Acronym  's
D or DL
or DS
DAB - Digital Audio Broadcasting - broadcasting
of radio programs in digital format.
DAC - Digital to Analog Converter - device
that converts digital pulses into analog signals
daemon - UNIX program that executes in
the background ready to perform an operation when required. Functioning
like an extension to the operating system, a daemon is usually an
unattended process that is initiated at startup
DARPA - Defense Advanced Research Projects
Agency - name given to the U.S. Advanced Research Projects Agency
during the 1980s - later renamed back to ARPA
DAVID - Digital Audio/Video Interactive
Decoder - operating system for set-top boxes based on Microware's
OS-9 realtime operating system, it is used for interactive TV, video
on demand and Internet applications
DBS - Direct Broadcast Satellite - a
service whereby you receive subscription television from a single
high-powered satellite. DBS dishes are small, stationary, and generally
require payment to only one provider
DCC - Digital Content Creation - development
of material for distribution over the Internet or other digital
media
DCMA - Dynamic Channel Multicarrier Architecture
- a technology developed by ComSpace Corp. used for specialized
mobile radio networks that can configure the number and bandwidth
of voice and data channels basedon a carrier's requirements
DCT - Discreet Cosine Transform - a technique
for representing waveform data as a weighted sum of cosines, commonly
used for data compression, as in JPEG
DDR - Digital Disk Recorder
DDR DRAM - Double Data Rate Synchronous
DRAM
DECT - Digital Enhanced Cordless Telecommunications,
a standard issued by the ETSI (European Telecommunications Standards
Institute)
DES - Data Encryption Standard - a symmetric
key encryption method developed in 1975 and standardized by ANSI
in 1981. DES uses a 56-bit key
DHCP - Dynamic Host Configuration Protocol
- a protocol that enables a computer to obtain an IP address and
other information from the DHCP server during booting
DIMMS - Dual In-line Memory Module
DIP - DIP switch - a series of tiny switches
built into circuit boards - the DIP is the housing for switches
which has the same shape as a chip - they enable you to configure
a circuit board for a particular type of computer or application
DLL - Dynamic Link Library - executable
program module that performs some function. When needed, they are
called for by a running application and are loaded to provide additional
functionality
DLS - Downloadable Sample
DMA - Direct Memory Access - technique
for transferring data from main memory to a device without passing
it through the CPU (Central Processing Unit). This is useful for
making quick backups and for real-time applications
DNS - Domain Name Service - translates
host names into IP addresses
DOCSIS - Data-Over-Cable Service Interface
Specification - A set of standards for transferring data via cable
TV
DOD - The Department of the Defense model
- a term sometimes used to describe the layers involved in the TCP/IP
model
DOS - Disk Operating System - single-user
operating system from Microsoft for the PC. It was the first OS
for the PC and is still the underlying control program for Windows
3.1. Windows 95/98 and Windows NT build in their own version of
DOS to support existing DOS applications
DRAM - Dynamic Random Access Memory -
most common type of RAM for PCs
DRM - Digital Rights Management - system
for protecting the copyrights of digital content that is distributed
online, may include the accounting for paying royalties to the authors
of the material
DSL - Digital Subscriber Line - Technologies
that use sophisticated modulation schemes to pack data onto copper
wires
DSLAMS - Digital Subscriber Line Access
Multiplexers - Used in circumstances in which the xDSL-equipped
line carries both POTS (Plain Old Telephone Service) and data channels.
In this instance, the carrier must separate those two streams when
they reach the telephone company's central office (CO). The DSLAM
and CO xDSL modem send the customer's POTS traffic to the public
circuit-switched telephone network. It sends the customer's data
traffic (combined with that of other xDSL users) to a packet-switched
data network. Thus, the data traffic, after traversing the local
loop, avoids the circuit-switched telephone network altogether
DSM - Deep Submicron
DSP - Digital Signal Processor - a specialized
microprocessor that performs mathematical operations on a data stream
in real time to produce a second (modified) data stream
DSS - Decision Support Systems - computer-based
problem solving systems that assist choices between alternatives
in complex and controversial domains - provides a structured presentation
of alternatives, context, tools for design, evaluation, and selection
DSSS - Direct Sequence Spread Spectrum
- One variety of radio transmission methods that continuously change
frequencies or signal patterns, which is used in CDMA. DSSS multiplies
the data bits by a very fast pseudo-random bit pattern (PN sequence)
that "spreads" the data into a large coded stream that takes the
full bandwidth of the channel
DTV - Digital Television - A standard
that will provide improved picture/sound quality compared to current
NTSC broadcast standards
DVB - Digital Video Broadcasting - international
digital broadcast standard for TV, audio and data. DVB can be broadcast
via satellite, cable or terrestrial systems. It has been initially
used in Europe and the Far East
DVD - Digital Versatile/Video Disc -
family of optical discs that are the same overall dimensions of
a CD, but have higher capacities and are double sided
DWDM - Dense Wave Division Multiplexing
- WDM is a technology that uses multiple lasers and transmits several
wavelengths of light simultaneously over a single optical fiber.
Each signal travels within its color band, which is modulated by
the data (text, voice, video, etc.). WDM enables the existing fiber
infrastructure of the telephone companies and other carriers to
be increased. DWDM systems can support more than 150 wavelengths,
each carrying up to 10 Gbps. Such systems provide more than a terabit
per second of data transmission on one optical strand, thinner than
a human hair
DXF - Data Exchange File - two dimensional
graphics file format supported by virtually all PC-based CAD (Computer
Aided Design) products - created by AutoDesk for the AutoCAD system
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