CompTIA A+

What is eSATA?

eSATA (e standing for external) provides a variant of SATA meant for external connectivity. It uses a more robust connector, longer shielded cables, and stricter (but backward-compatible) electrical standards. The protocol and logical signaling (link/transport layers and above) are identical to internal SATA.

Client server resource model

(also known as server based) is better the the peer-to-peer model for large networks (more than 10 computers) that need a more secure environment and centralized control Server-based networks use one or more dedicated centralized servers. All administrative functions and resource sharing are performed from this point

What is UEFI?

Unified Extensible Firmware Interface (UEFI) is a specification for a software program that connects a computer's firmware to its operating system (OS). UEFI is expected to eventually replace BIOS. Like BIOS, UEFI is installed at the time of manufacturing and is the first program that runs when a computer is turned on. It checks to see what hardware components the computing device has, wakes the components up and hands them over to the operating system. The new specification addresses several limitations of BIOS, including restrictions on hard disk partition size and the amount of time BIOS takes to perform its tasks.

Input devices

- mouse - touchpad - keyboard - scanner - barcode reader - digitizer - biometric devices - gamepads and joysticks - motion sensor - smart card reader - multimedia devices - webcams - MIDI-enabled devices - digital cameras and camcorders - mircophones

Output devices

- printers - speakers - display devices

Input and output devices

- touchscreens - KVM switches = allows you to have multiple systems attached to the same keyboard, monitor and mouse - smart TV - set-top boxes

What are the main types of motherboards?

1. ATX (Advanced Technology Extended) is the most commonly used form factor today. It is an open, nonproprietary industry specification originally developed by Intel in 1995, and has undergone several revisions since then. 2. The microATX (MATX) form factor is a major variation of ATX and addresses some technologies that have emerged since the original development of ATX. MicroATX reduces the total cost of a system by reducing the number of expansion slots on the motherboard, reducing the power supplied to the board, and allowing for a smaller case size.

What are the 3 types of hard drives?

1. Mechanical hard drive (HDD) 2. Solid state drive 3. Hybrid drive The larger hard drive is a magnetic drive, and the smaller hard drive is a solid-state drive. Each drive has two connections for cables: The power cable connects to the power supply, and another cable, used for data and instructions, connects to the motherboard. HHD is cheaper and lasts longer. Solid state drive offer larger capacities and are faster but is more expensive. Hybrid drives - better performance than the standard HDD's - Best of both worlds but more expensive than HDD. -

Can a 64-bit CPU can be used either with a 32-bit or 64-bit version of the Microsoft Windows operating system?

64-bit CPUs are compatible with 32-bit Microsoft operating systems, although it performs best with 64-bit.

What is a DVI port?

A DVI (Digital Video Interface) port transmits digital or analog video. Three types of DVI ports exist. The DVI connector on a device is given one of three names, depending on which signals it implements: DVI-I (integrated, combines digital and analog in the same connector; digital may be single or dual link) DVI-D (digital only, single link or dual link) DVI-A (analog only)

What is a display port?

A DisplayPort transmits digital video and audio (not analog transmissions) and is slowly replacing VGA and DVI ports on personal computers.

What is a Firewire Port?

A FireWire port (also called an IEEE 1394 port, pronounced "I-triple-E 1394 port") is used for high-speed multimedia devices such as digital camcorders.

What is a PS/2 port?

A PS/2 port, also called a mini-DIN port, is a round 6-pin port used by a keyboard or mouse. The ports look alike but are not interchangeable. On a desktop, the purple port is for the keyboard, and the green port is for the mouse. Many newer computers use USB ports for the keyboard and mouse rather than the older PS/2 ports.

What is a Thunderbolt port?

A Thunderbolt port transmits video, data, and power on the same port and cable and is popular with Apple computers. The port is shaped the same as the DisplayPort and is compatible with DisplayPort devices. Apple's Thunderbolt 3 protocol uses the USB-C connector type. Thunderbolt 3 is also compatible with USB-C, so a Thunderbolt 3 port will work with both a Thunderbolt 3 and USB-C connector. Similarly the Thunderbolt versions 1 and 2 use a standard Display Port connector. Thunderbolt 3 uses Universal Serial Bus (USB) type C. The older versions of Apple products (Thunderbolt 1, and 2) use the Mini DisplayPort (MDP).

What are USB ports?

A USB (Universal Serial Bus) port is a multipurpose I/O port that comes in several sizes and is used by many different devices, including printers, mice, keyboards, scanners, external hard drives, and flash drives. Some USB ports are faster than others. Hi-Speed USB 2.0 is faster than regular USB, and Super-Speed USB 3.0 is faster than USB 2.0.

What is a VGA port?

A VGA (Video Graphics Array) port, also called a DB-15 port, DB15 port, HD15 port, or DE15 port, is a 15-pin, D-shaped, female port that transmits analog video.

How does the computer get power?

A computer power supply, also known as a power supply unit (PSU), is a box installed in a corner of the computer case that receives and converts the house current so that components inside the case can use it. Most power supplies have a dual-voltage selector switch on the back of the computer case where you can switch the input voltage to the power supply to 115 V used in the United States or 220 V used in other countries.

What is a modem port?

A modem port, also called an RJ-11 port, is used to connect dialup phone lines to computers. A modem port looks like a network port, but is not as wide. In the photo, the right port is a modem port and the left port is a network port, shown for comparison.

What do expansion cards do?

A motherboard has expansion slots to be used by expansion cards. An expansion card, also called an adapter card, is a circuit board that provides more ports than those provided by the motherboard. e.g. graphics or video cards

What does the term multicore mean?

A multi-core processor is a single computing component with two or more independent actual processing units (called "cores"), which are units that read and execute program instructions.[1] The instructions are ordinary CPU instructions (such as add, move data, and branch), but the multiple cores can run multiple instructions at the same time, increasing overall speed for programs amenable to parallel computing.[2] Manufacturers typically integrate the cores onto a single integrated circuit die (known as a chip multiprocessor or CMP), or onto multiple dies in a single chip package. A multi-core processor implements multiprocessing in a single physical package. Designers may couple cores in a multi-core device tightly or loosely.

What is a network port?

A network port, also called an Ethernet port, or an RJ-45 port, is used by a network cable to connect to the wired network. Fast Ethernet ports run at 100 Mbps (megabits per second), and Gigabit Ethernet runs at 1000 Mbps or 1 Gbps (gigabits per second). A megabit is one million bits and a gigabit is one billion bits. A bit is a binary value of 1 or 0.

What is a parallel port?

A parallel port, also called an LPT port, is a 25-pin female port used by older printers. This older port has been replaced by USB ports.

What are audio ports?

A system usually has three or more round audio ports, also called sound ports, for a microphone, audio in, audio out, and stereo audio out. These types of audio ports can transmit analog or digital data. If you have one audio cable to connect to a speaker or earbuds, plug it into the lime green sound port in the middle of the three ports. The microphone uses the pink port.

Network topologies

A topology is the way of laying out the network. When you plan and install a network you need to choose the right topology for your situation. There are 5 primary topologies: 1. Bus 2. star 3. ring 4. mesh 5. hybrid

What is the maximum length of a Lightning cable typically used for charging Apple smartphones?

According to Apple the Lightning cable can extend up to 2 meters (6.5 feet) and work optimally.

What does CMOS battery do?

Alternatively referred to as a Real-Time Clock (RTC), Non-Volatile RAM (NVRAM) or CMOS RAM, CMOS is short for Complementary Metal-Oxide Semiconductor. CMOS is an on-board, battery powered semiconductor chip inside computers that stores information. This information ranges from the system time and date to system hardware settings for your computer. The CMOS battery is generally a CR2032 lithium coin cell. If your computer is losing its time or date settings, or you are receiving a message CMOS Read Error, CMOS Checksum Error, or CMOS Battery Failure, the CMOS battery needs to be replaced. To do this, follow the steps below.

Motherboard power connector

An ATX power supply provides a number of peripheral power connectors and (in modern systems) two connectors for the motherboard: a 4-pin auxiliary connector providing additional power to the CPU and a main 24-pin power supply connector, an extension of the original 20-pin version. Different form factors use different numbers, types, shapes and sizes of connectors between the power supply and motherboard. The ATX 24 pin power supply connector is the standard motherboard power connector in computers today. You can plug a 20 pin ATX power cable into a motherboard with a 24 pin ATX connector. The 24 pin motherboard connector is actually just the 20 pin connector with 4 extra pins added on the end. The original 20 pins were unchanged. The extra 4 pins are not separate rails. They're just extra lines to provide more current to the same rails.

What is an HDMI port?

An HDMI (High-Definition Multimedia Interface) port transmits digital video and audio (not analog transmissions) and is often used to connect to home theater equipment.

What is a S-Video port?

An S-Video port is a 4-pin or 7-pin round video port sometimes used to connect to a television.

What is a S/PDIF (Sony/phillips digital interface) sound port?

An S/PDIF (Sony/Philips Digital Interface) sound port connects to an external home theater audio system, providing digital audio output and the best signal quality. S/PDIF ports always carry digital audio and can work with electrical or optical cable. When connected to a fiber-optic cable, the port is called an optical connector.

What is a external SATA port?

An external SATA (eSATA ) port is used by an external hard drive or other device using the eSATA interface. eSATA is faster than FireWire.

What is a serial port?

An older serial port, sometimes called a DB9 port, is a 9-pin male port used on older computers. It has been mostly replaced by USB ports. Occasionally, you see a serial port on a router where the port is used to connect the router to a device a technician can use to monitor and manage the router.

The CPU generates a lot of heat. What do you need to compensate for this?

Because the CPU generates heat, a fan and heat sink might be installed on top to keep it cool. A heat sink consists of metal fins that draw heat away from a component. The fan and heat sink together are called the processor cooler. Thermal paste is also spread on the CPU under the heat sink to help cool it down.

Star topology

Branches each network device off a central device called a hub or a switch making it easy to add a new workstation. If a workstation goes down , it does not effect the entire network but if the central device goes down the whole network does.

Optical storage devices

CD-ROM'S - CD SS - capacity 650MB, 700MB, 800MB, 900MB DVD-ROM'S - DVD-R/RW SS, SL = capacity 4.71GB (4.7GB) - DVD+R/RW SS, SL = capacity 4.71GB (4.7GB) - DVD-R, DVD+R DS, SL = capacity 9.4GB - DVD-R, SS, DL = capacity 8.54GB (8.5GB) - DVD+R, SS, DL = capacity 8.55GB (8.5GB) - DVD+R, DS, DL = capacity 17.1GB BD-ROMS - BD-R/RE SS, SL = capacity 25GB - BD-R/RE SS, DL = capacity 50GB - BD-R/RE DS,SL = capacity 100GB

Cables

Coaxial - contains a center conductor core made of copper, which is surrounded in a plastic jacket with braided shield over it Twisted pair - is the most popular type of cabling to use because of it's flexibility and low cost - it consists of several pairs of wire twisted around each other within an insulated jacket - 2 types 1. Shielded twisted pair (STP) 2. unshielded twisted pair (UTP) both types of cable have two or four pairs of twisted wires going through them (STP - has extra layer of braided foil shielding surrounding the wires to decrease electrical interference Twisted pair - uses a connector type called a RJ (registered jack) connectors (RJ45 and RJ11) - wire color order = white/green, green, white/orange, blue, white/blue, orange, white/brown, brown - patch (straight through) cable is the same on both ends - crossover cable is different on each end (connect computer directly to router)

What does the PCI slot do?

Conventional PCI, often shortened to PCI, is a local computer bus for attaching hardware devices in a computer. PCI is the initialism for Peripheral Component Interconnect[2] and is part of the PCI Local Bus standard. Attached devices can take either the form of an integrated circuit fitted onto the motherboard itself (called a planar device in the PCI specification) or an expansion card that fits into a slot.

What Digital Visual Interface (DVI) connector types does not provide support for digital signal transmission?

DVI-A is the connector type that uses analog only, and does not support digital signal transmission.

Types of Servers

Dedicated servers - is assigned to provide specific applications or services for the network and nothing else - a dedicated server specialises in only a few tasks so it requires less resources than a nondedicated server might require from the computer hosting it. this can translate to more efficiency and a have beneficial impact on network performance Nondedicated servers - are assigned to provide one or more network services and local access - is expected to be slightly more flexible in it's day to day use than a dedicated server - a non dedicated web server serves out websites but might also function as a print server on the local network or as the administrator's workstation

DDR SDRAM

Double data rate synchronous dynamic random-access memory (DDR SDRAM) is a class of memory integrated circuits used in computers. DDR SDRAM, also called DDR1 SDRAM, has been superseded by DDR2 SDRAM, DDR3 SDRAM and DDR4 SDRAM. None of its successors are forward or backward compatible with DDR1 SDRAM, meaning DDR2, DDR3, and DDR4 memory modules will not work in DDR1-equipped motherboards, and vice versa. DDR - DIMM pins = 184 - SO-DIMM = 200 - micro dimm = 172 DDR2 - DIMM pins = 240 - SO-DIMM = 200 - micro dimm = 214 DDR3 - DIMM pins = 240 - SO-DIMM = 200 - micro dimm = 214 DDR4 - DIMM pins = 288 - SO-DIMM = 256 - micro dimm = -- DDR (DDR1) was superseded by DDR2 SDRAM, which had modifications for higher clock frequency and again doubled throughput, but operates on the same principle as DDR. Competing with DDR2 was Rambus XDR DRAM. DDR2 dominated due to cost and support factors. DDR2 was in turn superseded by DDR3 SDRAM which offered higher performance for increased bus speeds and new features. DDR3 has been superseded by DDR4 SDRAM, which was first produced in 2011 and whose standards were still in flux (2012) with significant architectural changes. MicroDIMM DDR2 SDRAM modules typically used by laptops - Micro typically means a smaller form factor used for laptops. The amount of pins it has is 214.

DVD transfer rates

Drive speed Data rate Write time (minutes)[34] Mbit/s MB/s Single-Layer Dual-Layer 1× 11.08 1.39 57 103 2× 22.16 2.77 28 51 2.4× 26.59 3.32 24 43 2.6× 28.81 3.60 22 40 4× 44.32 5.54 14 26 6× 66.48 8.31 9 17 8× 88.64 11.08 7 13 10× 110.80 13.85 6 10 12× 5 9 16× 4 6 18× 3 6 20× 3 5 22× 3 5 24× 2 4

Dual-layer recording

Dual-layer recording (sometimes also known as double-layer recording) allows DVD-R and DVD+R discs to store significantly more data—up to 8.5 gigabytes per disc, compared with 4.7 gigabytes for single-layer discs.[25] Along with this, DVD-DLs have slower write speeds as compared to ordinary DVDs. When played, a slight transition can sometimes be seen in the playback when the player changes layers. Dual-layer recording allows DVD-R and DVD+R discs to store significantly more data, up to 8.5 gigabytes per disc, compared with 4.7 gigabytes for single-layer discs.

Ring topology

Each computer connects to two other computers, joining them in a circle and creating a unidirectional path where messaged move from workstation to workstation. Each entry participating in the ring reads a message and then regenerates it and hands it to it's neighbor on a different network cable. Difficult to add new computers. Whole ring network will go down if one entry is removed from the ring. Very expensive and fault tolerance is low.

What is ECC memory?

Error-correcting code memory (ECC memory) is a type of computer data storage that can detect and correct the most common kinds of internal data corruption. ECC memory is used in most computers where data corruption cannot be tolerated under any circumstances, such as for scientific or financial computing.

What is a RJ11 connector?

Establishes a bridged connection for one telephone line

What is a hard drive?

Hard drives and other drives. A system might have one or more hard drives, an optical drive, a tape drive, or, for really old systems, a floppy drive. A hard drive, also called a hard disk drive (HDD), is permanent storage used to hold data and programs.

What does the front side bus do?

Front-side bus (FSB) is between the CPU and northbridge, while the Back-side bus connects the CPU to the cache. it is the bus between the Central Processing Unit (CPU) and the northbridge

What is hyper-threading

Hyper-threading makes multitasking on your system much easier, allowing two or more processes to run using the same resources.

In order to work, an integrated component such as Network Interface Card (NIC) on a newly assembled computer system may need to be first?

If the computer is newly assembled it likely needs the device driver before the NIC will be functional. It is possible that the device could be disabled in the Windows control panel and BIOS however this is not a default functionality of either system.

A single IEEE 1394 (Institute of Electrical and Electronics Engineers) host controller can support up to how many devices at a given time?

If using a daisy chain IEEE 1394 (FireWire) can support up to 63 devices at one time.

What is a drawback of using integrated graphics?

Integrated GPU (Graphics Processing Unit) or Integrated Graphics is a technology that allows a motherboard to handle graphics generation without a dedicated expansion card with a GPU. Generally this requires that some of your system memory (RAM) be assigned to the GPU instead of the CPU and results in slower performance.

Hybrid topology

Is simple a mix of the other topologies. Most networks today are not only hybrid but include a mix of components of different types and brands. More expensive than some topologies but it takes the best features from all the other topologies and exploits them.

Mesh topology

Is the most complex in terms of physical design. In this topology, each device is connected to every other device. Rarely found in LAN's because of the complex cabling involved. Due to it's design it is Expensive to install and maintain. Has high fault tolerance. With mesh topology there will always be a way to get the data from source to destination. Uses to connect multiple sites across WAN links.

Bus topology

Is the simplest and cheapest. It consists of a single cable that runs to every workstation. Uses least amount of cabling. Each computer shares same data and address path. Difficult to add new workstations to bus topology later. Expensive to maintain and difficult to troubleshoot

Types of networks

LAN's - local area network - used to connect computers in a single office or building - LAN's exist in many homes (wireless networks) and nearly all businesses WAN's - wide area network - expanded the LAN's to include networks outside the local environment and to also distribute resources across great distances PAN's - personal area network - is a very small scale network designed around one person within a limited boundary area - bluetooth networks MAN's - metropolitan area network - bigger than a LAN but not as big as a WAN

What is the purpose of the No-eXecute (NX bit) technology used in Intel CPUs?

Malware protection No-eXecute allows the administrator to mark certain areas as "non-executable" which can protect the system against different forms of Malware.

Molex connector

Molex connector is the vernacular term for a two-piece pin and socket interconnection, most frequently disk drive connectors. Several connector types have become established for connecting power in desktop PCs, because of the simplicity, reliability, flexibility, and low cost of the Molex design. Certain Molex connectors are used for providing power to the motherboard, fans, floppy disk drive, CD/DVD drive, video card, some older hard drive models, and more.

What is NFC?

Near-field communication (NFC) is a set of communication protocols that enable two electronic devices, one of which is usually a portable device such as a smartphone, to establish communication by bringing them within 4 cm (2 in) of each other. NFC devices are used in contactless payment systems, similar to those used in credit cards and electronic ticket smartcards and allow mobile payment to replace/supplement these systems. NFC is used for social networking, for sharing contacts, photos, videos

What does the PCIE slot do?

PCI Express (Peripheral Component Interconnect Express), officially abbreviated as PCIe, is a high-speed serial computer expansion bus standard, designed to replace the older PCI, PCI-X, and AGP bus standards. PCIe has numerous improvements over the older standards, including higher maximum system bus throughput, lower I/O pin count and smaller physical footprint, better performance scaling for bus devices, a more detailed error detection and reporting mechanism (Advanced Error Reporting, AER[1]), and native hot-plug functionality. More recent revisions of the PCIe standard provide hardware support for I/O virtualization. PCI Express (standard) Various slots on a computer motherboard, from top to bottom: PCI Express ×4 PCI Express ×16 PCI Express ×1 PCI Express ×16 Legacy PCI (32-bit, 5 V) A PCI Express card fits into a slot of its physical size or larger (with ×16 as the largest used), but may not fit into a smaller PCI Express slot; for example, a ×16 card may not fit into a ×4 or ×8 slot. Some slots use open-ended sockets to permit physically longer cards and negotiate the best available electrical and logical connection. PCIe can scale from one to 32 separate lanes; it is usually deployed with 1, 4, 8, 12, 16 or 32 lanes. The lane count of a PCIe card is a determining factor in its performance and therefore in its price. For example, an inexpensive PCIe device like a NICs might only use four lanes (PCIe x4). By comparison, a high-performance graphics adapter that uses 32 lanes (PCIe x32) for top-speed transmission would be more expensive. Peripheral devices that use PCIe for data transfer include graphics adapter cards, network interface cards (NICs), storage accelerator devices and other high-performance peripherals.

What is PnP?

Plug and Play (PnP) - if a Plug and Play (PnP) device is not supported the driver must be manually installed by the administrator to find the necessary drivers on the product website or material provided.

What is RAID?

RAID (originally redundant array of inexpensive disks, now commonly redundant array of independent disks) is a data storage virtualization technology that combines multiple physical disk drive components into a single logical unit for the purposes of data redundancy, performance improvement, or both.[1] Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the required level of redundancy and performance. The different schemas, or data distribution layouts, are named by the word RAID followed by a number, for example RAID 0 or RAID 1. Each schema, or RAID level, provides a different balance among the key goals: reliability, availability, performance, and capacity. RAID levels greater than RAID 0 provide protection against unrecoverable sector read errors, as well as against failures of whole physical drives. RAID 0 - RAID 0 consists of striping, without mirroring or parity. The capacity of a RAID 0 volume is the sum of the capacities of the disks in the set, the same as with a spanned volume. There is no added redundancy for handling disk failures, just as with a spanned volume. Thus, failure of one disk causes the loss of the entire RAID 0 volume, with reduced possibilities of data recovery when compared to a broken spanned volume. RAID 1 - RAID 1 consists of data mirroring, without parity or striping. Data is written identically to two drives, thereby producing a "mirrored set" of drives. Thus, any read request can be serviced by any drive in the set. If a request is broadcast to every drive in the set, it can be serviced by the drive that accesses the data first (depending on its seek time and rotational latency), improving performance. - Actual read throughput of most RAID 1 implementations is slower than the fastest drive. Write throughput is always slower because every drive must be updated, and the slowest drive limits the write performance. The array continues to operate as long as at least one drive is functioning. RAID 5 - RAID 5 consists of block-level striping with distributed parity. Unlike RAID 4, parity information is distributed among the drives, requiring all drives but one to be present to operate. Upon failure of a single drive, subsequent reads can be calculated from the distributed parity such that no data is lost. RAID 5 requires at least three disks.[12] - RAID 5 implementations are susceptible to system failures because of trends regarding array rebuild time and the chance of drive failure during rebuild (see "Increasing rebuild time and failure probability" section, below).[23] Rebuilding an array requires reading all data from all disks, opening a chance for a second drive failure and the loss of the entire array RAID 10 - also known as RAID 1+0, combines disk mirroring and disk striping to protect data. A RAID 10 configuration requires a minimum of four disks, and stripes data across mirrored pairs. As long as one disk in each mirrored pair is functional, data can be retrieved - RAID 10 provides redundancy and performance, and is the best option for I/O-intensive applications. One disadvantage is that only 50% of the total raw capacity of the drives is usable due to mirroring.

What is RAM?

RAM - Random access memory RAM is volatile. it's contents are lost when the device is powered off. Memory, also called RAM (random access memory), is temporary storage for data and instructions as they are being processed by the CPU. Memory modules. A desktop motherboard has memory slots, called DIMM (dual inline memory module) slots, to hold memory modules. Video cards also contain some embedded RAM chips for video memory.

What is ROM?

Read-only memory or ROM is also a form of data storage that can not be easily altered or reprogrammed. Stores instructions that are not necessary for re-booting up to make the computer operate when it is switched off.They are hardwired. It is non-volatile i.e. its contents are retained even when the device is powered off. The types of ROM include PROM, EPROM and EEPROM. - Programmable read-only memory (PROM), - Erasable programmable read-only memory (EPROM) - Electrically erasable programmable read-only memory (EEPROM)

What is Serial SATA

Serial ATA (SATA) Is a computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives. Serial ATA succeeded the older Parallel ATA (PATA) standard, offering several advantages over the older interface: reduced cable size and cost (seven conductors instead of 40 or 80), native hot swapping, faster data transfer through higher signaling rates, and more efficient transfer through an (optional) I/O queuing protocol. Serial ATA (Sata) cables only support one device per cable. PATA cables do support multiple devices using a single cable. Both SATA and Micro SATA use a 7 pin data connector

OSI model cont

Seven layers (listed from top to bottom): 7. Application layer - allows access to network services - this is the layer at which file services, print services and other applications operate 6. Presentation layer - determines to look or format of the data - this layer performs protocol conversions and manages data compression, data translation and encryption 5. Session layer - allows applications on different computers to establish, maintain and end a session - a session is one virtual conversion 4. Transport layer - this layer controls the data flow and troubleshoots any problems with transmitting or receiving datagrams - the TCP protocol (one of the 2 options at this layer) has the important job of verifying that the destination host has received all packets, providing error checking and reliable end to end communications 3. Network layer - this layer is responsible for logical addressing of messages - at this level data is organized into chunks called packets - this layer manages traffic through packet switching, routing and controlling congestion of data 2. Data link layer - arranges data into chunks called frames - allows error checking within the frames 1. Physical layer - describes how the data gets transmitted over a communication medium

OSI layers

Seven layers (listed from top to bottom): 7. Application layer 6. Presentation layer 5. Session layer 4. Transport layer 3. Network layer 2. Data link layer 1. Physical layer

What is a NIC card?

Short for Network Interface Card, the NIC is also referred to as an Ethernet card and network adapter. It is an expansion card that enables a computer to connect to a network; such as a home network, or the Internet using an Ethernet cable with an RJ-45 connector.

What is BIOS?

The BIOS (an acronym for Basic Input/Output System and also known as the System BIOS, ROM BIOS or PC BIOS) is a type of firmware used to perform hardware initialization during the booting process (power-on startup) on IBM PC compatible computers, and to provide runtime services for operating systems and programs. The BIOS firmware is built into personal computers (PCs), and it is the first software they run when powered on. The fundamental purposes of the BIOS in modern PCs are to initialize and test the system hardware components, and to load a boot loader or an operating system from a mass memory device. The BIOS additionally provides an abstraction layer for the hardware, i.e., a consistent way for application programs and operating systems to interact with the keyboard, display, and other input/output (I/O) devices. The Basic Input/Output System's (BIOS) main functionality when a computer is powered on is to perform a Power On Self Test (POST) which verifies that the required computer components are installed and functional.

What is RTC?

The Real Time Clock (RTC) is a chip embedded in most electronic devices. The RTC keeps the time for a device and must have an alternative power source to use when the device is powered off. For computers this is the CMOS battery.

What is the CPU?

The central processing unit (CPU), also called the processor or microprocessor, does most of the processing of data and instructions for the entire system. Thermal paste is spread on the CPU to help cool it down.

What is the chipset?

The chipset manages the flow of data between the core components of the motherboard, such as memory, processor, and other peripherals.

What is the maximum cable length allowable for all IEEE 1394 (FireWire) devices?

The copper wire can extend up to 4.5 meters (15 feet) and was replaced by Thunderbolt in newer Macintosh models.

What is the motherboard?

The motherboard, also called the main board, the system board, is the largest and most important circuit board in the computer. The motherboard contains a socket to hold the processor or CPU. All hardware components are either located on the motherboard or directly or indirectly connected to it because they must all communicate with the CPU

What is eMMC?

The term eMMC is short for "embedded Multi-Media Controller" and refers to a package consisting of both flash memory and a flash memory controller integrated on the same silicon die. The eMMC solution consists of at least three components - the MMC (multimedia card) interface, the flash memory, and the flash memory controller - and is offered in an industry-standard BGA package. Today's embedded applications such as digital cameras, smart phones, and tablets almost always store their content on flash memory. eMMC is suitable for high performance applications such as portable consumer electronic products for e.g. smartphones, digital tablets, multi-media players, PDAs, navigational systems and digital cameras. eMMC can thus be used for mobile devices, enhanced storage solutions and as replacement for traditional storage media (i.e., HDDs). - See more at: https://www.datalight.com/solutions/technologies/emmc/what-is-emmc#sthash.KAZoVPXi.dpuf

DVD capacity

https://en.wikipedia.org/wiki/DVD#DVD_recordable_and_rewritable DVD+R DL (DL stands for Double Layer) - DVD+R DL discs employ two recordable dye layers, each capable of storing nearly the 4.7 GB capacity of a single-layer disc, almost doubling the total disc capacity to 8.5 GB. Discs can be read in many DVD devices (older units are less compatible) and can only be created using DVD+R DL and Super Multi drives. Disk Type nominal capacity in GB DVD-R (SL) 4.7 DVD+R (SL) 4.7 DVD-R DL 8.5 DVD+R DL 8.5

Peer-to-peer model

in a peer-to-peer network the computers act as both service providers and service requestors Peer-to-peer model is great for small, simple, inexpensive networks. This model cam be setup almost instantly with little extra hardware required Also referred to as workgroups - No centralized control. can make it difficult to administer the network - network isn't very secure

Network operating system

networks use a network operating system (NOS) to control the communication with resources and the flow of data across the network the NOS runs on the server some of the more popular NOS's are UNIX and Linux and Microsoft's windows server series