DAB (Digital Audio Broadcasting)
Along with the revolution in digital TV comes the revolution in digital radio. Although still in its infancy, digital radio will end hissing, sweeping and those annoying warbling noises on weak signals or between stations. The level of signal needed to achieve a perfect signal on digital radio is far lower so you can achieve greater audio clarity more of the time.
DAT (Digital Audio Tape)
Higher storage capacity tape recording system that uses digital recording methods. Used for digital audio and video as well as data back-ups.
DDR-SDRAM (Double Data Rate-Synchronous DRAM)
Short for Double Data Rate-Synchronous DRAM, a type of SDRAM that supports data transfers on both edges of each clock cycle (the rising and falling edges), effectively doubling the memory chip's data throughput. DDR-SDRAM also consumes less power, which makes it well-suited to notebook computers. DDR-SDRAM is also called SDRAM II. and DDRAM.
Dial-up
Dial-up pertains to a telephone connection in a system of many lines shared by many users. A dial-up connection is established and maintained for a limited time duration. The alternative is a dedicated connection, which is continuously in place. Dial-up lines are sometimes called switched lines and dedicated lines are called nonswitched lines. A dedicated line is often a leased line that is rented from a telephone company.
Digital Camera
Portable optical recorder that captures images on an internal memory chip, removable PC cards, or other digital media. Images can be transferred electronically to a computer for manipulation, e-mailing or website creation. A digital camera looks and behaves like a regular camera, except instead of using film, it stores the image it sees in memory as a file for later transfer to a computer. Many digital cameras offer additional storage besides their own internal memory; a few sport some sort of disk but the majority utilize some sort of flash card. Digital cameras are usually much more convenient for computer applications. Another related device is called a scanner.
Digital Television
Digital television (DTV) is the transmission of television signals using digital rather than conventional analog methods. Conventional standards - National Television Standards Committee, Phase Alternation Line, and Sequential Couleur avec Memoire - specify analog transmission. However, both the audio and video components of a television signal can be transmitted in digital form.
DirectX
DirectX is an application program interface (API) for creating and managing graphic images and multimedia effects in applications such as games or active Web pages that will run in Microsoft's Windows operating systems. (Such an application program might be written in C++, or Visual C/C++, or Java.) The capability to "play" DirectX applications comes as an integrated part of Microsoft's Internet Explorer
DLL (Dynamic Link Library)
Refers to a type of file that is stored either locally or remotely and is a collection of commands and/or data which can be shared by different programs on the same platform.
Typical DLL files contain commands and/or data that are common to a certain task, for instance Windows has many DLL files built-in which other programs access and utilise. A common example of this is spool32.dll which is used for printing control within Windows 95/98 by other applications.
The one time you may become aware of DLL files is when your computer crashes and you are presented with a message such as an "invalid page fault".
The errors associated with DLL files are beyond the scope of this page, however, DLL files can be updated and most of the time a problem can be solved by updating the DLL file in question.
DMA (Direct Memory Access)
A technique that some PC hardware devices use to transfer data to and from the memory without using the CPU.
DNS (Domain Name System)
The address mapping system used to match numeric internet addresses, e.g. 192.95.543.095 with www. web addresses.
DOS (Disk Operating System)
DOS was the standard operating system for PCs until Windows 95 came out. Will run on any PC. Controlled by typing in text commands and has several serious limitations, but requires a much less powerful computer than Windows 95 and there is a huge library of software available for it.
DPI (Dots Per Inch)
A measure of picture quality, often used to measure printer capabilities. The higher the number, the better the quality.
DRAM (Dynamic Random Access Memory)
A type of memory (RAM) widely used in today's PCs. DRAM works differently to SDRAM as it needs to be refreshed to continue holding the data, this means a slight loss of speed as the memory refreshes itself with a pulse of current to each of its cells.
Device Driver
This is a program that is written specifically to control a certain piece of hardware such as a soundcard, modem, graphics card, printer, scanner etc.
Each manufacturer supplies drivers for their specific products, these drivers are often updated with time so it is a good idea to keep your drivers current. To find specific drivers for any of your devices it is best to start at the manufacturer's website as they normally have updated drivers in their respective support pages.
DSL (Digital Subscriber Line)
A high-speed Internet connection technology that uses a regular telephone line for connectivity. DSL comes in several varieties, including Asynchronous (ADSL) and Synchronous (SDSL), and many speeds. Typical home-user DSL connections are ADSL with a download speed of up to 1.5 Mbps and an upload speed of 384 Kbps.
Duron
A lower-cost version of AMD's Athlon series of CPUs.
DVD (Digital Versatile Disc)
A CD media format that provides for 4.17 GB of video or data storage. New DVD9 (Dual Layer) discs can be burnt onto in two-layers which give a total capacity of approximately 9GB of data.
