An Online Glossary of Computer Terms and Acronyms

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Here's an alphabetical listing of the most commonly used Computer Terms and Acronyms.


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.

ATC (Advanced Transfer Cache) - A type of L2 cache contained within the Pentium processor housing that is embedded on the same core processor die as the CPU itself.

ANSI (American National Standards Institute) - A non-profit organization dedicated to creating trade and communications standards.

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, therefore, slower than synchronous SRAM.

AT - A form factor 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.

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.

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.

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.


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.

BIOS (Basic Input/Output System) - Firmware that can control much of a computer's input/output functions, such as communications with the floppy drive and the monitor. Also called ROM BIOS.

bit (binary digit) - An 0 or 1 used by the binary number system.

blog - A Blog is the short for a Weblog and is a journal which is available on the Internet. A Blog is frequently updated and this is known as 'blogging'. The person who keeps a blog is a 'Blogger'. Blogs usually represent the personal thoughts of the 'Blogger'. Click here to view my blog.

bootable disk - For DOS and Windows, a floppy disk that can upload the OS files necessary for a computer startup. For DOS or Windows 9X, it must contain the files Io.sys, Msdos.sys and

Broadband - A transmission technique that carries more than one type of transmission on the same medium such as a cable modem or DSL.

brownouts - Temporary reduction in voltage, which can sometimes cause data loss.

bus - The paths or lines on the motherboard on which data, instructions and electrical power move from component to component.

bus speed - The speed or frequency at which the data on the motherboard is moving.

byte - A collection of 8 bits that is equivalent to a single character. When referring to system memory, an additional error-checking bit might be added, making the total 9 bits.


cable modem - A technology that uses cable TV lines for data transmission requiring a modem at each end. From the modem, a network cable connects to a NIC in the user's PC.

CPU (Central Processing Unit - Also called a microprocessor or processor. The heart and brain of the computer which receives data input, processes information and executes instructions.

chip set - A group of chips on the motherboard that controls the timing and flow of data and instructions to and from the CPU.

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.

CMOS (Complementary Metal-Oxide Semiconductor) - One of two types of technologies 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 lower and produce less heat than TTL chips. The configuration or setup chip is a CMOS chip.

CMOS Setup - (1) The chip on the motherboard that holds configuration information about the system, such as date and time, on which CPU, hard drives or floppy drives are installed. Also called CMOS or CMOS RAM. The chip is powered by a battery when the PC is turned off. (2) The program in system BIOS that can change the values in CMOS RAM.

Config.sys - A text file used by DOS and supported 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.


data bus - The lines on the system bus that CPU uses to send and receive data.

defragment - To 'optimize' or re-write a file to a disk in one contiguous chain of clusters thus speeding up data retrieval.

device driver - A program stored on the hard drive that tells the computer how to communicate with an input/output device such as a printer or a 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.

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.

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 a data moving to/from the device and memory.

DNS (Domain Name Service) - 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 the host to locate information in the pool.

domain name - A unique text-based name that identifies a network.

dot pitch - The distance between the dots that the electronic beam hits on a monitor screen.

DDR SDRAM (Double Data Rate SDRAM) - A type of memory technology used on DIMMs that runs at twice the speed of the system clock.

DSL (Digital Subscriber Line) - A telephone line that carries digital data from end to end and can be leased for telephone company for individual use. DSL lines are rated at 5Mbps, about 50 times faster than regular telephone lines.

DRAM (Dynamic Ram) - The most common type of system memory, it requires refreshing every few milliseconds.


EEPROM (Electrically Erasable Programmable ROM) - A type of chip in which higher voltage may be applied to one of the pins to erase its previous memory before a new instruction set is electronically written.

EIDE (Enhanced IDE) - A standard for managining the interface between secondary storage devices and a computer system. A system can support up to 4 IDE devices such as hard drives, CD-ROM drives and Zip drives.

encryption - The process of putting readable data into an encoded form that can only be decoded (or decrypted) through use of a key.

EPP (Enhanced Parallel Port) - A parallel port that allows data to flow in both directions (bidirectional port) and is faster than original parallel ports on PCs that allow communication only in one direction.

ESD (Elesctrostatic Discharge) - Another name for static electricity which can damage chips and destroy motherboards even though it might not be felt or seen with the naked eye.

EPROM (Erasable Programmable ROM) - A type of chip with a special window that allows the current memory content to be erased with special ultraviolet light so that the chip can be reprogrammed. Many BIOS chips are EPROMs.

ethernet - A LAN architecture that uses a bus or star topology, uses CSMA/CD when two computers are trying to gain access to the network at the same time, and is the most popular network architecture in use today.

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 capability of the computer.


FAT (File Allocation Table) - A table on a hard drive or floppy disk that tracks the clusters used to contain a file.

firewall - Hardware or software that protects a computer or network from unauthorized access.

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 desk top monitor that uses an LCD panel.

Flex ATX - A version of the ATX form factor that allows for maximum flexibility in the size and shape of cases and motherboards. Flex ATX is ideal for custom systems.

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.

FTP (File Transfer Protocol) - The protocol used to transfer files over a TCP/IP network such that the file does not need to be converted to ASCII format before transferring it.

full-duplex - Communication that happens in both directions at the same time.


gigahertz (GHz) - One thousand MHz or one billion cycles per second.

graphics accelerator - A type of video card that has an on-board processor that can substantially increase speed and boost graphical and video performance.


hard boot - Restart the computer by turning off the power or by pressing the reset button. Also called a 'cold boot'.

hard drive - The main secondary storage device of a PC; a small case that contains magnetic coated platters that rotate at high speed.

hardware - The physical components that constitute the computer system such as the monitor, the keyboard, the motherboard and the printer.

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.

HTML (HyperText Markup Language) - A markup language used for hypertext documemnts 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.


IBM-compatible PC - A computer that uses an Intel (or compatible) processor and can run DOS and Windows.

IDE (Integrated Drive Electronics) - A hard drive whose disk controller is integrated into the drive eliminating the need for a controller cable and thus increasing speed as well as reducing price.

IEE 1284 - A standard for parallel ports and cables developed by the Institute for Electrical and Electronics Engineers and supported by many hardware manufacturers.

IEE 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.

ISP (Internet Service Provider) - A commercial group that provides Internet access for a monthly fee. AOL, Earthlink and CompuServe are large ISPs.

ISDN (Integrated Services Digital Network) - A digital telephone line that can carry data at about five times the speed of regular telephone line. Two channels (telephone numbers) share a single pair of wires.


keyboard - A common input device through which data and instructions may be typed into computer memory.


LAN (Local Area Network) - A computer network that covers only a small area usually within one building.


MBR (Master Boot Record) - 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.

megahertz (MHz) - One million Hz or one million cycles per second.

memory - Physical microchips that can hold data and programming located on the motherboard or expansion cards.

micro ATX - A recent version of the ATX form factor. Micro ATX addresses some new technologies that have been developed since the original introduction of ATX.

mini ATX - A smaller ATX board that can be used with regular ATX cases and power supplies.

MMX (Multimedia Extensions) - Multimedia instructions built into Intel processors to add functionality 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 format.

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.

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.


NIC (Network Interface Card) - An expansion card that plugs into a computer's motherboard and provides a port on the back of the card to connect a PC to a network. Also called a network adapter.

NTFS (NT File System) - The file system for the Windows NT/2000/XP Operating System. NTFS cannot be accessed by other Operating Systems such as DOS. It provides increase reliability and security in comparison to other methods of organizing and accessing files. There are several versions of NTFS that might or might not be compatible.


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.


P1 connector - Power connector 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.

parallel port - A female 25-pin port on a computer that can transmit data in parallel, 8 bits at a time and is usually used with a printer. The names for parallel ports are LPT1 and LPT2.

PCI (Peripheral Component Interconnect) - A bus common on Pentium computers that runs at speeds of up to 33MHz or 66MHz 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.

pin grid array (PGA) - A feaure of a CPU socket whereby the pins are aligned in uniform rows around the socket.

POST (Power-On Self Test) - A self-diagnostic program used to perform a single 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.


RAM (Random Access Memory) - Memory modules on the motherboard containing microchips used to temporarily hold data and programs while the CPU processes both. Information in RAM is lost when the PC is turned off.

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 data base that Windows uses to store hardware and software configuration information, user preferences and setup information.

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.

RIMM (Rambus Inline Memory Module) - A type of memory module used on newer motherboards produced by Rambus, Inc.

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 (Network Interface Card).


SCSI (Small Computer System Interface) - A fast interface between a host adapter and the CPU that can daisy chain as many as seven or fifteen devices on a single bus.

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.

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.

SMTP (Simple Mail Transfer Protocol) - The protocol used by e-mail clients and servers to send e-mail messages over the Internet.

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.

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.

synchronus 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 signals, enabling the cache to run in step with the CPU.


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 responsible for routing.

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 memory-resident anti-virus program.


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.

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 (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.


V.92 - The latest standard for data transmission over phone lines that can attain a speed of 56Kbps.

video card - An interface card installed in the computer to control visual output on a monitor. Also called display adapter.

virtual memory - A method whereby the OS uses the hard drive as though it were RAM.

virus - A program that often has an incubation period, is infectious and is intended to cause damage. A virus program might destroy data and programs or damage a disk drive's boot sector.


WAN (Wide Area Network) - A network or group of networks that span a large geographical area.

worm - An infestation designed to copy itself repeatedly to memory on drive space or on a network until little memory or disk space remains.


zero insertion force (ZIF) socket - a socket that uses a small lever to apply even force when you install the microchip into the socket.

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