Glossary - Index D

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Daisy-chain: Connecting devices together in a string. Most often associated with SCSI devices.

Data Execution Prevention (DEP): DEP is a security feature that can help prevent damage to your computer from viruses and other security threats. DEP can help protect your computer by monitoring programs to make sure they use system memory safely. If a program tries running (also known as executing) code from memory in an incorrect way, DEP closes the program.

DDR: Double Data Rate - a type of Synchronous DRAM, or SDRAM. DDR SDRAM enables data transfers to occur on both edges of the clock cycle, thus doubling the memory throughput of the chip.

DDR RAM: An extention of SDRAM technology, DDR effectively doubles the bandwidth available by sending data on the falling edge of the clock cycle as well as on the rising edge.

Defrag: In the maintenance of file systems, defragmentation is a process that reduces the amount of fragmentation. It does this by physically organizing the contents of the mass storage device or HDD used to store files into the smallest number of contiguous regions (fragments).

Desktop: No, not the thing your keyboard and mouse are sitting on, but rather the main screen on your monitor where you find your icons, background wallpaper and maybe your screensaver.

DHCP: Dynamic Host Configuration Protocol - Method of assigning temporary IP addresses to computers to ensure network security.

Digi board: Hardware to build a ras server.

Dimm: DIMM RAM is characterized by its 168 pins.

DIMM Slots: DIMM memory fits into special 168 pin slots which are located on the motherboard, usually adjacent from the processor.

DNS: Domain Name System (DNS), an hierarchical naming system for computers or any resource connected to the Internet.

DOCSIS: Data Over Cable Service Interface Specification - A standard for transferring internet data over cable lines.

Domain Name: A domain name is a common network name under which a collection of network devices are organized (e.g., www.majorgeeks.com)

DOS: DOS, short for "Disk Operating System", is an acronym for several closely related operating systems that dominated the IBM PC compatible market between 1981 and 1995, or until about 2000 if one includes the partially DOS-based Microsoft Windows versions 95, 98, and Millennium Edition.

Dot Pitch: Used to describe the horizontal size of pixels on CRT and LCD displays. The smaller the dot pitch (for example 0.25 mm) the better the resolution of the display.

Double Click: 2 clicks of the mouse at the same time. If the program detects a double click it often will open the selected application.

Download: In computer networks, to download means to receive data to a local system from a remote system, or to initiate such a data transfer. Examples of a remote system from which a download might be performed include a webserver, FTP server, email server, or other similar systems. See Upload

Driver: In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device. A driver typically communicates with the device through the computers USB or communications subsystem to which the hardware connects.

DSL: Digital Subscriber Line - High-speed internet connection offered by telephone companies over existing phone lines.

DVD: Digital Versatile Disc - Introduced in 1996, the optical discs share the same overall dimensions of a CD, but have significantly higher capacities - holding from 4 to 28 times as much data.

DVD Video: Popular format for high quality MPEG2 video and digital surround sound. Enables multi-language, multi-subtitling and other advanced user features.

DVD+RW: DVD ReWritable - It is the only rewritable format that provides full, non-cartridge, compatibility with existing DVD-Video players and DVD-ROM drives for both real-time video recording and random data recording across PC and entertainment applications.

DVD-Audio: This audio-only storage format similar to CD-Audio, however offers 16, 20 and 24-bit samples at a variety of sampling rates from 44.1 to 192KHz, compared to 16 bits and 44.1KHz for CDs. DVD-Audio discs can also contain music videos, graphics and other information.

DVD-RAM: DVD Random Access Memory - A rewritable DVD disc endorsed by Panasonic, Hitachi and Toshiba. It is a cartridge-based, and more recently, bare disc technology for data recording and playback. DVD-RAM bare discs are fragile and do not guarantee data integrity. The first DVD-RAM drives had a capacity of 2.6GB (single sided) or 5.2GB (double sided). DVD-RAM Version 2 discs have double-sided 9.4GB discs. DVD-RAM drives typically read DVD-Video, DVD-ROM and CD media. The current installed base of DVD-ROM drives and DVD-Video players cannot read DVD-RAM media.

DVD-ROM: Read Only Memory - This read-only DVD disc is used for storing data and interactive sequences as well as audio and video. DVD-ROMs run in DVD-ROM or DVD-RAM drives, not DVD-Video players connected to TVs and home theaters. However, most DVD-ROM drives will play DVD-Video movies.

DVD-RW: DVD ReWritable - A rewritable DVD format that is similar to DVD+RW, but its capability to work as a random access device is not as good as +RW. It has a read-write capacity of 4.7 GB.

DVI: Digital Visual Interface is a video interface standard covering the transmission of video between a source device (such as a personal computer) and a display device. The DVI standard has achieved widespread acceptance in the PC industry, both in desktop PCs and monitors. Most contemporary retail desktop PCs and LCD monitors feature a DVI interface, and many other devices (such as projectors and consumer televisions) support DVI indirectly through HDMI, another video interface standard. Most laptops still have legacy VGA and, in some models, HDMI ports, but fewer have DVI.