Computer Networking Hardware/Software/ETC
Local area network (LAN)
A LAN is generally a small group of computers and peripherals linked together over a relatively small geographical area. The computer lab at your school or the network serving the floor of the office building where you work is probably a LAN.
Wide area network (WAN)
A WAN comprises large numbers of users over a wider physical area or separate LANs that are miles apart. Businesses often use WANs to connect two or more geographically distant locations. For example, a college might have a west and an east campus located in two different towns. The LAN at the west campus is connected to the LAN at the east campus, forming one WAN connected either by dedicated telecommunications lines or by satellite links. Students on both campuses can share data and collaborate through the WAN
Computer Bus
A bus is a channel over which information flows. • Think of a bus as a highway on which data travels in a computer. • A bus has two parts: - Address bus - Data bus
Single Core Processor
A core on a CPU refers to the components on the chip that are needed for processing. • A single core processor has only one core. Usually this means one arithmetic logic unit and one control unit
Multicore Processor
A multicore processor has two or more cores that are responsible for processing. • A multicore processor has the ability to execute two or more sets of instructions at the same time. • This is called hyperthreading
virtual private network (VPN)
A network that uses the public Internet communications infrastructure to build a secure, private network among various locations.
Pixel
A pixel is the smallest element in an electronic image. • The more pixels in an image, the better the image quality.
intranet
A private network set up by a business or an organization that's used exclusively by a select group of employees, customers, suppliers, volunteers, or supporters.
CPU
A processor or central processing unit (CPU) is the brains of the computer where most calculations take place.
Protocol
A protocol is a set of rules for communication between devices that determines how data is transmitted and received. • There are many protocols that are used to help streamline the communication of all digital devices. • WiFi uses the 802.11 protocol. This protocol ensures that devices enabled with WiFi can connect to any WiFi network.
What are network protocols?
A protocol is a set of rules for exchanging communications.
authentication server
A server that keeps track of who's logging on to the network and which services on the network are available to each user.
bus (linear bus) topology
A system of networking connections in which all devices are connected in sequence on a single cable.
Gigabyte - (GB).
About 1 billion bytes - One gigabyte is equal to 341 digital images (3 MB average file size.
Megabyte (MB)
About 1 million bytes - One megabyte is equal to about 875 pages of text.
Kilobyte (KB)
About 1 thousand bytes - One kilobyte is equal to about one page of text
Terabyte (TB)
About 1 trillion bytes - One terabyte is equal to about 349,000 digital images (3 MB average file size) or 40 single-sided Blu-ray discs.
ASCII
American Standard Code for Information Interchange (pronounced AS-key) is a common encoding standard. • ASCII code is capable of representing 26 uppercase and lowercase letters used in the English language, numbers, and many different symbols. • ASCII can represent a total of 256 characters.
extranet
An area of an intranet that only certain entities or individuals can access; the owner of the extranet decides who will be permitted to access it.
Blu-ray
Blu-ray discs are a type of optical media used in optical drives. • Blu-ray discs can store up to 50 GB of data. • Most Blu-ray drives are capable of reading CDs, DVDs, and Blu-ray discs.
Bluetooth
Bluetooth is a short-distance wireless communication technology that uses relatively short-wavelength radio waves to transfer data. • Because it uses shortwavelength radio waves, Bluetooth signals easily pass through walls, furniture, etc. • Most Bluetooth transmissions remain strong up to 10 feet away and then start to reduce in signal strength.
Bus width
Bus width is the amount of data that can be transmitted at a given time. • The wider the bus, the more information that can travel along the bus, which creates faster transmission speeds. • Bus width is measured in bits
Clock speed
Clock speed, also referred to as clock rate, is the speed at which the processor performs the operations required to run a digital device and instructions executed by the digital device. • Clock speed is measured in hertz (Hz).
What's a computer?
Computers are digital devices that: - Accept input - Process and store the input - Provide output
Bit
Computers communicate using their own language. • This language is called binary. • Binary language consists of two digits - 0 and 1. • Each 0 or 1 is called a bit. • Bits are the smallest unit of data a computer can process.
Blur-ray R and RW
Data and information can be stored on optical media such as Blu-ray and DVD. • A DVD-R can have data written to it one time. • A DVD-RW can have data erased and re-written a number of times.
DVD
Digital versatile discs (DVD) are a type of optical media used in optical drives. • DVDs can store up to 8.5 GB of data. • Most DVD drives are capable of reading CDs and DVDs.
Disk Cache
Disk cache is high-speed memory used by the hard drive to store frequently accessed data.
Downward Compatibility
Downward compatibility is the ability of hardware or software to work with data and information produced by older product or software. • Most DVD and Blu-ray drives are downward compatible
Byte
Eight bits grouped together are called a byte. • Each number, special character, and letter of the alphabet is represented by a unique combination of bits. • For example, an ampersand (&) is represented as 00100110.
Petabyte (PB)
Equals 1,000 terabytes - One petabyte is equal to about 358,000,000 digital images (3 MB average file size) or about 42,000 single-sided Blu-ray discs.
FireWire
FireWire ports are a type of Thunderbolt port. • Thunderbolt ports allow for up to 6 different peripherals to be connected to one device. • FireWire is commonly found on Apple computers and devices.
Gigahertz
Gigahertz is abbreviated GHz and is equal to one billion cycles (or instructions) per second. • 3.8 GHz is 3.8 billion instructions per second.
Hertz
Hertz is used to measure frequency, or how often something occurs. • Hertz is abbreviated Hz. • The speed of most modern processors is measured in Gigahertz, or billions of computer operations each second. • It is named for Heinrich Rudolf Hertz, the first person to provide proof of electromagnetic waves
HDMI
High-Definition Multimedia Interface (HDMI) is a standard interface for audio-video connectivity. • HDMI allows for the transmission of highdefinition audio and video signals.
What does a bus topology look like?
In a bus (or linear bus) topology, all computers are connected in sequence on a single cable, as shown in Figure 12.8. This topology has largely become legacy technology because star topologies are more efficient on Ethernet networks, and a bus topology isn't designed to easily support wireless connections. However, bus topologies are still found in some manufacturing facilities where groups of computer-controlled machines are connected.
IrDA
IrDA stands for the Infrared Data Association which establishes the protocols for infrared communication transfer. • Longer wavelength waves don't easily pass through walls or furniture (line-ofsight only). • IrDA is a wireless connection that uses Infrared (relatively long) radio waves to transmit data. IrDA devices are often used with a wireless mouse, keyboard, remote control, etc. • Because they use longer wavelength radio waves, IrDA signals don't easily pass through walls or furniture. These devices are for line-of-sight only.
Megahertz
Megahertz is abbreviated MHz and is equal to one million cycles (or instructions) per second. • 1 MHz is one million instructions per second.
Memory Cache
Memory cache is highspeed memory used by the CPU to store frequently accessed data and instructions. Memory cache is referred to by levels. - L1 cache is small and integrated into the CPU. - L3 cache is larger and next to the CPU
MIDI
Musical Instrument Digital Interface (MIDI) allows for the interface and connectivity of digital musical devices to computers. • MIDI is capable of carrying digital music signals and are common in today's music scene.
Native Resolution
Native resolution is the maximum resolution of the display device. • A laptop with 1920 (horizontal pixels) x 1080 (vertical pixels) has 2,073,600 total pixels. • The first number is horizontal resolution, and the second is vertical resolution
Overclocking
Overclocking refers to running the processor faster than recommended by the manufacturer.
ROM
ROM or read-only memory is a storage area in a digital device that is installed by the digital device manufacturer. • Most ROM can't be altered or removed. Information that is commonly stored in ROM includes a digital device's boot instructions.
What is RAM?
Random Access Memory (RAM) is a type of memory found on the motherboard of a digital device. RAM is electronic and has no moving parts. • RAM is also called main memory, which means the memory available to programs to execute tasks. • RAM is a temporary storage area and is cleared when a device is powered off.
Resolution
Resolution is the clarity of an image. • The resolution of monitors and other display devices is measured in pixels. • The more pixels in a display device, the higher the resolution. - SD 720x480 - Full HD 1920x1080 - Quad HD 2560x1440 - 4K 3840x2160
SSD Capacity
SSD capacity is the amount of storage you have available to save data and information. • Capacity is usually measured in gigabytes (billions of bytes). • The more SSD capacity you need, the more money it will cost. • SSD capacity is one of the most determinant factors of price when buying a tablet or smartphone.
SSD
Solid state drives (SSD) are all-electronic storage devices. • SSD are used in a variety of products, smartphones, cameras, and tablet computers. • SSDs have no moving parts, which makes them faster and more durable than hard drives
ALU
The ALU performs the following mathematical tasks: - Arithmetic: addition, subtraction, multiplication, and division - Comparison: equal-to-, lessthan, greater than - Logic: AND, OR, and NOT
Control Unit
The Control Unit locates, analyzes and executes each program instruction residing in memory. • Essentially, it tells the computer's memory, arithmetic logic unit, and input and output devices how to respond to a program's instructions.
Boot Process
The boot process is the loading of an operating system into the main memory of a device. • The boot process consists of 4 steps. 1. The device is powered on and the CPU activates BIOS. 2. The Power-On Self-Test is executed. 3. The OS is loaded into RAM. 4. The OS checks the registry settings and loads saved configuration settings.
Computers on a bus network behave like a group of people having a conversation in that.
The computers "listen" to the network data traffic on the media. When no other computer is transmitting data (that is, when the "conversation" stops), the computer knows it's allowed to transmit data. This means of taking turns "talking" prevents data collisions.
How does data get from point to point on a bus network?
The data is broadcast throughout the network via the media to all devices connected to the network. The data is broken into small segments, each called a packet. Each packet contains the address of the computer or peripheral device to which it's being sent. Each computer or device connected to the network listens for data that contains its address. When it "hears" data addressed to it, it takes the data off the media and processes it.
electronic data interchange (EDI)
The exchange of large amounts of data in a standardized electronic format. (such as orders for merchandise)
tunneling
The main technology for achieving a virtual private network; the placement of data packets inside other data packets.
Processor speed
The speed of a digital device's processor is determined by a number of factors. - Clock speed - Bus width
Unicode
Unicode is a common encoding standard that is capable of representing all of the world's languages. • Unicode is a 16 bit encoding standard.
USB
Universal Serial Bus (USB) is a type of interface that enables communication between digital devices. • USB allows for data transfer between devices and for devices to be electrically charged. • USB drives are sometimes referred to as thumb drives, flash drives or jump drives. USB drives use solid-state flash memory to store information on an internal memory chip. • USB drives allow for fast data transfer, are inexpensive, and durable
data collision
When two computers send data at the same time and the sets of data collide somewhere in the transmission media.
WiFi
WiFi is a wireless local area network. • The word WiFi is a play on the old audio term High-Fi. • A WiFi transmission site is called a Hotspot. • Most computers, tablets, smartphones, and gaming platforms are WiFi capable. • WiFi uses the 802.11 protocol - 2.4 GHz and 5.0 GHz radio waves.
Wireless Ports
Wireless ports allow for the transmission of data between fixed and mobile devices using short-range radio waves or light waves. • Most Bluetooth transmissions remain strong up to 10 feet away and then start to reduce in signal strength. • Infrared requires line-ofsight transmission
Word Size
Word size refers to the amount of data a processor can hold and process at one time. • Today's processors generally have word sizes of 32 or 64 bits. • A 64-bit processor can process information faster than a 32-bit processor.
Because two signals transmitted at the same time on a bus network may cause a data collision
an access method has to be established to control which computer is allowed to use the transmission media at a certain time.
A limitation of bus networks is that
data collisions can occur fairly easily because a bus network is essentially composed of one main communication medium (a single cable).
Extranets are useful for enabling
electronic data interchange (EDI)
Machine Cycle
fetch, decode, execute, store
How do VPNs work?
he main technology for achieving a VPN is called tunneling In tunneling, data packets are placed inside other data packets. The format of these external data packets is encrypted and can be understood only by the sending and receiving hardware, which is known as a tunnel interface. The hardware is optimized to seek efficient routes of transmission through the Internet. This provides a high level of security and makes information much more difficult to intercept and decrypt. Using a VPN is the equivalent of hiring a limousine and an armed guard to drive a package (your data) through a private tunnel directly to the destination
How is information kept secure on intranets and extranets?
ntranets and extranets often use virtual private networks to keep information secure.
What are the key components of a client/server network?
servers network topologies (the layout of the components) transmission media network adapters network navigation devices a network operating system
Cache
• Cache is high-speed storage usually located directly on the CPU. • Cache is smaller but faster than RAM. • Cache is used to quickly access repeated instructions
