memory specifically designed and optimized for graphical data. This memory is more expensive, but results in better performance. Integrated graphics (onboard video cards) share system memory with the CPU for video processing.

rm

Deletes files and directories from the file system. For example, to delete the widget.odt file, you would enter rm widget.odt at the shell prompt.

Configure for a Network Environment

Depending on the implementation, it may be necessary to take the following steps in order to configure the SOHO router for a particular network environment: Enable and configure a DMZ (demilitarized zone) host. Configuring a DMZ on a SOHO router causes all incoming port traffic to be forwarded to the specified DMZ host. Because this can open up the network to a variety of external threats, configure a DMZ only if you understand all the implications associated with it. Configure quality of service (QoS) settings. Most SOHO routers provide basic QoS functionality. When enabled, QoS prioritizes certain network communications over others. For example, VoIP network traffic would be given higher priority and more bandwidth than HTTP (web browser) traffic. Enable the Universal Plug and Play (UPnP) networking protocol. UPnP is a networking protocol that allows UPnP enabled devices to easily discover each other on the network and share data and media content.

Nickel Cadmium (NiCad)

Develops a memory and begins to store less power as it is repeatedly recharged. To avoid battery memory problems, completely drain the battery before recharging it. Takes up more physical space than lithium ion batteries. Very heat sensitive. No longer used on new laptops.

storage space components

Devices are the hard disks or other types of storage from which storage pools are created. You can use a variety of devices such as SATA drives and external drives to create storage pools. Pools of storage are created from the available disk space. A pool is a logical concept composed of the free space available on the specified storage devices. Storage spaces define logical units of space created from a pool. One or more storage spaces can be created from the pool. To the Windows system and the user, storage spaces appear as disks with typical drive letters (e.g., E: drive, F: drive).

celluar connections types

Devices can connect to a cellular internet connection in a variety of ways: Many smart phones use a technique known as tethering to provide cellular internet to another device. Tethering typically requires the smart phone to be connected via a USB cable. A mobile hotspot is a cellular device that provides internet access by creating a small Wi-Fi network to which multiple devices can connect. Most smart phones have built-in mobile hotspot functionality. Some mobile devices (e.g., notebook computers and tablets) have integrated cellular antennas. USB cellular adapters can be connected to most mobile devices to provide cellular access.

self powered USB

Devices that rely on their own power supply (i.e., they are plugged into an AC outlet) are self-powered devices (sometimes called active devices). USB 2.0 devices that draw more than 500 mA of power are required to be self-powered; USB 3.0 devices that draw more than 900 mA of power are required to be self-powered.

IRQ

Devices use IRQ (Interrupt Request) to interact with the CPU. An IRQ allows a device to interrupt the CPU and request processing time. All new devices allow the sharing of an IRQ; older (legacy) devices had to be assigned a unique IRQ.

NFC modes

Devices using NFC operate in one of three modes: Reader/writer mode is used to read information stored on an NFC chip. Peer-to-Peer mode enables two devices to communicate and exchange information. Card Emulation mode emulates the functionality of a smart card in order to perform contactless payment or ticketing (this mode is typically used by smart phones).

Video files do not play, audio plays but no video

Digital video can be saved in one of several file formats (called codecs). Before you can play a video file, your computer must have the corresponding codecs installed. Many video files use two codecs: one for video and one for audio. If the audio plays but the video does not, you know you have the correct audio codec but need the video codec installed.

DirectX/OpenGL

DirectX is a collection of application program interfaces (APIs) that improves graphic, animation, and multimedia creations. DirectX includes multiple components targeted to a different aspect of multimedia. For example, Direct3D is the 3D rendering component of DirectX. Applications (typically games) are written using features included in specific DirectX versions. To view content written to a specific DirectX version, your video card must also support that (or a higher) version. OpenGL is an alternative standard to DirectX that is used by some applications. Most video cards support both DirectX and OpenGL.

Disable DHCP for Wireless Clients

Disabling DHCP on the wireless access points allows only users with a valid, static IP address in the range to connect. An attacker would have to be able to discover or detect the IP address range, subnet mask, and default gateway information to connect to the access point.

Client Server Disadvantages

Disadvantages of client-server networks include the following: Expensive server operating systems Extensive advanced planning required

Peer to Peer Disadvantages

Disadvantages of peer-to-peer networks include the following: Difficult to expand (not scalable) Difficult to support Lack centralized control No centralized storage

Disk Cleanup

Disk Cleanup helps manage disks by locating and disposing of files that can be safely removed from the disk. You can type Cleanmgr at the command prompt to run Disk Cleanup.

Disk Defragmenter

Disk Defragmenter optimizes the performance of your hard drive by joining fragments of files that are in different locations on your hard drive into a single location. Run Defrag at a command prompt to run Disk Defragmenter in a text mode.

ls

Displays a list of files and subdirectories that exist within a directory. Several options are commonly used with this command: -a displays all files, including hidden files. -l displays a detailed (long) listing of directory contents including ownership, permissions, modification dates, and file sizes. -R displays the contents of the directory and all of its subdirectories.

info

Displays more extensive documentation about the command. Use the Q key to quit and go back to the shell prompt.

ifconfig

Displays the IP address and the subnet mask assigned to this system.

less

Displays the contents of a text file on the screen, pausing the output one screen at a time. For example, to view the contents of the widget.txt file one page at a time, you would enter less widget.txt at the shell prompt.

cat

Displays the contents of a text file on the screen. For example, to view the contents of the widget.txt file, you would enter cat widget.txt at the shell prompt.

head

Displays the first few lines of a text file on the screen. For example, to view the first lines of the widget.txt file, you would enter head widget.txt at the shell prompt.

tail

Displays the first few lines of a text file on the screen. For example, to view the first lines of the widget.txt file, you would enter head widget.txt at the shell prompt.

man

Displays the manual page for a command. It's very similar to the help screen, but it provides more detail. Use the Q key to quit and go back to the shell prompt.

pwd

Displays the path of the current directory on the screen. pwd stands for print working directory.

Nickel Metal Hydride (NiMH)

Does not develop a memory. 40% longer lifetime than nickel cadmium. Greater charge capacity than nickel cadmium. Less toxic than nickel cadmium. Slightly more expensive than nickel cadmium.

smart zoom

Double-tap with two fingers to zoom in on a web page, image, or document (double-tap again to zoom out).

Hardware RAID

Hardware RAID uses a special controller card that includes a RAID processor. Hardware RAID is the most expensive method but provides much better performance and is more reliable than other methods.

RJ11

Has 4 connectors Supports up to 2 pairs of wires Uses a locking tab to keep a connector secure in an outlet Used primarily for telephone wiring

RJ45

Has 8 connectors Supports up to 4 pairs of wires Uses a locking tab to keep a connector secure in an outlet Used for Ethernet networks

Cat 7

Has the strictest specifications for crosstalk and noise.

CD-ROM facts

Have lands and pits and use reflective light to interpret the data on the disc. Hold about 737 MB of data with error correction or 847 MB total. Transfers data at a rate of 150 KBps. Drive speeds are measured as multiples of this original speed. To calculate an estimate of your CD-ROM drives transfer rate, multiply its speed by 150 kilobyte (1x = 150 KBps, 2x drive = 300 KBps, 4x drive = 600 KBps, 72x = 10,800 KBps).

heat sink

Heat sinks are made of a heat conductive material (usually aluminum or copper) and are attached to components using a thermal paste or pad. Heat sinks are designed with fins to increase the surface area exposed to air, allowing heat to dissipate from the component much faster. Heat sinks can be either active or passive. Active heat sinks have an attached fan that helps cool off the component at a faster rate. Active heat sinks are used with the following components: CPUs High-end video cards Some motherboard chipsets with integrated graphics Passive heat sinks do not have a fan and instead rely on increased surface area and passive air movement to cool the component. Passive heat sinks are used with the following components: Most motherboard chipsets Low-end video cards Memory modules (heat sinks on memory modules are also called heat spreaders) Because passive heat sinks do not use a fan, they are 100% reliable. However, active heat sinks can dissipate heat much faster than passive ones.

Printer Command Language (PCL)

Hewlett-Packard has created several versions of a printer command language called PCL. Many modern printers understand PCL.

HTPC case

Home theatre PC (HTPC) cases are designed to connect to TVs and be used as a home media computer. HTPC cases are compatible with microATX and Mini-ITX form factors.

hot-swappable

Hot swappable devices are devices that can be added and removed without shutting down the computer (technically speaking, hot plug refers to automatically detecting and configuring devices that are added, while hot swap refers to the ability to both add and remove devices). Hot swapping must be supported by the BIOS, the bus type or controller, the device, and the driver/operating system. USB and FireWire devices are examples of buses and devices designed specifically with hot swap support. Most newer SATA drives are hot swappable. When you connect a hot swappable device, Windows automatically detects the device, configures a driver (if one is not already installed), and enables the device. To remove a hot swappable component, use the Safely Remove Hardware feature to shut down the device before unplugging it from the system.

Three-way Mirroring

Three-way mirror requires at least five storage devices. The data is written to three storage devices. This option provides redundancy for the data if two storage devices fail at one time.

Throttling

Throttling is the process of modifying the operating characteristics of a processor based on current conditions. Throttling is often used in mobile processors to change the operating frequency to minimize power consumption and heat output. Throttling can also be used in low memory conditions to slow down the processing of I/O memory requests, processing one sequence at a time in the order the request was received. Related to throttling, processors or the operating system can shut down unused cores in multi-core systems to conserve energy.

Common reasons for editing the CMOS settings are:

To change the boot device order. To enable or disable motherboard devices. To add a password to the setup program to prevent unauthorized access. If you set a BIOS/UEFI password and then forget it, you will be unable to edit CMOS settings. To remove the password for most motherboards, move or remove a jumper, then replace it after a specific period of time. To configure processor or memory settings (e.g., when you need to set operating speeds or when you want to overclock hardware settings). (In rare cases) To manually configure device properties for legacy devices.

Defragmenter Facts

To improve defragmentation, disable programs that run in the background like screensavers and virus software. Any disk access while Disk Defragmenter is running (whether to read from or write to the disk) will slow down the defragmentation process. The more information that is on the drive, the more time it will take to defragment the drive.

USB

To troubleshoot USB and FireWire devices, consider the following: Install the driver before plugging in the device. Overloading the USB bus's power resources can cause devices to not have sufficient power to work properly. Make sure that you are not exceeding 500 mA of power through the USB bus. The cable might be too long for the current setup. Remember that shorter cable lengths are best. Try not to use cables that are longer than 3-4 feet. Verify BIOS/UEFI settings for onboard USB. Make sure onboard ports are enabled and that the correct USB version is enabled.

touchpad

Touch pads are typically found on notebook computers and are used in place of a mouse. Users slide their finger on the touch pad to manipulate the cursor. Touch pads can also be used with desktop computers. These touch pads connect to the computer through a USB port and are used instead of a mouse.

Fiber Optic Single Mode

Transfers data through the core using a single light ray (the ray is also called a mode) Has a core diameter of around 10 microns Supports a large amount of data Allows cable lengths to extend a great distance

Fiber - Optic Multimode

Transfers data through the core using multiple light rays Has a core diameter of around 50 to 100 microns Limits the distance of cable lengths

TCP (Transmission Control Protocol)

Transmission Control Protocol (TCP) - TCP is a connection-oriented protocol. To ensure reliable delivery of data, TCP requires the recipient of a network transmission to send an acknowledgement of each and every IP packet it receives to the sender. Packets that don't make it are retransmitted. This ensures that the data is delivered reliably.

Bluetooth Speeds & Distances

Transmission speeds and max distance depends on the version and device class: Version Speed 1.2 1 Mbps 2.0 3 Mbps 3.0 24 Mbps 4.0 Class Distance 1 100 m 2 10 m 3 1 m

Two-way Mirroring

Two-way mirror requires at least two storage devices. The data is written to two devices. Two-way mirror requires twice as much device space as the amount of storage allocated to the storage space. This option protects you from a single storage device failure.

bus powered USB

USB cables have wires to carry both power and data. Bus-powered (sometimes called passive) devices get their power via the USB cable. Bus-powered devices are classified as low-powered or high-powered devices, depending on the amount of power they draw from the USB bus. Low powered devices use 100 mA or less High-powered devices use between 100 and 500 mA (up to 900 mA for USB 3.0) Like USB devices, USB hubs can be bus-powered or self-powered. You cannot connect high-powered devices to a bus-powered hub (you can connect only low-powered or self-powered devices to a bus-powered hub). Therefore, self-powered hubs that provide 500 mA per port are recommended to ensure an adequate power supply to all bus-powered devices that you may wish to connect to the hub.

UniDIMM

UniDIMM (Universal DIMM) is a specification for DIMMs and is designed to carry DRAM chips. UniDIMMs can be populated with either DDR3 or DDR4 chips, but do not support any additional memory control logic. Because of this, the computer's memory controller must support both DDR3 and DDR4 memory standards. UniDIMM: Is an upgrade to the current SODIMM standard Allows mobile platform users to use both DDR3 and DDR4

UTP

Unshielded twisted pair (UTP) has only an outer plastic sheath. UTP cables are easier to work with and are less expensive than shielded cables.

upgrading hard drives

Upgrade to the fastest hard disk possible. Hard disk drives come in a variety of different rotation speeds

Hard Drive Interfaces

Upgrading your disk interface will greatly improve the throughput of data to and from your hard disk drive. For optimal performance, consider upgrading to SATA3. This will upgrade your speed to 600 Mbps.

Chkdsk commands

Use Chkdsk with the /f switch to automatically fix errors without scanning for bad sectors. Use the /r switch to scan and fix bad sectors and other errors. Use the /? command for help.

paper type

Use the correct paper type for the printer. Most paper will be labeled as appropriate for a specific type of printer. For example: Using glossy paper in inkjet printers could lead to smeared ink because the ink is not being absorbed into the paper. Using glossy paper could cause the paper to not be pulled into the rollers correctly. Be careful when using thick paper or cardstock in a laser printer; they can cause paper jams. The weight of laser printer paper should generally be between 70 and 130 grams per square meter (GSM). On some laser printers, you can change the paper path for thick paper so it is fed through the printer in a straight line (rather than curling the paper up to the top of the printer). Such straight line paper paths can help prevent paper jams with thick paper.

phone cable

Used to connect a modem to a phone jack in a wall outlet to establish a dial-up internet connection Has two pairs of twisted cable (a total of 4 wires).

Escape Codes

Used to control dot matrix printers. Escape codes are primitive compared to today's standards.

MT-RJ Connector

Used with single mode and multi-mode cabling Composed of a plastic connector with a locking tab Uses metal guide pins to ensure it is properly aligned A single connector with one end holds both cables Uses a ceramic ferrule to ensure proper core alignment and prevent light ray deflection

LC Connector

Used with single mode and multi-mode cabling Composed of a plastic connector with a locking tab, similar to an RJ45 connector A single connector with two ends keeps the two cables in place Uses a ceramic ferrule to ensure proper core alignment and prevent light ray deflection Half the size of other fiber optic connectors

ST Connector

Used with single mode and multi-mode cabling Keyed, bayonet-type connector Also called a push in and twist connector Each wire has a separate connector Nickel plated with a ceramic ferrule to ensure proper core alignment and prevent light ray deflection As part of the assembly process, it is necessary to polish the exposed fiber tip to ensure that light is passed on from one cable to the next with no dispersion

SC Connector

Used with single mode and multi-mode cabling Push on, pull off connector type that uses a locking tab to maintain connection Each wire has a separate connector Uses a ceramic ferrule to ensure proper core alignment and prevent light ray deflection As part of the assembly process, it is necessary to polish the exposed fiber tip

UDP (User Datagram Protocol)

User Datagram Protocol (UDP) - UDP is a connectionless protocol. Unlike TCP, UDP does not require acknowledgements. One of the key drawbacks of using TCP is the fact that its reliability introduces latency. For small data transmissions, such as sending an email, moderate latency is not a problem. However, for large data transmissions, such as video or audio streaming, the latency associated with TCP is unacceptable. By using UDP instead, the latency of the transmission is significantly reduced, with the assumption that an occasional lost packet won't be detrimental.

Geostationary Satellite (GEO):

Uses a transmitter with an antenna (dish) directed skywards to a satellite Requires line-of-sight to the satellite (dish placement is crucial) Is affected by mild atmospheric and weather conditions (fog, rain, or snow can disrupt service) May have a long delay time (latency) between requests and downloads Can be a portable solution for cars or trucks with an attached satellite dish Provides nearly 100% global coverage

Device Manager

Utility that enables techs to examine and configure all the hardware and drivers in a Windows PC.

System sounds a POST beep code indicating a CPU fault upon boot:

Verify that the CPU is receiving sufficient power by checking the power outputs. If these are good, replace the CPU. If the fault remains, the problem is with the motherboard.

Verify the network adapter

Verify that your computer has detected and properly configured the network adapter card. To view a list of available network connections, do one of the following: In the notification area, right-click the Network icon and select Open Network & Internet settings. Select Change adapter options. In Windows 8 and Windows 10, right-click Start and select Network Connections. If the network interface card is detected and configured, you should see an Ethernet or Wi-Fi icon in the Network Connections window. Make sure that the connection is enabled. If there is no icon, check Device Manager to make sure that the device is detected, has the appropriate drivers, and is enabled. If there is no network device, then the hardware could not be detected.

Fiber optic disadvantages

Very expensive Difficult to work with Special training required to attach connectors to cables

Twisted Pair Disadvantages

Very susceptible to EMI Cables are easily damaged Vulnerable to eavesdropping

display connectors

Video cards have one or more connectors for attaching an external display. Always try to select a video card with connectors that match your display. VGA monitors use a VGA (DB-15) connector. LCD and LED monitors use one (or more) of the following connectors: DVI-Integrated (DVI-I) connector HDMI connector (also used by HDTVs) DisplayPort connector DVI-I connectors are able to send either analog or digital signals. Older video cards might use DVI-A (analog) or DVI-D (digital) connectors. Some video cards have dual heads (two output connectors capable of displaying video simultaneously) and are able to support dual monitors. If necessary, you can use special connector adapters to convert from one connector type to another (e.g., DVI to HDMI). However, it's usually best to match the connector type of the video card with the display connectors.

bus type

Video cards must be compatible with the expansion slots on the motherboard. Common slot types used by video cards include the following: PCIe x16 PCI AGP and VESA (used by older video cards) Motherboards with integrated graphics embed the functionality with the buses on the system (e.g., PCIe, AGP, or PCI).

VoIP

VoIP devices provide voice communication over a packet-switched network (an IP network). The most common VoIP device is an IP phone. Instead of using the standard public switched telephone network, IP phones connect to an Ethernet network using an RJ45 connection. Basic VoIP services include Skype or Google Voice. Businesses that use VoIP typically hire a third-party entity (such as Vonage or Jive) to set up the service and configure devices.

Voice over IP (VoIP)

Voice over IP (VoIP) sends voice phone calls using the TCP/IP protocol over digital data lines. With VoIP, phone calls are made through your internet connection, not through a phone line. When you make a phone call, the call is converted into digital data and sent through the internet. VoIP is provided by many ISPs to replace existing analog telephone lines (even using the same phone number). Desktop computers can be used to make VoIP calls by using VoIP software and the computer's microphone and speakers. The most common example of this is the VoIP application Skype.

dynamic disk characteristics

Volumes on dynamic disks are like partitions and logical drives on basic disks. Dynamic disks support up to 128 volumes. Dynamic disks support volumes that use noncontiguous disk space. Simple volumes contain disk space from a single hard disk (either contiguous or noncontiguous space). Spanned volumes contain disk space from multiple hard disks grouped as a single logical volume. Dynamic disks store partitioning information in a hidden database on all dynamic disks in the system.

Wired Equivalent Privacy (WEP)

WEP is an optional component of the 802.11 specifications that were deployed in 1997. WEP has the following weaknesses: A static pre-shared key (PSK) is configured on the AP and the client. It cannot be dynamically changed or exchanged without administration. As a result, every host on large networks usually uses the same key. Because key values are short and don't change, the key can be captured and easily broken. Because of the inherent security flaws, avoid using WEP whenever possible. If using WEP cannot be avoided, implement it only using open authentication. Shared key authentication with WEP uses the same key for both encryption and authentication, exposing the key to additional attacks.

Wi-Fi Protected Access (WPA)

WPA is the implementation name for wireless security based on initial 802.11i drafts that was deployed in 2003. It was intended to be an intermediate measure to take the place of WEP while a fully secured system (802.11i) was prepared. WPA: Uses Temporal Key Integrity Protocol (TKIP) for encryption Supports both pre-shared key (WPA-PSK or WPA Personal) and 802.1x (WPA Enterprise) authentication Can use dynamic keys or pre-shared keys Can typically be implemented in WEP-capable devices through a software/firmware update WPA keys can also be predicted by reconstructing the Message Integrity Check (MIC) of an intercepted packet, sending the packet to an AP, and observing whether the packet is accepted by the AP.

Wi-Fi Protected Access 2 (WPA2) or 802.11i

WPA2 is the implementation name for wireless security that adheres to the 802.11i specifications. It was deployed in 2005. It is built upon the idea of Robust Secure Networks (RSN). Like WPA, it resolves the weaknesses inherent in WEP. It is intended to eventually replace both WEP and WPA. WPA2: Uses Advanced Encryption Standard (AES) as the encryption method Supports both pre-shared key (WPA2-PSK or WPA2 Personal) and 802.1x (WPA2 Enterprise) authentication Can use dynamic keys or pre-shared keys

Wi-Fi Protected Access 3 (WPA3)

WPA3 is a new authentication launched in 2018. It is a more resilient version of WPA2. WPA3: Uses password-based authentication Provides better protection against password guessing attempts by using Simultaneous Authentication of Equals (SAE) Offers 192-bit cryptographic strength, giving additional protection for networks dealing with sensitive data

Webcam

Webcams are camera and microphone systems that allow users to communicate through the internet with audio and video. Most laptops have a built-in webcam, but you can purchase one and connect it to the computer through a USB port.

SATA2 in SATA1

When installing a newer SATA2 drive into a system that supports only SATA1, you might need to: Configure the drive to operate in SATA1 mode. This is typically done by setting a jumper. Update the BIOS/UEFI to recognize the new drive. Even with these steps, some SATA2 drives will not work in a motherboard that supports only SATA1. In that case, install a SATA2 controller card.

Create a Whitelist and Blacklist

When securing devices or navigation access, there are two options to create lists that either allow or deny access through the Firewall security: Whitelisting means that only the devices on the list are allowed access. Basically, everyone is blocked access except for the devices on the whitelist. Blacklisting means all devices are allowed access except for the ones on the blacklist. It's just the opposite of Whitelisting.

Laser Printer Considerations

When working with laser printers, be aware of the following: A laser printer's fuser operates at a high temperature and can burn you. Because an OPC drum is sensitive to light, it can lose its effectiveness if it is over-exposed. Do not put any materials in a laser printer that melt below 180 degrees Fahrenheit. When they pass through the fuser, they can melt and permanently damage the laser printer. Do not attempt to print on paper with photocopied or laser printed images already on it. The images can come off onto parts of the laser printer and smear your print jobs. To clean up toner spills, scoop up large quantities of toner or use a damp cloth to wipe up lesser quantities. Use toner vacuums that are specially designed to clean up toner spills. Never use a household vacuum to clean up a toner spill. Because toner is very fine, it is likely to pass through a household vacuum's filter and be blown into the air. Also, it can be attracted to magnets in the motor and ruin the vacuum or cause a fire.

Packaging (Form)

When you are purchasing RAM for a system, the most important consideration is the packaging, also called memory form. The packaging controls both the physical size of the memory module and the memory standard (e.g., DDR2, DDR3, DDR4). If you purchase the wrong type of RAM, it will most likely not fit. If it does, it might have different voltage requirements than what is supported by your motherboard. Memory packaging (memory form) and capacity must match what is supported by the motherboard.

formatting facts

When you format a disk, you identify the file system type and identify the cluster size used to store data. Reformatting removes the existing file system and replaces it with the new file system type. Reformatting a drive deletes all existing data. If your system or disk supports multiple operating systems, be sure to select a file system supported by all necessary operating systems. NTFS is not recommended for disks smaller than 10 MB. When using NTFS on removable devices, you must use Safely Remove Hardware before removing the flash device to prevent file corruption. If you run a Full Format, files are removed from the volume you scan and the system checks the hard disk for bad sectors. If you run a Quick Format, the system removes files from the partition, but does not scan the disk for bad sectors.

Print Spooling

Windows printing is dependent upon the Print Spooling service. The Print Spooling service is a software process that captures print jobs from applications, places them in the print queue, and then sends each print job to the print device. Use the Services snap-in to manage the Print Spooling service. By default, the Print Spooling service is configured to start automatically each time the system starts.

Security Camera

Wireless cameras transmit video through a RF transmitter. The video is sent to a receiver that connects to the viewing and recording device. That device gives easy access to all video footage recorded through the cameras. Many people use cloud storage to save the video footage for later viewing. Modern wireless camera technology tends to implement such features as motion detection, scheduled recording, remote viewing, and automatic cloud storage. But the extent to which these features are implemented may vary by company, model, and brand.

Range

Wireless standards have a limited range. Moving a notebook outside the effective range will weaken the signal and likely cause intermittent reception. Moving outside of the stated range can cause the connection to drop entirely.

Alternate IP Configuration

With an alternate IP configuration, the system attempts to use DHCP for TCP/IP configuration information. If a DHCP server cannot be contacted, the static configuration values are used. When you configure an alternate IP address, APIPA is no longer used. Use an alternate configuration: If you have a computer (e.g., a laptop) that connects to two networks (i.e., one with a DHCP server and another without a DHCP server). If you want to provide values to properly configure the computer in case the DHCP server is unavailable.

Shared Key

With shared key authentication, clients and APs are configured with a shared key (called a secret or a passphrase). Only devices with the correct shared key can connect to the wireless network. All APs and all clients use the same authentication key. Shared key authentication should be used only on small, private networks. Shared key authentication is relatively insecure, as hashing methods used to protect the key can be easily broken.

static IP address

With static addressing, you manually assign all configuration values. Static addressing is prone to error and should be used only under the following conditions: The network has a small number of hosts. The network will not change or grow. You have some hosts that must have the same address each time.

basic disk facts

You must create a logical drive in an extended partition before you can format and store data (the logical drive is the storage unit, not the partition). Basic disks are supported by all operating systems. A basic disk only supports volumes made up of contiguous disk space.

GPT facts to know

You'll probably want to use GPT when setting up a drive. However, if you need compatibility with old systems, like the ability to boot Windows off a drive on a computer with a traditional BIOS, you'll need to use MBR. Windows can only boot from GPT on UEFI-based computers running 64-bit versions of Windows 7, 8.x, 10, and the corresponding server versions. All versions of Windows 7 and later can read GPT drives and use them for data, but they cannot boot from them without UEFI. Because Windows 7 does not support UEFI on 32-bit platforms, you cannot boot from a GPT partition on Windows 7. Linux has built-in support for GPT. Apple's Intel Macs no longer use Apple's APT, or Apple Partition Table, scheme but uses GPT instead.

Z-Wave

Z-Waves work in the following way: Z-Wave was created by a Danish company named Zensys. It is a simpler and less expensive alternative to Zigbee. It uses the same AES-128 symmetric encryption as Zigbee. But, unlike Zigbee that operates on 2.4GHz, which is a major frequency for Wi-Fi, Z-Wave operates on the 800-900 MHz radio frequency range, so it doesn't suffer any major interference issues like Zigbee does. Like Zigbee, Z-Wave devices all link up together to form a mesh network. There's one central hub that connects to the internet and then the devices themselves don't have Wi-Fi at all, they use Z-Wave connectivity to talk to the hub either directly or through the mesh network. This is called a "source-routed mesh network topology." Z-Wave allows up to 232 nodes on the mesh network.

Zigbee

Zigbee is a standards-based wireless technology that enables wireless machine-to-machine (M2M) and IoT networks. It is designed for low-data rate, low-power applications, and is an open standard. Zigbee is a specification based on IEEE 802.15.4 and the WPANs operate on 2.4 GHz, 900 MHz and 868 MHz frequencies. Its networks are secured by 128-bit symmetric encryption keys. Zigbee has a defined rate of 250 kbps, best suited for intermittent data transmissions from a sensor or input device.

--help

displays a brief summary of how to use the command

802.11g specs

frequency 2.4 GHz (ISM) memory speed 54 Mbps maximum distance 150 ft. Channels (non-overlapped) 11 (3) Modulation technique DSSS (and others) at lower data rates; OFDM, QPSK, BPSK at higher data rates Backwards compatibility 802.11b

802.11n

frequency 2.4 GHz (ISM) or 5 GHz (U-NII) memory speed 600 Mbps maximum distance 300 ft. Channels (non-overlapped) 2.4 GHz: 11 (3 or 1) 5 GHz: 23 (12 or 6) Modulation technique OFDM (and others, depending on implementation) Backwards compatibility 802.11a/b/g, depending on implementation

802.11ac

frequency 5 GHz (U-NII) memory speed 1.3 Gbps maximum distance 150 ft. Channels (non-overlapped) Depends on configuration Modulation technique OFDM Backwards compatibility 802.11b/g/n

802.11b specs

frequency 2.4 GHz (ISM) memory seed 11 Mbps maximum distance 150 ft. Channels (non-overlapped) 11 (3) Modulation technique DSSS, CCK, DQPSK, DBPSK Backwards compatibility None

ifconfig (Linux/macOS)

ifconfig is used on Linux and macOS systems and displays the installed network interfaces and the current configuration settings for each interface, including the MAC address, IP address, broadcast address, and subnet address. Use the ifconfig command as follows: Use ifconfig [interface_name] down to disable the specified network interface. Use ifconfig [interface_name] up to enable the specified network interface. Use the following utilities to display additional networking information not provided by ifconfig: The hostname command displays the system's hostname. The route command displays the default gateway configuration settings. On Linux systems, the iwconfig command is used to display information about wireless network interfaces.

ipconfig (Windows OS)

ipconfig displays IP configuration information for network adapters. Use the ipconfig command as follows: Use ipconfig to view IP address, subnet mask, and default gateway configuration. Use ipconfig /all to view detailed configuration information, including the MAC address and the DHCP server used for configuration. Use ipconfig /release to release the IP configuration information obtained from the DHCP server. Use ipconfig /renew to request new IP configuration information from the DHCP server. Use ipconfig /displaydns and ipconfig /flushdns to view and manage the local DNS cache. The first command displays the contents of the local DNS cache that Windows maintains and updates every 24 hours. The second option flushes (or removes) all the entries in the current DNS cache. If the IP address of a network server is changed, your local cache will contain the old IP address until the cache is updated or the flushdns option is used.

Micro-ATX

microATX towers are smaller cases designed to be placed on desktops. microATX towers typically have only one drive bay and are compatible with the following form factors: microATX Mini-ITX Some microATX towers have a slim design. These cases are typically half the width of a microATX tower and are designed to lie flat or upright

microUSB

microUSB connectors are designed for smart phones and tablet devices. microUSB connectors are approximately half the thickness of miniUSB connectors, making them more appropriate for smaller devices.

nbtstat

nbtstat is used to diagnose issues regarding NetBIOS over TCP/IP. You can use the following options with nbtstat: -c displays the NetBIOS cache of remote machine names and their IP addresses. -n displays NetBIOS names that have been registered on the local system. -r displays names resolved by broadcast and via WINS. -R clears and then reloads the remote cache name table. -S displays current NETBIOS sessions with the destination IP addresses. -s displays current NETBIOS sessions by NETBIOS names.

netstat

netstat displays the following IP-related statistics: Current connections Incoming and outgoing connections Active sessions, ports, and sockets The local routing table

nslookup

nslookup resolves (looks up) the IP address of the specified hostname. It also displays additional name resolution information, such as the DNS server used for the lookup request.

ping

ping sends an ICMP echo request/reply packet to a remote host. A response from the remote host indicates that both hosts are correctly configured and a connection exists between them. You can ping a host by IP address or use the DNS name. When the DNS name is used, the computer must look up the corresponding IP address before performing the ping test. -a looks up the hostname from a given IP address. -t performs a continuous ping test (press Ctrl + C to stop sending the ping tests). -l [size] specifies the packet payload size (in bytes) to use in the test. This can help determine whether packets above a certain size are being lost.

repeat

read the cards again

System locks up shortly after startup:

shutting down, letting the system cool off, and restarting the computer to verify whether the problem repeats itself. Check the following if overheating seems to be the problem: Check the heat sink and fan for placement and condition. Verify that thermal paste or a thermal pad has been used between the processor and the heat sink. Ensure the heat sink is firmly attached to the CPU. Verify that the CPU is properly seated in its socket. Make sure system case fans are working and that the case and expansion slots are in place. If the computer is not overheating but has this symptom, the problem could be the clock or system timers in the BIOS/UEFI are set incorrectly.

scroll

slide up or down using two fingers to scroll up or down

zoom

spread two fingers apart to zoom in bring fingers back together to zoom out

Powersupply

supplies power to serve - also called PSU, this device converts AC to DC

right-click

tap with two fingers to right click

software

the programs and other operating information used by a computer.

tracert, traceroute

tracert is similar to the ping utility because it tests connectivity between devices; however, tracert also shows the path between the two devices. Responses from each hop on the route are measured three times to accurately report how long the packet takes to reach the specific host and then return. On a Windows system, use the tracert command. On Linux and macOS systems, use the traceroute command.

Overheating

when a computer's internal components generate heat that does not dissipate harming the computers functions and hardware.

Verify the IP configuration

If the network adapter has a physical connection, verify the IP configuration for the connection. Use ipconfig to view the IP address, subnet mask, and default gateway configured for the system. Use ipconfig /all to view additional information including the MAC address of the network adapter and the DNS server addresses. Verify that all configuration values are correct. If the computer is using DHCP and if you see an IP address beginning with 169.254.x.x and a mask of 255.255.0.0, the computer was not able to contact the DHCP server and used the APIPA feature to configure the address automatically. In this case, verify that the DHCP server is connected to the network and properly configured.

crash screens

If you experience a Blue Screen of Death (BSOD) on a Windows machine or Spinning Pinwheel of Death (SPOD) on a MAC, several events may have occurred. You could have a fatal system error that is preventing the system from operating safely, or just one application may have failed. Often, rebooting the computer solves the problem. If that doesn't work, you can attempt to revert the system to a previous state to undo any software or hardware changes that are causing problems. Scan your computer for viruses, roll back drivers, update drivers, update your operating system, update BIOS or return them to their factory settings, repair permissions, or clear the dyld cache.

Verify physical connectivity

If you have a network connection in Windows, verify that the adapter can establish a physical connection to the network. For wired connections: The notification area includes a Network icon that indicates the physical status of the connection. If the cable is unplugged or the NIC cannot find a connected device, the Network icon will have an X on it. Check the status lights on the back of the NIC to verify the physical status. There should be a link light that is green. An unlit link light or one that is another color (like red or yellow) indicates a physical connectivity problem. For wireless connections: The notification area includes a Wireless Network icon that indicates the connection status. If the computer is not connected to any wireless network, the icon will have an X on it. Make sure the wireless NIC is installed properly and, if applicable, has any necessary antennae installed. If you suspect a problem with the physical connection, try the following: For wired connections: Use a different network cable that you know works. You can use a cable tester or cable certifier to test the network cabling behind the wall between the wall jack and the punch-down panel. You can also use a tone generator (sometimes called a toner) and probe to trace the location of cables through the wall and ceiling. Connect the cable to a different hub or switch port and check the status lights on the port. Try installing a different network adapter, such as an external adapter that connects through a USB port. For wireless connections: Verify that the SSID settings are correct. If the SSID is hidden, make sure the manually entered SSID has been entered correctly. Make sure both the authentication type and passphrase are correct. If MAC address filtering is being used, ensure the device has been properly configured on the access point. If the SSID is hidden, make sure the manually entered SSID has been entered correctly. Use a wireless analyzer, which can be installed on a smart phone or tablet, to do the following: Locate wireless networks. Identify crowded channels or sources of interference. Find locations with poor wireless coverage. Detect rogue access points.

not enough memory slots

If you receive Not Enough Memory or Out of Memory errors when you try to open and use more than one program at a time, you may need more physical memory.

Print to File

If you use Print to File, Windows saves the formatting and layout information of your file so a printer can create the document without the program or computer that created it. This allows you to: Archive a document and print it later Send a document or photo to a commercial printer Send a document to someone who has the same printer, but doesn't have the program you used to create the document Print to file has some limitations. It's generally designed for parallel printers and it doesn't work well with newer USB printers. In addition, both the computer used to print the saved file and the computer used to create the file must have the same printer driver.

Configure the Wireless Protocol

If your access point supports multiple wireless protocols, select the protocols to support, such as 802.11n only or mixed mode (both 802.11n and 802.11g). Be aware that when using mixed mode, most access points will throttle all clients to the slowest connected protocol speeds (i.e. if a 802.11g client connects to the network, 802.11n clients will operate at 802.11g speeds).

Image retention, screen burn-in

Image retention (IR) is caused by a static image being displayed for too long on a screen, creating a shadow of the image that is visible even when the display is off. This is typically a problem for plasma displays only. Most of the time, IR can be fixed by displaying bright white on the screen for an extended period of time. When the image cannot be fixed and is permanent on the screen, it is known as burn-in.

Bus Topology tips

In a bus topology: Signals travel from one node to all other nodes. A device called a terminator is placed at both ends of the trunk cable. Terminators absorb signals and prevent them from reflecting repeatedly back and forth on the cable. It can be difficult to isolate cabling problems.

Client-Server

In a client-server network, hosts have specific roles. For example, some hosts are assigned server roles, which allow them to provide network resources to other hosts. Other hosts are assigned client roles, which allow them to consume network resources.

Peer-to-Peer

In a peer-to-peer network, each host can provide network resources to other hosts or access resources located on other hosts. Each host is in charge of controlling access to those resources.

Obstructions

In situations where there is no clear line-of-sight between transmitter and receiver due to obstructions (e.g., concrete or metal studs), the wireless signal is reflected along multiple paths before finally being received. This can cause phase shifts, time delays, and attenuation. To address this, implement antenna diversity, which uses two or more radio antennas to increase the quality and reliability of a wireless link. There are two common antenna diversity implementations: Spatial diversity uses multiple antennas that are physically separated from one another. Pattern diversity uses two or more co-located antennas with different radiation patterns.

Colors not correct Colors are not smooth

Incorrect colors are often caused by low color depth settings. A color palette is the current list of colors that can be shown on the screen. Color shift occurs when a new image must load a different palette than is currently used. To correct color shift, increase the color depth of the display.

Twisted Pair Advantages

Inexpensive compared to other media types Easy to install and manage Very common (media and tools are easy to obtain) The most common (and most supported) network medium

Infrared (IR)

Infrared uses invisible light waves for communication. Infrared: Is a line-of-sight medium. Objects cannot be in the path of communications. Communicates at 9600 bps up to 4 Mbps and uses the resources of a COM port. Works best for devices within 1 meter, but can operate up to 30 meters in areas without ambient light interference. Offers no security for transmissions. Infrared is typically used for remote control devices or for sending data between two devices. Most smart phones have integrated IR capabilities.

Inkjet

Inkjet printers are quiet, non-impact printers with ink stored in a reservoir. Bubble jet printers are the most popular form of inkjet printers. The ink reservoir is in a disposable cartridge that includes the printing mechanism. Bubble jet printers print by heating the ink and squirting it through tiny nozzles in the print head and onto the paper. The crispness of an inkjet printer's image is usually rated as dots per inch or dpi. Inkjets range from 150 to over 1400 dpi. A new generation of inkjet printers produce photo-quality printouts when used with photo-quality paper. Photo-quality inkjet printers mix up to 16 drops of ink to form a single dot of color on the page. Inkjet printers feed single cut sheets of paper from a feed tray by clamping them between rollers and advancing them one print line at a time, from top to bottom, through the printer. The newly printed paper is then placed into a tray other than the feed tray. Inkjet printers are an inexpensive way to produce color printouts.

Ring Topology tips

Installation requires careful planning to create a continuous ring. Isolating problems can require going to several physical locations along the ring. A malfunctioning node or cable break can prevent signals from reaching nodes further along on the ring.

Pointing Devices

Instead of a mouse, notebooks use one (or more) of the following devices: Pointing sticks are small knobs in the center of the keyboard. Pushing on this knob moves the cursor. The touchpad is located below the keyboard. Moving your finger across the pad moves the mouse. You can also tap the touchpad to click the mouse. Buttons below the keyboard replace mouse buttons for clicks, double-clicks, and right-clicks. A digitizer pad is used in laptop and PDA systems to receive input. Input is written onto the pad with a stylus pen and then those motions are transferred into data that is processed by the system. You can also use the PS/2 connector or a USB connector to connect an external mouse. Touchpads are more common than pointing sticks. Notebooks with a pointing stick often come with a touchpad as well.

Airplane Mode

Instead of a physical switch, some portable devices have a software-controlled switch called Airplane Mode. When in Airplane Mode, all wireless functionality is disabled. When in Airplane Mode, some wireless functionality (e.g., Wi-Fi or Bluetooth) can be manually enabled individually without needing to disable Airplane Mode.

CPU Manufacturer

Intel and AMD are the two major producers of processors used in modern PCs.

Atmospheric and EMI Conditions

Interference from weather or EMI can degrade the signal and cause service interruptions.

Intermittent Device Failure

Intermittent device failure occurs when a component occasionally stops working. This usually indicates that the device itself is failing. The best remedy is to replace the failing device because it will fail completely at some point. Immediate replacement prevents this from happening. Intermittent device failures may also be caused by device drivers that aren't functioning properly. Device drivers are software and may contain coding errors. Before replacing a device experiencing intermittent failures, first verify that the latest drivers for that device have been loaded. Sometimes downloading the latest driver and installing it will solve the problem. If it doesn't, then the device itself may need to be replaced.

Internal hard disks

Internal hard disks are typically 2.5" or 3.5" and very thin compared to desktop hard disks. SATA, solid state drives, and Flash drives are used in portable devices.

Overheating

Internal system components within a computer generate a great deal of heat that must be dissipated. Overheating causes premature component failure. Overheating could be caused by several conditions: Inadequate air flow. This may be the result of an inadequate number of fans in the system or fans that are too small. In this situation, additional fans can be added to the system to increase air flow. Improperly installed fans. Fans must be oriented to force air through the system in the same direction, otherwise they may fight against each other and prevent air from flowing properly. Failing fans. A failing fan moves less air than a properly functioning fan. It's not uncommon for a failing fan to generate a screeching noise that is caused by worn parts within the fan assembly. This condition can be fixed by replacing the failing fan. Dust buildup. Excessive dust within the system can block air flow and cause overheating. Use compressed air or an anti-static vacuum to remove dust buildup. Environmental heat. If the air temperature outside the computer is already overly warm, then the temperature inside will be overly warm as well. A properly balanced HVAC system must be implemented in the work area to remove excess heat from the environment. The internal temperature of computer systems should be monitored. Most motherboards include several sensors that can be used to monitor the system temperature. Usually, the current temperature can be viewed within the BIOS/UEFI setup. There are also software applications available that can read the current temperature values from the sensors and display them on screen. Unlike using a BIOS/UEFI monitoring utility, these tools allow the temperature to be monitored dynamically while the system is in use. Most motherboards include a thermal shutdown feature. If the system temperature rises too high, the thermal shutdown feature immediately shuts the computer down to prevent component damage. However, it typically does not shut the system down cleanly, so there is a risk of data corruption if this happens.

Driver Issues

It is important to make sure that the following driver issues are addressed when troubleshooting printers: Verify that the latest version of the driver for the specific make and model of the printer has been installed. If the incorrect driver is installed, this can lead to post-script text, garbled text, and other irregular activity. Incorrectly configured network printing often leads to users installing the wrong driver on their machine. Make sure to configure your network so that users don't have to install the driver on their machine, especially without supervision. On occasion, driver files may become corrupted. If this is the case, you should reinstall the latest version of the driver from the manufacturer's website.

Environment

Keeping printers in a clean, safe area helps prevent premature failure. An optimal printing environment includes: Keeping the printer in an area with minimal amounts of dust or other air debris will help the printer to run smoothly and will extend the life of its mechanical components. Using surge protectors will help protect a printer from the effects of power surges and spikes. Providing proper ventilation will help a printer to not overheat. Excessive heat causes electrical components to degrade rapidly. Avoid keeping printers in closets or rooms that aren't properly ventilated.

LCD (liquid crystal display)

LCDs (liquid-crystal displays) use liquid crystal technology to display visual information. LCDs are the most common type of display device and range in size from less than an inch to over 10 feet. Modern LCDs use LEDs (light-emitting diodes) to backlight the screen. Older LCD monitors and some LCD HDTVs use cold cathode fluorescent lamps (CCFLs) for backlighting. CCFLs are able to produce better colors than EL-WLED and full-array WLED technologies, but consume a lot more energy and require an internal inverter.

Lightweight Directory Access Protocol (LDAP) 389, 636

LDAP is a protocol used to access information about network resources stored by a directory service, such as Active Directory or eDirectory. LDAP uses port 389 for clear text transmissions and port 636 for secure transmissions.

Memory

Laptop memory uses SODIMM and UniDIMM packages with SDRAM and DDR/DDR2/DDR3/DDR4 memory. These modules are sometimes called MicroDIMMs. Many notebooks come with a base amount of memory built onto the motherboard and one or two additional slots. When replacing notebook memory, make sure the size of modules you purchase are supported by the system.

Latency

Latency on wireless networks can be affected by several factors. Wireless communication operates in half-duplex (shared, two-way communication). Devices can both send and receive, but not at the same time. Therefore, devices must take turns using the transmission channel. Typically, once a device begins receiving a signal, it must wait for the transmitter to stop transmitting before replying. An unstable wireless network signal can increase the processing that is performed on the signal by both the hardware and software.

Coaxial advantages

Less susceptible to electromagnetic Interference (EMI) Resistant to physical damage Large existing infrastructure

SSH

Like Telnet, the SSH utility is used for remote server management; however, SSH encrypts all communications and is much more secure. SSH can be used to remotely log onto a server and complete configuration tasks. In order to establish an SSH session, the server must have the SSH process running and configured to allow remote connections. Use the following syntax to establishing an SSH connection: ssh [username]@[server_address]

Line of Site

Line of site internet access (also called fixed wireless broadband) is similar to satellite internet; however, instead of antennas being directed to a satellite in orbit, they are pointed at a large antenna on land. The antennas use radio signals--typically microwaves--to transmit and receive data.

liquid cooling

Liquid cooling systems are used when air cooling is not sufficient. Liquid-based cooling systems are composed of tubes, cooling plates, a reservoir, and a radiator. Cooling plates have tubes connected to them and are attached to components. Liquid coolant is then circulated through the system, cooling it. Because liquid cooling can dissipate heat much faster than air cooling, it is primarily used for high-end gaming computers and high-performance systems.

check disk errors

Lost clusters are a series of used clusters on the hard disk drive that are not associated with a specific file. A cross-linked file occurs when two files claim the same cluster. Check Disk will identify cross-linked files and correct their cluster associations. Orphaned files are files that exist on the hard drive but are not associated with a directory in the index. Normally Check Disk can re-associate the file with the correct directory. A bad sector is a portion of the hard disk that cannot be used. Bad sectors are marked so that they are no longer used. Any used bad sectors are redirected to another sector.

Multiple-Input, Multiple-Output (MIMO)

MIMO increases bandwidth by using multiple antennas for both the transmitter and receiver. A system is described by the number of sending and receiving antennas. The 802.11n specifications allow up to four sending and four receiving antennas. The benefit of adding additional antennas declines as the number increases; going above 3x3 provides a negligible performance increase.

Multi-User MIMO (MU-MIMO)

MU-MIMO is an enhancement to MIMO that allows multiple users to use the same channel. In addition to adding MU-MIMO, 802.11ac doubled the number of MIMO radio streams from four to eight.

Connection Interface

Make sure that the printer you choose has an interface supported by your computer. The two most common interfaces in modern printers are USB and network interfaces.

hard disk disadvantages

Many hard disks are internal devices, though you can get external enclosures. They are prone to failure. They are vulnerable to physical damage (e.g., when dropped).

Change the Default SSID

Many manufacturers use a default SSID that contains identifying information (such as device manufacturer and model number), so it is important to change the device's SSID from the default. In addition to changing the default SSID, it is also possible to disable the SSID broadcast. This is known as SSID suppression or cloaking. With broadcasting disabled, the SSID needs to be manually entered into devices for them to connect to the network (the SSID will not show up in the list of available networks). Even with the broadcast disabled, it's relatively easy to identify the SSID of a network by using readily available applications. Because of this, SSID suppression should not be the only form of protection.

Wireless

Many printers allow you to connect using a wireless connection. This is especially useful when working with laptop computers. Bluetooth is a wireless technology for creating simple connections between two devices. Unlike infrared, line-of-sight connections are not required. 802.11a/b/g wireless standards use radio waves and are used to create wireless networks between multiple devices.

error messages

Memory error usually indicate a failing module or discrepancies between new and old memory. Avoid the latter problem by not mixing new and old memory. Ensure that the memory is functioning properly and is compatible with the system. If the memory is good and fully compatible, these error messages could mean that the motherboard has a problem. The following are some common error messages you may encounter: Memory mismatch error Memory parity interrupt at x Memory address error at x Memory failure at x, read y, expecting z Memory verify error at x

CPU socket type

Memory module compatibility Number of memory slots Maximum supported memory Expansion slot count and type Onboard devices (video, audio, or network)

star star topology

Messages are sent directly to (and only to) the destination device.

ring ring/star topology

Messages are sent from device to device in a predetermined order until they reach the destination device.

mesh mesh topology

Messages are sent from one device to the next around the ring until they reach the destination device.

bus bus/star topology

Messages are sent to all devices connected to the bus.

Print to PDF

Microsoft Print to PDF allows you to print your document to PDF format.

New Technology File System (NTFS)

Microsoft's default file system.

Mini TRS

Mini TRS ports on the sound card accept 3.5mm plugs for analog audio I/O. The number of ports on the sound card depends on the type of I/O support (e.g., the number of speaker channels, microphone, or line-in support). Ports are often labeled with text or graphics to identify its function. Standardized color coding might also be helpful in determining the proper connection. Pink = Mic in (mic-level) Light blue = Line in (line-level) Lime green = Line out (front speakers or headphones) Black = Line out (rear speakers) Orange = Line out (center and subwoofer) Although these colors are standard, be sure to consult the sound card documentation for specific details.

Mini-ITX

Mini-ITX towers are designed to house mini-ITX motherboards. They are typically smaller than microATX towers.

mission control

Mission Control is a desktop and windows management utility used to access several Mac OS features.

Mobile processors

Mobile CPUs are used in mobile computers and cell phones where portability and mobility are a concern. Special versions of processors are built to minimize power consumption and the amount of heat generated.

BNC

Molded onto the cable Used in legacy 10Base2 Ethernet networks Used in specialized industries Used to connect composite video displays on commercial video devices.

SOHO (Small office/home office)

Most SOHO networks have the following characteristics: Supports between 1-10 connected hosts (computers, mobile devices, or printers) Uses Ethernet or 802.11 wireless networking (or both) as the network medium Uses a single internet connection that is shared among all hosts Uses a single subnet Employs a workgroup networking model (i.e., there are no dedicated servers and a domain is not used)

digital audio

Most audio devices, such as stereo consoles, TVs, and speakers require analog audio. Newer devices, such as some CD players, DVD players, and HDTVs, are capable of processing digital audio signals. Digital audio support in a sound card: Allows you to play digital audio directly from an internal CD player Allows for compression of audio data to support Dolby Digital or DTS surround sound Can use fiber optic cables to eliminate electrical interference Sound cards support digital audio in the following ways: An internal connector on the sound card connects to a digital audio output connector on a CD/DVD drive. Through this connection, you can play CDs directly through the sound card. An internal connector on the sound card sends HD audio, such as from a DVD or Blu-ray disc, to an audio pass-through on a video card. This allows the HD audio signal to be combined with the video signal through an HDMI connector. Sony/Philips Digital Interface Format (S/PDIF) is a consumer standard for digital audio. These are either optical or coaxial external connectors and allow input and output between other digital audio-capable devices.

memory slots

Most motherboards have multiple memory slots. Memory slots are designed to be compatible with a specific type of memory module.

heat sensor

Most motherboards include the following heat sensors: CPU sensor (located on the circuit board underneath the processor) System case sensor (located either on the motherboard or on a cable attached to the motherboard) Room temperature sensor (usually connected to the motherboard by a cable and mounted on a case slot) Special software can monitor the temperature levels and be configured to send warnings when high temperature conditions exist. The BIOS in most motherboards can also be configured to automatically shut the system down when a specified thermal threshold is exceeded.

Networking

Most notebooks include built-in networking devices such as an Ethernet port, a modem port, wireless, Bluetooth, and/or infrared. Wireless networking capabilities are often provided by a small card that plugs into an internal mini-PCI slot (located under the keyboard or accessible through the back). The wireless antennae might be a wire that extends around the screen. You can use USB or ExpressCards to add missing or malfunctioning networking features.

USB

Most printers use a USB connection, allowing for configurations that also include scanners, external drives, or additional printers. The USB connection increases speed considerably over a standard serial or parallel port.

mv

Moves files and directories from one location in the file system to another. For example, to move the widget.odt file to the /home/rtracy directory, you would enter mv widget.odt /home/rtracy at the shell prompt.

Near Field Communication (NFC)

NFC enables communication between two devices that are in very close proximity with each other. NFC operates in the 13.56 MHz frequency and has a maximum transmission speed of 424 Kbps. Special chips called NFC chips are used to send, receive, and store data.In order to communicate, devices must be within 2 inches of each other. Data transmissions can be secured by using encryption algorithms.Even though NFC has slower transmission speeds than Bluetooth, it consumes much less power and sets up connections much faster.

NFC uses

NFC has seen widespread use in the following areas: Contactless payment (e.g., using a smart phone as a payment method) Identification (e.g., passports that contain an NFC chip) Video gaming

Near Field Communication (NFC)/ Tap Pay Device

NFC is a set of communication protocols that allows devices to communicate when they are within 1.6 inches of one another. NFC technology is most often employed between a base and a smart phone to allow Tap Pay transactions at stores and restaurants; the user places their phone within proximity of the base and uses an app to make an electronic transactions from their mobile phone. NFC is also used to share contacts, photos, videos, and documents, such as identity documents and key cards.

NLX

NLX (new low profile extended) is an old form factor that was designed for use in slimline desktop computers. NLX: Uses a detachable riser card to provide expansion slots (the motherboard itself has no expansion slots). Allows the motherboard to slide in or out of the system case easily. Was replaced by microATX and Mini-ITX.

NetBIOS

NetBIOS is the term used to describe the combination of two protocols: NetBEUI and NetBIOS. NetBIOS was used in early Windows networks. Because NetBIOS is a non-routable protocol, it was often combined with IP to enable internetwork communications. NetBIOS over TCP/IP, or NetBT, is used to allow older computers and applications that rely on NetBIOS to communicate on a TCP/IP network.

Server

Networks contain two types of hosts, hosts that consume a service, and hosts that provide a service. Hosts that provide a service are called servers. The following are some of the more common types of servers:

plug and play

Newer systems use plug and play to automatically configure the resources each device needs. Be aware of the following about plug and play: The device, the BIOS, and the operating system must support plug and play standards. All new devices and operating systems are plug and play compatible. Plug and play allows IRQ sharing and ensures that the DMA and I/O resources used by each device are unique. A legacy device is one that does not support Plug and Play. In older systems, you had to manually configure the resources used by each device. Troubleshooting legacy systems often involved finding and resolving resource conflicts. Although a plug and play system attempts to assign configuration resources around a legacy device's needs, legacy devices often interfere with a plug and play system's ability to properly assign resources.

6+2-pin PCIe

Newer video cards require more power than can be supplied through the PCI Express bus. The 6+2-pin PCIe connector plugs directly into the video card to supply additional, dedicated power. The 6+2-pin PCIe: -Provides up to 150 watts -Is also known as a PEG6+2 (PCI Express Graphics 6+2 pin) -Some motherboards only have a 6-pin PCIe connector. These connectors provide up to 75 watts.

Keyboard

Notebook keyboards are smaller than standard keyboards. Keys are often a bit smaller and closer together. Keys such as the number pad and some function keys might be left off, but are accessible by pressing a special Fn key to provide alternate functions for regular keys. You can use a USB port to connect an external keyboard; some laptops include a PS/2 port.

OLED (organic light-emitting diode)

OLED displays use a thin layer of an organic compound (called an OLED) that lights up in response to an electrical current. OLED displays are more efficient, offer a wider viewing angle, and provide faster response times (< 0.01 ms). However, they are costly to manufacture; OLEDs are the most expensive type of display device. In addition, the pixels in OLEDs (the organic compound) wears out faster than the pixels in LED or plasma displays. OLEDs can be used in any device that uses a flat-panel display. And because of their size, OLEDs can even be used in textiles (clothing and upholstery). Flexible materials can be used to create OLED screens, resulting in a bendable—sometimes even foldable—screen. These types of OLEDs are called FOLEDs (flexible OLEDs).

Dynamic Host Configuration Protocol (DHCP)

On a network configured with DHCP, IP hosts contact a DHCP server for IP addressing and other configuration information. This ensures error-free host configuration. With DHCP: The host uses broadcast messages to locate a DHCP server when it boots. The DHCP server assigns IP address and mask values to the host (called an address lease). The DHCP server ensures that no two hosts are assigned the same IP address. You can configure the DHCP server to deliver default gateway, DNS server, and other configuration information to hosts. DHCP requires a special DHCP server, which is built-in to most SOHO routers.

defragmentation

On an SSD storage device, fragmentation is much less of an issue than it is for standard hard disk drives. File systems such as NTFS still fragment files when writing them to the drive in order to optimize storage space. However, an SSD storage device doesn't have read-write heads, and no repositioning must occur to read heavily fragmented files. As a result, fragmented files can be read as quickly as contiguous files. When working with SSD drives, you should not defragment them as you do standard hard disk drives. This is because SSDs wear out over time. Each cell in a flash memory bank has a finite lifetime and can only be written to and erased a certain number of times before it fails. Running defragmentation utilities causes unnecessary write/erase operations to occur. Use Security and Maintenance in Control Panel to disable automatic disk defragmentation on SSD storage devices.

TRIM

One method for extending an SSD device's life is to enable TRIM functionality. TRIM configures the operating system to communicate with an SSD device and to tell it which blocks of data on the device are no longer required and can be wiped clean. This prevents the SSD device from storing unnecessary data and being overused. Later versions of Windows should automatically detect the presence of an SSD device and enable TRIM. You can verify this by opening a command window and entering fsutil behavior query DisableDeleteNotify. This command will return either a 0 or a 1. A value of 0 indicates that TRIM is enabled, but a value of 1 indicates that it is not. If it is disabled, you can manually enable TRIM on an SSD drive by entering fsutil behavior set DisableDeleteNotify 0.

Intermittent problems

One of the tougher detection challenges is the intermittent occurrence of error messages, crashes, or sudden reboots. The trouble in diagnosing this situation is the number of potential problems, including timing, heat, corrosion, fluctuating power, loose connections, EMI, or a combination of these problems.

Open

Open authentication requires that clients provide a MAC address in order to connect to the wireless network. You can use open authentication to allow any wireless client to connect to the AP. Open authentication is typically used on public networks. You can implement MAC address filtering to restrict access to the AP to only known (or allowed) MAC addresses.Because MAC addresses are easily spoofed, this provides little practical security.

operating system RAID

Operating system RAID uses RAID features within the operating system. Like software RAID, the system CPU is used for RAID operations, but performance is typically better than software RAID because of integration with the operating system.

optical disk

Optical discs such as CDs, DVDs, and Blu-ray discs are a storage medium that uses lasers for both reading and writing information. Optical discs store information through pits in their reflective coating. As the disc spins, the optical drive sends laser optics to the disk and receives the stored information through the deflected output.

distended capacitors

Over time, the capacitors on the motherboard may become overstressed or overheated.

distended capacitors

Over time, the capacitors on the motherboard may become overstressed or overheated. When this happens, they may bulge or even begin to leak fluid. Distended capacitors usually fail at some point, causing the motherboard to fail. For example, if the fans in the power supply spin up when you power on a system, but the motherboard itself doesn't start, it is possible that capacitors on the motherboard have become distended. If this happens, inspect the motherboard and look for capacitors that are swollen on top or leaking brown liquid. While it is possible to carefully replace a failed capacitor on the motherboard, it is usually faster and more cost-effective to replace the entire motherboard.

overclocking

Overclocking is pushing a CPU beyond its designed specifications. Overclocking can give you a marginal increase in performance, but will decrease your CPU's life. Some Intel processors include a Turbo Boost feature. Turbo Boost, the opposite of throttling, allows the processor to dynamically run above its rated speed to improve performance. Unlocked processors are processors whose speed can be changed above their rated speed through overclocking. With overclocking, you increase the speed and often the voltage to increase the performance of the processor. Overclocking typically voids the CPU warranty and could lead to shorter component lifetimes. Some multi-core processors (such as a triple-core CPU) have additional cores that have been disabled. With the appropriate motherboard support, you might be able to unlock and use the additional core(s). However, stability of the extra cores is not guaranteed.

Peripheral Component Interconnect (PCI)

PCI was developed to replace the obsolete ISA and VESA bus standards. PCI: Is processor independent, meaning the CPU and PCI bus can process concurrently Supports plug-and-play, meaning installed devices are detected and configured automatically Is used most commonly by devices such as sound cards, modems, network cards, and storage device controllers Can run at 33 MHz and transfer data at 133 MBps or run at 66 MHz and transfer data at 266 MBps

PCI Express (PCIe)

PCIe was developed to replace PCI, PCI-X, and AGP. Instead of a shared bus, each PCIe slot links to a switch that prioritizes and routes data through a point-to-point dedicated connection and provides a serial, full-duplex method of transmission. PCIe uses several different connection types. PCIe types are defined by the number of transmission lanes that are used to transfer data. For example, PCIe x1 provides one lane for transmission (x1), while PCIe x16 provides sixteen lanes for transmission. PCIe defines x2, x4, x8, x16, and x32 connection types. PCIe data rates depend on the protocol version and number of transmission lanes: 1.0: 250 MBps (x1); 4 GBps (x16) 2.0: 500 MBps (x1); 8 GBps (x16) 3.0: 1 GBps (x1); 16 GBps (x16) 4.0: 2 GBps (x1); 32 GBps (x16) In addition to greatly increased speed, PCIe offers higher quality service. PCIe can run alongside legacy PCI technology (e.g., both PCIe and PCI buses can be in the same system). PCIe x1 slots are typically used for network cards, USB cards, and sound cards. PCIe x16 slots are primarily used for dedicated video cards. PCIe cards are cross-size compatible, as long as the slot size is the same or larger than the card size. For example, a PCIe x1 card can be installed in a PCIe x16 slot, but a PCIe x16 card cannot be installed in a PCIe x1 slot.

Post Office Protocol 3 (POP3) 110

POP3 is part of the IP protocol suite and used to retrieve email from a remote server to a local client over an IP connection. With POP3, email messages are downloaded to the client.

parity ram

Parity memory is a type of memory that checks for common kinds of internal data corruption. It does not correct internal data corruption. Non-parity memory does not perform error checking. Parity RAM is no longer used. Today, PC systems use ECC for error detection and correction.

Parity

Parity requires that you have at least three storage devices. This option uses parity information to reconstruct data if one of the storage devices fails. Parity uses less space for redundancy than the mirror options, but performance is not as good as the mirror options if a device failure occurs. Parity requires only 50 percent more redundancy space than storage space.

test page

Perform a test print from the workstation. Open an application and try to print directly from the application. If this does not work, access the printer properties in Devices and Printers and then click Print Test Page. This option bypasses the application. If it works, troubleshoot the printing configuration in the application. Perform a test print from the printer console. If successful, the problem is with the workstation or the connection to the printer. If unsuccessful, the problem is with the printer itself.

plasma disadvantages

Plasma displays consume two to three times as much power as LCDs. They generate much more heat than other display types. The gasses inside the cells are sensitive to air pressure fluctuations. Plasma displays also suffer from a problem known as image retention (IR). Static images that are displayed for a long time cause the phosphors to overheat, which creates a temporary shadow of the image that is visible even when the display is turned off. If the static image was displayed for too long, screen burn-in can occur, and the shadow image will be permanent.

plasma

Plasma displays use millions of small cells that contain electrically charged ionized gases. When electrical current is applied to a plasma cell, the gas within the cell forms a plasma and emits a photon of light. Each pixel in a plasma display is made up of a red, green, and blue cell. As with OLED monitors, plasma monitors don't require a backlight.

plasma advantages

Plasma displays usually display colors more accurately than LCD displays. Because no backlighting is used, plasma displays have high contrast and can produce true black (displays that use backlighting can only display very dark grey). Plasma displays have almost no motion blur due to the speed of the gas reaction and the way they draw frames. Because of this, most plasma displays do not specify response times.

One of the main jobs of the BIOS/UEFI is to help start the system. The following process is used when you turn a computer on:

Power is supplied to the processor. The processor is hard-coded to look at a special memory address for the code to execute. This memory address contains a pointer or jump program which instructs the processor where to find the BIOS program. The processor loads the BIOS program. The first BIOS process to run is the power-on self-test (POST) process. POST does the following: Verifies the integrity of the BIOS/UEFI code. Looks for the BIOS on the video card and loads it. This powers the video card and results in information being shown on the monitor. Looks for BIOS programs on other devices, such as hard disk controllers and loads those. Tests system devices, such as verifying the amount of memory on the system. After POST tests complete, the BIOS identifies other system devices. It uses CMOS settings and information supplied by the devices themselves to identify and configure hardware devices. Plug-and-play devices are allocated system resources. Then the BIOS searches for a boot drive using the boot order specified in the CMOS. On the boot device, the BIOS/UEFI searches for the master bootloader, then loads the bootloader program. At this point, the BIOS/UEFI stops controlling the system and passes control to the bootloader program. The bootloader program is configured to locate and load the operating system. As the operating system loads, additional steps are taken to load all additional programs and configure devices for use by the operating system.

Power over Ethernet

Power over Ethernet (PoE) technology is used to distribute electrical power along with network data on twisted-pair Ethernet cabling (CAT 5 or higher). Power is usually supplied by a PoE-enabled Ethernet switch. PoE is commonly used to power network devices that are located where physical access to a power outlet may not be available. For example, a PoE-enabled surveillance camera mounted on a tall pole can be powered via its Ethernet cabling. You can use a Power over Ethernet (PoE) injector to add PoE capability to regular non-PoE network links. PoE injectors can be used to upgrade existing LAN installations to PoE and provide a solution where fewer PoE ports are required. To upgrade a network connection to PoE, patch it through the PoE injector. Power injection is controlled and automatic.

power issues

Power supplies wear out over time, especially if they're overheated or overstressed. If the power supply can't provide adequate amounts of electricity to the system, the computer may exhibit one of several behaviors: It may unexpectedly shut down. It may continuously reboot itself. It may not power on at all. Pin 8 on the power supply connector connects to the power good wire on the motherboard. If power disappears off that wire, the motherboard shuts down. If power quickly reappears on that wire, the system may attempt to come back on by itself, resulting in continual reboots. If power does not reappear on this wire, then the system will shut off. For example, a failing power supply may not provide enough voltage on this wire for the system to initially boot up. If these symptoms are observed, test the power supply to determine if it's the source of the problem. Turn the power supply on and then test the voltage supplied on either a motherboard connector or on a hard disk connector. If the voltage is less than expected, then the power supply may be at fault. For example, if a 12 volt wire is carrying less than 11 volts, the power supply is probably failing. If this is the case, do the following to rectify the issue: Purchase a new power supply. Remove the old power supply from the system Mount the new power supply. Connect the new power supply to the motherboard and to all other internal devices. Power the system on and verify that the symptoms have been eliminated.

Print Speed

Print SpeedPrint speed is expressed as the number of pages that can be printed in a minute (PPM or pages per minute). Printers often rate both the black and white and color print speeds.

Print Drivers

Print drivers allow you to utilize the following configuration settings: Duplex allows you to print on both sides of a sheet of paper. Collate organizes and orders a document into separate sets. Orientation allows you to change the orientation of the paper so you can print in both portrait and landscape. Quality lets you modify the print quality of the text and images on the paper.

Print Quality

Print quality is often measured in dots per inch (DPI). The higher the DPI, the higher quality the image.

Print to Image

Print to Image allows you to print any document into an image file that is independent of the application you use to view them. For example, you can convert a Word document into a .jpg file. The resulting images are print-ready and optimized for websites, smart phones, and tablets. You can also print them on a physical printer for excellent printouts.

Print to XPS

Print to XPS allows you to create .xps files using any program that you can print from in Windows. Use the Microsoft XPS Document Writer when you want to view, save, share, digitally sign, and protect your document's content.

Memory

Printers can improve performance by having significant built-in memory. Additional memory improves performance and reduces the processing load on computers. In some cases, you can add or upgrade the memory in a printer.

Additional Features

Printers can include additional features such as: Additional paper sizes Double-sided (duplex) printing Document or sheet feeders Built-in scanners, copiers, or faxing capabilities Automatic collation or stapling Color printing Built-in network support Built-in hard drives or memory for storing and recalling printed documents

speed

Processors operate using an internal clock that is the same as, or is a multiple of, the motherboard bus speed. The speed is represented in megahertz (MHz) and is also referred to as the frequency. You can purchase processors of the same type but with different speed ratings. When selecting a processor, make sure the motherboard supports the processor speed by reading the motherboard documentation first. Most motherboards automatically detect the processor speed. If not, you might need to use jumpers or edit the CMOS to configure the processor speed.

projector

Projectors are display devices that use light to project display output onto a wall or screen. Projectors are often used in classrooms and meetings to display information for a large audience. The brightness of light from projectors and other output devices is measured in lumens. Projectors may use light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), or other hardware.

4-pin mini-Molex

Provides both 5 and 12 volts and is used by floppy drives

Remote Desktop Protocol (RDP) 3389

RDP allows you to view and use the graphical desktop of a remote computer system as if you were sitting in front of it.

RGB-LED

RGB-LED displays have an array of special LEDs that are able to emit red, green, and blue light, resulting in superior color accuracy. RGB-LED displays are the most expensive type of backlighting technology.

eSATA facts

Removable storage devices are typically connected through eSATA or USB. A hard drive enclosure allows you to connect a SATA hard drive to the USB port of your computer, making the hard drive a form of portable storage. eSATA cards offer simple connectivity between a host computer and eSATA devices. And remember that you also have the option to use expansion cards as needed.

line of site requirements

Requires a direct line of site between two fixed antennas. A single, large antenna provides connections for all subscribers in an area Provides internet access without needing to run cables or lines to each subscriber's premise Can provide internet to remote areas by installing a single antenna Ss affected by weather conditions, similar to satellite networking Offers speeds of up to 1520 Mbps

System crashes on startup or when running a software application or certain group of applications:

Run repetitive tests using diagnostic software. After replacing a seemingly faulty CPU and the symptom remains, run similar tests on the motherboard and chipset. Do not forget to check for a corrupt file in the software.

SATA power

SATA devices use a special 15-pin power connector that supplies 3.3, 5, and 12 volts. You can use an adapter cable to convert a 4-pin Molex connector to a SATA power connector, but if you do, the resulting cable will not have 3.3 volts (3.3 volts are typically not used in most SATA devices).

SATA1

SATA1 is the original SATA standard. It provided for 1.5 Gbps (150 MBps) data transfer.

Secure FTP (SFTP) 22

SFTP addresses one of the key weaknesses of FTP; namely, FTP doesn't use encryption. All data, including usernames and passwords, is sent clear text. SFTP provides the same functionality as FTP, but secures the data transmissions using the SSH protocol.

Service Location Protocol (SLP) 427

SLP is a protocol that is able to organize and locate various network devices and services, such as printers, shared disk drives, directories, etc.

Server Message Block (SMB) 445

SMB enables the sharing of folders and printers on the network. Using SMB, remote users can access files in a shared folder on a server or workstation. Likewise, a remote user can send print jobs to a shared printer. SMB is also known as Common Internet File System (CIFS). SMB running directly over TCP uses port 445. SMB running on "NetBIOS over TCP/IP" uses UDP ports 137 & 138 and TCP ports 137 & 139.

Simple Mail Transfer Protocol (SMTP) 25

SMTP is used to route electronic mail through the internetwork. Email applications provide the interface to communicate with SMTP or mail servers.

Simple Network Management Protocol (SNMP) 161, 162

SNMP is used to monitor and manage network devices. SNMP agents can be installed on network devices such as PCs, switches, and routers. These agents send data to an SNMP manager application running on an administrative workstation, which aggregates the information and displays an overview of the current network status. Thresholds can be configured which trigger alerts if exceeded.

Static RAM (SRAM)

SRAM stores data using four transistors for every bit of data. SRAM does not require constant power to maintain the contents of memory. SRAM is more complex and less dense (e.g., lower storage capacity) than DRAM. SRAM is faster and requires less power than DRAM. Regular SRAM still requires periodic power to maintain the state of memory, but the rate of refresh is less than with DRAM. Non-volatile SRAM (nvSRAM) is able to maintain memory contents when the power is turned off. SRAM is typically used in cache memory, such as CPU cache, hard disk cache, and cache in networking devices.

Secure Shell (SSH) 22

SSH allows for secure interactive control of remote systems. SSH is a much more secure alternative to Telnet.

Satellite

Satellite networking uses radio signals sent and received from a satellite. Satellite networking is divided into two categories, Geostationary Satellites (GEOs) and Low Earth Orbit Satellites (LEOs).Some satellite internet access solutions are limited to download only. Another solution, such as dial-up, is required to provide upload capabilities.

SATA

Serial ATA (SATA) is computer bus technology primarily designed for the transfer of data from a hard disk. SATA: Uses serial communication (meaning each device is on its own channel). Provides built-in support for disk protection methods. Provides for easy configuration. Just connect the device to the SATA port. Has an L-shaped connector. Supports external devices through the external SATA (also called eSATA) standard. eSATA is faster than USB.

Image missing, doesn't fill the screen, skewed, or cut off

Set the display resolution to the monitor's native resolution. If the display isn't visible at all, check the monitor's brightness settings to verify that the screen isn't dimmed.

HDD slow performance

Several things can help increase the performance of a slow HDD: Maintain a healthy amount of free disk space on the drive. A mostly empty disk runs faster than a mostly full disk. If a disk is getting full, migrate to a newer, bigger disk. Keep the disk defragmented. A heavily fragmented disk can run quite slowly. You'll need ample free space to fully defragment the drive. Check the disk rotational speed. A disk that spins faster will perform better. Check the speed of the disk interface. If your system uses an older disk interface, upgrade to a faster interface (if possible).

STP

Shielded twisted pair (STP) has a grounded outer copper shield around the entire wire bundle or around each wire pair. STP provides additional EMI protection, but costs considerably more than UTP.

shutdown

Shuts down or reboots the system in a secure manner. The syntax of the shutdown command is shutdown -h|-r +m message. The options for the shutdown command include: +m specifies when to perform the shutdown operation. m is the amount of time is specified in minutes. -h instructs the system to shut down and power down. -r instructs the system to reboot after the shutdown. -p powers off the machine. message specifies a message that is sent to all users that accompanies the standard shutdown notification.

signature pad

Signature pads are used to obtain signatures for transactions and agreements. The user uses a stylus on a touch screen to sign his or her name. The signature is captured and stored digitally. Signature pads are commonly used in retail stores and restaurants.

signed drivers

Signed drivers are drivers that include a digital signature. The digital signature proves that the driver: Comes from the reported publisher. Has not been altered or modified.. Is compatible with the operating system version Drivers that have passed specific tests on Windows qualify for the Certified for Windows logo and are given a special digital signature. An unsigned driver is one without a digital signature; a self-signed driver is one that includes a digital signature, but the identity of the entity that signed the driver cannot be verified. You can install unsigned or self-signed drivers.

Cat 5e

Similar to Cat 5 but provides better EMI protection. Supports gigabit Ethernet (gigabit connections require the use of all four twisted pairs)

simple resiliency

Simple, which does not provide redundancy. This option simply adds space from the storage pool to the storage space. When you select the Simple option, all of the data in the storage space is lost if one of the drives fails.

single or double sided

Single-sided RAM has memory modules that are organized into a single logical bank; double-sided RAM has modules organized into two banks. The computer can access data in only one bank at a time. Therefore, single-sided RAM allows access to all of the memory, while with double-sided RAM, the computer must switch between banks. Originally, double-sided RAM had modules on both sides of the circuit board, and single-sided RAM had modules on only one side. However, you can also have double-sided RAM with modules on only one side, where the memory is divided into separate banks internally. Single-sided memory of the same capacity as double-sided memory uses half the number of memory modules (modules are denser, with a higher individual capacity). Some older motherboards are unable to use double-sided memory, while some that allow double-sided memory can use only up to half the total memory when all memory slots are filled, or mixing single- and double-sided together might not be allowed. Most motherboards support both single- and double-sided memory. However, verify compatibility before purchasing.

Enable NAT

Small networks use a single public IP address to connect to the internet. This IP address is shared by all devices on the private network. Network address translation (NAT) is a protocol that allows multiple computers to share a single public IP address used on the internet. The internet is classified as a public network. All devices on the public network must have a registered IP address. This address is assigned by the ISP. The SOHO network is classified as a private network. All devices on the private network use private IP addresses internally, but share the public IP address when accessing the internet. A NAT router associates a port number with each private IP address. Communications with the private hosts from the internet are sent to the public IP address and the associated port number. Port assignments are made automatically by the NAT router. The private network can use addresses in the following ranges that have been reserved for private use (i.e., they will not be used by hosts on the internet): 10.0.0.0 to 10.255.255.255 172.16.0.0 to 172.31.255.255 192.168.0.0 to 192.168.255.255

Bulb

Smart bulbs normally work with conventional lighting fixtures and bulb holders. That makes them easy to implement. They also come with wireless communication capabilities packed inside. Some of them use built-in Wi-Fi or Bluetooth which lets them communicate directly with your phone or tablet, eliminating the need for a hub or control device. There are even some higher-end bulbs that change colors, track motion, stream audio over Bluetooth, or double as connected cameras. On a small scale, that kind of plug-and-play simplicity is very convenient, but smart bulbs tend to be expensive so scaling up could be difficult depending on your budget. Also, smart bulbs won't work if the light is switched off; they're only smart when they're turned on.

Plug

Smart plugs automate anything with a plug on it. You can remotely turn on and off anything that's plugged into them using an app. They are an easy solution to making small appliances such as lamps, coffee makers, and toasters smart.

Speaker/Digital Assistant

Smart speakers/digital assistants work in the following way: Smart speakers use voice recognition software. Once they're on, smart speakers listen to all speech, waiting for what is known as a 'wake word' or 'hot word'. When they recognize this word, they begin to record your speech and send it over the internet. The speech file is sent to a voice recognition service in the cloud. The voice recognition service deciphers the speech and sends a response back to the smart speaker. The voice recognition service uses algorithms to familiarize itself with your way of speaking and choice of words. You can also send feedback to the voice recognition service about the accuracy of the responses that the smart speaker provides. When first setting up a smart speaker you are required to do a 'voice training' in which you read 20 to 30 key commands to your device and the voice recognition service starts to learn your speech patterns. Machines' ability to recognize speech is a complex process, especially when considering the huge variety of different speech patterns. But the simplified explanation of the process is recognizing sections of words known as 'phones'. Those phones build into 'phonemes' which can then be recognized as individual words.

Thermostat

Smart thermostats learn from your habits and schedule, give you the freedom to control the climate in your home remotely, show you energy consumption in real-time, and can even adjust themselves depending on ambient conditions like humidity.

Software RAID

Software RAID uses a driver and the system CPU for controlling RAID operations. This is the slowest form of RAID. Some RAID controller cards support RAID configuration, but without the onboard RAID processor. These solutions are classified as software RAID (sometimes called fake RAID) even though you install a controller card to provide RAID capabilities. Many motherboards include built-in (onboard) support for RAID. RAID implemented in this way is typically software/driver RAID. Software RAID uses a driver and the system CPU to control RAID operations. This is the slowest form of RAID.

Software-generated memory problems

Software errors include: Registry error - Parts of the registry are written to faulty sections of RAM. Exception error - A software bug can cause this type of error. General-protection fault - A software bug can cause this type of error. Page fault - A software bug can cause this type of error. For software errors, check to see if the memory address indicated in the error is consistently the same. If so, check the memory. Otherwise, reboot the system or update the software.

Program or system lockup, system crashes, slow video performance

Software or system problems can be caused by incorrect video settings, especially for programs that have high video demands. To correct the problem: Update the video card drivers. Decrease the video acceleration settings. This decreases the amount of processing done by the video card.

Solid Ink

Solid ink printers melt ink onto the print head (which is as wide as the paper). The head jets the melted ink onto the paper as the paper passes by on the print drum (similar to the laser printing process). Solid ink printers offer the following advantages: Simple design Excellent print quality Easy set up and maintenance The head takes as long as 15 minutes to heat prior to printing.

RAID Facts

Some RAID controllers support combined levels of RAID. For example, RAID 0+1 is a striped array that is mirrored. Other combined configurations that might be supported include RAID 1+0 (also called RAID 10), RAID 5+0, and RAID 5+1. For all RAID configurations, the amount of disk space used on each disk must be of equal size. If disks in the array are of different sizes, the resulting volume will be limited to the smallest disk. Remaining space on other drives can be used in other RAID sets or as traditional storage. While some RAID configurations provide fault tolerance in the event of a disk failure, configuring RAID is not a substitute for regular backups.

High Disk Usage

Some operating systems send data to the hard disk drive if there is not enough physical memory available. If you hear the hard drive constantly operating as you work, or if the hard drive light on the front of the system case stays illuminated for long periods of time, you may need to add more physical memory to the computer.

Wireless On/Off Switch

Some portable devices have a physical wireless switch on the outside of the device. The wireless switch turns the device's integrated wireless network adapter on and off. When in the off position, no wireless networks are displayed as available.

Network

Some printers also have their own network interface card, which allows them to connect directly to a network. Network printers can also be connected to a computer that is connected to the network. Another way to connect a non-network-ready printer to a network is with a network interface device. Network printers are useful for allowing multiple people to share the same printer. This is a common way to connect printers used in a business environment.

disk safety

Some recordable discs use a foil placed on the top of the disc instead of imbedding the foil inside the plastic. Be very careful when working with these types of discs. A scratch or even some types of markers can damage this layer.. To help prevent scratching, keep the disc in its case when not being used. To minimize the effect of scratches that might be generated while wiping a disc, wipe the disc in straight lines from the center to the edge (like the spokes of a wheel). Keep the disc away from direct sunlight and other sources of heat.

Risers

Some small form factor cases (e.g., microATX and Mini-ITX towers) use riser cards for installing expansion boards. Riser cards are installed in an expansion slot and allow the expansion board to be installed parallel to the motherboard, instead of perpendicular

IEEE 1394

Some sound cards include one or more IEEE 1394 (FireWire) ports. These ports function as normal IEEE 1394 ports.

Multi-GPU

Some video cards can be linked together and share the graphic processing load between the two GPUs. Multi-GPU configurations are manufacturer-specific: NVIDIA uses SLI (Scalable Link Interface). AMD uses CrossFire. Video cards are linked using a special bridge clip or through software (depending on the implementation). The motherboard and each video card must use the same connection method (SLI or CrossFire). The motherboard must also have multiple PCIe x16 slots. In most cases, both video cards must be identical. Some motherboards allow you to link an integrated graphics controller with a video card installed in the expansion slot; however, this offers a negligible performance boost.

bus support

Sound cards can be installed via an expansion slot (e.g., PCI or PCIe x1) on the motherboard. When selecting a sound card, make sure the bus type is compatible with your motherboard. Most new motherboards have an onboard sound card.

spotlight

Spotlight is an indexing utility that can perform system-wide searches to locate folders, files, apps, and internet results that contain the specified search phrase. Spotlight is access pressing Command(⌘)+Spacebar or by selecting the Spotlight icon on the Status menu.

standard ATX power supplies

Standard ATX power supplies provide + 3.3 volts, +/- 5 volts, and +/- 12 volts of DC power. Most modern components require +12 volt output.

4-pin 12 V (P4) power

Starting with the Pentium 4 (P4) processor, CPUs required more power than could be provided through the ATX power plug. The 4-pin 12 V connector: -connects to the motherboard -provides two dedicated 12 V wires to the CPU (older processors only used 5 V power) *The 4-pin 12 V CPU connector is not the same as the 20+4-pin ATX power connector.

bash

Starts a new Bourne-again shell (bash) session.

storage space

Storage spaces are logical drives that display in File Explorer for storing data and other user files. Storage spaces are created by pooling space from multiple disk drives, or other storage devices, and then creating logical drives from the pooled space. A storage space appears to the user as one drive regardless of the number of disks or devices contributing space to the storage pool. The storage spaces feature is available only in Windows 8.x and 10; it is not included in Windows 7.

Data Resiliency

Storage spaces can include data resiliency. Choosing an option that provides resiliency requires you to allocate space for redundant information. The options for storage spaces data resiliency include: simple, Two-Way Mirroring, Three-Way Mirroring, and parity.

creating storage space

Storage spaces eliminate the need for such tasks as repartitioning drives, resizing volumes, and backing up data in order to repartition. When you need more disk space for your storage spaces, follow these steps: Install a new storage device to the system. Add the free space on that device to a storage pool. Allocate space to an existing storage space.

Cat 5

Supports up to 100 Mbps Ethernet.

switch facts

Switches use the MAC address to send frames to the destination device. Switches can operate in full-duplex mode, where a device uses a different channel for sending and receiving and where the transmission paths are dedicated to only the communicating devices. You should use a switch instead of a hub in every situation. Many switches allow you to configure Quality of Service (QoS) settings, which prioritize certain types of network traffic over others. For example, if your network includes Voice over IP (VoIP) telephones, you could increase the priority of VoIP traffic on the switch to increase call quality. You must configure a switch before you implement it. An unmanaged switch is a low-end switch that you plug it into a power outlet and connect your network devices with UTP cables. While unmanaged switches are convenient and easy to implement, they lack many of the advanced management and security features available. It is preferable to use a managed switch instead. A managed switch is a switch that must be configured before you can use it.

other failing CPU symptoms

System will not boot. System boots, but the operating system fails to load. System has POST parity problems with a number of devices.

TCP/IP

TCP/IP is the protocol suite used on the internet and on most networks. Nearly all computers today use TCP/IP for communication. The Internet Protocol (IP) is a key component of the TCP/IP protocol suite. The IP protocol is responsible for determining how to deliver data from the sending host to the destination host. However, it does not provide a mechanism for segmenting and sequencing packets in a communication. To accomplish this, IP is used in conjunction with another transport protocol:

LCD TN panels

TN (twisted nematic) panels are the most common technology used by LCDs. TN panels have very good response times (1-5 ms) and refresh rates (60-144 Hz), so are great for PC gaming. TN panels have imperfect color reproduction because only six bits per color can be displayed. They mimic true 24-bit color using dithering and other techniques. TN panels have poor viewing angles and contrast ratios.

Tablets

Tablet devices use a touchscreen interface instead of the touchpad and keyboard used by notebook PCs. The touchscreen interface is usually capacitive, meaning that it requires conductive material, such as your finger tip, for input. Capacitive touchscreens provide multi-touch capabilities, which allow the tablet to recognize multiple finger touches at the same time.

Remote Terminal Emulation (Telnet) 23

Telnet allows an attached computer to act as a dumb terminal, with data processing taking place on the IP host computer. It is still widely used to provide connectivity between dissimilar systems. Telnet can also be used to test a service by the use of HTTP commands. You should avoid using Telnet as it transmits all data (e.g., usernames and passwords) clear text.

terminal

Terminal is Mac OS's command line interface utility. It is similar to the terminal used in Linux systems. Terminal: Uses many of the same commands as the Linux terminal. Can be used to perform system management tasks, such as deleting files, changing permissions, etc. Is an excellent troubleshooting tool.

Tethering

Tethering is connecting one device to another. In the context of mobile phones and tablet computers, tethering allows sharing the internet connection of the phone or tablet with other devices like laptops. Connection of the phone or tablet with other devices can be done over wireless LAN (Wi-Fi), over Bluetooth, or by physical connection using a cable like USB.

Channel Interference

The 2.4 GHz frequency range is divided into 11 channels, with each channel having some overlap with the channels next to it. You might experience problems with your wireless network when other devices are trying to use the same or adjacent channels. There are also numerous devices that operate in the 2.4 GHz and 5 GHz ranges, which can create background noise and additional interference. Cordless telephones that operate in the 2.4 GHz range (900 MHz cordless phones do not cause interference) Other APs in the area (for example, each of your neighbors might have a wireless network, with each configured to use a similar channel) Microwave ovens Bluetooth devices Wireless game controllers To avoid interference, try changing the channel used on the AP. If the area has different wireless networks, configure each with a different channel, with at least two channels separating the channels in use (e.g., channels 1, 6, and 11). The strength of your Wi-Fi signal compared to the level of background noise is known as the signal-to-noise ratio (SNR). If the SNR is low, your wireless network will have problems with interference.

24-pin (20+4 pin) ATX connector

The 24-pin ATX power plug supplies power to the motherboard. -Some 24-pin connectors have one 20-pin plug and 4-pin plug (detachable)/ this allows for backwards compatibility with 20-pin motherboards. -You can plug a 24-pin ATX power plug into a 20-pin motherboard connector, leaving the four pins unconnected. *Older motherboards used 20 pin power plugs. With a 24 pin ATX power plug, the four extra pins supply an additional 3.3, 5, and 12 volts of DC power.

Basic Input/Output System (BIOS)

The BIOS is a legacy program stored in a read-only memory (ROM) chip that the CPU automatically loads and executes when it receives power. Important things to know about the BIOS are: The BIOS program controls the startup process and loads the operating system into memory. The BIOS is firmware. You should frequently check for BIOS updates from the manufacturer. Updating the BIOS (called flashing the BIOS) makes new features available, such as allowing the BIOS to recognize newer hardware devices. Most BIOS chips vary from 265 KB to 1 MB in size. Video cards include a BIOS chip on the device. These devices have their own ROM chip called an option ROM (OpROM).

BTX

The BTX (balanced technology extended) form factor was designed as a replacement for the ATX form factor. However, it did not gain widespread adoption. With BTX: The CPU is positioned in such a way that air flow is increased. There is no heatsink fan. Instead, a thermal module or shroud fits over the CPU to move heat directly out of the system. The back panel orientation and mounting location is reversed. BTX was implemented mainly by computer manufacturers such as Dell. Computer cases are designed to fit motherboard form factors. The following table describes

CMOS battery

The CMOS battery is used to keep an accurate date and time, even when the motherboard has no power. In older motherboards, the CMOS battery was also used to retain BIOS configuration settings, which were stored in volatile memory called the CMOS chip.

CPU socket

The CPU socket houses the CPU. There are a variety of CPU socket types, each of which have unique shapes, pin arrangements, or mounting configurations. Because of this, it's important to match the motherboard socket type with the processor socket type. Some motherboards support multiple processors and have a socket for each CPU.

DNS Server

The DNS server address identifies the DNS server that is used to resolve host names to IP addresses.

dock

The Dock is the main taskbar in Mac OS. The Dock is used to launch apps, switch between running apps, access the Trash, and access specific folders. Dock settings can be accessed in System Preferences or by right-clicking the Dock and selecting Dock Preferences.

Electrically Erasable Programmable Read-Only Memory (EEPROM)

The EEPROM is a RAM chip that replaced the CMOS chip. Important things about EEPROM are: EEPROM is a type of non-volatile memory used in computers and other electronic devices to store relatively small amounts of data. EEPROM allows individual bytes to be erased and reprogrammed. EEPROM replaced EPROM chips and are used for computer BIOS built after 1994. EEPROM chips allow you to update the BIOS/UEFI in your computer without having to open the computer and remove any chips.

exFAT

The Extended File Allocation Table (exFAT, sometimes called FAT64) file system is a special file system that is designed to support large flash drives. Using NTFS on flash drives is usually not a good idea due to its high overhead and risk of corruption if the device is not stopped properly prior to removal. However, many flash drives exceed the 32 GB limit discussed above. Microsoft introduced native exFAT support in Windows 7 to allow large removable flash storage devices to continue to use a FAT-type file system.

Failed

The Failed status shows for a volume that cannot be started, such as when the disk is damaged or the file system is corrupt. Make sure the disk is on and then try reactivating the volume. If that doesn't work, then you likely have data loss.

Formatting

The Formatting status is shown for volumes during the formatting process. After formatting is complete, the status for the volume changes to Healthy.

Healthy or Online

The Healthy or Online status indicates that the disk is turned on and can be accessed. The volume on the disk is valid and has no errors.

Home Network

The Home network location is designed for use on networks where you know and trust each device on the network. With the Home network location: Network discovery is enabled. This means other computers and devices on the network are able to see and connect to each other. Connected devices are able to join the network homegroup. The Windows firewall configuration is changed to allow certain types of network communication through. Because this network location is the least secure, select this location only if you know all the devices and people that are connected to the network.

IP Address

The IP address identifies both the logical host and the logical network addresses. Each host on the entire network must have a unique IP address. Two devices on the same subnet must have IP addresses with the same network portion of the address. Two devices on the same subnet must have unique host portions of the IP address. Do not use the first or the last host address on a subnet address range.

ITX

The ITX form factor was designed for low-power, small form factor (SFF) computers. The most common ITX form factor is the Mini-ITX form factor. The Mini-ITX form factor: Specifies a maximum motherboard size of 6.7" × 6.7" Has only one expansion slot Allows for small (100 watt) power supplies Is typically used with a home theater PC (HTPC) Other ITX form factors include the following: Nano-ITX (4.7" × 4.7") Pico-ITX (3.9" × 2.85") Mobile-ITX (2.9" × 1.7")

Initializing

The Initializing process shows while a disk is being converted from a basic disk to a dynamic disk. After the conversion, the status for the volume changes to Healthy.

Missing Offline

The Missing or Offline statuses show when a dynamic disk has failed, been removed, or turned off. If the disk is turned off, turn it back on, then reactivate the disk. If the disk no longer exists, then delete the disk from Disk Management.

No Media

The No Media status shows for an optical or removable media drive that does not contain a valid disc. This disk status only applies to CD-ROM, DVD-ROM, or removable disks.

Not Initialized Unknown

The Not Initialized or Unknown status indicates a disk without a valid master boot record or partition table (either missing or corrupt). To correct the problem, initialize the disk. If the partition table is invalid, use third party tools to try to recover the partition table.

Online (Errors)

The Online (Errors) status indicates that I/O errors have been detected on a dynamic disk. To correct the problem, try reactivating the disk.

The system boots, but the memory count is incorrect

The POST failed to recognize all of the memory. This can happen with incompatible memory installation. Remember to avoid combining dual-bank with single-bank memory. If any problem is detected during system boot, check the BIOS settings. The system will check only for memory installed in memory slots on the motherboard. Memory that is on expansion cards or installed on other devices will not be counted and tested.

Public Network

The Public network location is designed for use on unknown or public networks (e.g., a coffee shop or other public Wi-Fi network). With the Public network location: Network discovery is disabled. This means other computers on the network cannot see you and you cannot see them. Network sharing, such as printers and scanners, is disabled. The Windows firewall configuration is changed to block almost all inbound and most outbound communications. For applications to be able to communicate, they need to be manually allowed through the firewall. The Public network profile should be used when connecting to any unknown network location, such as a hotel's Wi-Fi network.

4-pin peripheral power

The SATA power connector has 15 pins and provides 3.3, 5, and 12 volts. As its name implies, it powers SATA devices. You can use a special adapter to convert a 4-pin peripheral power connector to a SATA connector. When using an adapter, or on some power supplies, the connector supplies only 5 and 12 volts.

SATA power connector

The SATA power connector has 15 pins and provides 3.3, 5, and 12 volts. As its name implies, it powers SATA devices. You can use a special adapter to convert a 4-pin peripheral power connector to a SATA connector. When using an adapter, or on some power supplies, the connector supplies only 5 and 12 volts.

Service Set Identifier (SSID)

The SSID, also called the network name, groups wireless devices together into the same logical network. All devices on the same network must use the same SSID.

Telnet

The Telnet utility is used for remote server management. The Telnet protocol must be running and configured on the remote server in order for a Telnet session to be established. By default, Telnet does not encrypt transmissions (they are sent as clear text). Telnet is mostly used by specialized industrial and scientific devices. In addition to sending transmissions in clear text, there are several well-known vulnerabilities in the Telnet protocol. Because of this, Telnet should not be used when sending sensitive information.

Unified Extensible Firmware Interface (UEFI)

The UEFI was designed to replace the BIOS. Important things about UEFI are: The UEFI is firmware. The UEFI program controls the startup process and loads the operating system into memory. The UEFI design improves the software interoperability and the address limitations of BIOS. The UEFI provides better security to protect against bootkit (malware attacks on the boot process) attacks. The UEFI provides faster startup times. The UEFI supports drives larger than 2.2 terabytes. The UEFI supports 64-bit firmware device drivers. The UEFI is compatible with both BIOS and UEFI hardware. You should frequently check for UEFI updates from the manufacturer. Updating the UEFI (called flashing the UEFI) makes new features available.

USB 3.0 micro B

The USB 3.0 Micro-B connector is used by portable devices, such as compact external storage devices, digital cameras, or smart phones.

USB 3.0 Type B

The USB 3.0 Type-B connector is larger in size and designed to carry both data and power. Due to their increased size, USB 3.0 Type-B connectors cannot be plugged into older USB Type-B ports. However, USB 3.0 peripherals that use this port are able to accept older USB Type-B connectors.

Unallocated

The Unallocated status shows for portions of a disk that have not been assigned to a partition or a volume.

Unavailable

The Unavailable status indicates that errors have occurred on physical or dynamic disks.

Unreadable

The Unreadable status indicates a hardware failure, I/O errors, or other corruption but might also be caused by a delay in reading the disk in Disk Management. Try rescanning the disk to see if the status changes. If it doesn't, troubleshoot the hardware or disk problem.

Configure Wi-Fi Protected Setup (WPS)

The WPS security protocol makes it easier for WPS-enabled devices (e.g., a wireless printer) to connect to the wireless network. WPS can use several methods for connecting devices, including the PIN method and the push button method. The method used to connect devices must be supported by both the access point and the wireless device. Because of the inherent security vulnerabilities with WPS, it is best to disable this feature on the access point.

Work Network

The Work network location is designed to be used in a SOHO environment or other small business network. With the Work network location: Network discovery is enabled; however, the computer is unable to create or join a homegroup. The Windows firewall configuration is changed to allow certain types of network communication.

NTFS Benefits

The ability to format larger partition sizes in Windows. Smaller cluster sizes for more efficient storage with less wasted space. File and folder permissions to control access to files. Encryption to hide the contents of a file. Compression to reduce the amount of space used by files. Disk quotas to restrict the amount of disk space that files saved by a user can use. Volume mount points that allow you to map disk space on another partition into an existing volume.

Multitasking

The ability to run multiple applications simultaneously

Multithreading

The ability to run multiple parts of an application simultaneously

Multiprocessing

The ability to use multiple processing devices

IP version 6 (IPv6) features

The address is made up of 32 hexadecimal numbers organized into 8 quartets (for example, 35BC:FA77:4898:DAFC:200C:FBBC:A007:8973). The quartets are separated by colons. Each quartet is represented as a hexadecimal number between 0 and FFFF. Each quartet represents 16 bits of data (FFFF = 1111 1111 1111 1111). Leading zeros can be omitted in each section. For example, the quartet 0284 could also be represented by 284. Addresses with consecutive zeros can be expressed more concisely by substituting a two colons for the group of zeros. For example: FEC0:0:0:0:78CD:1283:F398:23AB FEC0::78CD:1283:F398:23AB (concise form) If an address has more than one consecutive location where one or more quartets are all zeros, only one location can be abbreviated. For example, FEC2:0:0:0:78CA:0:0:23AB could be abbreviated as: FEC2::78CA:0:0:23AB or FEC2:0:0:0:78CA::23AB, but not FEC2::78CA::23AB

USB 3.0 Type A

The blue tab indicates that the connector is a USB 3.0 Type-A connector and capable of USB 3.0 speeds. USB 3.0 Type-A connectors are backwards compatible with all previous USB versions.

CD-RW wright facts

The bottom surface of a CD-RW drive is coated with a photo reactive crystalline coating. A red laser causes a crystal to form which creates the reflective and non-reflective areas on the bottom of the CD-RW disc. A CD-RW drive has a second, high power write laser. When this laser hits the bottom of this photo reactive material on the bottom of the CD-RW disc, it causes crystals to form. This is called phase shifting or a phase shifting media. A crystal forming on the bottom of a CD-RW disc is like a land on a CD-ROM disk, because it reflects light.

capacity

The capacity (sometimes called the size) refers to the storage capacity of the memory module (e.g., 256 MB, 512 MB, 1 GB). The total capacity of memory that you can install in your system is limited by: The number of memory slots on the motherboard. The maximum total capacity that can be installed. For example, most systems will have a maximum capacity of between 3 GB and 16 GB of RAM. The maximum module capacity. For example, the motherboard might only be able to accept up to 2 GB or 4 GB modules. The maximum amount of memory that can be addressed (used) by the operating system. A 32-bit operating system can use between 3 GB and 4 GB of memory, while a 64-bit operating system can use more. You can install more than 4 GB of memory in a system that uses a 32-bit operating system; however, the operating system will be able to use only between 3 GB and 4 GB of that memory. If your motherboard had a total of three slots, with a maximum module size of 1 GB and a system maximum of 3 GB, and if you had two 512 MB modules installed, you would be able to add only a single 1 GB module bringing the total up to 2 GB. You could also replace one or both of the 512 MB modules bringing the total to 2.5 or 3 GB respectively.

fiber optic components

The central core carries the signal. It is made of plastic or glass. The cladding maintains the signal in the center of the core as the cable bends. The protective layer provides a stiff structure to prevent the cladding and central core from breaking. The plastic sheath encases everything and protects the cable.

Configure the Channel

The channel identifies the portion of the wireless frequency used by the access point and connected devices. You should use a channel that does not overlap or conflict with other access points in the area. A simple rule to minimize conflicts is to remember that the frequencies used by channels 2-5 compete with the frequencies used by channels 1 and 6, while the frequencies used by channels 7-10 compete with the frequencies used by channels 6 and 11. Many access points have an automatic channel feature that detects other access points and automatically selects the channel with the least amount of traffic.

chipset

The chipset is a group of chips that facilitates communication between the processor, memory, and peripheral devices. With chipsets: The memory controller and graphics controller are on the CPU. The remaining functionality is combined into a single controller chip. Intel processors use the Platform Controller Hub (PCH). AMD processors use the Fusion Controller Hub (FCH). The front-side bus is replaced by the Direct Media Interface (DMI).

Cleaning

The cleaning phase prepares the drum by removing the previous image printed. It uses a rubber cleaning blade to remove any excess toner on the drum and then it scrapes off the debris into a debris cavity. Next, a heat roller is lubricated to ensure that enough heat will be evenly applied to transfer the next image printed. Then an electrostatic erase lamp neutralizes the electrical charges that remain on the drum from the previous printed image.

print process

The client application generates the print job on the local system. This process is known as spooling. The print job is sent to a print queue. The queue is a location for storing waiting print jobs. A print server is responsible for managing the flow of documents from the queue to the printer. When the printer is ready, the print server takes the next document out of the queue and sends it to be printed.

PCI Express (PCIe)

The connector that replaced PCI, PCI-X and AGP.

Kernel

The core of the operating system that is loaded into memory when the system boots up.

Default Gateway

The default gateway identifies the router to which communications for remote networks are sent. The default gateway address is the IP address of the router interface on the same subnet as the local host. Without a default gateway set, most clients will be unable to communicate with hosts outside of the local subnet.

Developing

The developing roller applies toner to the drum. The toner sticks to the charged areas on the drum.

eSATA

The eSATA (external SATA) standards are a subset of other standards specifically for externally connected devices. eSATA devices use a special SATA data cable with a locking clip to prevent the cable from being accidently disconnected. Because power is not supplied through the SATA data cable, eSATA devices require an external power connector or power source. eSATA is typically faster than USB. eSATA has a rectangular connector.

eSATAp

The eSATAp (Power over eSATA or Power eSATA) standards are meant to replace eSATA. eSATAp combines the functionality of an eSATA and a USB port with a source of power in a single connector. Both SATA data and device power are integrated in a single cable. The eSATAp connector and port are neither an L-shaped or rectangular.

Utilities

The features or programs included with an operating system that perform system-related tasks.

firmware

The firmware on a motherboard is stored on integrated flash memory. Motherboards use one of two firmware implementations: BIOS (Basic Input/Output System) UEFI (Unified Extensible Firmware Interface) Older motherboards stored the BIOS on removable, read-only memory (ROM) chips.

Prefix of IPv6 address

The first 64 bits are known as the prefix. The 64-bit prefix can be divided into various parts and each part has a specific meaning. Parts in the prefix can identify the geographic region, the ISP, the network, and the subnet. The prefix length identifies the number of bits in the relevant portion of the prefix. To indicate the prefix length, add a slash (/) followed by the prefix length number. Full quartets with trailing 0s in the prefix address can be omitted (for example, 2001:0DB8:4898:DAFC::/64). Because addresses are allocated based on physical location, the prefix generally identifies the location of the host. The 64-bit prefix is often referred to as the global routing prefix.

Fusing

The fusing assembly attaches the toner to the paper using rollers that press and melt the toner to the paper. As the paper leaves the printer, a static eliminator strip removes the static charge from the paper.

processing capabilities

The graphics processing unit (GPU) handles all video rendering tasks. GPUs are much more efficient at processing graphic data than a traditional CPU. Using the GPU to render graphics is often referred to as video hardware acceleration. Settings in the operating system can be used to control how much video processing is offloaded to the GPU. GPUs have a clock speed that is rated in MHz. A higher speed means better performance.

Hostname

The hostname identifies the logical name of the local system.

coaxial components

The inner conductor carries data signals and is made of solid copper or tin. The insulator surrounds the inner conductor and keeps the signal separated from the mesh conductor. It is made of PVC plastic. The braided mesh conductor is a second physical channel and also functions as a ground. It is made of aluminum or copper-coated tin. The sheath is made of PVC plastic and encases the cable, protecting it from external elements.

Internet

The internet is a large, world-wide, public network. The network is public because virtually anyone can connect to it, and users or organizations make services freely available on the internet. Users and organizations connect to the internet through an internet service provider (ISP). The internet uses a set of communication protocols (TCP/IP) for providing services. Individuals and organizations can make services (such as a website) available to other users on the internet.

interface ID of IPv6

The last 64 bits are the interface ID. This is the unique address assigned to an interface. Addresses are assigned to interfaces (network connections), not to the host. Technically, the interface ID is not a host address. In most cases, individual interface IDs are not assigned by ISPs, but are rather generated automatically or managed by site administrators. Interface IDs must be unique within a subnet, but can be the same if the interface is on different subnets. On Ethernet networks, the interface ID can be automatically derived from the MAC address. Using the automatic host ID simplifies administration.

AP Placement

The location of the AP can affect signal strength and network access. Keep in mind the following: With omnidirectional antennas, radio waves are broadcast in each direction, so the AP should be located in the middle of the area that needs network access. Devices often get better reception from APs that are above or below. In general, placing APs higher up prevents interference problems caused by going through building foundations. For security reasons, APs should not be placed near outside walls. The signal will emanate beyond the walls. Placing the AP in the center of the building decreases the range of the signals available outside of the building.

Determine Best Access Point Placement

The location of the access point can affect signal strength and network access. Keep in mind the following recommendations: Place access points in central locations. Radio waves are broadcast in each direction, so the access point should be located in the middle of the area that needs network access. Place access point to take advantage of the fact that devices often get better reception from access points that are above or below. In general, place access points higher up to avoid interference problems caused by going through building foundations. For security reasons, do not place access points near outside walls. The signal will extend outside beyond the walls. Placing the access point in the center of the building decreases the range of the signals available outside of the building. Do not place the access point next to sources of interference, such as other wireless transmitting devices (cordless phones or microwaves) or other sources of interference (motors or generators).

Printer Port

The means by which a print device connects to a print server (the printer's NIC). Many printers can be configured in the same way that most plug-and-play devices are.

flash devices advantages

The memory is re-programmable. They can retain content without power. They are optimal for use in devices like cameras. They are highly portable. They have a larger capacity than CDs and DVDs. They have relatively fast memory access.

SDD slow performance

The more an SSD is used, the slower the read/write speed will be. Make sure the file system being used is optimized for an SSD. Because SSDs store data differently than HDDs, they require special techniques to extend the life of the drive, such as wear leveling support. Update the SSD's firmware. Newer firmware versions are released to fix bugs and optimize how the SSD stores data. Run a manufacturer-specific SSD software utility. Most SSD manufacturers have specialized utilities that can check for errors and optimize an SSD's performance. Check the speed of the SATA connection. Older SATA versions have slower transfer speeds than newer SATA versions. If performance is too slow, consider upgrading components to the latest SATA version. When the SSD is too full, performance will decrease significantly. If this happens, try enabling features such as TRIM support in the OS. While features such as TRIM will help to an extent, the best way to maintain high performance is keeping an SSD below 90% capacity.

Laptop Components

The most common portable components used with laptop systems are keyboards, mice, digitizer pads, and antennae. The following list suggests troubleshooting methods to use when working with these components: A bad keyboard can be tested by plugging in an external keyboard to your laptop and seeing if it works. If it does, you can assume that your laptop keyboard is malfunctioning and needs to be replaced. Most laptop systems have features that cause keyboard keys to perform alternate functions, such as emulating 10-key functionality by turning on the NUM LOCK. Before troubleshooting other problems, make sure that no special features are enabled that may cause keys to perform alternate tasks. Sometimes the NUM LOCK indicator lights don't correctly correspond to the NUM LOCK's function state. Some power saving modes don't support indicator light function. Sometimes you must press the F LOCK key with the NUM LOCK key for it to respond. If neither of these is the case, the computer probably isn't properly maintaining the NUM LOCK state and may have damaged components. Mouse malfunction on a laptop is usually caused by the installation of an incorrect driver. Good indicators that the incorrect driver has been installed are if the laptop mouse's sensitivity isn't consistent or if the mouse doesn't recognize a double tap. A digitizer pad is used in laptop and PDA systems to receive input. Input is written onto the pad with a stylus pen, then those motions are transferred into data that is processed by the system. If this pad becomes scratched, the laptop or PDA cannot receive input correctly. This is most easily resolved by buying a cleaning product called Screen Clean. This product removes the top layer of plastic from the digitizer pad, thus removing existing scratches and giving the pad a fresh surface. However, you will need to replace the digitizer pad or buy a new system if the scratch is too deep. Another problem that digitizer pads face is called pointer drift or ghost cursor. Drift occurs when a pad's pressure sensors need to be realigned. If this is the case, your digitizer pad needs to be recalibrated. It is always best to address this issue before it progresses to the point that you can't access the recalibration utility. Though laptop antennae are supposed to be omni-directional, they sometimes need to be re-oriented to get the best reception. This can usually be done by moving the laptop until the reception picks up. If redirecting the antennae doesn't work and wireless reception is consistently poor, the antennae may need to be replaced. Many laptops include a switch that turns the wireless network card on and off. When troubleshooting wireless network connectivity, make sure the switch is turned on. If your speakers are not producing sound, begin troubleshooting by making sure the volume is turned all the way up and your speakers or headphones are connected correctly. Make sure your sound card works properly and is running with updated drivers. If that doesn't fix the issue, run the Windows Audio Troubleshooter program. If none of these solutions work, you may have damaged hardware components that need to be replaced. As long as your laptop runs, you can substitute an external device connected to a PS/2, USB, PCMCIA, or ExpressCard slot for most failed components, allowing you to continue using the computer.

Incorrect Configuration

The most common source of problems with wireless networking is incorrect configuration. Before considering other problems, verify that the correct SSID and WEP/WPA keys have been configured. Remember that WEP/WPA keys are not case sensitive, but passphrases are case sensitive. In the case of a standalone (or thick) configuration, make sure each individual AP is properly configured. With a controller-based (or thin) configuration, make sure each AP can communicate with the wireless controller. A similar form of an incorrect configuration is trying to access a wireless network that uses one standard (e.g., 802.11a) with a wireless card that supports a different standard (802.11b or 802.11g).

Media

The networking medium provides the path for signals to pass between devices. Copper cables use electrical signals. Fiber optic cables use light pulses. Wireless networks use radio waves or infrared waves. Networking media that use cables are considered bounded, because the transmission signals are contained within the wire. Networks that use wireless communications are considered unbounded.

Print Device

The physical device connected to the print server where print output occurs.

Print Queue

The portion of the hard drive where print jobs are stored before going to the print device.

Charging

The primary corona prepares the photosensitive drum for writing by causing it to receive a negative electrostatic charge. Depending on the printer, the primary corona will be wires or rollers.

Print Server

The print server is a software process that takes print jobs from the queue and sends them to the print device. A single print server services all print queues and print devices. To edit the print server properties do the following in Windows 10: Select Start. Select Settings. Select Devices. Select Devices and Printers. Select Print Server Properties. Edit the print server properties to: Add ports and modify the port for any printer Manage print drivers used on the system, including drivers required by network users Configure printing notifications Change the drive and directory used for all print queues (spooler location) on the system

Use a Print Server

The print server manages the flow of documents sent to the printer. Using a print server lets you customize when and how documents print. The print server can be any one of the following devices: An internal print server is inside the printer itself. You use special management software to connect to the print server and manage print jobs. You can configure a computer (either a server or a workstation) to perform print server functions. The computer can fill other roles on the network in addition to being the print server. Most operating systems include print server software. You can purchase an external print server. This device is used only as a print server, although many print servers can manage multiple printers.

Connect the Printer to the Network

The printer must have a connection to the network (either wired or wireless). This can be done in one the following ways: Install a network interface card in the printer. Connect the printer to a workstation or server that is connected to the network. The printer is shared to make it available to other computers. Connect the printer to a special print server that has a network connection. Use Bonjour networking technology service to allow you to share a printer on your local area network. Use AirPrint to enable wireless printing capability on Apple iOS devices. Use Google Cloud Print to wirelessly send jobs from internet-connected devices to a remote printer. If the printer itself does not have a network connection, use the USB port to connect the printer to another device.

Processing

The printer receives a document to be printed from the connected computer and converts it into a bitmap raster image, which is divided into horizontal raster lines.

Formatting

The process of preparing a partition to use a specific file system.

process size

The process size refers to the manufacturing process used to etch transistors onto the silicon wafer that will become the CPU. A smaller process size means smaller transistors, which translates into a smaller CPU die with more transistors and less power consumption. Process size is expressed in microns (such as .25 microns) or nanometers (90 nm which equals .09 microns).

display quality

The quality of images and animations is determined by both the video card and the external display. When selecting a video card, the following specifications should be considered: The resolution is the number of pixels displayed on screen. A higher resolution means that more information can be shown on the screen. A video card is rated by its max resolution, which is the highest possible resolution it can display (e.g., 1920 × 1080 or 4096 × 2160). The refresh rate is the number of times in one second that the GPU draws a frame. Refresh rates are measured in hertz. A refresh rate of 70 Hz or lower may cause eye fatigue. An optimal refresh rate is between 75 Hz and 85 Hz. For optimal image quality and graphic performance, it is best to select a display that matches the video card specifications, and vice versa.

sampling rate

The sampling rate is the number of analog signal samples taken in over a period of time. Sample rates are expressed in cycles per second, called hertz (1,000 hertz (Hz) = 1 kilohertz (kHz)). A high sampling rate gives a more accurate representation of the sound. Examples of different sampling rates include: 8 kHz (telephone) This is adequate for conversation because the human voice's full range is about 4 kHz. 22 kHz (radio quality). 44 kHz (CD quality) This sample rate can accurately reproduce the audio frequencies up to 20,500 hertz, covering the full range of human hearing. 48 kHz (Digital TV, DVD movies). 96 kHz (DVD audio). 192 kHz, used by: LPCM (Linear Pulse Code Modulation), a DVD-music production format. BD-ROM (Blu-ray Disc-ROM). Higher sample rates require more bits of data per sample. 8-bit sound cards use a sampling size of 256. 16-bit sound cards use a sampling size of 65,536. 20-bit sound cards use a sampling size of 1,048,576. 24-bit sound cards use a sampling size of 16,777,216. 32-bit sound cards use a sampling size of 4,294,967,296. The bit portion of a sound card's sampling size does not correspond with the bus size.

SATA2

The second generation of SATA devices support up to 3 Gbps (300 MBps). SATA2 includes the following enhancements: Xbox360 hard disk interface (called xSATA) Hot pluggable support, allowing drives to be added and removed while the system is running Improved connectors to reduce ESD, improved usability, and extended life when used with external devices Native Command Queuing (NCQ) for increased performance Port multiplier support, allowing multiple devices to be connected to a single SATA port

Proccessing

The second stage of the computing process, in which the computer analyzes information input by the user.

Print Driver

The software that allows the printer to communicate with the print device. Printer drivers provide the following support functions: Translate data into a recognizable form for the given printer Manage graphics via graphics drivers, converting graphics into the appropriate printer commands Allow management of the print job by displaying print and printer properties in the operating system

ATX

The standard ATX form factor is the form factor that all other variants are modeled after. ATX motherboards: Measure 12" × 9.6" Have up to seven expansion slots Have between six and nine mounting holes Extended ATX (EATX) The EATX form factor is the largest ATX variant. EATX: Measures 12" × 13" Typically uses extra space for additional memory slots microATX The microATX form factor is a smaller version of the ATX form factor. The microATX form factor: Measures 9.6" × 9.6" Has four expansion slots

Subnet Mask

The subnet mask identifies which portion of the IP address is the network address and which portion is the host address. Two devices on the same subnet must be configured with the same subnet mask.

Soft Off

The system appears to be off. This state is comprised of a full shutdown and boot cycle.

Mechanical Off

The system is completely off and consumes no power. The system returns to a working state only after a full reboot.

Network

The term network often describes a computer system controlled by a single organization. This could be a local area network at a single location or a wide area network used by a single business or organization. If two companies connected their internal networks to share data, you could call it one network. In reality, however, it is two networks, because each network is managed by a different company.

SATA3

The third generation of SATA devices support up to 6 Gbps (600 MBps). This standard mainly addresses solid state drives with SATA (hard disk drives are not capable with sending data at this rate). The standard includes new connectors for solid state devices and thin optical drives.

Transferring

The transfer roller charges the paper to attract the toner.

Configure a Mount Point

The volume with the empty folder must be formatted with NTFS. You can create mount points on basic or dynamic volumes. The folder on the source volume must be empty. The target partition must not have a drive letter. Using a mount point is the only solution to adding space to the system volume using space on a different disk or non-contiguous disk space.

Working

The whole system is usable. Unused save power in a low power state.

flash devices disadvantages

Their storage capacity is not yet comparable to the capacity of modern hard disks. Different memory card formats require different readers

internal connectors

There are a number of connectors on motherboards for components such as power supplies, fans, and LED lights. Computer cases often have front panel ports (e.g., USB, FireWire, or audio ports) that need to be connected to the motherboard. These ports are connected to the motherboard's front panel connectors, which are also called headers. External ports that are not available on the motherboard are often added using expansion cards.

Scrambled or distorted images, blank screen

These problems are typically caused by improper resolution settings or settings outside the scope of the monitor. Always set the resolution to the display's native resolution. If necessary, upgrade the monitor to allow for higher resolutions.

Solid State Drive (SSD) advantages

They are faster than hard drives. They have no moving parts. They have lower power consumption than hard drives (good for laptops). They are less susceptible to physical damage (from dropping) and immune from magnetic fields. They are smaller and lighter than hard drives

optical disk advantages

They are great for music and video (they play in audio or video devices that aren't computers). They are portable and universal. They are cheap. You can buy discs that are recordable. They have a long shelf life and are relatively sturdy. Blu-ray discs can store a large amount of data (25 GB or more, depending upon the format).

optical disk disadvantages

They are slower than hard disks. They have a small capacity (650 MB for CDs, 4.7 GB for DVDs). There are some compatibility issues between disc formats and readers.

Hard disk advantages

They have lots of storage (starting at 16 GB up to several TB). They are significantly faster than floppy disks. The cost per MB is cheap.

Thin Provisioning Idealism

Thin provisioning is based on the premise that not all users will use all of space in their allocated storage space. Space is added to a user's storage space as the user consumes space.

Thin Provisioning

Thin provisioning or overbooking allows you to allocate larger storage spaces than the disk space available in the pool. If a storage space runs out of disk space, it will immediately unmount, leaving any I/O processes vulnerable to data corruption. An unmounted storage space must be brought back online manually. Files can be accessed after the storage space is brought back online manually, but you must add more physical disk space to the pool and add it to the storage space in order to use the storage space.

miniUSB

This connector is used by portable electronic devices, such as digital cameras and some portable storage devices.

Blurry images, strange color tints

This problem is often caused by a weak or corrupt signal from the video card. Make sure the monitor cable is securely fastened to the video card. Check for bent or missing pins.

Geotracking

Geotracking is the ability to identify a person's current physical location by obtaining GPS data from their smart phones or other GPS-enabled devices.

Launcher

Launcher is the name for the part of the GUI that lets users customize the home screen (the phone's desktop), launch mobile apps, make phone calls, and perform other tasks on Android devices.

Device Locator

Many smart phones and tablets have a device location feature to locate a lost or stolen device. This feature is usually a proprietary service specific to the device manufacturer; however, there are also third-party apps that offer location services. If the service has been set up on a device, the owner can use a website or software application to identify the approximate location of the device on a map. The service can also tell the device to take a picture with both the front and back cameras, then send the pictures to you. This can further help identify the device's exact location.

Firewalls

Use a firewall to inspect network traffic and to allow or block traffic based on a set of rules.

Interface

What allows the user to interact with the kernel and the utilities

Wireless Network Card

Wireless network cards might be integrated onto the motherboard, or added through add-on cards. Mini-PCI or mini-PCIe slots are used to add devices such as a wireless card. Some card slots might be accessible through a panel on the bottom, or underneath the memory or the hard drive. Otherwise, you will typically need to remove the keyboard and the palm rest, or the rest of the case, to get at the expansion slots. Wireless cards require an antenna. Connectors on the card connect to the antenna, which is usually a wire routed into the lid and around the display. Be sure to reconnect both the antenna and keyboard connectors when reassembling.

Hotspot

A hotspot is a physical location where you can obtain wireless internet access using a wireless local area network (WLAN) with a router connected to an internet service provider.

VPN

A mobile virtual private network (mobile VPN) provides mobile devices with access to network resources and software applications on their home network when they connect using other wireless or wired networks.

Sleep (Modern Standby)

Able to switch from a low-power state to a high-power state quickly.

Device Management

In addition to policies, mobile devices can be secured by using special Mobile Device Management (MDM) tools, which allow for remote management of multiple mobile devices. By using an MDM tool, an IT administrator can: Test configuration settings before deploying them. Create and enforce mobile device security policies. Remotely wipe mobile devices. Push OS updates to devices. The specific MDM you use depends on the mobile device's operating system. iOS devices use the Apple Configurator tool. Windows Mobile devices use the Microsoft Intune tool, which is a cloud-based mobile management app. Android devices can be managed using a variety of free or paid third-party MDM tools, including the Microsoft Intune tool.

Processor

Processors built especially for laptop computers have lower power consumption requirements and produce less heat than desktop processors. On most systems, you can configure the processor to use a lower bus speed when running from battery power, thereby conserving battery life. Many mobile processors are capable of automatic throttling to turn off extra cores or reduce the speed to conserve energy. Processors do not have the large heat sink and fan combinations to dissipate heat. Rather, heat is controlled by minimizing power consumption and small fans that draw away heat.

Fiber S/PDIF (pic)

The S/PDIF port is used to send a digital audio signal to high-end audio devices such as home theatre systems or Dolby Digital surround sound systems

Processor

The processor is typically located underneath the keyboard. Remove the keyboard to expose the processor. Some notebooks have processors soldered onto the motherboard. On these systems, you will not be able to upgrade or replace the processor. Because of the limited space in a notebook case, the processor uses a heat pipe to pull heat towards the side of the case where a small fan can vent the heat from the case.

Hibernate

The system appears to be off. Power consumption is at the lowest level. Volatile memory is saved to a hibernation file to preserve the system state. Some components are powered so the computer can wake from keyboard, LAN, or USB input.

Touchpad

The touchpad takes the place of a mouse. The most common problem for the touchpad is that the mouse cursor is not controlled properly based on where you press. In this case, recalibrate the touchpad. Some notebooks recalibrate the touchpad at every system boot. Reboot the computer, making sure not to press the touchpad during startup. Most notebooks include a utility for calibrating the touchpad. Run the utility and follow the instructions to recalibrate. A tablet PC with a touch screen might also need to be recalibrated periodically. If you need to replace the touchpad, it is typically connected to the palm rest which is part of the inside case. You will need to remove the keyboard and the palm rest to replace the touchpad.

Screen Locks

To secure access to a mobile device, such as a tablet or smart phone, configure the device's lock screen to use some sort of authentication. Several different types of lock screen authentication methods include: Swipe lock. Most mobile devices are configured to use a swipe lock screen. This means that anyone can unlock the device with a simple swipe of the screen; there's no authentication at all. For obvious reasons, this is not very secure. Biometric locks. The two most common biometric locks are fingerprint and facial recognition. With fingerprint recognition, the finger of the user is scanned and used to unlock the device. With facial recognition, the device's camera is used to scan the user's face and unlock the device. PIN. A PIN allows a user to enter the correct four or six numbers in order to unlock the mobile device. Pattern Unlock. Pattern unlock allows the user to create a line pattern on a nine point grid, used to unlock a mobile device. Passcode. Passcode authentication uses a user-defined password to unlock the device. The password can be a mix of letters, numbers, and symbols

Architecture

Two computer architectures are used by mobile devices: x86: The x86 architecture is compatible with standard x86 PC hardware and software, which allows the device to run operating systems such as Windows. Some newer versions of Android can also run on the x86 architecture. ARM: Some tablets, such as the iPad, use the ARM architecture. ARM is more power-efficient and less expensive to manufacture than x86. Android runs primarily on ARM.

Keyboard Problems

When experiencing problems with the keyboard: Cleaning the keyboard might correct stuck keys or keys that will not display a character when typed. If numbers type instead of letters (such as 1 for J, 2 for K, etc.), make sure that the Num Lock is turned off. If the keyboard doesn't work, you can connect an external keyboard to continue using the system until the keyboard is replaced.

thunderbolt

a port that transmits both video and data on the same port and cable. The port is shaped the same as the DisplayPort and is compatible with DisplayPort devices.

storage device

devices that contain no volatile memory

Hardware

the physical parts of a computer

network and communication

the practice of connecting two or more computers for the flow of data.

output

the process of the computer presenting, displaying data

Audio Jack

used to send or receive audio signals. used a 3.5 mm TRS connectors to connect audio devices

No Display

A mobile device's display can stop working for a several reasons. If you are troubleshooting a mobile device with a display issue, consider the following: Make sure the device is fully charged and powered on. It is possible that the device is powered off or the battery is drained. Check the device's brightness level. If the brightness level is too low, it may appear as though the display is off. Look at the screen in a dark room to make sure this isn't the case. Find out if the device was dropped. When a mobile device is dropped, it is possible for the screen to be damaged, even if there is no physical damage. Look for physical damage. If the screen is cracked or the device has physical damage, the display is most likely broken and needs to be replaced. If your device is displaying but won't cast to an external device, such as a television, make sure both devices are using updated versions, have permission to connect to other devices, and have paired correctly. Use online forums to search your symptoms and find solutions for your specific devices or contact the devices' manufacturers for support.

Driver

A type of computer program that enables the operating system to interact with hardware devices.

additional video

Additional problems with laptop displays include: Dead Spots - Dead spots are areas on your screen (sometimes entire rows or columns of pixels) that no longer work. This means that your LCD assembly is no longer functioning and you will need to replace it. Be aware that it is often cheaper to purchase a new laptop computer than to replace the display. Bad Backlight - A bad backlight may cause a display to become dim. It is important to note that dimming the backlight is a power saving method used by laptop computers to conserve power, so you should always verify that this isn't the cause for a dimmed screen before choosing to replace the backlight. Flickering Screen - A flickering screen can be caused by a faulty backlight or inverter. Replacement parts can be purchased from your laptop's manufacturer. If you know that your LCD needs to be replaced but you don't have the resources to buy a new LCD or a new laptop, you can consider converting your laptop into a desktop system by hooking it up to an external monitor permanently. If the video card is bad, you might be able to use a remote solution, such as Remote Desktop, to connect to the laptop from an external system.

OS Updates and Patches

Always keep the device's operating system up-to-date. Hackers are constantly trying to find new ways to exploit various technologies, and mobile devices are no exception. These exploits can be anything from relatively harmless adware to dangerous Trojans that take complete control of a device. The way a device receives an update depends heavily on the type of mobile device, the manufacturer, and, if it's a smart phone, the cellular carrier.

Accelerometer

An accelerometer is also called a g-sensor. It detects a tablet's physical movements by measuring its linear acceleration in one dimension. The user interface can be automatically rotated to portrait or landscape mode, depending on the unit's orientation.

App Scanner

An app scanner is a tool that can be used to identify problems with installed apps. When installed, the app scans all installed apps on the mobile device and uses a definitions list to identify any issues. App scanners can be configured to automatically scan the mobile device on a specified schedule. Because app scanners use a definitions list to identify problems, it is important that the list is always kept up to date.

Authenticator Applications

An authenticator application is a specialized app called an "authenticator." The app is pre-set by you to work with the service and provides a constantly rotating set of codes that you can use to utilize two-factor authentication or verification. The codes in authenticator apps sync across your accounts and provide an extra layer of security. For example, implementing two-factor authentication on your Gmail account would require you to use your username, password and one of the generated codes from the authenticator apps to log in to your Gmail account. It may take a little longer to log in, but it provides you with an added layer of security.

Device Encryption

Another line of defense that can be implemented, and is used by default on most new devices, is encryption. Encryption prevents someone from accessing the stored information in any capacity. This means even if someone got a hold of a device and were somehow able to copy the contents of the device, they wouldn't be able to view any of the information. It would be encrypted. There are two types of encryption methods used by mobile devices: Partial device encryption. With this method, only the sections of the device's storage that contain files are encrypted. This type of encryption is fast, but it doesn't encrypt deleted files, which can be recovered using special software. Full device encryption. This method encrypts every single sector of the device's storage, regardless of whether it has data or not. This protects the entirety of the device, including deleted files. If a mobile device doesn't encrypt contents by default, it's important to make sure that full device encryption is enabled and configured.

Trusted vs. Untrusted Apps

Applications for mobile devices can be placed into two categories: trusted and untrusted. Trusted apps are those that have been reviewed and approved by the device's app service. When approved, the app is signed with a certificate that identifies it as a trusted app. For the most part, this means the app is safe to install and does not contain malicious code. Untrusted apps are those that have not been verified and approved by the app service. While it's possible that an untrusted app could be entirely safe, it's just too risky to install one. In fact, most devices won't allow them to be installed by default. Software for mobile devices should be restricted to trusted app stores such as Google Play, the Microsoft Store, or Apple App Store.

Unauthorized Access

Because smart phones connect to so many networks, it is possible for someone unauthorized to access your data, mobile device account, location, camera, and microphone. There are several things you can do to mitigate this risk: Data: your phone is a unique vulnerability because it is so portable--it is very easy for someone to steal. In addition to protecting your data with basic security practices like locking your phone with a strong password, be aware of data theft from the inside as well. Mobile phones are computers that hackers can access using the same methods they use for desktop and laptop computers. Any financial, personal, or sensitive information on your phone is equally vulnerable, if not more so. Many social media applications allow third-party app developers to collect and sell information about their users. Account: share your mobile device account information only with authorized vendors and people who share your mobile device plan. Carefully select who to share a mobile phone plan with. Ensure they have proved themselves honest and trustworthy because when you share a mobile phone plan, you share a lot of personal information. If you suspect a plan provider's employee has accessed your account without authorization, contact your provider and explain your concerns as soon as possible. Location: any time you turn on your cell phone's GPS tracking ability, you make yourself vulnerable to unauthorized location tracking. To mitigate this risk, turn the GPS location feature off when you aren't using GPS navigation and be wary of apps that ask to track your location, especially if they don't need to track your location to perform their function. Camera and microphone: be wary of any app that accesses your camera and microphone, especially if it doesn't need to access those features to function. If your camera and microphone are hacked, anything visual or auditory data your phone collects becomes accessible to the hacker.

Biometric Authentication

Biometric authentication is a type of authentication that relies on the unique physical characteristics of individuals to verify their identity for secure access. Some mobile devices support biometric authentication on lock screens. The two most common ones are fingerprint and facial recognition.

Bluetooth

Bluetooth is a wireless technology standard for exchanging data over short distances from fixed and mobile devices and for building personal area networks (PANs). It can connect several devices, overcoming problems of synchronization.

Lithium Ion (Li-Ion)

Does not develop a memory A rechargeable battery with twice the capacity of a nickel cadmium battery with significantly increased stability and safety. Takes up less physical space and weighs less than nickel cadmium or nickel metal hydride batteries for comparable power output. Has a shorter lifespan than nickel metal hydride. Not heat sensitive like nickel cadmium. Cannot be overcharged. More expensive than nickel cadmium or nickel metal hydride.

E-readers

E-readers are similar in size to tablets, but they lack the functionality of a tablet. Their primary purpose is for reading digital books, newspapers, magazines, and other periodicals. Most e-readers use E Ink to display digital content. E Ink is a special technology that creates a high-contrast, black and white display. Even though they can display only grayscale, E Ink screens are great for e-readers because they consume much less power than LCD screens and they don't suffer from visibility problems when used in bright sunlight.

Global Positioning System (GPS)

GPS is a space-based navigation system that provides location and time information in all weather conditions anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Mobile devices use GPS chips in order to calculate the device's location information. This is helpful for things like navigation applications and device location services.

Slow Performance

If the device seems to be running slow, there are a couple things you can look at in order to identify the problem: Identify system resources and usage. Many mobile devices have a system monitor that can be used to identify which apps are using system resources (i.e., memory, processor, etc.). Make sure the app being used is compatible with the mobile device. Older mobile devices have slower processors and might not be able to run all the latest mobile apps available to it. Check the amount of free storage on the mobile device. If a mobile device's storage is more than 80% full, performance can be reduced considerably. If the cell phone overheats, turn it off and place it in a cool place out of direct sunlight. It is possible for overheating to damage hardware, but generally, cooling down will correct issues. Avoid overheating by keeping the phone out of direct sunlight and extremely hot places, such as a car parked in direct sunlight. If your speakers do not perform correctly, begin troubleshooting by checking your sound settings. Make sure nothing is set to Mute, Vibrate, Do not Disturb, or Silent. Make sure your phone isn't connected to another device with Bluetooth. After that, plug headphones into your device. If you can hear sound through the headphones but not through the device's speakers, you may have a hardware issue. If turning the phone off and back on again doesn't fix the problem, you should contact your phone's manufacturer or your cell service provider for support. If your GPS isn't functioning, first, make sure your phone is receiving a clear signal. You need a clear signal for the GPS to work and to troubleshoot any GPS problems. Make sure you have enabled location permissions for the app you are trying to use. You can refresh location services by turning the Location function on and off or putting your phone in Airplane mode for a few moments. If these solutions don't work, you may have to reset all of your location and network data or restore your device's factory settings. You can review security and performance logs on your phone just as you can on a PC. This can help you troubleshoot performance issues. Review materials from your device manufacturer to learn how review logs on your phone. Note that you may need to connect your phone to a computer with a USB.

Applications

If you cannot load an app from the Microsoft Store, use the Windows Store Apps Troubleshooter to search for and correct problems. Third-party apps have varying levels of support. You may have to contact the developer to troubleshoot issues. If you are unable to decrypt an email, you probably do not have the correct private key. You will need to export it from another computer. If your GPS is not functioning, begin troubleshooting by running the Hardware and Device Troubleshooter program. You can also update Bluetooth drivers if you are having trouble pairing a GPS-dependent Bluetooth device. If the pairing device uses Window 7 or older, install the drivers in Compatibility mode for the correct Windows version. And as always, use known good devices to check for damaged hardware and replace components as necessary.

Video

If your laptop has no display at all, Press the Fn (Function) and the appropriate display key to switch the display output to the laptop monitor. If the built-in monitor isn't working, connect an external monitor to the laptop. Use the Fn keys to direct output to the external monitor. If you don't get a display on either monitor, you can assume that there is a problem with the video card. Repairing the video card typically means replacing the motherboard. If the display renders on the external monitor but still won't render on your laptop, then you can assume that there is a problem with your LCD display. If this is the case, you should verify that: Your LCD cutoff switch is working. Sometimes the switch can get stuck in the off position, thus preventing the display from being sent to the LCD. There aren't cracks in the bezel around your LCD. This can be an indicator that your LCD has been damaged. The power bundles that go from your laptop to the LCD are not damaged or cracked. You must remove the bezel around the LCD to inspect the power bundles.

Hard Drive

Internal hard drives are usually 2.5" or 3.5" in size. Verify the interface type (SATA), speed, capacity, and RPM speed supported by the notebook before purchasing a replacement drive. Most hard drives are replaced by removing a cover on the bottom or side of the computer. Some disk drives are placed inside a caddy with a special connector. You will need this caddy when replacing the drive.

Internal Storage

Internal storage is a hardware component located inside the device and used to store data. Some tablets use solid state drives (SSD). Others may use on-board flash memory (such as the iPad). Some also have external USB ports for removable storage.

Antivirus and Anti-Malware

It is a good idea to install an anti-malware app on mobile devices, especially devices that are used by an organization or connect to a company network. This will protect the device from malicious email attachments, downloads, or applications. It will also help prevent the spread of viruses onto a network.

Power

Laptops can run from either AC power through the transformer or from battery power. When troubleshooting power, verify that: The cord from the AC outlet to the power adapter is correctly plugged into both the wall and the adapter unit. Move it around to see if a more secure connection can be made. The LED light on your power adapter is lit. If it isn't lit, this means that your point of failure is between the outlet and the adapter. Your battery is sufficiently charged. If the battery reads it is fully charged in Windows, disconnect your laptop from its power source. If the battery lasts only a short amount of time, you can assume that your battery needs to be replaced. If the computer runs for only a short time even while plugged in, it could be that the power adapter is bad. If the adapter is not working, the computer will run off of the battery until the battery is drained. Try using a different adapter, or verify the power coming from the adapter. If your battery seems to be losing the ability to hold a charge, or if the power drops shortly after starting to use it, you might need to recalibrate the battery.

Lightning

Lightning is a proprietary computer bus and power connector created by Apple Inc. to replace its previous proprietary 30-pin dock connector. It is used to connect Apple mobile devices like iPhones, iPads and iPods to host computers, external monitors, cameras, USB battery chargers, and other peripherals.

Unauthorized Access

Mobile devices are vulnerable to many of the same attacks that target desktop systems. One such attack is unauthorized access, where an attacker gains access to a specific feature or functionality of the mobile device. Unauthorized account access occurs when an attacker obtains the login credentials for a cloud backup service or the device itself. This can result in leaked personal files and data. To protect against this, make sure to use some sort of authentication on the mobile device. Also make sure to use complex passwords and, if possible, set up two-factor authentication with all accounts that contain sensitive information. Unauthorized root access is typically the result of a virus or malicious program installed on the mobile device. With root access, the malicious program can make low-level system changes to the mobile device, including modifying root certificates. To protect against unintended root access, install a anti-malware app on the mobile device and keep it up to date. Unauthorized location tracking occurs when the GPS on the device is being used to track your location without your permission. To protect against this, review the device's security settings and identify which installed apps have access to location services. You can then modify each app's permissions to deny location tracking access. Unauthorized camera/microphone activation is when the device's camera or microphone is being used without the user's permission. This can be caused by a malicious program or individual, or it could be caused by an installed application that has been granted permission to use these services. Most mobile devices have an LED or icon that indicates if the camera is being used. If a camera is being used without permission, review the device's security settings and app permission settings. In addition, you can install an anti-malware app and run a scan on the device to remove any malicious apps. If you become locked out of your phone, you can always get back in by performing a factory reset, but note that this will remove all data from your device.

Networking Capabilities

Mobile devices implement 802.11b/g/n networking to provide networking connectivity. Bluetooth is also commonly implemented for connecting peripherals in place of wired USB connections.

Non-Responsive Touchscreen

Mobile devices use capacitive touchscreens, which require a conductive material touching the screen to work. If the touchscreen is not functioning or is inaccurate, you should: Look for liquid on the screen. Because water is conductive, any type of moisture on the screen will result in erratic touchscreen behavior. Check for cracks or physical damage. A cracked screen can disrupt the current flow across the screen and cause specific sections of the touchscreen to fail. Make sure the screen is calibrated. If the touchscreen is inaccurate, try calibrating it using the device's built-in calibration app.

Mobile Payment Service

Mobile payment services operated under financial regulation and are performed using a mobile device. Instead of paying with cash, check, or credit cards, a consumer can use a mobile phone to pay for a wide range of services and digital or hard goods.

Weak or No Signal

Most connectivity issues are a result of a weak signal or some sort of interference. If a mobile device is having connectivity problems, try the following: If the device is having problems connecting to a wireless network: Make sure the wireless adapter is turned on. Verify that the wireless configuration settings are correct. Use a Wi-Fi analyzer to identify the network's signal strength as well as interference sources (e.g., other network signals). Verify that you are not over your data limit and being denied data access. If the device is having problems with cellular service: Make sure the mobile device has a SIM card installed. Use a cell tower analyzer to identify network coverage, signal strength, and network type (i.e., 1x, 3G, 4G). Identify whether or not the mobile device has a data plan. If it does, make sure the device has not gone over the data limits specified in the plan.

Failed Login Attempts

Most mobile devices are configured by default to allow only a set number of failed login attempts, which is usually ten. If more than ten failed logins are attempted, the mobile device will automatically wipe the entire contents of the device and reset it to the factory defaults. It's important to make sure that this feature is enabled on all mobile devices. This is one of the best lines of defense you can provide to a mobile device. Even if the passcode or PIN aren't very secure, it will be pretty hard to guess the right one with only ten attempts at your disposal.

Memory

Most notebooks use a small panel on the bottom to access the additional memory slots. Some notebooks include a base amount of memory built onto the motherboard or a memory module soldered into the first memory slot. You will not be able to remove or upgrade this memory. Some notebooks have one memory slot located underneath the keyboard, and a second slot accessible through a door on the bottom of the case, or both slots are accessible from the bottom. The amount of base memory installed will affect the total amount of system memory you can have.

Multifactor Authentication

Multifactor authentication is a type of authentication that requires multiple authentication credentials to verify the user's identity for a login or other transaction. For example, you might require a user to enter a username, password, pin, and fingerprint before authenticating to a computer system.

LCD Display components

Multiple components make up the LCD display: The bezel is the case in which the LCD is set. The backlight illuminates the LCD by evenly dispersing light over the entire screen. These backlights are usually cold cathode fluorescent lamps (CCFL) or LEDs. The inverter is a power supply for the LCD screen that converts the DC power used by the computer to AC power needed for the backlight.An inverter is not used with LED backlights because LEDs use DC power. The remainder of the LCD screen comes as a unit. The antenna for wireless network cards is typically housed in the display bezel.

Remote Backup Applications

Remote backup applications allow you to recover important business data and personal files (e.g., pictures and texts) from a lost, stolen, or broken phone. Most cellular providers offer some type of cloud backup service. In addition, each mobile OS offers their own proprietary backup service: iOS devices have two different backup tools: The desktop application iTunes can be used to backup and restore iOS devices. iTunes requires mobile devices to be connected to the desktop computer via a USB cable. Apple devices can also use the iCloud service to backup and synchronize files and settings across all Apple devices (i.e., mobile and desktop devices). iCloud is a cloud-based backup service and requires the user to have an Apple ID, which needs to be logged into and configured on each Apple device. Apple devices can then synchronize and backup files over the internet. Android devices use the Google sync service to sync and backup mail, contacts, calendar, and files across all android devices. Google sync is a cloud-based service and requires a Google account. Windows Mobile devices have two backup tools: OneDrive is Microsoft's cloud-based backup service and requires a Microsoft account. Windows Mobile devices can also be backed up using a desktop computer with the Windows OS installed.

Remote Wipe

Remote wipe is used to remotely format a mobile device. It's a feature that's built into a lot of mobile devices, especially smart phones. But, it's also possible to use third-party software, such as Windows Intune, to achieve this functionality. Remote wipe requires some sort of connection to the device. This means that in order to send a remote wipe command, the device needs to be powered on and have cellular or Wi-Fi connection.

Smart Phones

Smart phones combine the functionality of a cellular phone with the features of a desktop computer. Smart phones can access the internet either through a Wi-Fi connection or by using a 3G, 4G, and LTE cellular connection. They can also be used as a GPS navigation unit, a portable gaming device, and a mobile music player. Smart phones typically have a screen size between 2.5 inches and 5 inches. Most smart phones use the Android and iOS operating systems, but there is also a Microsoft Windows system called Lumia and a Google Chrome operating system called Fuchsia.

Prevent Unintended Connections

Some mobile devices are configured to automatically connect to open Wi-Fi networks or accept other types of wireless connections (e.g., Bluetooth). This presents a serious security threat. For example, if a mobile device were to connect to an AP owned by a malicious individual, any information sent by the device can be captured by the malicious person. To prevent against unintended Wi-Fi connections: Configure Wi-Fi settings to always ask for permission to connect to unknown wireless networks. If Wi-Fi is not being used, consider turning off the Wi-Fi adapter. If a mobile device has already connected to an unknown wireless network, remove the network from the saved networks list in order to prevent future connections. To prevent against unintended Bluetooth pairing: Unless Bluetooth is actively being used, turn it off. This will not only prevent Bluetooth pairing and discovery, but also increase the device's battery life. If a the mobile device has been accidentally paired with another device, navigate to Bluetooth settings and delete (unpair) the device.

Sleep

The system appears to be off. Volatile memory is refreshed. Some components are powered so the computer can wake from keyboard, LAN, or USB input. In Hybrid Sleep mode, used on desktops, the hibernation file saves the system state in case the system loses power.

Policies and Procedures

Use policies and procedures to secure your mobile devices. BYOD vs. corporate owned. Some organizations implement security policies that forbid users from connecting their personal mobile devices to the organizational network (wired or wireless). Some organizations allow mobile devices; in fact, they may even provide users with mobile devices.However, there is a risk in this situation that company data may be copied to these devices that could be compromised if a device is lost. As a safeguard, many of these organizations require that remote wipe be enabled on the device so that if it is lost or stolen, a command can be sent remotely to the device to remove all data on it. Profile security requirements. Utilize an Acceptable Use Policy to specify how users: Connect their personally-owned mobile devices to the organization's wireless network. If they can, the policy may also specify rules for what internet resources they are allowed to access using those devices. Use company-owned computers for personal uses, such as shopping for personal items on ecommerce websites.

Wearable Devices

Wearable devices are a type of mobile device meant to be worn somewhere on the body. These devices range from being as simple as a fitness tracker wrist band to as complex as glasses or a virtual reality headset. Most wearable devices are designed to interface with another device. For example, a smart watch by itself has a limited set of functionality; however, smart watches are designed to connect to smart phones using Bluetooth. Doing this unlocks additional functionality, such as reading texts or answering phones calls through the smart watch.

keyboard replacement

When replacing the keyboard, be aware of the following: You can replace the pointer stick pad by simply pulling off the old one and replacing it. Screws at the bottom of the notebook case or underneath a plastic bevel on the top hold the keyboard in place. A laptop keyboard is generally connected to the system board using a flat, ribbon-like cable. You will typically need to remove the keyboard to replace other internal components (such as the processor, wireless card, or video card).

LCD Display replacement

When replacing video components: You will need to remove the keyboard and any palm rests in order to remove the video card or the display components. Some video cards are integrated on the motherboard and cannot be replaced. If the video card can be replaced, you will need to disconnect the display wires first. Power cables run from your laptop to the LCD through the hinges that attach the LCD to the laptop. If these cables become bent or frayed, they can cause your LCD to lose power or display. To remove the display assembly, remove the screws holding the lid that are typically located beneath the keyboard or a plastic cover above the keyboard. Unplug the video cables and the wireless antenna or other device cables. To access the inverter, backlight, or other display components, remove the screws in the bezel. These screws are typically underneath rubber pads that keep the lid from hitting the palm rests. When replacing the video card or LCD components, be sure to reconnect the wireless network antenna when reassembling.

Wi-Fi Analyzer

Wi-Fi analyzers are special apps that can be used to troubleshoot Wi-Fi connectivity issues. Most Wi-Fi analyzer apps provide the following functionality: Identify the number of APs that are broadcasting Display the signal strength and channel of each wireless network Obtain wireless network information (e.g., signal band, SSID, security mode, etc.)