The s

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*DAC*		Digital-to-Analog Converter.
DAT		Digital Audio Tape. A storage format for musical and/or computer data. Most data types cannot be interchanged, however, because of different connectors.
data		Plural of datum, a piece of information. Generally, information of any type, but especially any information in a computer.
data processing		A general term for any work done on a computer, especially work done by the computer. Often applies especially to database work, as distinguished from desktop publishing, word processing, programming, or spreadsheet calculation.
date		The day, month, and year displayed by a computer with a battery-powered clock circuit. Also the DOS command for setting the date.
daughterboard		A printed circuit board that adds functionality to another board or card. Usually mounted parallel to the card it supports. Compare expansion card.
DB connector		Short for Data Bus connector. Usually shown with a number that represents the number of conductors in the connector, for example, DB-25.
decimal		The numbering system in common use where place value indicates powers of ten.
default		The option that the software or system chooses when you don't indicate a choice yourself. For example, Windows uses a default set of colors unless you choose other colors in the Desktop control panel.
delimiter		A character that separates the parts of a DOS command. For example, a backslash is the delimiter between subdirectory names. Also, the character (typically a comma or tab) that separates field items in a database.
desktop		The main working area on the screen when running Windows. Contains icons and windows. See GUI.
desktop publishing		See DTP.
device		Any identifiable subsystem of a computer. Identifiable to the computer. Drives, video circuitry, printers, the keyboard, the mouse, and ports are devices.
device driver		Software that enables a computer to communicate with a specific device, especially a peripheral.
device name		The label used by DOS to identify a component. LPT1, COM2, and CON are device names.
Dhrystone		A popular benchmark. Measures string operations.
digital		Operating in discrete units or steps. Not continuous. Since microcomputers operate using discrete voltages and timing pulses, they are said to be digital. Usually contrasted with analog.
digital-to-analog converter		A device that converts digital signals into their equivalent analog signals, usually sound or monitor electron gun voltages.
DIMM		Dual Inline Memory Module. Circuit board with pins connecting to different memory chips on both sides of the board, which allows for wider and faster data transfer (128-bit). Thought to eventually replace the SIMM as the market standard.
*DIN connector*		(For Deutsch Industrie Norm.) A round multipin connector.
DIP switch		Dual Inline Package switch. A bank of switches in a single housing. Used to change configurations or parameters.
DIR		The DOS command to list filenames. This command accepts several switches and parameters. For example, dir/w lists filenames in five columns across the screen. Type "help dir" at a DOS prompt to see a list of the switches and parameters.
directory		A list of the files in a disk or logical division of a disk. Also The logical division itself.
DirectX		Microsoft's set of standardized application programming interfaces (APIs) for games and other multimedia applications, including DirectDraw, Direct3D, DirectSound and others.
disc		A compact disc, or CD. Note the spelling.
disk		A random access data storage medium that uses disks of mylar or aluminum coated with a material that can be magnetized. See "floppy disk" and "hard disk drive."
disk cache		RAM that holds data that is frequently read from or written to a disk. This is faster than getting the data from the disk. Some hard disk controller cards are equipped with their own on-board cache.
disk controller		Circuitry that manages the physical activity of a disk drive, such as moving the drive heads and creating the actual signals recorded on the disks. The controller is usually a card on the underside of the drive itself. The expansion card that connects to the drive by a ribbon cable enables communication between the disk drive and the computer and is called an adapter or host adapter. (Sometimes the adapter circuitry is directly on the system board.) Older hard drives had two ribbon cables to the expansion card because one part of the card held controller circuitry and another part held the adapter circuitry.
disk directory		See directory
disk drive		The mechanism that spins, writes data to, and reads data from a disk.
disk operating system		Originally, an operating system loaded from disk in contrast to memory-resident operating systems and operating systems loaded from paper tape. See operating system.
disk partition		See partition.
diskette		See floppy disk. It's redundant to say floppy diskette.
display		The monitor screen. Also what shows on the screen.
display adapter, -board, -card, -controller		See video controller.
distributed network		A network architecture in which each node has equal function and precedence, as if every node were a file server. Same as peer-to-peer.
DLL		Dynamic Linked Library. A part of a computer program that links itself to application programs as they run. This code can be shared between different parts of the program rather than having to insert it in several different places.
DMA		Direct Memory Access. A method for transferring data, usually between memory and a disk drive, without going through the CPU.
DMI		Desktop Management Interface. A standard for PCs that allows manipulation of PC components over a network from a centralized location.
DNS		Domain Name System. A database system used to translate ASCII host names into numerical Internet addresses.
domain		A group of computers whose names share the same suffix or "domain name". e.g. ".com" (commercial), ".org" (organization), ".gov" (government), ".mil" (military), ".edu" (educational institution), ".net" (network operations). There are also two letter domain names for individual countries, such as ".us" (United States), and ".uk" (United Kingdom).
DOS		Disk Operating System. See operating system.
DOS prompt		An indicator on the display that indicates that MS-DOS is ready to receive a command. The default prompt is the current drive letter followed by a greater-than sign (>): C:> Most AUTOEXEC.BAT files include a PROMPT command (prompt=$p$g) that modifies the DOS prompt to display the current directory, too.
dot		The period. Called dot in computer parlance because it is easier to say.
dot-matrix		A type of printer that prints by driving a set of pins onto an inked ribbon, pressing small portions of the ribbon against the paper so dots of ink appear on the paper. The dots are close together and appear to be letters or graphic shapes.
double-click		To press and release the mouse button twice quickly without moving the mouse between clicks.
dot pitch		The amount of space between pixels in a monitor. The lower the number, the higher the monitor quality.
double-density disk		A 5.25" diskette that holds up to 360K bytes of information, or a 3.5" diskette that holds 720K.
down		Non-functional, especially when something is wrong, such as a system failure. Compare up.
download		To copy a file from a storage device (especially another computer) into your computer, or to send something from a computer to a printer.
downsize		To update a company computer system by retiring the mini or mainframe and using a system of distributed, smaller CPUs, such as networked microcomputers.
downward compatibility		A characteristic of software that runs correctly on old versions of a current operating system. Compare upward compatibility.
dpi		Dots Per Inch. A measure of resolution. A high resolution monitor has about 95dpi resolution; a typical laser printer has about 300dpi. The human eye can see at about 1200dpi.
draft quality		Printer output that is readable, but doesn't look good enough to use in business correspondence.
drag		To hold down the mouse button and move the mouse while the button is down. Also the movement of an object on the screen when the mouse is moved this way.
DRAM		(dee-ram) Dynamic Random Access Memory. RAM that requires external refresh circuitry and a minimum clock speed to retain its state. If dynamic RAM loses power, all its little capacitors discharge and it forgets everything. Compare SRAM.
drive		See disk drive.
drive array		Two or more hard disk drives used to store data simultaneously in order to enhance speed and reliability.
drive letter		The single-letter DOS name that designates a drive. Always followed by a colon.
driver		A software routine that controls or regulates a hardware device.
DSTN		Double Supertwisted Nematic. Also referred to as "dual-scan" screens. They are brighter than previous passive-matrix designs and less likely to temporarily lose a moving mouse pointer or scrolling text.
DSVD		Digital Simultaneous Voice & Data. New modem technology that allows you to transmit data and talk over the same phone line using a dual-processor system: one for data transmission, one for voice. However, you can only talk to the person who is receiving the data, and the two computers must have identical modems for this technology to work.
DTP		Desktop Publishing. Producing finished or camera-ready written documents using microcomputer-based page layout software and a high resolution printer. Usually requires a fast computer with a large screen, lots of memory, large storage capacity, and many typefaces.
dual scan display		Color LCD display where the screen is divided in half and has two refreshes.
DVD, DVD-ROM		Digital Video Disk. A hardware technology designed to replace audio and information CDs, laserdiscs, and even video tapes. Each DVD can hold the equivalent of 7 times a regular CD (more than 120 minutes of video), uses MPEG-2 video compression and is backwards compatible with CD-ROMs and music CDs.
DX		Suffix on the name of an 80x86 CPU chip that means the chip has a floating point unit, 32-bit internal data path, and internal cache.
DX/2		Suffix on the name of an 80486DX CPU that means the clock rate inside the chip is twice the clock rate of the circuit board on which the chip resides.
Dynalink (error)		Occurs when one of the following conditions exist: More than one version of a .dll is running or the .dll is corrupt or missing.
dynamic		Refers to microcircuitry that requires a clock to maintain its state. Compare static.

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