Computer Terms and Abbreviations
100BaseT An Ethernet standard that operates at 100 Mbps and uses STP cabling. Also called Fast Ethernet. Variations of 100BaseT are 100BaseTX and 100BaseFX.
10Base2 An Ethernet standard that operates at 10 Mbps and uses small coaxial cable up to 200 meters long. Also called ThinNet.
10Base5 An Ethernet standard that operates at 10 Mbps and uses thick coaxial cable up to 500 meters long. Also called ThickNet.
32-bit flat memory mode A protected process- ing mode used by Windows NT/2000/XP to process programs written in 32-bit code early in the boot process.
3-D RAM Special video RAM designed to improve 3-D graphics simulation.
80 conductor IDE cable An IDE cable that has 40 pins but uses 80 wires, 40 of which are ground wires designed to reduce crosstalk on the cable. The cable is used byATA/66,ATA/100, and ATA/133 IDE drives.
802.lib See IEEE 802.1 Ib.
access point (AP) A device connected to a LAN that provides wireless communication so that computers, printers, and other wireless devices can communicate with devices on the LAN.
ACPI (Advanced Configuration and Power Interface) Specification developed by Intel, Compaq, Phoenix, Microsoft, and Toshiba to control power on notebooks and other devices. Windows 98 and Windows 2000/XP support ACPI.
active backplane A type of backplane system in which there is some circuitry, including bus connectors, buffers, and driver circuits, on the backplane.
Active Directory A Windows 2000 and Windows .NET directory database service that allows for a single point of administration for all shared resources on a network, including files, peripheral devices, databases. Web sites, users, and services.
active matrix A type of video display that ampli- fies the signal at every intersection in the grid of electrodes, which enhances the pixel quality over that of a dual-scan passive matrix display.
active partition The primary partition on the hard drive that boots the OS. Windows NT/2000/XP calls the active partition the system partition.
active terminator A type of terminator for single-ended SCSI cables that includes voltage regulators in addition to the simple resistors used with passive termination.
adapter address See MAC address.
adapter card A small circuit board inserted in an expansion slot and used to communicate between the system bus and a peripheral device. Also called an interface card.
administrator account In Windows NT/ 2000/XP, an account that grants to the adminis- trators) rights and permissions to all hardware and software resources, such as the right to add, delete, and change accounts and to change hardware configurations.
Advanced Options menu A Windows 2000/XP menu that appears when you press F8 when Windows starts. The menu can be used to troubleshoot problems when loading Windows 2000/XP.
Advanced SCSI Programming Interface (ASPI) A popular device driver that enables operating systems to communicate with a SCSI host adapter. (The "A" originally stood for Adaptec.)
Advanced Transfer Cache (ATC) A type ofL2 cache contained within the Pentium processor housing that is embedded on the same core processor die as the CPU itself.
AirPort The term Apple computers use to describe the IEEE 802. lib standard.
alternating current (AC) Current that cycles back and forth rather than traveling in only one direction. In the United States, the AC voltage from a standard wall outlet is normally between 110 and 115 V. In Europe, the standard AC volt- age from a wall outlet is 220V.
ammeter A meter that measures electrical cur- rent in amps.
ampere or amp (A) A unit of measurement for electrical current. One volt across a resistance of one ohm will produce a flow of one amp.
amplifier repeater A repeater that does not distinguish between noise and signal; it amplifies both.
ANSI (American National Standards Institute) A nonprofit organization dedicated to creating trade and communications standards.
answer file A text file that contains information that Windows NT/2000/XP requires in order to do an unattended installation.
antivirus (AV) software Utility programs that prevent infection or scan a system to detect and remove viruses. McAfee Associates'VirusScan and Norton AntiVirus are two popular AV packages.
application program interface (API) call A request from software to the OS to access hard- ware or other software using a previously defined procedure that both the software and the OS understand.
ARP (Address Resolution Protocol) A proto- col that TCP/IP uses to translate IP addresses into physical network addresses (MAC addresses).
ASCII (American Standard Code for Information Interchange) A popular standard for writing letters and other characters in binary code. Originally, ASCII characters were seven bits, so there were 127 possible values. ASCII has been expanded to an 8-bit version, allowing 128 additional values.
asynchronous SRAM Static RAM that does not work in step with the CPU clock and is, there- fore, slower than synchronous SRAM.
AT A form factor, generally no longer produced, in which the motherboard requires a full-size case. Because of their dimensions and configuration, AT systems are difficult to install, service, and upgrade. Also called full AT.
AT command set A set of commands that a PC uses to control a modem and that a user can enter to troubleshoot the modem.
ATAPI (Advanced Technology Attachment Packet Interface) An interface standard, part of the IDE/ATA standards, that allows tape drives, CD-ROM drives, and other drives to be treated like an IDE hard drive by the system.
attenuation Signal degeneration over distance. Attenuation is solved on a network by adding repeaters to the network.
ATX The most common form factor for PC systems presently in use, originally introduced by Intel in 1995. ATX motherboards and cases make better use of space and resources than did the AT form factor.
audio/modem riser (AMR) A specification for a small slot on a motherboard to accommodate an audio or modem riser card. A controller on the motherboard contains some of the logic for the audio or modem functionality.
autodetection A feature on newer system BIOS and hard drives that automatically identifies and configures a new drive in the CMOS setup.
Autoexec.bat A startup text file once used by DOS and used by Windows to provide backward- compatibility. It executes commands automatically during the boot process and is used to create a 16-bit environment.
Automated System Recovery (ASR) The Windows XP process that allows you to restore an entire hard drive volume or logical drive to its state at the time the backup of the volume was made.
autorange meter A multimeter that senses the quantity of input and sets the range accordingly.
Baby AT An improved and more flexible version of the AT form factor. Baby AT was the industry standard from approximately 1993 to 1997 and can fit into some ATX cases.
back side bus The bus between the CPU and the L2 cache inside the CPU housing.
backplane system A form factor in which there is no true motherboard. Instead, motherboard components are included on an adapter card plugged into a slot on a board called the backplane.
backup An extra copy of a file, used in the event that the original becomes damaged or destroyed.
backup domain controller (BDC) In Windows NT, a computer on a network that holds a read-only copy of the SAM (security accounts manager) database.
Backup OperatorA Windows 2000/XP user account that can back up and restore any files on the system regardless of its having access to these files.
bandwidth In relation to analog communica- tion, the range of frequencies that a communica- tions channel or cable can carry. In general use, the term refers to the volume of data that can travel on a bus or over a cable stated in bits per second (bps), kilobits per second (Kbps), or megabits per second (Mbps).Also called data throughput or line speed.
bank An area on the motherboard that contains slots for memory modules (typically labeled bank 0, 1,2, and 3).
baseline The level of performance expected from a system, which can be compared to current measurements to determine what needs upgrading or tuning.
basic disk A way to partition a hard drive, used by DOS and all versions of Windows, that stores information about the drive in a partition table at the beginning of the drive. Compare to dynamic disk.
batch file A text file containing a series of OS commands. Autoexec.bat is a batch file.
baud rate A measure of line speed between two devices such as a computer and a printer or a modem. This speed is measured in the number of times a signal changes in one second. See also bits per second (bps).
beam detect mirror Detects the initial presence of a laser printer's laser beam by reflecting the beam to an optical fiber.
best-effort protocol See connectionless protocol.
binary number system The number system used by computers; it has only two numbers, 0 and 1, called binary digits, or bits.
binding The process by which a protocol is asso- ciated with a network card or a modem card.
BIOS (basic input/output system) Firmware that can control much of a computer's input/ output functions, such as communication with the floppy drive and the monitor. Also called ROM BIOS.
bit (binary digit) A 0 or 1 used by the binary number system.
bits per second (bps) A measure of data trans- mission speed. For example, a common modem speed is 56,000 bps, or 56 Kbps.
block mode A method of data transfer between hard drive and memory that allows multiple data transfers on a single software interrupt.
blue screen A Windows NT/2000/XP error that displays against a blue screen and causes the system to halt. Also called a stop error.
Bluetooth A standard for wireless communication and data synchronization between devices, devel- oped by a group of electronics manufacturers and overseen by the Bluetooth Special Interest Group. Bluetooth uses the same frequency range as 802. lib, but does not have as wide a range.
BNC connector A connector used with thin coaxial cable. Some BNC connectors are T-shaped and called T-connectors. One end of the T connects to the NIC, and the two other ends can connect to cables or end a bus formation with a terminator.
boot loader menu A startup menu that gives the user the choice of which operating system to load such as Windows 98 or Windows 2000 which are both installed on the same system, creating a dual boot.
boot partition The hard drive partition where the Windows NT/2000/XP OS is stored. The system partition and the boot partition may be different partitions.
boot record The first sector of a floppy disk or logical drive in a partition; it contains information about the disk or logical drive. On a hard drive, if the boot record is in the active partition, then it is used to boot the OS. Also called boot sector.
boot sector See boot record.
boot sector virus An infectious program that can replace the boot program with a modified, infected version of the boot command utilities, often causing boot and data retrieval problems.
Boot.ini A Windows NT/2000/XP hidden text file that contains information needed to build the boot loader menu.
bootable disk For DOS and Windows, a floppy disk that can upload the OS files necessary for computer startup. For DOS or Windows 9x, it must contain the files lo.sys, Msdos.sys, and Command, corn.
bootstrap loader A small program at the end of the boot record that can be used to boot an OS from the disk or logical drive.
bridge A device used to connect two or more network segments. It can make decisions about allowing a packet to pass based on the packet s destination MAC address.
bridging protocol See line protocol.
Briefcase A system folder in Windows 9x that is used to synchronize files between two computers.
broadband A transmission technique that carries more than one type of transmission on the same medium, such as cable modem or DSL.
broadcast Process by which a message is sent from a single host to all hosts on the network, without regard to the kind of data being sent or the destination of the data.
brouter A device that functions as both a bridge and a router. A brouter acts as a router when han- dling packets using routable protocols such as TCP/IP and IPX/SPX. It acts as a bridge when handling packets using nonroutable protocols such as NetBEUI.
brownouts Temporary reductions in voltage, which can sometimes cause data loss.
buffer A temporary memory area where data is kept before being written to a hard drive or sent to a printer, thus reducing the number of writes to the devices.
built-in user account An administrator account . and a guest account that are set up when Windows NT/2000/XP is first installed.
burst EDO (BEDO) A refined version of EDO memory that significantly improved access time over EDO. BEDO was not widely used because Intel chose not to support it. BEDO memory is stored on 168-pin DIMM modules.
burst SRAM Memory that is more expensive and slightly faster than pipelined burst SKAM. Data is sent in a two-step process; the data address is sent, and then the data itself is sent without interruption.
bus The paths, or lines, on the motherboard on which data, instructions, and electrical power move from component to component.
bus mouse A mouse that plugs into a bus adapter card and has a round, 9-pin mini-DIN connector.
bus riser See riser card.
bus speed The speed, or frequency, at which the data on the motherboard is moving.
bus topology A LAN architecture in which all the devices are connected to a bus, or one communication line. Bus topology does not have a central connection point.
byte A collection of eight bits that is equivalent to a single character. When referring to system mem- ory, an additional error-checking bit might be added, making the total nine bits.
cabinet file A file with a .cab extension that con- tains one or more compressed files and is often used to distribute software on disk. The Extract com- mand is used to extract files from the cabinet file.
cable modem A technology that uses cable TV lines for data transmission requiring a modem at each end. From the modem, a network cable con- nects to a NIC in the users PC.
CAM (Common Access Method) A standard adapter driver used by SCSI.
capacitor An electronic device that can maintain an electrical charge for a period of time and is used to smooth out the flow of electrical current. Capacitors are often found in computer power supplies.
CardBus The latest PCMCIA specification. It improves I/O speed, increases the bus width to 32 bits, and supports lower- voltage PC Cards, while maintaining backward compatibility with earlier standards.
cards Adapter boards or interface cards placed into expansion slots to expand the functions of a computer, allowing it to communicate with exter- nal devices such as monitors or speakers.
carrier A signal used to activate a phone line to confirm a continuous frequency; used to indicate that two computers are ready to receive or trans- mit data via modems.
CAS Latency (CL) A feature of memory that reflects the number of clock cycles that pass while data is written to memory.
CAU (ControUed-Access Unit) See MAU.
CCITT (Comite Consultatif International Telegraphique et Telephonique) An inter- national organization that was responsible for developing standards for international communica- tions. This organization has been incorporated into the ITU. See also ITU.
CD (change directory) command A com- mand given at the command prompt that changes the default directory, for example CD XWindows.
CDFS (Compact Disc File System) The 32-bit file system for CD discs and some CD-R and CD-RW discs that replaced the older 16-bit mscdex file system used by DOS. Also see Universal Disk Format (UDF).
CD-R (CD-recordable) A CD drive that can record or write data to a CD. The drive may or may not be multisession, but the data cannot be erased once it is written.
CD-RW (CD-rewritable) A CD drive that can record or write data to a CD. The data can be erased and overwritten. The drive may or may not be multisession.
central processing unit (CPU) Also called a microprocessor or processor. The heart and brain of the computer, which receives data input, processes information, and executes instructions.
chain A group of clusters used to hold a single file.
checksum A method of error checking transmit- ted data, whereby the digits are added and their sum compared to an expected sum.
child directory See subdirectory.
child, parent, grandparent backup method A plan for backing up and reusing tapes or remov- able disks by rotating them each day (child), week (parent), and month (grandparent).
chip creep A condition in which chips loosen because of thermal changes.
chip set A group of chips on the motherboard that controls the timing and flow of data and instructions to and from the CPU.
CHS (cylinder, head, sector) mode The tradi- tional method by which BIOS reads from and writes to hard drives by addressing the correct cylinder, head, and sector. Also called normal mode.
circuit board A computer component, such as the main motherboard or an adapter board, that has electronic circuits and chips.
CISC (complex instruction set computing) Earlier CPU type of instruction set.
clamping voltage The maximum voltage allowed through a surge suppressor, such as 175 or 330 volts.
clean install Installing an OS on a new hard drive or on a hard drive that has a previous OS installed, but without carrying forward any settings kept by the old OS, including information about hardware, software, or user preferences. A fresh installation.
client/server A computer concept whereby one computer (the client) requests information from another computer (the server).
client/server application An application that has two components. The client software requests data from the server software on the same or another computer.
clock speed The speed, or frequency, expressed in MHz, that controls activity on the motherboard and is generated by a crystal or oscillator located somewhere on the motherboard.
clone A computer that is a no-name Intel- and Microsoft-compatible PC.
cluster One or more sectors that constitute the smallest unit of space on a disk for storing data (also referred to as a file allocation unit). Files are written to a disk as groups of whole clusters.
CMOS (complementary metal-oxide semiconductor) One of two types of tech- nologies used to manufacture microchips (the other type is TTL, or transistor-transistor logic chips). CMOS chips require less electricity, hold data longer after the electricity is turned off, are slower, and produce less heat than TTL chips. The configuration, or setup, chip is a CMOS chip.
CMOS configuration chip A chip on the motherboard that contains a very small amount of memory, or RAM. Enough to hold configuration, or setup, information about the computer. Also called CMOS setup chip or CMOS RAM chip.
CMOS setup (1) The chip on the motherboard that holds configuration information about the system, such as date and time, and which CPU, hard drives, or floppy drives are installed. Also called CMOS or CMOS RAM. The chip is pow- ered by a battery when the PC is turned off. (2) The program in system BIOS that can change the values in CMOS RAM.
CMOS setup chip See CMOS configuration chip.
COAST (cache on a stick) Memory modules that hold memory used as a memory cache. See memory cache.
coaxial cable Networking cable used with 10-Mbps Ethernet ThinNet orThickNet.
cold boot See hard boot.
combo card An Ethernet card that contains more than one transceiver, each with a different port on the back of the card, in order to accom- modate different cabling media.
Command, corn Along with Msdos.sys and lo.sys, one of the three files that are the core com- ponents of the real-mode portion of Windows 9x. Command, corn provides a command prompt and interprets commands.
comment A line or part of a line in a program that is intended as a remark or comment and is ignored when the program runs. A semicolon or an REM is often used to mark a line as a comment.
communication and networking riser (CNR) A specification for a small expansion slot on a motherboard that accommodates a small audio, modem, or network riser card.
compact case A type of case used in low-end desktop systems. Compact cases, also called low-profile or slimline cases, follow either the NLX, LPX, or Mini LPX form factor. They are likely to have fewer drive bays, but they generally still provide for some expansion.
Compatibility Mode utility A Windows XP utility that provides an application with the older Microsoft OS environment it was designed to operate in.
compressed drive A drive whose format has been reorganized in order to store more data. A compressed drive is really not a drive at all; its actually a type of file, typically with a host drive called H.
computer name Character-based host name or NetBIOS name assigned to a computer.
Config.sys A text file used by DOS and sup- ported by Windows 9x that lists device drivers to be loaded at startup. It can also set system variables to be used by DOS and Windows.
Configuration Manager A component of Windows Plug and Play that controls the configu- ration process of all devices and communicates these configurations to the devices.
connectionless protocol A protocol such as UDP that does not require a connection before sending a packet and does not guarantee delivery. An example of a UDP transmission is streaming video over the Web. Also called a best-effort protocol.
connection-oriented protocol In networking, a protocol that confirms that a good connection has been made before transmitting data to the other end. An example of a connection-oriented protocol is TCP.
console A centralized location from which to execute commonly used tools.
constant angular velocity (CAV) A technology used by hard drives and newer CD-ROM drives whereby the disk rotates at a constant speed.
constant linear velocity (CLV) A CD-ROM format in which the spacing of data is consistent on the CD, but the speed of the disc varies depending on whether the data being read near the center or the edge of the disc.
continuity A continuous, unbroken path for the flow of electricity. A continuity test can determine whether or not internal wiring is still intact, or whether a fuse is good or bad.
control blade A laser printer component that prevents too much toner from sticking to the cylinder surface.
conventional memory Memory addresses between 0 and 640K. Also called base memory.
CRC (cyclical redundancy check) A process in which calculations are performed on bytes of data before and after they are transmitted to check for corruption during transmission.
credit card memory A type of memory used on older notebooks that could upgrade existing memory by way of a specialized memory slot.
C-RIMM (Continuity RIMM) A placeholder RIMM module that provides continuity so that every RIMM slot is filled.
cross-linked clusters Errors caused when more than one file points to a cluster, and the files appear to share the same disk space, according to the file allocation table.
crossover cable A cable used to connect two PCs into the simplest network possible. Also used to connect two hubs.
CVF (compressed volume file) The file on the host drive of a compressed drive that holds all compressed data.
data bus The lines on the system bus that the CPU uses to send and receive data.
data cartridge A type of tape medium typically used for backups. Full-sized data cartridges are 4 X 6 X % inches in size. A minicartridge is only y/4 X 2^ X % inches in size.
data line protector A surge protector designed to work with the telephone line to a modem.
data path size The number of lines on a bus that can hold data, for example, 8, 16, 32, and 64 lines, which can accommodate 8, 16, 32, and 64 bits at a time.
data throughput See bandwidth.
datagram See packet.
DC controller A card inside a notebook that converts voltage to CPU voltage. Some notebook manufacturers consider the card to be an FRU
DCE (Data Communications Equipment) - The hardware, usually a dial-up modem, that pro- vides the connection between a data terminal and a communications line. See also DTE.
default gateway The gateway a computer on a network will use to access another network unless it knows to specifically use another gateway for quicker access to that network.
default printer The printer Windows prints to unless another printer is selected.
defragment To "optimize" or rewrite a file to a disk in one contiguous chain of clusters, thus speeding up data retrieval.
demodulation The process by which digital data that has been converted to analog data is con- verted back to digital data. See modulation.
desktop The initial screen that is displayed when an OS has a GUI interface loaded.
device driver A program stored on the hard drive that tells the computer how to commu- nicate with an input/output device such as a printer or modem.
DHCP (Dynamic Host Configuration Protocol) server A service that assigns dynamic IP addresses to computers on a network when they first access the network.
diagnostic cards Adapter cards designed to dis- cover and report computer errors and conflicts at POST time (before the computer boots up), often by displaying a number on the card.
diagnostic software Utility programs that help troubleshoot computer systems. Some DOS diag- nostic utilities are CHKDSK and SCANDISK. PC-Technician is an example of a third-party diagnostic program.
dial-up networking A Windows 9x and Windows NT/2000/XP utility that uses a modem and telephone line to connect to a network.
differential backup Backup method that backs up only files that have changed or have been cre- ated since the last full backup. When recovering data, only two backups are needed: the full backup and the last differential backup.
differential cable A SCSI cable in which a signal is carried on two wires, each carrying voltage, and the signal is the difference between the two. Differential signaling provides for error checking and greater data integrity. Compare to single- ended cable.
digital signature Digital codes used to identify and authenticate the source of a file or document.
DIMM (dual inline memory module) A miniature circuit board used in newer computers to hold memory. DIMMs can hold up to 2 GB of RAM on a single module.
diode An electronic device that allows electricity to flow in only one direction. Used in a rectifier circuit.
DIP (dual inline package) switch A switch on a circuit board or other device that can be set on or off to hold configuration or setup information.
direct current (DC) Current that travels in only one direction (the type of electricity provided by batteries). Computer power supplies transform AC to low DC.
Direct Rambus DRAM A memory technol- ogy by Rambus and Intel that uses a narrow, very fast network-type system bus. Memory is stored on a RIMM module. Also called RDRAM or Direct RDRAM.
Direct RDRAM See Direct Rambus DRAM.
directory table An OS table that contains file information such as the name, size, time and date of last modification, and cluster number of the file's beginning location.
discrete L2 cache A type of L2 cache contained within the Pentium processor housing, but on a different die, with a cache bus between the proces- sor and the cache.
disk cache A method whereby recently retrieved data and adjacent data are read into memory in advance, anticipating the next CPU request.
disk cloning Making an exact image of a hard drive, including partition information, boot sec- tors, operating system installation, and application software to replicate the hard drive on another system or recover from a hard drive crash. Also called disk imaging.
disk compression Compressing data on a hard drive to allow more data to be written to the drive.
disk imaging See disk cloning.
Disk Management A Windows 2000/XP utility used to display and create and format partitions on basic disks and volumes on dynamic disks.
disk quota A limit placed on the amount of disk space that is available to users. Requires a Windows 2000/XP NTFS volume.
disk thrashing A condition that results when the hard drive is excessively used for virtual memory because R^AM is full. It dramatically slows down processing and can cause premature hard drive failure.
Display Power Management Signaling (DPMS) Energy Star standard specifications that allow for the video card and monitor to go into sleep mode simultaneously. See also Energy Star.
DMA (direct memory access) channel A number identifying a channel whereby the device can pass data to memory without involving the CPU. Think of a DMA channel as a shortcut for data moving to/from the device and memory.
DNS (domain name service or domain name system) A distributed pool of information (called the name space) that keeps track of assigned domain names and their corresponding IP addresses, and the system that allows a host to locate information in the pool. Compare to WINS.
DNS server A computer that can find an IP address for another computer when only the domain name is known.
docking station A device that receives a note- book computer and provides additional secondary storage and easy connection to peripheral devices.
domain In Windows NT/2000/XP, a logical group of networked computers, such as those on a college campus, that share a centralized directory database of user account information and security for the entire domain.
domain controller A Windows NT/2000 computer which holds and controls a database of (1) user accounts, (2) group accounts, and (3) computer accounts used to manage access to the network.
domain name A unique, text-based name that identifies a network.
DOS box A command window.
Dosstart.bat A type of Autoexec.bat file that is executed by Windows 9x in two situations: when you select Restart the computer in MS-DOS mode from the shutdown menu or you run a pro- gram in MS-DOS mode.
dot pitch The distance between the dots that the electronic beam hits on a monitor screen.
Double Data Rate SDRAM (DDR SDRAM) A type of memory technology used on DIMMs that runs at twice the speed of the system clock.
Emergency Repair Disk (ERD) A Windows NT record of critical information about your system that can be used to fix a prob- lem with the OS. The ERD enables restoration of the Windows NT registry on your hard drive.
Emergency Repair Process A Windows 2000 process that restores the OS to its state at the com- pletion of a successful installation.
emergency startup disk (ESD) See rescue disk.
Emm386.exe A DOS and Windows 9x utility that provides access to upper memory for 16-bit device drivers and other software.
Encrypted File System (EFS) A way to use a key to encode a file or folder to protect sensitive data. Because it is an integrated system service, EFS is transparent to users and applications and is difficult to attack.
encrypting virus A type of virus that transforms itself into a nonreplicating program in order to avoid detection. It transforms itself back into a replicating program in order to spread.
encryption The process of putting readable data into an encoded form that can only be decoded (or decrypted) through use of a key.
Energy Star "Green" systems that satisfy the EPA requirements to decrease the overall con- sumption of electricity. See also Green Standards.
enhanced BIOS A system BIOS that has been written to accommodate large-capacity drives (over 504 MB, usually in the gigabyte range).
EPIC (explicitly parallel instruction computing) The CPU architecture used by the Intel Itanium chip that bundles programming instructions with instructions on how to use multiprocessing abilities to do two instructions in parallel.
EPP (Enhanced Parallel Port) A parallel port that allows data to flow in both directions (bidi- rectional port) and is faster than original parallel ports on PCs that allowed communication only in one direction.
EPROM (erasable programmable ROM) A type of chip with a special window that allows the current memory contents to be erased with special ultraviolet light so that the chip can be repro- grammed. Many BIOS chips are EPROMs.
error correction The ability of a modem to iden- tify transmission errors and then automatically request another transmission.
Ethernet A LAN architecture that uses a bus or star topology, uses CSMA/CD when two com- puters are trying to gain access to the network at the same time, and is the most popular network architecture in use today.
Execution Trace Cache A type of Level 1 cache used by some CPUs to hold decoded operations waiting to be executed.
executive services In Windows NT/2000/XP, a group of components running in kernel mode that interfaces between the subsystems in user mode and the HAL.
expansion bus A bus that does not run in sync with the system clock.
expansion card A circuit board inserted into a slot on the motherboard to enhance the capabil- ity of the computer.
expansion slot A narrow slot on the motherboard where an expansion card can be inserted. Expansion slots connect to a bus on the motherboard.
extended memory Memory above 1024K used in a DOS or Windows 9x system.
extended partition The only partition on a hard drive that can contain more than one logical drive.
external cache Static cache memory, stored on the motherboard or inside the CPU housing, that is not part of the CPU (also called L2 or L3 cache).
external command Commands that have their own program files.
faceplate A metal plate that comes with the motherboard and fits over the ports to create a well-fitted enclosure around them.
Fast Ethernet See 100BaseT.
FAT (file allocation table) A table on a hard drive or floppy disk that tracks the clusters used to contain a file.
FAT12 The 12-bit wide, one-column file alloca- tion table for a floppy disk, containing information about how each cluster or file allocation unit on the disk is currently used.
fault tolerance The degree to which a system can tolerate failures. Adding redundant components, such as disk mirroring or disk duplexing, is a way to build in fault tolerance.
Fiber Distributed Data Interface (FDDI) A ring-based network that does not require a centralized hub and can transfer data at a rate of 100 Mbps.
field replaceable unit (FRU) A component in a computer or device that can be replaced with a new component without sending the computer or device back to the manufacturer. Examples: power supply, DIMM, motherboard, floppy disk drive.
file allocation unit See cluster.
file extension A three-character portion of the name of a file that is used to identify the file type. In command lines, the file extension follows the filename and is separated from it by a period. For example, Msd.exe, where exe is the file extension.
file system The overall structure that an OS uses to name, store, and organize files on a disk. Examples of file systems are FAT32 and NTFS.
file virus A virus that inserts virus code into an executable program and can spread wherever that program is accessed.
filename The first part of the name assigned to a file. In DOS, the filename can be no more than eight characters long and is followed by the file extension. In Windows, a filename can be up to 255 characters.
fire-wall Hardware or software that protects a computer or network from unauthorized access.
FireWire See IEEE 1394.
firmware Software that is permanently stored in a chip. The BIOS on a motherboard is an example of firmware.
flash ROM ROM that can be reprogrammed or changed without replacing chips.
flat panel monitor A desktop monitor that uses an LCD panel.
FlexATX A version of the ATX form factor that allows for maximum flexibility in the size and shape of cases and motherboards. FlexATX is ideal for custom systems.
flow control When using modems, a method of controlling the flow of data to adjust for problems with data transmission. Xon/Xoffis an example of a flow control protocol.
folder See subdirectory.
folder 'redirection A Windows XP feature that allows a user to point to a folder that can be on the local PC or somewhere on the network, and its location can be transparent to the user.
forced perfect terminator (FPT) A type of SCSI active terminator that includes a mechanism to force signal termination to the correct voltage, eliminating most signal echoes and interference.
forgotten password floppy disk A Windows XP disk created to be used in the event the user forgets the user account password to the system.
form factor A set of specifications on the size, shape, and configuration of a computer hardware component such as a case, power supply, or motherboard.
formatting Preparing a new floppy disk for use by placing tracks and sectors on its surface to store information (for example, FORJVLAT A:). Old disks can be reformatted, but all data on them will be lost.
FPM (fast page mode) A memory mode used before the introduction of EDO memory. FPM improved on earlier memory types by sending the row address just once for many accesses to mem- ory near that row.
fragmentation The distribution of data files on a hard drive or floppy disk such that they are stored in noncontiguous clusters.
fragmented file A file that has been written to different portions of the disk so that it is not in contiguous clusters.
frame The header and trailer information added to data to form a data packet to be sent over a network.
front-side bus See system bus.
FTP (File Transfer Protocol) The protocol used to transfer files over a TCP/IP network such that the file does not need to be cdnverted to ASCII format before transferring it.
full AT See AT.
full backup A complete backup, whereby all of the files on the hard drive are backed up each time the backup procedure is performed. It is the safest backup method, but it takes the most time.
full-duplex Communication that happens in two directions at the same time.
fully qualified domain name (FQDN) A host name and a domain name such as jsmith.amazon.com. Sometimes loosely referred to as a domain name.
gateway A computer or other device that con- nects networks.
GDI (Graphics Device Interface) A Windows 9x component that controls screens, graphics, and printing.
General Protection Fault (GPF) A Windows error that occurs when a program attempts to access a memory address that is not available or is no longer assigned to it.
Gigabit Ethernet The newest version of Ethernet. Gigabit Ethernet supports rates of data transfer up to 1 gigabit per second but is not yet widely used.
gigahertz (GHz) One thousand MHz, or one billion cycles per second.
global user account Sometimes called a domain user account, the account is used at the domain level, created by an administrator, and stored in the SAM (security accounts manager) database on a Windows 2000 or Windows .NET domain controller.
graphics accelerator A type of video card that has an on-board processor that can substantially increase speed and boost graphical and video performance.
Green Standards A computer or device that conforms to these standards can go into sleep or doze mode when not in use, thus saving energy and helping the environment. Devices that carry the Green Star or Energy Star comply with these standards.
ground bracelet A strap you wear around your wrist that is attached to the computer case, ground mat, or another ground so that ESD is discharged from your body before you touch sensitive com- ponents inside a computer. Also called static strap, ground strap, ESD bracelet.
group profile A group of user profiles. All pro- files in the group can be changed by changing the group profile.
guard, tone A tone that an answering modem sends when it first answers the phone, to tell the calling modem that a modem is on the other end of the line..
Guest user A user who has limited permissions on a system and cannot make changes to it. Guest user accounts are intended for one-time or infre- quent users of a workstation.
HAL (hardware abstraction layer) The low- level part of Windows NT/2000/XP, written specifically for each CPU technology, so that only the HAL must change when platform components change.
half life The time it takes for a medium storing data to weaken to half of its strength. Magnetic media, including traditional hard drives and floppy disks, have a half-life of five to seven years.
half-duplex Communication between two devices whereby transmission takes place in only one direction at a time.
handshaking When two modems begin to com- municate, the initial agreement made as to how to send and receive data.
hard boot Restart the computer by turning off the power or by pressing the Reset button. Also called a cold boot.
hard copy Output from a printer to paper.
hard drive The main secondary storage device of a PC, a small case that contains magnetic coated platters that rotate at high speed.
hard drive controller The firmware that con- trols access to a hard drive contained on a circuit board mounted on or inside the hard drive hous- ing. Older hard drives used firmware on a con- troller card that connected to the drive by way of two cables, one for data and one for control.
hard drive standby time The amount of time before a hard drive will shut down to con- serve energy.
hard-disk loading The illegal practice of installing unauthorized software on computers for sale. Hard-disk loading can typically be identified by the absence of original software disks in the original system s shipment.
hardware The physical components that consti- tute the computer system, such as the monitor, the keyboard, the motherboard, and the printer.
hardware address See MAC address.
hardware cache A disk cache that is contained in RAM chips built right on the disk controller.
hardware interrupt An event caused by a hard- ware device signaling the CPU that it requires service.
hardware profile A set of hardware configura- tion information that Windows keeps in the reg- istry. Windows can maintain more than one hard- ware profile for the same PC.
HCL (hardware compatibility list) The list of all computers and peripheral devices that have been tested and are officially supported by Windows NT/2000/XP (see www.microsoft.com/hd).
head The top or bottom surface of one platter on a hard drive. Each platter has two heads.
heat sink A piece of metal, with cooling fins, that can be attached to or mounted on an integrated chip (such as the CPU) to dissipate heat.
hertz (Hz) Unit of measurement for frequency, calculated in terms of vibrations, or cycles per second. For example, for 16-bit stereo sound, a fre- quency of 44,000 Hz is used. See also megahertz.
hexadecimal notation (hex) A numbering sys- tem that uses 16 digits, the numerals 0 to 9, and the letters A to F. Hexadecimal notation is often used to display memory addresses.
hidden file A file that is not displayed in a direc- tory list. Whether to hide or display a file is one of the files attributes kept by the OS.
high memory area (HMA) The first 64K of extended memory.
High Voltage Differential (HVD) A type of SCSI differential signaling requiring more expensive hardware to handle the higher voltage. HVD became obsolete with the introduction of SCSI-3.
high-level formatting Formatting performed by means of the DOS or Windows Format pro- gram (for example, FORMAT C:/S creates the boot record, FAT, and root directory on drive C and makes the drive bootable). Also called OS formatting.
Himem.sys The DOS and Windows 9x memory manager extension that allowed access to memory addresses above 1 MB.
hive Physical segment of the Windows NT/ 2000/XP registry that is stored in a file.
hop count See time to live (TTL).
host Any computer or other device on a network that has been assigned an IP address.
host adapter The circuit board that controls a SCSI bus supporting as many as seven or fifteen separate devices. The host adapter controls com- munication between the SCSI bus and the PC.
host bus See memory bus or system bus.
host drive Typically drive H on a compressed drive. See compressed drive.
host name A name that identifies a computer, printer, or other device on a network.
hot-pluggable See hot-swappable.
hot-swappable A device that can be plugged into a computer while it is turned on and the computer will sense the device and configure it without rebooting, or the device can be removed without an OS error. Also called hot-pluggable.
HTML (HyperText Markup Language) A markup language used for hypertext documents on the World Wide Web. This language uses tags to format the document, create hyperlinks, and mark locations for graphics.
HTTP (HyperText Transfer Protocol) The protocol used by the World Wide Web.
HTTPS (HTTP secure) A version of the HTTP protocol that includes data encryption for security.
hub A network device or box that provides a cen- tral location to connect cables.
hypertext Text that contains links to remote points in the document or to other files, documents, or graphics. Hypertext is created using HTML and is commonly distributed from Web sites.
LLmk See IEEE 1394.
I/O addresses Numbers that are used by devices and the CPU to manage communication between them. Also called ports or port addresses.
I/O controller card An older card that can con- tain serial, parallel, and game ports and floppy drive and IDE connectors.
IBM-compatible PC A computer that uses an Intel (or compatible) processor and can run DOS and Windows.
ICMP (Internet Control Message Protocol) Part of the IP layer that is used to transmit error messages and other control messages to hosts and routers.
IDE (Integrated Drive Electronics) A stan- dard governing hard drive technology and how secondary storage devices, such as hard drives, CD-ROM drives, and Zip drives, related to a system.
IEEE 1284 A standard for parallel ports and cables developed by the Institute for Electrical and Electronics Engineers and supported by many hardware manufacturers.
IEEE 1394 Standards for an expansion bus that can also be configured to work as a local bus. It is expected to replace the SCSI bus, providing. an easy method to install and configure fast I/O devices. Also called FireWire and i.Link.
IEEE 1394.3 A standard, developed by the 1394 Trade Association, that is designed for peer-to-peer data transmission and allows imaging devices to send images and photos directly to printers without involving a computer.
TFFF 802. lib An IEEE specification for wireless communication and data synchronization that com- petes with Bluetooth. Also known as Wi-Fi. Apple Computers version of 802. lib is called AirPort.
IMAP4 (Internet Message Access Protocol version 4) Version 4 of the IMAP protocol, which is an e-mail protocol that has more func- tionality than its predecessor, POP IMAP can archive messages in folders on the e-mail server and can allow the user to choose not to download attachments to messages.
incremental backup A time-saving backup method that only backs up files changed or newly created since the last full or incremental backup. Multiple incremental backups might be required when recovering lost data.
infestation Any unwanted program that is trans- mitted to a computer without the users knowl- edge and that is designed to do varying degrees of damage to data and software. There are a number of different types of infestations, including viruses, Trojan horses, worms, and logic bombs.
information (.inf) file Text file with an .inffile extension, such as Msbatch.inf, that contains infor- mation about a hardware or software installation.
initialization files Configuration information files for Windows. System.ini is one of the most important Windows 9x initialization files.
Installable File System (IFS) A Windows 9x Plug and Play component that is responsible for all disk access.
Institute of Electrical and Electronics
Engineers (IEEE) A nonprofit organization that develops standards for the computer and elec- tronics industries.
instruction set The set of instructions, on the CPU chip, that the computer can perform directly (such as ADD and MOVE).
Integrated Device Electronics or Integrated Drive Electronics (IDE) A hard drive whose disk controller is integrated into the drive, elimi- nating the need for a controller cable and thus increasing speed, as well as reducing price.
intelligent UPS A UPS connected to a com- puter by way of a serial cable so that software on the computer can monitor and control the UPS.
interlaced A type of display in which the elec- tronic beam of a monitor draws every other line with each pass, which lessens the overall effect of a lower refresh rate.
internal bus The bus inside the CPU that is used for communication between the CPUs internal components.
internal cache Memory cache that is faster than external cache, and is contained inside 80486 and Pentium chips (also referred to as primary, Level 1, or LI cache).
internal command Commands that are embed- ded in the Command, corn file.
Internet Connection Firewall (ICF) Windows XP software designed to protect a PC from unauthorized access from the Internet.
Internet Connection Sharing (ICS) A Windows 98 and Windows XP utility that uses NAT and acts as a proxy server to manage two or more computers connected to the Internet.
Internet service provider (ISP) A commercial group that provides Internet access for a monthly fee. AOL, Earthlink, and CompuServe are large ISPs.
intranet A private network that uses the TCP/IP protocols.
lo.sys Along with Msdos.sys and Command.com, one of the three files that are the core components of the real mode portion of Windows 9x. It is the first program file of the OS.
IP (Internet Protocol) The rules of communi- cation in the TCP/IP stack that control segment- ing data into packets, routing those packets across networks, and then reassembling the packets once they reach their destination.
IP address A 32-bit address consisting of four numbers separated by periods, used to uniquely identify a device on a network that uses TCP/IP protocols. The first numbers identify the network; the last numbers identify a host. An example of an IP address is 206.96.103.114.
IPX/SPX (Internetwork Packet Exchange/ Sequenced Packet Exchange) A networking protocol suite first used by Novell NetWare, and which corresponds to the TCP/IP protocols.
IRQ (interrupt request) line A line on a bus that is assigned to a device and is used to signal the CPU for servicing. These lines are assigned a reference number (for example, the normal IRQ for a printer is IRQ 7).
ISA (Industry Standard Architecture) slot An older slot on the motherboard used for slower I/O devices, which can support an 8-bit or a 16-bit data path. ISA slots are mostly replaced by PCI slots.
ISDN (Integrated Services Digital Network) A digital telephone line that can carry data at about five times the speed of regular telephone lines. Two channels (telephone numbers) share a single pair of wires.
isochronous data transfer A method used by IEEE 1394 to transfer data continuously without breaks.
ITU (International Telecommunications Union) The international organization respon- sible for developing international standards of communication. Formerly CCITT.
JPEG (Joint Photographic Experts Group) A graphical compression scheme that allows the user to control the amount of data that is averaged and sacrificed as file size is reduced. It is a common Internet file format. Most JPEG files have a .jpg extension.
jumper Two wires that stick up side by side on the motherboard and are used to hold configu- ration information. The jumper is considered closed if a cover is over the wires, and open if the cover is missing.
kernel The portion of an OS that is responsible for interacting with the hardware.
kernel mode A Windows NT/2000/XP "privileged" processing mode that has access to hardware components.
key (1) In encryption, a secret number or code used to encode and decode data. (2) In Windows, a section name of the Windows registry.
keyboard A common input device through which data and instructions may be typed into computer memory.
LAN (local area network) A computer net- work that covers only a small area, usually within one building.
lands Microscopic flat areas on the surface of a CD or DVD that separate pits. Lands and pits are used to represent data on the disk.
laptop computer See notebook.
large-capacity drive A hard drive larger than 504MB.
large mode A mode of addressing information on hard drives that range from 504 MB to 8.4 GB, addressing information on a hard drive by translat- ing cylinder, head, and sector information in order to break the 528-MB hard drive barrier. Another name for large mode. Also called ECHS mode.
Last Known Good configuration In Windows NT/2000/XP, registry settings and device drivers that were in effect when the com- puter last booted successfully. These settings can be restored during the startup process to recover from errors during the last boot.
LBA (logical block addressing) mode A mode of addressing information on hard drives in which the BIOS and operating system view the drive as one long linear list of LBAs or addressable sectors, permitting drives to be larger than 8.4 GB (LBA 0 is cylinder 0, head 0, and sector 1).
Level 1 (LI) cache See internal cache.
Level 2 (L2) cache See external cache.
Level 3 (L3) cache See external cache.
Limited user Windows XP user accounts known as Users in Windows NT/2000, which have read- write access only on their own folders, read-only access to most system folders, and no access to other users' data.
line conditioner A device that regulates, or con- ditions, power, providing continuous voltage dur- ing brownouts and spikes.
line protocol A protocol used to send data pack- ets destined for a network over telephone lines. PPP and SLIP are examples of line protocols.
line speed See bandwidth.
line-interactive UPS A variation of a standby UPS that shortens switching time by always keep- ing the inverter that converts AC to DC working, so that there is no charge-up time for the inverter.
LMHosts A text file located in the Windows folder that contains NetBIOS names and their associated IP addresses. This file is used for name resolution for a NetBEUI network.
local bus A bus that operates at a speed synchro- nized with the CPU frequency. The system bus is a local bus.
local I/O bus A local bus that provides I/O devices with fast access to the CPU.
local printer A printer connected to a computer by way of a port on the computer. Compare to network printer.
local profile User profile that is stored on a local computer and cannot be accessed from another computer on the network.
local user account A user account that applies only to a local computer and cannot be used to access resources from other computers on the network.
logic bomb Dormant code added to software that is triggered by a predetermined time or event.
logical drive A portion or all of a hard drive par- tition that is treated by the operating system as though it were a physical drive. Each logical drive is assigned a drive letter, such as drive C, and con- tains a file system. Also called a volume.
logical geometry The number of heads, tracks, and sectors that the BIOS on the hard drive con- troller presents to the system BIOS and the OS. The logical geometry does not consist of the same values as the physical geometry, although calcula- tions of drive capacity yield the same results.
Logical Unit Number (LUN) A number assigned to a logical device (such as a tray in a CD changer) that is part of a physical SCSI device, which is assigned a SCSI ID.
lost allocation units See lost clusters.
lost clusters File fragments that, according to the file allocation table, contain data that does not belong to any file. The command CHKDSK/F can free these fragments. Also called lost allocation units.
low insertion force (LIF) socket A socket that requires the installer to manually apply an even force over the microchip when inserting the chip into the socket.
low-level formatting A process (usually per- formed at the factory) that electronically creates the hard drive tracks and sectors and tests for bad spots on the disk surface.
low-profile case See compact case.
Low Voltage Differential (LVD) A type of dif- ferential signaling that uses lower voltage than does HVD, is less expensive, and can be compatible with single-ended signaling on the same SCSI bus.
LPX A form factor in which expansion cards are mounted on a riser card that plugs into a motherboard. The expansion cards in LPX systems are mounted parallel to the motherboard, rather than perpendicular to it as in AT and ATX systems.
MAC (Media Access Control) address A 6-byte hexadecimal hardware address unique to each NIC card and assigned by the manufacturer. The address is often printed on the adapter. An example is 00 00 OC 08 2F 35.Also called a physical address, an adapter address, or a hard- ware address.
macro A small sequence of commands, contained within a document, that can be automatically exe- cuted when the document is loaded, or executed later by using a predetermined keystroke.
macro virus A virus that can hide in the macros of a document file. Typically, viruses do not reside in data or document files.
main board See motherboard.
mandatory user profile A roaming user profile that applies to all users in a user group, and indi- vidual users cannot change that profile.
Master Boot Record (MBR) The first sector on a hard drive, which contains the partition table and a program the BIOS uses to boot an OS from the drive.
master file table (MFT) The database used by the NTFS file system to track the contents of a logical drive.
material safety data sheet (MSDS) A docu- ment that explains how to properly handle sub- stances such as chemical solvents; it includes infor- mation such as physical data, toxicity, health effects, first aid, storage, disposal, and spill procedures.
megahertz (MHz) One million Hz, or one mil- lion cycles per second. See hertz (Hz).
memory Physical microchips that can hold data and programming, located on the motherboard or expansion cards.
memory address A number assigned to each byte in memory. The CPU can use memory addresses to track where information is stored in RAM. Memory addresses are usually displayed as hexadecimal numbers in segment/offset form.
memory bus See system bus.
memory cache A small amount of faster RAM that stores recently retrieved data, in anticipation of what the CPU will request next, thus speeding up access. See also system bus.
memory dump The contents of memory saved to a file at the time an event halted the system. Support technicians can analyze the dump file to help understand the source of the problem.
memory extender For DOS and Windows 9x, a device driver named Himem.sys that manages RAM, giving access to memory addresses above 1 MB.
memory paging In Windows, swapping blocks of RAM memory to an area of the hard drive to serve as virtual memory when RAM is low.
memory-resident virus A virus that can stay lurking in memory even after its host program is terminated.
microATX A recent version of the ATX form factor. MicroATX addresses some new tech- nologies that have been developed since the origi- nal introduction of ATX.
microprocessor See central processing unit (CPU).
Microsoft Management Console (MMC) A utility to build customized consoles. These consoles can be saved to a file with an .msc file extension.
Mini-ATX A smaller ATX board that can be used with regular ATX cases and power supplies.
minicartridge A tape drive cartridge that is only 3X X 214 X % inches. It is small enough to allow two drives to fit into a standard 5^-inch drive bay of a PC case.
minifile system In Windows NT/2000/XP, a simplified file system that is started so that Ntldr (NT Loader) can read files from any file system the OS supports.
Mini-LPX A smaller version of the LPX motherboard.
mixed mode A Windows 2000 mode for domain controllers used when there is at least one Windows NT domain controller on the network.
MMX (Multimedia Extensions) Multimedia instructions built into Intel processors to add func- tionality such as better processing of multimedia, SIMD support, and increased cache.
modem From MOdulate/DEModulate. A device that modulates digital data from a computer to an analog format that can be sent over telephone lines, then demodulates it back into digital form.
modem eliminator See null modem cable.
modem riser card A small modem card that uses an AMR or CNR slot. Part of the modem logic is contained in a controller on the motherboard.
modem speed The speed at which a modem can transmit data along a phone line, measured in bits per second (bps).Also called line speed.
modulation Converting binary or digital data into an analog signal that can be sent over standard telephone lines.
monitor The most commonly used output device for displaying text and graphics on a computer.
motherboard The main board in the computer, also called the system board. The CPU, ROM chips, SIMMs, DIMMs, RIMMs, and interface cards are plugged into the motherboard.
motherboard bus See system bus.
motherboard mouse See PS/2-compatible mouse.
mouse A pointing and input device that allows the user to move a cursor around a screen and select programs with the click of a button.
MP3 A method to compress audio files that uses MPEG level 3. It can reduce sound files as low as a 1:24 ratio without losing much sound quality.
MPEG (Moving Pictures Experts Group) A processing-intensive standard for data compres- sion for motion pictures that tracks movement from one frame to the next and only stores the data that has changed.
Msdos.sys In Windows 9x, a text file that con- tains settings used by lo.sys during booting. In DOS, the Msdos.sys file was a program file that contained part of the DOS core.
multicasting A process in which a message is sent by one host to multiple hosts, such as when a video conference is broadcast to several hosts on the Internet.
multimeter A device used to measure the various components of an electrical circuit. The most common measurements are voltage, current, and resistance.
multipartite virus A combination of a boot sec- tor virus and a file virus. It can hide in either type of program.
multiplier The factor by which the bus speed or frequency is multiplied to get the CPU clock speed.
multiscan monitor A monitor that can work within a range of frequencies and thus can work with different standards and video cards. It offers a variety of refresh rates.
multisession A feature that allows data to be read from or written to a CD during more than one session. This is important if the disk was only par- tially filled during the first write.
Multistation Access Unit (MSAU or MAU) A centralized hub used in token ring networks to connect stations. Also called CAU.
multitasking Doing more than one thing at a time. A true multitasking system requires two or more CPUs, each processing a different thread at the same time. Compare to cooperative multitask- ing and preemptive multitasking.
multithreading The ability to pass more than one function (thread) to the OS kernel at the same time, such as when one thread is performing a print job while another reads a file.
name resolution The process of associating a NetBIOS name or host name to an IP address.
narrow SCSI One of the two main SCSI specifi- cations. Narrow SCSI has an 8-bit data bus. The word "narrow" is not usually included in the names of narrow SCSI devices.
NAT (Network Address Translation) A process that converts private IP addresses on a LAN to the proxy server s IP address before a data packet is sent over the Internet.
native mode A Windows 2000 mode used by domain controllers when there are no Windows NT domain controllers present on the network.
NetBEUI (NetBIOS Extended User Interface) A fast, proprietary Microsoft networking protocol used only by Windows-based systems, and limited to LANs because it does not support routing.
NetBIOS (Network Basic Input/Output System) An API protocol used by some appli- cations to communicate over a NetBEUI net- work. NetBIOS has largely been replaced by Windows Sockets over a TCP/IP network.
network adapter See network interface card.
network drive map Mounting a drive to a computer, such as drive E, that is actually hard drive space on another host computer on the network.
network interface card (NIC) An expansion card that plugs into a computers motherboard and provides a port on the back of the card to connect a PC to a network. Also called a network adapter.
network operating system (NOS) An operat- ing system that resides on the controlling com- puter in the network. The NOS controls what software, data, and devices a user on the network can access. Examples of an NOS are Novell Netware and Windows 2000 Server.
network printer A printer that any user on the network can access, through its own network card and connection to the network, through a con- nection to a standalone print server, or through a connection to a computer as a local printer, which is shared on the network.
NLX A low-end form factor that is similar to LPX but provides greater support for current and emerging processor technologies. NLX was designed for flexibility and efficiency of space.
NNTP (Network News Transfer Protocol) The protocol used by newsgroup server and client software.
node Any computer, workstation, or device on a network.
noise An extraneous, unwanted signal, often over an analog phone line, that can cause commu- nication interference or transmission errors. Possible sources are fluorescent lighting, radios, TVs, lightning, or bad wiring.
noninterlaced A type of display in which the electronic beam of a monitor draws every line on the screen with each pass.
non-memory -resident virus A virus that is ter- minated when the host program is closed. Compare to memory-resident virus.
nonparity memory Eight-bit memory without error checking. A SIMM part number with a 32 in it (4 X 8 bits) is nonparity.
nonvolatile Refers to a kind of RAM that is sta- ble and can hold data as long as electricity is pow- ering the memory.
normal mode See CHS mode.
North Bridge That portion of the chip set hub that connects faster I/O buses (for example, AGP bus) to the system bus. Compare to South Bridge.
notebook A portable computer that is designed for travel and mobility. Notebooks use the same technology as desktop PCs, with modifications for conserving voltage, taking up less space, and oper- ating while on the move. Also called a laptop computer.
NTFS (NT file system) The file system for the Windows NT/2000/XP operating systems. NTFS cannot be accessed by other operating systems such as DOS. It provides increased reliability and security in comparison to other methods of orga- nizing and accessing files. There are several versions of NTFS that might or might not be compatible.
Ntldr (NT Loader) In Windows NT/2000/XP, the OS loader used on Intel systems.
NTVDM (NT virtual DOS machine) An emulated environment in which a 16-bit DOS application resides within Windows NT/2000/XP with its own memory space or WOW (Win 16 on Win32).
null modem cable A cable that allows two data terminal equipment (DTE) devices to communicate in which the transmit and receive wires are cross- connected and no modems are necessary.
octet Term for each of the four 8-bit numbers that make up an IP address. For example, the IP address 206.96.103.114 has four octets.
ohm (Q) The standard unit of measurement for electrical resistance. Resistors are rated in ohms.
on-board ports Ports that are directly on the motherboard, such as a built-in keyboard port or on-board serial port.
operating system (OS) Software that controls a computer. An OS controls how system resources are used and provides a user interface, a way of managing hardware and software, and ways to work with files.
operating system formatting See high-level formatting.
PI connector Power connection on an ATX motherboard.
P8 connector One of two power connectors on an AT motherboard.
P9 connector One of two power connectors on an AT motherboard.
packet Segment of network data that also includes header, destination address, and trailer information that is sent as a unit. Also called data packet or datagram.
page fault An OS interrupt that occurs when the OS is forced to access the hard drive to satisfy the demands for virtual memory.
page file See swap file.
Pagefile.sys The Windows NT/2000/XP swap file.
page-in The process in which the memory man- ager goes to the hard drive to return the data from a swap file to RAM.
page-out The process in which, when RAM is full, the memory manager takes a page and moves it to the swap file.
pages 4K segments in which Windows NT/ 2000/XP allocates memory
parallel port A female 25-pin port on a com- puter that can transmit data in parallel, 8 bits at a dme, and is usually used with a printer. The names for parallel ports are LPT1 and LPT2.
parity An error-checking scheme in which a ninth, or "parity," bit is added. The value of the parity bit is set to either 0 or 1 to provide an even number of ones for even parity and an odd num- ber of ones for odd parity.
parity error An error that occurs when the number of Is in the byte is not in agreement with the expected number.
parity memory Nine-bit memory in which the ninth bit is used for error checking. A SIMM part number with a 36 in it (4 X 9 bits) is parity. Older PCs almost always use parity chips.
partition A division of a hard drive that can be used to hold logical drives.
partition table A table at the beginning of the hard drive that contains information about each partition on the drive. The partition table is con- tained in the Master Boot Record.
passive backplane A type of backplane system in which the backplane contains no circuitry at all. Passive backplanes locate all circuitry on a mother- card plugged into a backplane.
passive terminator A type of terminator for single-ended SCSI cables. Simple resistors are used to provide termination of a signal. Passive termina- tion is not reliable over long distances and should only be used with narrow SCSI.
patch An update to software that corrects an error, adds a feature, or addresses security issues. Also called an update or service pack.
patch cable A network cable that is used to con- nect a PC to a hub.
path (1) A drive and list of directories pointing to a file such as C:\Windows\command. (2) The OS command to provide a list of paths to the system for finding program files to execute.
PC Card A credit-card-sized adapter card that can be slid into a slot in the side of many notebook computers and is used for connecting to modems, networks, and CD-ROM drives. Also called PCMCIA Card.
PC Card slot An expansion slot on a notebook computer, into which a PC Card is inserted. Also called a PCMCIA Card slot.
PCI (Peripheral Component Interconnect) bus A bus common on Pentium computers that runs at speeds of up to 33 MHz or 66 MHz, with a 32-bit- wide or 64-bit-wide data path. PCI-X, released in September 1999, enables PCI to run at 133 MHz. For some chip sets, it serves as the middle layer between the memory bus and expansion buses.
PCMCIA (Personal Computer Memory Card International Association) Card See PC Card.
PCMCIA Card slot See PC Card slot.
PDA (Personal Digital Assistant) A small, handheld computer that has its own operating system and applications.
peer-to-peer network A network of computers that are all equals, or peers. Each computer has the same amount of authority, and each can act as a server to the other computers.
peripheral devices Devices that communicate with the CPU but are not located directly on the motherboard, such as the monitor, floppy drive, printer, and mouse.
physical address See MAC address.
physical geometry The actual layout of heads, tracks, and sectors on a hard drive. Refer also to logical geometry.
PIF (program information file) A file used by Windows to describe the environment for a DOS program to use.
pin grid array (PGA) A feature of a CPU socket whereby the pins are aligned in uniform rows around the socket.
Ping (Packet Internet Groper) A Windows and Unix command used to troubleshoot network connections. It verifies that the host can commu- nicate with another host on the network.
pinout A description of how each pin on a bus, connection, plug, slot, or socket is used.
pipelined burst SRAM A less expensive SRAM that uses more clock cycles per transfer than non- pipelined burst but does not significantly slow down the process.
pits Recessed areas on the surface of a CD or DVD, separating lands, or flat areas. Lands and pits are used to represent data on a disc.
pixel A small spot on a fine horizontal scan line. Pixels are illuminated to create an image on the monitor.
Plug and Play (PnP) A standard designed to make the installation of new hardware devices eas- ier by automatically configuring devices to elimi- nate system resource conflicts (such as IRQ or I/O address conflicts). PnP is supported by Windows 9x,Windows 2000, and Windows XP.
polling A process by which the CPU checks the status of connected devices to determine if they are ready to send or receive data.
polymorphic virus A type of virus that changes its distinguishing characteristics as it replicates itself. Mutating in this way makes it more difficult for AV software to recognize the presence of the virus.
POP (Post Office Protocol) The protocol that an e-mail server and client use when the client requests the downloading of e-mail messages. The most recent version is POP3. POP is slowly being replaced by IMAP.
port (1) As applied to services running on a com- puter, a number assigned to a process on a com- puter so that the process can be found by TCP/IP. Also called a port address or port number. (2) Another name for an I/O address. See also I/O address. (3) A physical connector, usually at the back of a computer, that allows a cable from a peripheral device, such as a printer, mouse, or modem, to be attached.
port address See I/O address.
port number See port.
port replicator A device designed to connect to a notebook computer in order to make it easy to connect the notebook to peripheral devices.
port settings The configuration parameters of communications devices such as COM1, COM2, or COM3, including IRQ settings.
port speed The communication speed between a DTE (computer) and a DCE (modem). As a gen- eral rule, the port speed should be at least four times as fast as the modem speed.
POST (power-on self test) A self-diagnostic program used to perform a simple test of the CPU, RAM, and various I/O devices. The POST is performed by startup BIOS when the computer is first turned on, and is stored in ROM-BIOS.
power conditioner A line conditioner that regu- lates, or conditions, power, providing continuous voltage during brownouts.
power-on password A password that a computer uses to control access during the boot process.
power scheme A feature of Windows XP sup- port for notebooks that allows the user to create groups of power settings for specific sets of condi- tions.
power supply A box inside the computer case that supplies power to the motherboard and other installed devices. Power supplies provide 3.3, 5, and 12 volts DC.
PPP (Point-to-Point Protocol) A protocol that governs the methods for communicating via modems and dial-up telephone lines. The Windows Dial-up Networking utility uses PPP.
PPPoE (Point-to-Point Protocol over Ethernet) The protocol that describes how a PC is to interact with a broadband converter box, such as cable modem, when the two are con- nected by an Ethernet cable, connected to a NIC in a PC.
preemptive multitasking A type of pseudo- multitasking whereby the CPU allows an applica- tion a specified period of time and then preempts the processing to give time to another application.
primary cache See internal cache.
primary domain controller (PDC) In a Windows NT network, the computer that con- trols the directory database of user accounts, group accounts, and computer accounts on a domain. Also see backup domain controller.
primary partition A hard disk partition that can contain only one logical drive.
primary storage Temporary storage on the motherboard used by the CPU to process data and instructions. Memory is considered primary storage.
printer A peripheral output device that produces printed output to paper. Different types include dot matrix, ink-jet, and laser printers.
printer maintenance kit A kit purchased from a printer manufacturer that contains the parts, tools, and instructions needed to perform routine printer maintenance.
private IP address An IP address that is used on a private TCP/IP network that is isolated from the Internet.
process An executing instance of a program together with the program resources. There can be more than one process running for a program at the same time. One process for a program happens each time the program is loaded into memory or executed.
processor See central processing unit (CPU).
processor speed The speed, or frequency, at which the CPU operates. Usually expressed in GHz.
product activation The process that Microsoft uses to prevent software piracy. For example, once Windows XP is activated for a particular com- puter, it cannot be installed on another computer.
program A set of step-by-step instructions to a computer. Some are burned directly into chips, while others are stored as program files. Programs are written in languages such as BASIC and C++.
program file A file that contains instructions designed to be executed by the CPU.
protected mode An operating mode that sup- ports preemptive multitasking, the OS manages memory and other hardware devices, and programs can use a 32-bit data path. Also called 32-bit mode.
protocol A set of rules and standards that two entities use for communication.
Protocol.ini A Windows initialization file that contains network configuration information.
proxy server A server that acts as an intermedi- ary between another computer and the Internet. The proxy server substitutes its own IP address for the IP address of the computer on the network making a request, so that all traffic over the Internet appears to be coming from only the IP address of the proxy server.
PS/2-compatible mouse A mouse that plugs into a round mouse PS/2 port on the mother- board. Sometimes called a motherboard mouse.
public IP address An IP address available to the Internet.
QIC (Quarter-Inch Committee or quarter-inch cartridge) A name of a standardized method used to write data to tape. These backup files have a .qic extension.
RAID (redundant array of inexpensive disks or redundant array of independent disks) Several methods of configuring multiple hard drives to store data to increase logical volume size and improve performance, and to ensure that if one hard drive fails, the data is still available from another hard drive.
RAM (random access memory) Memory modules on the motherboard containing microchips used to temporarily hold data and pro- grams while the CPU processes both. Information in RAM is lost when the PC is turned off.
RAM drive An area of memory that is treated as though it were a hard drive, but works much faster than a hard drive. The Windows 9x startup disk uses a RAM drive. Compare to virtual memory.
RARP (Reverse Address Resolution Protocol) A protocol used to translate the unique hardware NIC addresses (MAC addresses) into IP addresses (the reverse ofARP).
RDRAM See Direct Rambus DRAM.
read/write head A sealed, magnetic coil device that moves across the surface of a disk either read- ing data from or writing data to the disk.
real mode A single-tasking operating mode whereby a program has 1024K of memory addresses, has direct access to RAM, and uses a 16-bit data path. Using a memory extender (Himem.sys) a program in real mode can access memory above 1024K. Also called 16-bit mode.
Recovery Console A Windows 2000/XP com- mand interface utility and OS that can be used to solve problems when Windows cannot load from the hard drive.
rectifier An electrical device that converts AC to DC. A PC power supply contains a rectifier.
refresh The process of periodically rewriting data, such as on dynamic RAM.
refresh rate As applied to monitors, the number of times in one second an electronic beam can fill the screen with lines from top to bottom. Also called vertical scan rate.
registry A database that Windows uses to store hardware and software configuration information, user preferences, and setup information.
re-marked chips Chips that have been used and returned to the factory, marked again, and resold. The surface of the chips may be dull or scratched.
Remote Assistance A Windows XP feature that allows a support technician at a remote location to have full access to the Windows XP desktop.
repeater A device that amplifies signals on a network so they can be transmitted further down the line.
rescue disk A floppy disk that can be used to start up a computer when the hard drive fails to boot. Also called emergency startup disk (ESD) or startup disk.
resistance The degree to which a device opposes or resists the flow of electricity. As the electrical resistance increases, the current decreases. See ohm and resistor.
resistor An electronic device that resists or opposes the flow of electricity. A resistor can be used to reduce the amount of electricity being supplied to an electronic component.
resolution The number of pixels on a monitor screen that are addressable by software (example: 1024 X 768 pixels).
restore point A snapshot of the Windows Me/XP system state, usually made before installation of new hardware or applications.
REt (Resolution Enhancement technology) The term used by Hewlett-Packard to describe the way a laser printer varies the size of the dots used to create an image. This technology partly accounts for the sharp, clear image created by a laser printer.
RIMM A type of memory module used on newer motherboards, produced by Rambus, Inc.
ring topology A network topology in which the nodes in a network form a ring. Each node is connected only to two other nodes, and a cen- tralized hub is not required.
RISC (Reduced Instruction Set Computing) chips Chips that incorporate only the most frequently used instructions, so that the computer operates faster (for example, the PowerPC uses RISC chips).
riser card A card that plugs into a motherboard and allows for expansion cards to be mounted par- allel to the motherboard. Expansion cards arc plugged into slots on the riser card.
RJ-11 A phone line connection found on modems, telephones, and house phone outlets.
RJ-45 connector A connector used with twisted-pair cable that connects the cable to the NIC.
roaming user profile A user profile for a roam- ing user. Roaming user profiles are stored on a server so that the user can access the profile from anywhere on the network.
ROM (read-only memory) Chips that contain programming code and cannot be erased.
ROM BIOS See BIOS.
root directory The main directory created when a hard drive or disk is first formatted. In Linux, its indicated by a forward slash. In DOS and Windows, it's indicated by a backward slash.
routable protocol A protocol that can be routed to interconnected networks on the basis of a net- work address. TCP/IP is a routable protocol, but NetBEUI is not.
router A device that connects networks and makes decisions as to the best routes to use when forwarding packets.
sampling rate The rate of samples taken of an analog signal over a period of time, usually expressed as samples per second, or hertz.
SBAC (SCSI bus adapter chip) The SCSI chip within a device housing that controls data transfer over the SCSI bus.
SCAM (SCSI Configuration AutoMatically) A method of configuring SCSI device settings that follows the Plug and Play standard. SCAM makes installation of SCSI devices much easier, provided that the devices are SCAM-compliant.
scanning mirror A component of a laser printer consisting of an octagonal mirror that can be directed in a sweeping motion to cover the entire length of a laser printer drum.
SCSI (Small Computer System Interface) A fast interface between a host adapter and the CPU that can daisy chain as many as 7 or 15 devices on a single bus.
SCSI ID A number from 0 to 15 assigned to each SCSI device attached to the daisy chain.
SDRAM II See Double Data Rate SDRAM (DDR SDRAM).
secondary storage Storage that is remote to the CPU and permanently holds data, even when the PC is turned off, such as a hard drive.
sector On a disk surface one segment of a track, which almost always contains 512 bytes of data.
security accounts manager (SAM) A portion of the Windows NT/2000/XP registry that man- ages the account database that contains accounts, policies, and other pertinent information about local accounts.
sequential access A method of data access used by tape drives, whereby data is written or read sequentially from the beginning to the end of the tape or until the desired data is found.
serial mouse A mouse that uses a serial port and has a female 9-pin DB-9 connector.
serial port A male 9-pin or 25-pin port on a computer system used by slower I/O devices such as a mouse or modem. Data travels serially, one bit at a time, through the port. Serial ports are sometimes configured as COM1, COM2, COM3, or COM4.
service pack See patch.
session An established communication link between two software programs. On the Internet, a session is created by TCP.
SFC (System File Checker) A Windows tool that checks to make sure Windows is using the correct versions of system files.
SGRAM (synchronous graphics RAM) Memory designed especially for video card pro- cessing that can synchronize itself with the CPU bus clock.
shadow RAM or shadowing ROM ROM pro- gramming code copied into RAM to speed up the system operation, because of the faster access speed of RAM.
shell The portion of an OS that relates to the user and to applications.
shielded twisted-pair (STP) cable A cable that is made of one or more twisted pairs of wires and is surrounded by a metal shield.
shortcut An icon on the desktop that points to a program that can be executed or to a file or folder.
signal-regenerating repeater A repeater that is able to distinguish between noise and signal. It reads the signal and retransmits it without the accompanying noise.
Sigverif.exe A Windows 2000/XP utility that allows you to search for digital signatures.
SIMD (single instruction, multiple data) A process that allows the CPU to execute a single instruction simultaneously on multiple pieces of data, rather than by repetitive looping.
SIMM (single inline memory module) A miniature circuit board used in older computers to hold RAM. SIMMs hold 8,16, 32, or 64 MB on a single module.
simple volume A type of dynamic volume used on a single hard drive that corresponds to a pri- mary partition on a basic disk.
single-ended (SE) cable A type of SCSI cable in which two wires are used to carry a signal, one of which carries the signal itself; the other is a ground for the signal.
single-voltage CPU A CPU that requires one voltage for both internal and I/O operations.
slack Wasted space on a hard drive caused by not using all available space at the end of clusters.
sleep mode A mode used in many "Green" sys- tems that allows them to be configured through CMOS to suspend the monitor or even the drive, if the keyboard and/or CPU have been inactive for a set number of minutes. See also Green Standards.
slimline case See compact case.
SLIP (Serial Line Internet Protocol) A line protocol used by regular telephone lines that has largely been replaced by PPP.
Smart Multistation Access Unit (SMAU) See MAU.
SMARTDrive A hard drive cache program that came with Windows 3.x and DOS and can be executed as a TSR from the Autoexec.bat file (for example, Device=Smartdrv.sys 2048).
SMTP (Simple Mail Transfer Protocol) The protocol used by e-mail clients and servers to send e-mail messages over the Internet. See POP and IMAP.
snap-ins Components added to a console using the Microsoft Management Console.
SNMP (Simple Network Management Protocol) A protocol used to monitor and manage network traffic on a workstation. SNMP works with TCP/IP and IPX/SPX networks.
socket See session.
SO-DIMM (small outline DIMM) A type of memory module used in notebook computers that uses DIMM technology and can have either 72 pins or 144 pins.
soft boot To restart a PC without turning off the power, for example, by pressing three keys at the same time (Ctrl, Alt, and Del). Also called warm boot.
soft power See soft switch.
soft switch A feature on an ATX system that allows an OS to power down the system and allows for activity such as a keystroke or network activity to power up the system. Also called soft power.
software Computer programs, or instructions to perform a specific task. Software may be BIOS, OSs, or applications software such as a word-processing or spreadsheet program.
software cache Cache controlled by software whereby the cache is stored in RAM.
SO-RIMM (small outline RIMM) A 160-pin memory module used in notebooks that uses Rambus technology.
South Bridge That portion of the chip set hub that connects slower I/O buses (for example, an ISA bus) to the system bus. Compare to North Bridge.
spacers See standoffs.
spanned volume A type of dynamic volume used on two or more hard drives that fills up the space allotted on one physical disk before moving to the next.
SPI (SCSI Parallel Interface) The part of the SCSI-3 standard that specifies how SCSI devices are connected.
spikes Temporary surges in voltage, which can damage electrical components.
spooling Placing print jobs in a print queue so that an application can be released from the print- ing process before printing is completed. Spooling is an acronym for simultaneous peripheral opera- tions online.
SSE (Streaming SIMD Extension) A technol- ogy used by the Intel Pentium III and later CPUs and designed to improve performance of multime- dia software.
staggered pin grid array (SPGA) A feature of a CPU socket whereby the pins are staggered over the socket in order to squeeze more pins into a small space.
standby time The time before a "Green" system will reduce 92 percent of its activity. See also Green Standards.
standoffs Round plastic or metal pegs that sepa- rate the motherboard from the case, so that com- ponents on the back of the motherboard do not touch the case.
star bus topology A LAN that uses a logical bus design, but with all devices connected to a central hub, making a physical star.
star ring topology A topology that is physically arranged in a star formation but is logically a ring because of the way information travels on it. Token ring is the primary example.
star topology A LAN in which all the devices are connected to a central hub.
start bits Bits that are used to signal the approach of data.
startup BIOS Part of system BIOS that is responsible for controlling the PC when it is first turned on. Startup BIOS gives control over to the OS once it is loaded.
startup disk See rescue disk.
startup password See power-on password.
stateless Term for a device or process that man- ages data or some activity without regard to all the details of the data or activity.
static electricity See ESD.
static IP address An IP address permanently assigned to a workstation.
static RAM (SRAM) RAM chips that retain information without the need for refreshing, as long as the computer s power is on. They are more expensive than traditional DRAM.
static VxD A VxD that is loaded into memory at startup and remains there for the entire OS session.
stealth virus A virus that actively conceals itself by temporarily removing itself from an infected file that is about to be examined, and then hiding a copy of itself elsewhere on the drive.
stop error An error severe enough to cause the operating system to stop all processes.
streaming audio Downloading audio data from the Internet in a continuous stream of data without first downloading an entire audio file.
striped volume A type of dynamic volume used for two or more hard drives that writes to the disks evenly rather than filling up allotted space on one and then moving on to the next. Compare to spanned volume.
subdirectory A directory or folder contained in another directory or folder. Also called a child directory or folder.
subnet mask A subnet mask is a group of four numbers (dotted decimal numbers) that tell TCP/IP if a remote computer is on the same or a different network.
subsystems The different modules into which the Windows NT/2000/XP user mode is divided.
surge suppressor or surge protector A device or power strip designed to protect electronic equipment from power surges and spikes.
suspend time The time before a "Green" system will reduce 99 percent of its activity. After this time, the system needs a warm-up time so that the CPU, monitor, and hard drive can reach full activity.
swap file A file on the hard drive that is used by the OS for virtual memory. Also called a page file.
switch A device used to segment a network. It can decide which network segment is to receive a packet, on the basis of the packet s destination MAC address.
synchronization The process by which files and programs are transferred between PDAs and PCs.
synchronous DRAM (SDRAM) A type of memory stored on DIMMs that runs in sync with the system clock, running at the same speed as the motherboard.
synchronous SRAM SRAM that is faster and more expensive than asynchronous SRAM. It requires a clock signal to validate its control sig- nals, enabling the cache to run in step with the CPU.
SyncLink DRAM (SLDRAM) A type of DRJ\M developed by a consortium of 12 DRAM manufacturers. It improved on regular SDRAM but is now obsolete.
Sysedit The Windows System Configuration Editor, a text editor generally used to edit system files.
system BIOS BIOS located on the motherboard.
system board See motherboard.
system bus The bus between the CPU and memory on the motherboard. The bus frequency in documentation is called the system speed, such as 200 MHz. Also called the memory bus, front- side bus, local bus, or host bus.
system clock A line on a bus that is dedicated to timing the activities of components connected to it. The system clock provides a continuous pulse that other devices use to time themselves.
system disk Windows terminology for a bootable disk.
System.ini A text configuration file used by Windows 3.x and supported by Windows 9x for backward-compatibility
system partition The active partition of the hard drive containing the boot record and the specific files required to load Windows NT/2000/XP.
system resource A channel, line, or address on the motherboard that can be used by the CPU or a device for communication. The four system resources are IRQ, I/O address, DMA channel, and memory address.
System Restore A Windows Me/XP utility, sim- ilar to the ScanReg tool in earlier versions of Windows, that is used to restore the system to a restore point. Unlike ScanReg, System Restore cannot be executed from a command prompt.
system state data In Windows 2000/XP, files that are necessary for a successful load of the oper- ating system.
System Tray An area to the right of the taskbar that holds the icons of small applets launched at startup.
TAPI (Telephony Application Programming Interface) A standard developed by Intel and Microsoft that can be used by 32-bit Windows 9x communications programs for communicating over phone lines.
TCP (Transmission Control Protocol) Part of the TCP/IP protocol suite. TCP guarantees deliv- ery of data for application protocols and establishes a session before it begins transmitting data.
TCP/IP (Transmission Control Protocol/ Internet Protocol) The suite of protocols that supports communication on the Internet. TCP is responsible for error checking, and IP is responsi- ble for routing.
telephony A term describing the technology of converting sound to signals that can travel over telephone lines.
terminating resistor The resistor added at the end of a SCSI chain to dampen the voltage at the end of the chain.
termination A process necessary to prevent an echo effect of power at the end of a SCSI chain, resulting in interference with the data transmission.
ThickNet See 10Base5 Ethernet.
ThinNet See 10Base2 Ethernet.
thread Each process that the CPU is aware of; a single task that is part of a longer task or program.
time to live (TTL) Number of routers a net- work packet can pass through on its way to its des- tination before it is dropped. Also called hop count.
token ring An older LAN technology developed by IBM that transmits data at 4 Mbps or 16 Mbps.
top-level domain The highest level of domain names, indicated by a suffix that tells something about the host. For example, .corn is for commer- cial use and .edu is for educational institutions.
tower case The largest type of personal computer case. Tower cases stand vertically and can be as high as two feet tall. They have more drive bays and are a good choice for computer users who anticipate making significant upgrades.
trace A wire on a circuit board that connects two components or devices.
track One of many concentric circles on the sur- face of a hard drive or floppy disk.
training See handshaking.
transceiver The component on a NIC that is responsible for signal conversion. Combines the words transmitter and receiver.
transformer A device that changes the ratio of current to voltage. A computer power supply is basically a transformer and a rectifier.
transistor An electronic device that can regulate electricity and act as a logical gate or switch for an electrical signal.
translation A technique used by system BIOS and hard drive controller BIOS to break the 504-MB hard drive barrier, whereby a different set of drive parameters are communicated to the OS and other software than that used by the hard drive controller BIOS.
Travan standards A popular and improved group of standards for tape drives based on the QIC standards and developed by 3M.
Trojan horse A type of infestation that hides or disguises itself as a useful program, yet is designed to cause damage at a later time.
TSR (terminate-and-stay -resident) A program that is loaded into memory and remains dormant until called on, such as a screen saver or a mem- ory-resident antivirus program.
UART (universal asynchronous receiver- transmitter) chip A chip that controls serial ports. It sets protocol and converts parallel data bits received from the system bus into serial bits.
UDP (User Datagram Protocol) A connec- tionless protocol that does not require a connec- tion to send a packet and does not guarantee that the packet arrives at its destination. UDP is faster than TCP because TCP takes the time to make a connection and guarantee delivery.
unattended installation A Windows NT/ 2000/XP installation that is done by storing the answers to installation questions in a text file or script that Windows NT/2000/XP calls an answer file so that the answers do not have to be typed in during the installation.
Universal Disk Format (UDF) file system A file system for optical media used by all DVD discs and some CD-R and CD-RW discs.
unshielded twisted-pair (UTP) cable A cable that is made of one or more twisted pairs of wires and is not surrounded by a metal shield.
upgrade install The installation of an OS on a hard drive that already has an OS installed in such a way that settings kept by the old OS are carried forward into the upgrade, including information about hardware, software, and user preferences.
upper memory In DOS and Windows 9x, the memory addresses from 640K up to 1024K, origi- nally reserved for BIOS, device drivers, and TSRs.
upper memory block (UMB) In DOS and Windows 9x, a group of consecutive memory addresses in RAM from 640K to 1MB that can be used by 16-bit device drivers andTSRs.
UPS (uninterruptible power supply) A device designed to provide a backup power supply during a power failure. Basically, a UPS is a battery backup system with an ultrafast sensing device.
URL (Uniform Resource Locator) An address for a resource on the Internet. A URL can contain the protocol used by the resource, the name of the computer and its network, and the path and name of a file on the computer.
USB host controller Manages the USB bus. For the 400 series Intel chip set, the USB host con- troller is included in the PCI controller chip. The USB uses only a single set of resources for all devices on the bus.
USB (universal serial bus) port A type of port designed to make installation and configuration of I/O devices easy, providing room for as many as 127 devices daisy-chained together.
user account The information, stored in the SAM database, that defines a Windows NT/ 2000/XP user, including username, password, memberships, and rights.
user component A Windows 9x component that controls the mouse, keyboard, ports, and desktop.
user mode In Windows NT/2000/XP, a mode that provides an interface between an applica- tion and the OS, and only has access to hard- ware resources through the code running in kernel mode.
user profile A personal profile about a user that enables the users desktop settings and other oper- ating parameters to be retained from one session to another.
User State Migration Tool (USMT) A Windows XP utility that helps you migrate user files and preferences from one computer to another in order to help a user makes a smooth transition from one computer to another.
V.92 The latest standard for data transmission over phone lines that can attain a speed of 56 Kbps.
value data In Windows, the name and value of a setting in the registry.
VCACHE A built-in Windows 9x 32-bit soft- ware cache that doesn't take up conventional memory space or upper memory space as SMARTDrive did.
VESA (Video Electronics Standards Association) VL bus An outdated local bus used on 80486 computers for connecting 32-bit adapters directly to the local processor bus.
VFAT (virtual file allocation table) A varia- tion of the original DOS 16-bit FAT that allows for long filenames and 32-bit disk access.
video card An interface card installed in the computer to control visual output on a monitor. Also called display adapter.
virtual device driver (VxD orVDD) A Windows device driver that may or may not have direct access to a device. It might depend on a Windows component to communicate with the device itself.
virtual machine One or more logical machines created within one physical machine by Windows, allowing applications to make serious errors within one logical machine without disturbing other programs and parts of the system.
virtual memory A method whereby the OS uses the hard drive as though it were RAM. Compare to RAM drive.
virtual real mode An operating mode that works similarly to real mode provided by a 32-bit OS for a 16-bit program to work.
virus A program that often has an incubation period, is infectious, and is intended to cause dam- age. A virus program might destroy data and pro- grams or damage a disk drive s boot sector.
virus signature A set of distinguishing character- istics of a virus used by antivirus software to iden- tify the virus.
VMM (Virtual Machine Manager) A Windows 9x program that controls virtual machines and the resources they use including memory. The VMM manages the page table used to access memory.
volatile Refers to a kind of RAM that is tempo- rary, cannot hold data very long, and must be fre- quently refreshed.
volt (V) A measure of potential difference in an electrical circuit. A computer ATX power supply usually provides five separate voltages: + 12V,-12V, +5V,-5V,and+3.3V.
voltage Electrical differential that causes current to flow, measured in volts. See volt.
voltmeter A device for measuring electrical AC or DC voltage.
volume See logical drive.
VRAM (video RAM) RAM on video cards that holds the data that is being passed from the computer to the monitor and can be accessed by two devices simultaneously. Higher resolutions often require more video memory.
VxD See virtual device driver.
wait state A clock tick in which nothing hap- pens, used to ensure that the microprocessor isn't getting ahead of slower components. A 0-wait state is preferable to a 1-wait state. Too many wait states can slow down a system.
"WAN (wide area network) A network or group of networks that span a large geographical area.
'warm boot See soft boot.
watt (W) The unit used to measure power. A typ- ical computer may use a power supply that pro- vides 200W.
wattage Electrical power measured in watts.
WDM (Win32 Driver Model) The only Windows 9x Plug and Play component that is found in Windows 98 but not Windows 95. WDM is the component responsible for managing device drivers that work under a driver model new to Windows 98.
WFP (Windows File Protection) A Windows 2000/XP tool that protects system files from modification.
wide SCSI One of the two main SCSI specifica- tions. Wide SCSI has a 16-bit data bus.
Wi-Fi See IEEE 802. lib.
wildcard A * or ? character used in a command line that represents a character or group of charac- ters in a filename or extension.
Winl6 on Win32 (WOW) A group of programs provided by Windows NT/2000/XP to create a virtual DOS environment that emulates a 16-bit Windows environment, protecting the rest of the OS from 16-bit applications.
Win386.swp The name of the Windows 9x swap file. Its default location is C:\Windows.
Win.ini The Windows initialization file that con- tains program configuration information needed for running the Windows operating environment. Its functions were replaced by the registry begin- ning with Windows 9x, which still supports it for backward compatibility with Windows 3.x.
WINS (Windows Internet Naming Service) A Microsoft resolution service with a distributed database that tracks relationships between NetBIOS names and IP addresses. Compare to DNS.
WinSock (Windows Sockets) A part of the TCP/IP utility software that manages API calls from applications to other computers on a TCP/IP network.
wireless LAN (WLAN) A type of LAN that does not use wires or cables to create connections, but instead transmits data over radio or infrared waves.
workgroup In Windows, a logical group of computers and users in which administration, resources, and security are distributed throughout the network, without centralized management or security.
worm An infestation designed to copy itself repeatedly to memory, on drive space or on a net- work, until little memory or disk space remains.
WRAM (window RAM) Dual-ported video RAM that is faster and less expensive than VRAM. It has its own internal bus on the chip, with a data path that is 256 bits wide.
zero insertion force (ZIF) socket A socket that uses a small lever to apply even force when you install the microchip into the socket.
zone bit recording A method of storing data on a hard drive whereby the drive can have more sec- tors per track near the outside of the platter.