AC power connector
Socket that is used to connect the AC power adapter to a computer or docking station.
AC power cord
Cable that transfers electricity from the AC power supply to the computer power supply.
Accelerated Graphics Port (AGP)
High-speed, 32-bit bus technology designed to support the acceleration of 3D computer graphics.
Access Control List (ACL)
List managed by a network administrator that itemizes what a user is permitted to access and the type of access granted.
access point
Device that connects wireless devices to form a wireless network. An access point usually connects to a wired network, and can relay data between wired and wireless devices. Connectivity distances can range from several feet or meters, to several miles or kilometers.
active partition
Partition on a hard disk drive that is set as the bootable partition and usually contains the operating system to be used on the computer. Only one partition on a computer can be set as an active or bootable partition on a hard disk drive.
ActiveX
Applet or small program created by Microsoft to control interactivity on web pages that has to be downloaded to gain access to the full functionality.
adapter card
Expansion card that increases the number of controllers and ports available on a computer.
Address Resolution Protocol (ARP)
Discovers the local address (MAC address) of a station on the network when the IP address is known. End stations as well as routers use ARP to discover local addresses:
-a Switch used with the ARP command that displays the cache.
-d Switch used with the ARP command that deletes an entry from the ARP cache.
-s Switch used with the ARP command that adds a permanent IP-to-MAC address mapping.
administrator
Person who queries the User Registrar to analyze individual subscriber status and to gather data.
Advanced Configuration and Power Interface (ACPI)
Interface that allows the operating system to control power management. Replaces Advanced Power Management (APM).
Advanced Power Management (APM)
Interface that allows the BIOS to control the settings for power management. This has been replaced by the Advanced Configuration and Power Interface (ACPI).
Advanced Technology Extended (ATX) power connector
20-pin or 24-pin internal power supply connector.
Advanced Technology Extended (ATX)
Standard computer case form factor for modern computers.
adware
Software program that displays advertising on a computer, usually distributed with downloaded software.
all-in-one type printer
Multi-functional device designed to provide services such as printing, fax, and copier functions.
alternating-current (AC)
Current that changes direction at a uniformly repetitious rate. This type of electricity is typically provided by a utility company and is accessed by wall sockets.
American National Standards Institute (ANSI)
Private, nonprofit organization that administers and coordinates the US voluntary standardization and conformity assessment system. ANSI identifies industrial and public requirements for national consensus standards and coordinates and manages their development, resolves national standards problems, and ensures effective participation in international standardization.
American Standard Code for Information Interchange (ASCII )
8-bit code for character representation (7 bits plus parity).
analog transmission
Signal transmission over wires or through the air in which information is conveyed through the variation of some combination of signal amplitude, frequency, and phase.
answer file
File that contains predefined settings and answers to the questions that are required by the operating system setup wizard.
antistatic bag
Packaging material that protects components from ESD.
antistatic mat
Surface that provides a safe environment for computer components by dissipating ESD.
antistatic wrist strap
Device worn on the wrist to dissipate ESD between a person and electronic equipment.
anti-virus application
Program that is installed on a system to prevent computer viruses from infecting the computer.
AppleTalk
Protocol suite to network Macintosh computers. It is comprised of a comprehensive set of protocols that span the seven layers of the OSI reference model.
application layer
Layer 7 of the OSI reference model. This layer provides services to application processes such as electronic mail, file transfer, and terminal emulation that are outside of the OSI model. The application layer identifies and establishes the availability of intended communication partners and the resources required to connect with them, synchronizes cooperating applications, and establishes agreement on procedures for error recovery and control of data integrity. Corresponds roughly with the transaction services layer in the Systems Network Architecture (SNA) model. The OSI reference model includes application layer, presentation layer, session layer, transport layer, network layer, data link layer, and physical layer
application software
Program that performs a specific function by accepting input from the user and then manipulating it to achieve a result, known as the output.
bulletarm (Acorn RISC Machine) architecture
Low-power RISC CPU.
Asymmetric DSL (ADSL)
Currently the most common DSL implementation. Speeds vary from 384 kbps to more than 6 Mbps downstream. The upstream speed is typically lower.
asymmetric encryption
Method for encrypting data on a network. Uses a private key for writing messages and a public key to decode the messages. Only the private key needs to be kept secret. Public keys can be distributed openly.
attention (AT) command set
Issues dial, hang up, reset, and other instructions to the modem. It is based on the Hayes command set.
Automatic Private IP Addressing (APIPA)
Operating system feature that enables a computer to assign itself an address if it is unable to contact a DHCP server. The Internet Assigned Numbers Authority (IANA) has reserved private IP addresses in the range of 169.254.0.0 -169.254.255.255 for APIPA.
Automatic Update
Utility to schedule the Windows Update feature to check for critical updates.
auxiliary (AUX) power connector
4-, 6-, or 8-pin connector that supplies extra voltage to the motherboard from the power supply.
backplane
Physical connection between an interface processor or card, the data buses, and the power distribution buses inside a chassis.
backup
Copy of data saved onto alternate media, and should be physically removed from the source data.
backward compatible
Hardware or software systems that can use interfaces and data from earlier versions of the system or with other systems. Also known as backward-compatible or backwards compatible.
bandwidth
Amount of data that can be transmitted within a fixed time period.
base station
Device that attaches a laptop to AC power and to desktop peripherals.
Basic Input/Output System (BIOS)
Program stored in a ROM chip in the computer that provides the basic code to control the computer’s hardware and to perform diagnostics on it. The BIOS prepares the computer to load the operating system.
Basic Rate Interface (BRI)
ISDN interface composed of two B channels and one D channel for circuit-switched communication of voice, video, and data. Compare with PRI.
battery latch
Tool used to insert, remove, and secure the laptop battery.
battery status indicator LED
Light that indicates the condition of the laptop battery.
battery
Electrical device that converts chemical energy into electrical energy.
beep code
Audible reporting system for errors that are found by the BIOS during the POST, represented by a series of beeps.
Berg power connector
Keyed connector that supplies power to a floppy drive.
biometric device
Tool that uses sensors, such as a fingerprint or retinal scanner, that identify physical characteristics of the user to allow access to a device or a network.
bit rate
Speed at which bits are transmitted, usually expressed in bits per second (bps).
bit
Smallest unit of data in a computer. A bit can take the value of either 1 or 0. A bit is the binary format in which data is processed by computers.
blackout
Complete loss of AC power.
Bluetooth
Wireless industry standard that uses an unlicensed radio frequency for short-range communication enabling portable devices to communicate over short distances.
boot
To start a computer.
boot record
512-byte file containing a table that describes the partition, the number of bytes per sector, and the number of sectors per cluster.
bootable disk
Troubleshooting tool that allows the computer to boot from a disk when the hard drive will not boot.
broadband
Multiple signals using multiple frequencies over one cable.
broadband optical telepoint
Infrared broadband transmission capable of handling high-quality multimedia requirements.
broadband satellite
Network connection using a satellite dish.
brownout
Temporary drop in AC power.
buffer
Storage area used for handling data in transit. Buffers are used in internetworking to compensate for differences in processing speed between network devices. Bursts of data can be stored in buffers until they can be handled by slower processing devices. Sometimes referred to as a packet buffer.
bus topology
Network with each computer connecting on a common cable.
bus
Media through which data is transferred from one part of a computer to another. The bus can be compared to a highway on which data travels within a computer.
byte
A unit of measure that describes the size of a data file, the amount of space on a disk or other storage medium, or the amount of data being sent over a network. One byte consists of 8 bits of data.
C: drive
Generally the label for the first hard drive in a computer system. Drive A and Drive B are reserved for floppy drives. Drive B is rarely used on current computers.
cable modem
Acts like a LAN interface by connecting a computer to the Internet. The cable modem connects a computer to the cable company network through the same coaxial cabling that feeds cable TV (CATV) signals to a television set.
cable tie
Fastener used to bundle cables inside and outside of a computer.
cable
Set of conductors, bundled and sheathed together, made of insulated copper or optical fiber that transport signals and power between electrical devices.
cache
Data storage area that provides high-speed access for the system.
Caps lock indicator LED
Light that shows the on/off status of the caps lock.
card key
Identity card with a chip that stores user data, including the level of access.
Category 3
Cable that is primarily used in telephone connections.
Category 5
Cable that contains four pairs of wires, with a maximum data rate of 1 Gbps.
Category 5e
Cable that provides more twists per foot than Category 5 at the same data rate of 1 Gbps.
Category 6
Cable that is enhanced with more twists than Category 5e cable. It contains a plastic divider that separates the pairs of wires to prevent crosstalk.
cellular WAN
Wide area network that has the technology for the use of a cell phone or a laptop for voice and data communications.
central processing unit (CPU)
Interprets and processes software instructions and data. Located on the motherboard, the CPU is a chip contained on a single integrated circuit called the microprocessor. The CPU contains two basic components, a control unit and an Arithmetic/Logic Unit (ALU).
chip
Small slice of silicon or germanium processed to have electrical characteristics so that it can be developed into an electronic component. Also called semiconductor.
chip set
Chips on a motherboard that enable the CPU to communicate and interact with the other components of the computer.
CHKDSK
Command used to check the integrity of files and folders on a hard drive by scanning the disk surface for physical errors.
client/server network
Network in which services are located in a dedicated computer that responds to client, or user, requests.
cluster
Smallest unit of space used for storing data on a disk. Also called file allocation unit.
CMOS battery
Battery that supplies power to maintain basic configuration information, including the real time clock, when the computer is turned off.
CMYK
Display colors: cyan, magenta, yellow, and black.
coaxial cable
Copper-cored cable surrounded by a heavy shielding used to connect computers in a network.
cold boot
To power up a computer from the off position.
color ink jet printer
Type of printer that uses liquid-ink–filled cartridges that spray ink to form an image on the paper.
Comité Consultatif International Téléphonique et Télégraphique (CCITT)
Committee that defines international communications standards. The CCITT defines the standards for sending fax documents and the standards for data transmission over telephone lines.
command line interface (CLI)
Interface, such as a DOS prompt, that requires commands to be entered manually on the command line.
compact disc - read only memory (CD-ROM)
Optical storage media for audio and data.
compact disc (CD) drive
Optical device that reads compact discs.
compact disc-recordable (CD-R)
Optical media that allows data to be recorded but not modified.
compact disc-rewritable (CD-RW)
Optical storage media that allows data to be recorded and modified.
Complementary Metal Oxide Semiconductor (CMOS)
Type of semiconductor, or low-power memory firmware, that stores basic configuration information.
Complex Instruction Set Computer (CISC)
Architecture that uses a broad set of instructions, with several choices for almost every operation. The result is that a programmer can execute precisely the command needed, resulting in fewer instructions steps per operation.
compressed air
Air under pressure in a can that blows dust off of computer components without creating static. Also called canned air.
computer
Electrical machine that can execute a list of instructions and perform calculations based on those instructions.
computer network
Two or more computers connected together by some medium to share data and resources.
computer system
Combination of hardware and software components. Hardware is the physical equipment such as the case, floppy disk drives, keyboards, monitors, cables, speakers, and printers. Software describes the programs that operate the computer system.
computer-aided design (CAD)
Application used for creating architectural, electrical, and mechanical design. More complex forms of CAD include solid modeling and parametric modeling, which allow objects to be created with real-world characteristics.
conduit
Casing that protects the infrastructure media from damage and unauthorized access.
configuration tool
Service management tool or a Element management service tool with a GUI.
connector
Device used to terminate cable.
conventional memory
All memory addresses from 0 to 640 KB.
cookie
Small text file that is stored on the hard disk that allows a website to track the user’s association to that site.
copy backup
Backs up user-selected files to tape. This backup does not reset the archive bit.
crosstalk
Interfering energy, such as Electro Magnetic Interference (EMI) that is transferred from one circuit to another.
current (I)
Flow of electrons in a conductor that is measured in amperes.
customer replaceable unit (CRU)
Component that customers may install at their location.
cylinder
All the tracks on a hard disk with the same number. Collectively, the same track on all platters of a multi-platter hard drive.
daily backup
Backs up only the files that are modified on the day of the backup. This backup does not reset the archive bit.
data backup
Information on a computer stored on removable backup media that can be kept in a safe place. If the computer hardware fails, the data backup can be restored so that processing can continue.
data transfer rate
Refers to how fast the computer can transfer information into memory.
database
Organized collection of data that can be easily accessed, managed, indexed, searched, and updated.
data-link layer
Layer 2 of the OSI reference model. This layer provides reliable transit of data across a physical link. The data-link layer is concerned with physical addressing, network topology, line discipline, error notification, ordered delivery of frames, and flow control. The IEEE has divided this layer into two sub layers, the MAC sub layer and the LLC sub layer. Sometimes simply called link layer. Roughly corresponds to the data link control layer of the SNA model. The OSI reference model includes application layer, presentation layer, session layer, transport layer, network layer, data link layer, and physical layer.
default gateway
Route taken so that a computer on one segment can communicate with a computer on another segment.
default installation
Installation that requires minimal user interaction. Also called a typical installation.
default printer
First option that an application uses when the user clicks the printer icon. The default printer can be changed by the user.
DEFRAG
Command that rearranges the data and rewrites all the files on the hard drive to the beginning of the drive, making it easier and faster for the hard drive to retrieve data.
denial of service (DoS)
Form of attack that prevents users from accessing normal services, such as e-mail or a web server, because the system is busy responding to abnormally large amounts of requests. DoS works by sending an abundance of requests for a resource to cause the system to overload and cease to operate.
desktop
Metaphor used to portray file systems. A desktop consists of pictures, called icons, which show files, folders, and any resource available to a user in a GUI operating system.
desktop computer
Type of computer designed to fit on top of a desk, usually with the monitor on top of the computer to conserve space. Desktop computers are not mobile like laptop computers.
Device Manager
Application that displays a list of all the hardware that is installed on the system.
diagnostic software
Programs that assist in the troubleshooting process.
diagnostic tools
Utilities that monitor the network server.
dial-up networking (DUN)
Using the public telephone system or network to communicate.
differential backup
Backs up all the files that have been created or modified since the last full backup. It does not reset the archive bit.
digital audio tape (DAT)
Tape standard that uses 4 mm digital audiotapes to store data in the Digital Data Storage (DSS) format.
digital linear tape (DLT)
Technology offers high capacity and relatively high-speed tape backup capabilities.
digital multimeter (DMM)
Tool that combines the functionality of a voltmeter, ohmmeter, and ammeter into one easy measuring device.
digital subscriber line (DSL)
Public network technology that delivers high bandwidth over conventional copper wiring at limited distances. Always-on technology that allows users to connect to the Internet.
digital versatile disc (DVD)
Removable media that is used primarily for movie and data storage.
Digital Visual Interface (DVI)
Interface that supplies uncompressed digital video to a digital monitor.
direct memory access (DMA)
Method for bypassing the CPU when transferring data from the main memory directly to a device.
direct-current (DC)
Current flowing in one direction, as used in a battery.
directory
1) Type of file that organizes other files in a hierarchical structure. 2) Related program and data files organized and grouped together in the DOS file system.3) Place to store data in the Windows file-management system.
disk cleanup
Disk management software that is used to clear space on a hard drive by searching for files that can be safely deleted, such as temporary Internet files.
disk management
System utility used to manage hard drives and partitions, such as initializing disks, creating partitions, and formatting partitions.
disk operating system (DOS)
Collection of programs and commands that control overall computer operations in a disk-based system.
display
Computer output surface and projecting mechanism that shows text and graphic images.
DNS poisoning
Changing the DNS records on a system to point to false servers where the data is recorded
docking connector
Socket used to attach a docking station to the laptop.
docking station
Device that attaches a laptop to AC power and desktop peripherals.
domain
Logical group of computers and electronic devices with a common set of rules and procedures administered as a unit.
Domain Name System (DNS)
System that provides a way to map friendly host names, or URLs, to IP addresses.
dot matrix printer
Printer that operates by impacting the ribbon to place an image on the paper.
dots per inch (dpi)
Measurement of print quality. How the quality of print is measured on a dot matrix printer, and the higher the dpi, the higher the quality of print.
drive bay
Standard-sized area for adding hardware to a computer case. The two most common drive bays are used to house a CD\DVD drive and a floppy drive.
drive letter
Designation that distinguishes the physical or logical drives in Windows.
drive mapping
Process of assigning a letter to a physical or logical drive.
dual core CPU
Two cores inside a single CPU chip. Both cores can be used together to increase speed, or they can be used in two locations at the same time.
dual in-line memory module (DIMM)
Circuit board with a 64-bit data bus that holds memory chips. Memory module with 168 pins. Supports 64-bit data transfers.
dual ring
All the devices on the network connect to two cables and the data travels in both directions. Only one cable is used at a time. In the event of a failure of one ring, data is transmitted on the other ring.
DVD drive
Optical device that reads DVDs. A DVD-ReWritable (DVD-RW) drive can write to DVD-RWs.
DVD-ROM
DVD format that is designed for storing computer files.
DVD-RW
Technology that allows the media to be recorded multiple times.
DVD-Video
DVD format that is used by standalone DVD players for movies and extras.
dye-sublimation printer
Printer that uses solid sheets of ink that change from solid to gas, in a process called sublimating. The gas then passes through the paper, where it turns back to a solid. The print head passes over a sheet of cyan, magenta, yellow, and a clear overcoat (CMYO). Also called thermal dye printer.
Dynamic Host Configuration Protocol (DHCP)
Software utility that automatically assigns IP addresses to client devices in a large network.
dynamic RAM (DRAM)
RAM that stores information in capacitors that must be periodically refreshed. Delays can occur because DRAMs are inaccessible to the processor when refreshing their contents. However, DRAMs are less complex and have greater capacity than SRAMs.
dynamic routing
Routing that adjusts automatically to network topology or traffic changes. Also called adaptive routing.
eject button
Lever that releases an object, such as the button on a floppy drive.
Electronic Industries Association (EIA)
Group that specifies electrical transmission standards. The EIA and TIA have developed numerous well-known communications standards, including EIA/TIA-232 and EIA/TIA-449.
electronic mail (e-mail)
Ability for users to communicate over a computer network. The exchange of computer-stored messages by network communication.
electrophotographic drum
Central part of the laser printer that acquires the toner to be printed on paper.
electrostatic discharge (ESD)
Discharge of static electricity from one conductor to another conductor of a different potential.
encryption
Security feature that applies a coding to a file so that only authorized users can view the file.
Encryption File System (EFS)
Microsoft specific file system for encryption.
Enhanced Integrated Drive Electronics (EIDE)
Enhanced version of the standard IDE interface that connects hard disks, CD-ROM drives, and tape drives to a PC.
Ethernet
Baseband LAN specification invented by Xerox Corporation and developed jointly by Xerox, Intel, and Digital Equipment Corporation. Ethernet networks use CSMA/CD and run over a variety of cable types at 10 Mbps or more. Ethernet is similar to the IEEE 802.3 series of standards.
Ethernet port
RJ-45 socket that is used to connect a computer to a cabled local area network.
event
Network message indicating operational irregularities in physical elements of a network or a response to the occurrence of a significant task, typically the completion of a request for information.
Event Viewer
Application that monitors system events, application events, and security events.
exhaust vent
Outlet that expels hot air from the interior of a device or room.
expansion card modem
Modem that is inserted into a motherboard expansion slot (ISA or PCI). Also called an internal modem.
expansion slot
Opening in a computer where a PC card can be inserted to add capabilities to the computer.
ExpressCard
High-throughput, laptop expansion card standard that was developed by the PCMCIA. The ExpressCard expansion slot uses the built-in PCI Express (x1) and/or USB bus of a laptop. ExpressCards have a 26-pin connector and are hot-swappable.
extended memory
Memory above 1 MB.
extended partition
Second partition on the hard drive.
extended-star topology
Star topology that is expanded to include additional networking devices.
external hard drive
Device that connects to the computer to provide additional data storage.
external modem
Modem that connects to the serial port (COM1 or COM2) of most computers. An external modem, such as a cable modem, is typically used for high-speed connections.
Fast Ethernet
Any of a number of 100-Mbps Ethernet specifications. Fast Ethernet offers a speed increase ten times that of the 10BASE-T Ethernet specification, while preserving such qualities as frame format, MAC mechanisms, and MTU. Such similarities allow the use of existing 10BASE-T applications and network management tools on Fast Ethernet networks. Based on an extension to the IEEE 802.3 specification. Compare with Ethernet.
FDISK
Command used to delete and create partitions on the hard drive:\STATUS Switch that displays partition information when used with the FDISK - command.
Fiber Distributed Data Interface (FDDI)
Type of Token Ring network that is used in larger LANs.
fiber-optic cable
Physical medium capable of conducting modulated light transmission. Compared with other transmission media, fiber-optic cable is more expensive, but is not susceptible to electromagnetic interference, and is capable of higher data rates. Sometimes called optical fiber.
fiber-optic cable
Uses glass or plastic wire, also called fiber, to carry information as light pulses. Conducts modulated light to transmit data.
field-replaceable unit (FRU)
Component that a trained service technician may install at a remote location.
file
A block of logically related data that is given a single name and is treated as a single unit.
file allocation table (FAT)
Table that the operating system uses to store information about the location of the files stored on a disk. This file is stored in track 0 on the disk.
file extension
Designation that describes the file format or the type of application that created a file.
file management
Hierarchical structure of files, folders, and drives in Windows.
file system
The two file systems available in Windows XP are FAT32 and NTFS. NTFS has greater stability and security features.
File Transfer Protocol (FTP)
Set of rules governing how files are transferred. FTP allows multiple simultaneous connections to remote file systems.
fingerprint reader
Input device that scans fingerprints to authenticate login using biometric identification.
firewall
Router or access server, or several routers or access servers, designated as a buffer between any connected public networks and a private network. A firewall router uses access lists and other methods to ensure the security of the private network.
FireWire
High-speed, platform-independent communication bus. FireWire interconnects digital devices such as digital video cameras, printers, scanners, digital cameras, and hard drives. FireWire is also known as IEEE 1394, i.Link (Sony proprietary), and linear heat detecting cable (LHDC) in the U.K.
firmware
Program that is embedded in a silicon chip rather than stored on a floppy disk.
Flash memory
Rewritable memory chip that retains data after the power is turned off.
flat-head screwdriver
Tool used to loosen or tighten slotted screws.
floppy data cable
External cable that transfers data between the computer and the floppy drive.
floppy disk drive (FDD)
Device that spins a magnetically coated floppy disk to read data from and write data to it.
floppy drive cable
External cable that connects the computer and the floppy drive.
form factor
Physical size and shape of computer components. Components that share the same form factor are physically interchangeable.
format
To prepare a file system in a partition to store files.
full backup
Backs up all files on a disk. Also called a normal backup.
full-duplex transmission
Data transmission that can go two ways at the same time. An Internet connection using DSL service is an example.
function key (Fn key)
Modifier key usually found on laptop computers. It is used in combination with other keys to perform specific functions.
gamepad
External controller used as an input device, primarily for gaming.
gigahertz (GHz)
Common measurement of a processor equal to one billion cycles per second.
Global System for Mobile Communications (GSM)
World-wide cellular network.
graphical user interface (GUI)
Interface that allows the user to navigate through the operating system using icons and menus.
graphics application
Creates or modifies graphical images. The two types of graphical images include object- or vector-based images, and bitmaps or raster images.
Graphics Device Interface (GDI)
Windows component to manage how graphical images are transmitted to output devices. GDI works by converting images to a bitmap that uses the computer instead of the printer to transfer the images.
grayware
Spyware that installs on a computer without being prompted and downloads additional applications without permission from the user.
half-duplex transmission
Data transmission that can go two ways, but not at the same time. A telephone and two-way radio are examples.
handshaking sequence
Series of short communications that occur between the two modems This establishes the readiness of the two modems and computers to engage in data exchange.
handwriting recognition
Ability of computer, especially mobile devices, to recognize letters and numbers written by hand and convert them to ASCII text.
hard disk drive (HDD)
Device that stores and retrieves data from magnetic-coated platters that rotate at high speeds. The hard drive, or HDD, is the primary storage medium on a computer.
Hardware Abstraction Layer (HAL)
Library of hardware drivers that communicate between the operating system and the hardware that is installed.
Hardware Compatibility List (HCL)
Utility that verifies existing hardware is compatible with an operating system.
hardware firewall
Hardware device that filters data packets from the network before reaching computers and other devices on a network.
hardware
Physical electronic components that make up a computer system.
Hayes-compatible command set
Set of AT commands that most modem software uses. This command set is named after the Hayes Microcomputer Products Company, which first defined them.
headphone jack
Socket that is used to attach an audio output device.
heat sink and fan assembly
Device that dissipates heat from electronic components into the surrounding air.
hex driver
Driver used to tighten nuts. Sometimes called a nut driver,
Hibernate/Standby indicator LED
Light that shows if the computer is in standby or hibernate mode.
hierarchical star topology
Extended star topology where a central hub is connected by vertical cabling to other hubs that are dependent on it.
High Data Rate DSL (HDSL)
Provides a bandwidth of 768 kbps in both directions.
High Definition Multimedia Interface (HDMI)
Video, plasma, LCD, or DLP projector.
HKEY_
Designation at the beginning of Windows Registry boot file names.
host
Computer system on a network. Similar to the term node except that host usually implies a computer system, whereas node generally applies to any networked system, including access servers and routers.
hot-swappable interface
Allows peripherals to be changed while the system is running. USB is an example.
hub
1) Generally, a term used to describe a Layer 1 device that serves as the center of a star-topology network.
2) Hardware or software device that contains multiple independent but connected modules of network and internetwork equipment. Hubs can be active (where they repeat signals sent through them) or passive (where they do not repeat, but merely split, signals sent through them).
3) In Ethernet and IEEE 802.3, an Ethernet multiport repeater, sometimes referred to as a concentrator.
Hypertext Markup Language (HTML)
Page-description language used by browser applications such as Windows Internet Explorer or Mozilla Firefox.
Hypertext Transfer Protocol (HTTP)
Governs how files are exchanged on the Internet.
I/O shield
Grounded metal plate installed in the rear of the case that enables the motherboard connectors to be accessed from the outside of the case.
icon
Image that represents an application or a capability.
IEEE 802.1
IEEE specification that describes an algorithm that prevents bridging loops by creating a spanning tree. The algorithm was invented by Digital Equipment Corporation. The Digital algorithm and the IEEE 802.1 algorithm are not exactly the same, nor are they compatible.
IEEE 802.12
IEEE LAN standard that specifies the physical layer and the MAC sub layer of the data-link layer. IEEE 802.12 uses the demand priority media-access scheme at 100 Mbps over a variety of physical media.
IEEE 802.2
IEEE LAN protocol that specifies an implementation of the LLC sub layer of the data-link layer. IEEE 802.2 handles errors, framing, flow control, and the network layer, Layer 3, service interface. Used in IEEE 802.3 and IEEE 802.5 LANs.
IEEE 802.3
IEEE LAN protocol that specifies an implementation of the physical layer and the MAC sub layer of the data-link layer. IEEE 802.3 uses CSMA/CD access at a variety of speeds over a variety of physical media. Extensions to the IEEE 802.3 standard specify implementations for Fast Ethernet. Physical variations of the original IEEE 802.3 specification include 10BASE2, 10BASE5, 10BASE-F, 10BASE-T, and 10Broad36. Physical variations for Fast Ethernet include 100BASE-T, 100BASE-T4, and 100BASE-X.
IEEE 802.3i
Physical variation of the original IEEE 802.3 specification that calls for using Ethernet type signaling over twisted pair networking media. The standard sets the signaling speed at 10 megabits per second using a baseband signaling scheme transmitted over twisted pair cable employing a star or extended star topology.
IEEE 802.4
IEEE LAN protocol that specifies an implementation of the physical layer and the MAC sub layer of the data-link layer. IEEE 802.4 uses token-passing access over a bus topology and is based on the token bus LAN architecture.
IEEE 802.5
IEEE LAN protocol that specifies an implementation of the physical layer and MAC sub layer of the data link-layer. IEEE 802.5 uses token passing access at 4 or 16 Mbps over shielded twisted-pair (STP) cabling and is similar to IBM Token Ring.
IEEE 802.6
IEEE MAN specification based on DQDB technology. IEEE 802.6 supports data rates of 1.5 to 155 Mbps.
impact printer
Class of printer that includes dot matrix and daisy wheel.
incremental backup
Procedure to back up all the files and folders that have been created or modified since the last full or normal backup.
infrared (IR)
Electromagnetic waves whose frequency range is above that of microwaves, but below that of the visible spectrum. LAN systems based on this technology represent an emerging technology.
infrared port
Line-of-sight wireless transceiver that is used for data transmission.
infrared scatter
Infrared signal that is bounced off ceilings and walls. Devices are able to connect without the line of sight, but data transfer rates are lower and distances are shorter.
inkjet printer
Type of printer that uses liquid-ink–filled cartridges that spray ink to form an image on the paper.
input/output (I/O)
Any operation, program, or device that transfers data to or from a computer.
input/output (I/O) address
Unique hexadecimal memory address that is associated with a specific device on a computer.
installation CD
Compact disc that includes new software with drivers and manuals. Additionally, may include diagnostic tools and trial software.
instant messaging (IM)
Real-time text-based method of communication conducted over a network between two or more users.
Institute of Electrical and Electronics Engineers (IEEE)
Organization that oversees the development of communication and network standards.
insulation
High resistance material that inhibits the flow of current between conductors in a cable.
Integrated Services Digital Network (ISDN)
Communication protocol, offered by telephone companies, that permits telephone networks to carry data, voice, and other source traffic.
interface
1) Connection between two systems or devices.
2) In routing terminology, a network connection.
3) In telephony, a shared boundary defined by common physical interconnection characteristics, signal characteristics, and meanings of interchanged signals.
4) The boundary between adjacent layers of the OSI model.
Interior Gateway Protocol (IGP)
Internet protocol that is used to exchange routing information within an autonomous system. Examples of common Internet IGPs include EIGRP, OSPF, and RIP.
International Electrotechnical Commission (IEC)
Industry group that writes and distributes standards for electrical products and components.
International Organization for Standardization (ISO)
International organization that sets standards for networking. ISO developed the OSI reference model, a popular networking reference model.
Internet
Largest global internetwork that connects tens of thousands of networks worldwide.
Internet Architecture Board (IAB)
Board of internetwork researchers who discuss issues pertinent to Internet architecture. Responsible for appointing a variety of Internet-related groups such as the IANA, IESG, and IRSG. The IAB is appointed by the trustees of the ISOC.
Internet Control Message Protocol (ICMP)
Used for network testing and troubleshooting, it enables diagnostic and error messages. ICMP echo messages are used by the ping utility to determine whether a remote device is reachable.
Internet Message Access Protocol (IMAP)
Used by local e-mail clients to synchronize and retrieve e-mail from a server.
Internet Protocol (IP)
Network layer protocol in the TCP/IP stack that offers a connectionless internetwork service. IP provides features for addressing, type-of-service specification, fragmentation and reassembly, and security. Documented in RFC 791.
Internet service provider (ISP)
Company that provides Internet service to home users, such as the local phone or cable company.
Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX)
Used by Novell Netware; IPX is a connectionless communication and SPX is the transport layer (Layer 7 of the OSI model).
interrupt request (IRQ)
A request from a device for communication with the CPU.
Java
Programming language for applets to run within a web browser. Examples of applets include a calculator or a counter.
JavaScript
Programming language developed to interact with HTML source code for interactive websites. Examples include a rotating banner or a popup window.
jumper
Electrical contact points used to set a hard drive as master or slave.
keyboard port
PS/2 socket used to attach an external keyboard.
keyboard
Input device with multi-functional keys.
kilobytes per second (KBps)
Measurement of the amount of data that is transferred over a connection such as a network connection. A data transfer rate of 1 KBps is a rate of approximately 1,000 bytes per second.
laptop battery
Rechargeable battery that powers the laptop.
laptop connector
Socket that is used to attach the laptop to a docking station.
laptop keyboard
Input device that includes alphanumeric, punctuation, and special function keys.
laptop latch
Lever used to open the laptop lid.
laptop
Small form factor computer designed to be mobile, but operates much the same as a desktop computer. Laptop hardware is proprietary and usually more expensive than desktop hardware.
laser printer
Type of printer that uses static electricity and a laser to form the image on the paper.
latent image
In laser printers, the undeveloped image.
LCD monitor
Output device that passes polarized light through liquid crystals to produce images on the screen.
light-emitting diode (LED)
Type of semiconductor that emits light when current is passed through it. The LED indicates whether components inside the computer are on.
line of sight
Characteristic of certain transmission systems such as laser, microwave, and infrared systems in which no obstructions in a direct path between transmitter and receiver can exist.
line-in connector
Socket that is used to attach an audio source.
liquid crystal display (LCD)
Type of light-weight, high-resolution display that works by blocking light rather than creating it.
local area network (LAN)
Communication network that covers a small geographical area and is under the control of a single administrator.
local security policy
Combination of security settings that define the security of the computer on which the settings reside.
logical drive
Section that a partition is divided into.
logical topology
Actual method (ring or bus) by which different computers and other equipment in a network communicate with one another. Contrast with physical topology.
loopback plug
Diagnostic tool that redirects signals back to the transmitting port to troubleshoot connectivity.
MAC address
Standardized data link layer address that is required for every port or device that connects to a LAN. Other devices in the network use these addresses to locate specific ports in the network and to create and update routing tables and data structures. MAC addresses are 6 bytes long and are controlled by the Institute of Electrical and Electronics Engineers (IEEE). Also known as a hardware address, a MAC-layer address, burnt-in address, or a physical address.
main distribution facility (MDF)
Primary communications room for a building. Also, the central point of a star networking topology where patch panels, hubs, and routers are located.
malware
Term taken from the words malicious and software. Malware is software designed to infiltrate or damage a computer system without the consent of the user.
Master Boot Record (MBR)
Program on the first sector of a hard disk that starts the boot process. The MBR determines which partition is used for booting the system and then transfers control to the boot sector of that partition, which continues the boot process. MBR allows programs such as DOS to load into RAM.
Material Safety and Data Sheet (MSDS)
A fact sheet that identifies hazardous materials.
mean time between failures (MTBF)
Average length of time that the device will work without failing. Information is found in the manual or on the manufacturer website.
media
The plural form of medium. The various physical environments through which transmission signals pass. Common network media include twisted-pair, coaxial and fiber-optic cable, and the atmosphere (through which microwave, laser, and infrared transmission occurs).
Media Access Control (MAC)
Lower of the two sub layers of the data link layer defined by the Institute of Electrical and Electronics Engineers (IEEE). The MAC sub layer handles access to shared media, such as whether token passing or contention will be used. Also the rules for coordinating the use of the medium on a LAN.
media-handling options
Options by which a printer handles media, including the orientation, size, and weight of the paper.
megabit
1,048,576 bits (approximately 1 million bits).
megabits per second (Mbps)
Common measurement of the amount of data that is transferred over a connection in one second. A data transfer rate of 1 Mbps is a rate of approximately 1 million bits or 1,000 kilobits per second.
megabyte (MB)
1,048,576 bytes (or approximately 1 million bytes).
mesh grip
Tool attached to the end of a cable to help pull cable.
mesh topology
Method of connecting users that provides alternate paths for data. If one path is severed or unusable, the data can take an alternate path to its destination.
microphone
Audio input device.
microphone jack
Socket used to connect a microphone used for audio input.
microwave
Electromagnetic waves that range from 1 to 30 GHz. Microwave-based networks are an evolving technology gaining popularity due to high bandwidth and relatively low cost.
mobile processor
CPU that is optimized to use less power allowing laptop batteries to last longer.
modem port
RJ-11 jack that connects a computer to a standard telephone line. The modem port can be used to connect the computer to the Internet, to send and receive fax documents, and to answer incoming calls.
modulator/demodulator (modem)
Device that converts digital computer signals into a format that is sent and received over an analog telephone line.
Molex power connector
Four-wire computer power connector used to connect many devices such as optical drives and hard drives.
monitor
Display device that works with the installed video card to present output from a computer. The clarity of a CRT monitor is based on video bandwidth, dot pitch, refresh rate, and convergence.
motherboard
Main printed circuit board that connects all the components of the computer such as the CPU, BIOS, memory, mass storage interfaces, serial and parallel ports, expansion slots, and controllers required for standard peripheral devices.
mouse port
PS/2 socket that is used to attach an external mouse.
MSCONFIG
Windows utility designed to aid in the troubleshooting of the operating system. Allows the user to edit start-up applications and access the BOOT.INI, SYSTEM.INI, and WIN.INI files.
multimeter
Troubleshooting tool that measures electrical voltage, resistance, and current.
multimode
Optical fiber that has a thicker core than single-mode. It is easier to make, can use simpler light sources, such as LEDs, and works well over short distances. This type of fiber allows light waves to be dispersed into many paths as they travel through the fiber.
multiprocessing
To enable programs to share two or more CPUs.
Multipurpose Internet Mail Extensions (MIME)
Standard that extends the e-mail format to include text in ASCII standard, as well as other formats such as pictures and word processor documents. Normally used in conjunction with SMTP.
multitask
To run two or more applications at the same time.
multithread
To divide a program into smaller parts that can be loaded as needed by the operating system. Multithreading allows individual programs to be multitasked.
multi-user
Two or more users running programs and sharing peripheral devices, such as a printer, at the same time.
My Computer icon
Desktop icon that provides access to the installed drives and other computer properties.
near letter quality (NLQ)
Quality of print that is better than draft quality, but not as good as letter quality.
needle-nose pliers
Tool with long and slender jaws that can be used to grasp small objects.
NetView
IBM network management architecture and related applications. NetView is a virtual telecommunications access method (VTAM) application used for managing mainframes in Systems Network Architecture (SNA) networks.
network
Group of two or more electronic devices, such as computers, PDAs, and smartphones which communicate with each other to share data and resources.
Network Access Point (NAP)
Point at which access providers are interconnected.
network administration
Task of maintaining and upgrading a private network that is done by network administrators.
Network Basic Input/Output System (NetBIOS)
Application programming interface (API) used by applications on an IBM LAN to request services from lower-level network processes. These services might include session establishment and termination, and information transfer.
network cable
Physical media used to connect devices together for communication.
network file services
Allow documents to be shared over a network to facilitate the development of a project.
network indicator LED
Light that shows the status of the network connection. The green link light indicates network connectivity. The other LED light indicates traffic.
network interface card (NIC)
Computer interface with the LAN. This card typically is inserted into an expansion slot in a computer and connects to the network medium.
network layer
Layer 3 of the Open System Interconnection (OSI) reference model. This layer provides connectivity and path selection between two end systems. The network layer is the layer at which routing occurs. Corresponds roughly with the path control layer of the Systems Network Architecture (SNA) model. The OSI reference model includes application layer, presentation layer, session layer, transport layer, network layer, data link layer, and physical layer.
network operating system (NOS )
Operating system designed specifically to provide additional network features.
network printer
Printer connected to the computer network that is set up to be shared by multiple users.
network server
Computer that provides some network service, such as file sharing, and is capable of handling multiple users and multiple jobs.
network topology
Way that computers, printers, and other devices are connected.
networking media
Material (either cable or air) by which signals are sent from one network device to another.
New Technology File System (NTFS)
Type of file system that provides improved fault tolerance over traditional file systems, and also provides file-level security.
nibble
Half a byte, or four bits.
node
1) The endpoint of a network connection or a junction common to two or more lines in a network. Nodes can be processors, controllers, or workstations. Nodes, which vary in routing and other functional capabilities, can be interconnected by links, and serve as control points in the network. Node is sometimes used generically to refer to any entity that can access a network, and is frequently used interchangeably with device.
2) In Systems Network Architecture (SNA), the basic component of a network, and the point at which one or more functional units connect channels or data circuits.
noise
Interference, such as EMI or RFI, that causes unclean power and may cause errors in a computer system.
non-bootable disk
Damaged or missing disk, or a disk that does not contain one or more system boot files.
northbridge
One of the two chips in the core logic chipset of a PC motherboard. It typically handles communications between the CPU, RAM, AGP, PCIe, and the southbridge core chip. Also called a Memory Controller Hub (MCH).
NSLOOKUP
Command that returns the IP address for a given host name. This command can also do the reverse and find the host name for a specified IP address.
NTDETECT
Program used by Intel-based systems to detect installed hardware.
Num lock indicator LED
Light that shows the on/off status of the 10-key number pad.
Ohm's Law
The mathematical relationship between current, resistance, and voltage where voltage is equal to the current multiplied by the resistance.
operating system
Software program that performs general system tasks, such as controlling RAM, prioritizing the processing, controlling input and output devices, and managing files.
optical drive activity indicator LED
Light that shows drive activity.
optical drive
Disk drive that uses a laser to read and/or write CDs and DVDs.
packet
Logical grouping of information which includes a header that contains control information and usually user data. Packets are most often used to refer to network layer units of data. The terms datagram, frame, message, and segment are also used to describe logical information groupings at various layers of the Open System Interconnection (OSI) reference model and in various technology circles.
Packet Internet Gopher (ping)
Simple but highly useful command-line utility that is included in most implementations of TCP/IP. Ping can be used with either the host name or the IP address to test IP connectivity. Determines whether a specific IP address is accessible by sending an ICMP echo request to a destination computer or other network device. The receiving device then sends back an ICMP echo reply message.
Page Description Language (PDL)
Code that describes the contents of a document in a language that the printer can understand.
pages per minute (ppm)
Designation for measuring the speed of a printer.
Paralle