Microsoft Internet & Networking Dictionary

Microsoft Internet & Networking Dictionary

digital data service n. See DDS.

digital data transmission

n. The transfer of information encoded as a series of bits rather than as a fluctuating (analog) signal in a communications channel.

digital fingerprinting

n. See digital watermark.

digital home

n. See smart home.

digital DNA

n. 1. Broadly, a reference to the bits that comprise digital information. 2. In the gaming world, a technology called “Cyberlife” that mimics biological DNA in the creation and development of trainable creatures known as Norns. Like real DNA, digital DNA is passed from parent to offspring and determines the artificial creature’s characteristics and adaptability.

digital modem

n. 1. A communications device that acts as the intermediary between a digital device such as a computer or terminal and a digital communications channel, such as a high-speed network line, an ISDN circuit, or a cable TV system. Although a digital modem supports standard (analog) modem protocols, it is not a “typical” modem in the sense of being a device whose primary function is to modulate (convert digital to analog) before transmission and demodulate (convert analog to digital) after transmission. It uses advanced digital modulation techniques for changing data frames into a format suitable for transmission over a digital line. See also terminal adapter. Compare modem. 2. A 56 Kbps modem. Such a modem is not purely digital but does eliminate the traditional digital-to-analog conversion for downstream transmissionsóthat is, transmissions moving from the Internet to the end user. A 56 Kbps modem is also digital in that it requires a digital connection, such as T1, between the telephone company and the user’s Internet Service Provider (ISP) in order to achieve its highest speed. See also 56-Kbps modem. 3. A term used to distinguish all-digital communications devices, such as ISDN and cable “modems” from the more traditional analog-to-digital, phone-based modems.

Digital Network Architecture

n. A multilayered architecture and set of protocol specifications for networks. Designed by the Digital Equipment Corporation, Digital Network Architecture is implemented in the set of products known by the name DECnet. Acronym: DNA. See also DECnet.

Digital Rights Management n. See DRM.

digital satellite system

n. A high-powered satellite system with the capability to deliver high-quality transmissions of hundreds of channels directly to television receivers. A DSS broadcast begins as a digital signal sent from a service provider’s station to a satellite. From there, it is directed to a satellite dish (typically 18 inches) at the user’s premises. The dish next transmits the signal to a converter box, which changes it to an analog signal before sending it to the television set. Acronym: DSS.

Digital Services n. See DS.

digital signature

n. A security mechanism used on the Internet that relies on two keys, one public and one private, that are used to encrypt messages before transmission and to decrypt them on receipt.

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Digital Signature Algorithm

n. The U.S. government standard for digital signatures, as specified by the National Institute of Standards and Technology, in FIPS 186, Digital Signature Standard. DSA is based on signature encryption based on a public and a private key. Acronym: DSA. See also digital signature.

Digital Signature Standard

n. A public key cryptographic standard issued in 1994 by the United States National Institute of Standards and Technology (NIST) to authenticate electronic documents. The DSS uses a Digital Signature Algorithm (DSA) to generate and verify digital signatures based on a public key, which is not secret, and a private key, which is known or held only by the person generating the signature. A digital signature serves to authenticate both the identity of the signer and the integrity of the transmitted information. Acronym: DSS. See also public key encryption.

Digital Simultaneous Voice and Data

n. A modem technology by Multi-Tech Systems, Inc., that allows a single telephone line to be used for conversation together with data transfer. This is accomplished by switching to packetmode communications when the need for voice transfer is detected; digitized voice packets are then transferred along with data and command packets. Acronym: DSVD.

digital subscriber line or Digital Subscriber Line n. See DSL.

Digital Subscriber Line Access Multiplexer or Digital Subscriber Line Multiplexer n. See DSLAM.

digital-to-analog converter

n. A device that translates digital data to an analog signal. A digital-to-analog converter takes a succession of discrete digital values as input and creates an analog signal whose amplitude corresponds, moment by moment, to each digital value. Acronym: DAC. Compare analog-to- digital converter.

digital TV or digital television

n. The transmission of television signals using digital rather than the conventional analog signals. A digital TV standard for the United States was approved by the FCC in 1996. Digital TV provides a better television experience and new information services. Digital signals produce higher quality pictures and CD-quality sound, compared to the analog signals used with today's television.

Digital TV can support interactive television, electronic program guides, and a variety of digital services, such as Internet channel broadcasting and data services. Acronym: DTV. Compare HDTV.

digital video

n. Video images and sound stored in a digital format. Acronym: DV.

digital watermark

n. A unique identifier embedded in a file to deter piracy and prove file ownership and quality. Digital watermarking is often used with graphics and audio files to identify the owner’s rights to these works. See also fingerprint2.

digiterati

n. See digerati.

DIN connector

n. A multipin connector conforming to the specification of the German national standards organization (Deutsch Industrie Norm). DIN connectors are used to link various components in personal computers.

Microsoft Internet & Networking Dictionary

direct broadcast satellite

n. A digital telecommunications service that delivers television programming via the Digital Satellite System (DSS). Direct broadcast satellite technology uses a geostationary orbit satellite (GEO) to receive digitized signals sent by ground-based uplink centers; the satellite then beams the signal across a wide swath on Earth. Subscribers within that swath use small (18-inch) satellite dishes to bring the signal into a set-top box decoder for playback. Although primarily used for television broadcasts, the technology is seen as having potential to also deliver highquality, digital communications and multimedia content in the future. Acronym: DBS. Also called: digital broadcast satellite. See also digital satellite system, geostationary orbit satellite, webcasting.

direct cable connection

n. A link between the I/O ports of two computers that uses a single cable rather than a modem or other active interface device. In most cases, a direct cable connection requires a null modem cable.

direct-connect modem

n. A modem that uses standard telephone wire and connectors and that plugs directly into a telephone jack, eliminating the need for an intermediary telephone.

directory

n. 1. A catalog for file names and other directories stored on a disk. A directory is a way of organizing and grouping the files so that the user is not overwhelmed by a long list of them. The uppermost directory is called the root directory; the directories within a directory are called subdirectories. Depending on how an operating system supports directories, file names in a directory can be viewed and ordered in various waysófor example, alphabetically, by date, by size, or as icons in a graphical user interface. What the user views as a directory is supported in the operating system by tables of data, stored on the disk, that indicate characteristics and the location of each file. In the Macintosh and Windows 9x operating systems, directories are called folders. 2. On a network, an index of names and pertinent information related to authorized users and network resources.

Directory Access Protocol

n. The protocol that governs communications between X.500 clients and servers. See also CCITT X series.

Directory Client Agent n. See DUA.

Directory Information Base n. See DIB (definition 2).

directory replication

n. The copying of a master set of directories from a server (called an export server) to specified servers or workstations (called import computers) in the same or other domains. Replication simplifies the task of maintaining identical sets of directories and files on multiple computers because only a single master copy of the data must be maintained. See also directory, server.

Directory Server Agent n. See DSA.

directory service

n. A service on a network that returns mail addresses of other users or enables a user to locate hosts and services.

Microsoft Internet & Networking Dictionary

Directory System Agent n. See DSA.

dirty adj. Of, pertaining to, or characteristic of a communications line that is hampered by excessive noise, degrading the quality of the signal. See also noise (definition 2).

discretionary access control list

n. The part of an object’s security descriptor that grants or denies specific users and groups permission to access the object. Only the owner of an object can change permissions granted or denied in a discretionary access control list (DACL); thus, access to the object is at the owner’s discretion. Acronym: DACL. See also distribution group.

discussion group

n. Any of a variety of online forums in which people communicate about subjects of common interest. Forums for discussion groups include electronic mailing lists, Internet newsgroups, and IRC channels.

diskless workstation

n. A station on a computer network that is not equipped with a disk drive and that uses files stored in a file server. See also file server.

disk server

n. A node on a local area network that acts as a remote disk drive shared by network users. Unlike a file server, which performs the more sophisticated tasks of managing network requests for files, a disk server functions as a storage medium on which users can read and write files. A disk server can be divided into sections (volumes), each of which appears to be a separate disk. Compare file server.

Distributed COM n. See DCOM.

Distributed Component Object Model n. See DCOM.

distributed database

n. A database implemented on a network. The component partitions are distributed over various nodes (stations) of the network. Depending on the specific update and retrieval traffic, distributing the database can significantly enhance overall performance.

distributed database management system

n. A database management system capable of managing a distributed database. Acronym: DDBMS. See also distributed database.

distributed denial of service attack n. See DDoS.

distributed file system

n. A file management system in which files may be located on multiple computers connected over a local or wide area network. Acronym: DFS.

distributed intelligence

n. A system in which processing ability (intelligence) is distributed among multiple computers and other devices, each of which can work independently to some degree but can also communicate with the other devices to function as part of the larger system. See also distributed processing.

Microsoft Internet & Networking Dictionary

distributed network

n. A network in which processing, storage, and other functions are handled by separate units (nodes) rather than by a single main computer.

distributed processing

n. A form of information processing in which work is performed by separate computers linked through a communications network. Distributed processing is usually categorized as either plain distributed processing or true distributed processing. Plain distributed processing shares the workload among computers that can communicate with one another. True distributed processing has separate computers perform different tasks in such a way that their combined work can contribute to a larger goal. The latter type of processing requires a highly structured environment that allows hardware and software to communicate, share resources, and exchange information freely.

distributed services n. See BISDN.

distributed system

n. A noncentralized network consisting of numerous computers that can communicate with one another and that appear to users as parts of a single, large, accessible “storehouse” of shared hardware, software, and data.

Distributed System Object Model

n. IBM’s System Object Model (SOM) in a shared environment, where binary class libraries can be shared between applications on networked computers or between applications on a given system. The Distributed System Object Model complements existing object-oriented languages by allowing SOM class libraries to be shared among applications written in different languages. Acronym: DSOM. See also SOM (definition 1).

distributed transaction processing

n. Transaction processing that is shared by one or more computers communicating over a network. Acronym: DTP. See also distributed processing, transaction processing.

distributed workplace

n. An environment other than the traditional office or factory, in which work is carried out on a regular basis. The flexibility afforded by the combination of communications and computing technologies enables many workers to conduct business anywhere the appropriate computer and data communications infrastructure has been set up. See also SOHO, telecommute.

distribution group

n. A group that is used solely for e-mail distribution and that is not security-enabled. Distribution groups cannot be listed in discretionary access control lists (DACLs) used to define permissions on resources and objects. Distribution groups can be used only with e-mail applications (such as Microsoft Exchange) to send e-mail messages to collections of users. If you do not need a group for security purposes, create a distribution group instead of a security group. See also discretionary access control list.

distribution list

n. A list of recipients on an e-mail mailing list. This can be in the form of either a mailing list program, such as LISTSERV, or an alias in an e-mail program for all recipients of an e-mail message. See also alias, LISTSERV, mailing list.

distribution services n. See BISDN.

distro1

Microsoft Internet & Networking Dictionary

n. 1. A distribution of software (usually a version of Linux), digital music, or an online magazine or e-zine. See also e-zine, Linux. 2. A company or individual that sells items, typically software, music CDs, or books, via the Web.

distro2

vb. To distribute or sell software releases, digital music, or text items via the Web.

DLC

n. Acronym for Data Link Control. An error-correction protocol in the Systems Network Architecture (SNA) responsible for transmission of data between two nodes over a physical link. Supported by Microsoft Windows NT and Windows 2000, DLC is designed to provide access to IBM mainframe computers and to Hewlett-Packard printers connected to the network. See also HDLC, SNA.

DLCI

n. See Data Link Connection Identifier.

DML

n. See declarative markup language.

DNA

n. See digital DNA, Digital Network Architecture, distributed network, Windows DNA.

DNS

n. 1. Acronym for Domain Name System. The hierarchical system by which hosts on the Internet have both domain name addresses (such as bluestem.prairienet.org) and IP addresses (such as 192.17.3.4). The domain name address is used by human users and is automatically translated into the numerical IP address, which is used by the packet-routing software. DNS names consist of a top-level domain (such as .com, .org, and .net), a second-level domain (the site name of a business, an organization, or an individual), and possibly one or more subdomains (servers within a second-level domain). See also domain name address, IP address. 2. Acronym for Domain Name Service. The Internet utility that implements the Domain Name System. DNS servers, also called name servers, maintain databases containing the addresses and are accessed transparently to the user. See also DNS server.

DNS name server n. See DNS server.

DNS server

n. Short for Domain Name System server, a computer that can answer Domain Name System (DNS) queries. The DNS server keeps a database of host computers and their corresponding IP addresses. Presented with the name apex.com, for example, the DNS server would return the IP address of the hypothetical company Apex. Also called: name server. See also DNS (definition 2), IP address.

DNS zone transfer n. See zone transfer.

DOCSIS

n. Acronym for Data Over Cable Service Interface Specification. The International Telecommunications Union standard (ITU Recommendation J.112) that specifies functions and internal and external interfaces for high-speed, bidirectional transfer of digital data between cable television networks and subscribers. DOCSIS-compliant equipment ensures interoperability between cable modems and the cable television infrastructure, regardless of manufacturer or provider. Initially developed by a group of cable television providers, including Time Warner and TCI, DOCSIS was designed to support data, video, and rapid Internet access. Data rates are 27

Microsoft Internet & Networking Dictionary

Mbps to 36 Mbps downstream (from the cable network) and 320 Kbps to 10 Mbps upstream (to the cable network). See also cable modem.

Document Content Architecture n. See DCA.

Document Content Description n. See DCD (definition 2).

Document Interchange Architecture n. See DIA.

document management

n. The full spectrum of electronic document creation and distribution within an organization.

document management system

n. A server-based network facility designed for the storage and handling of an organization’s documents. A document management system, or DMS, is built around a central library known as a repository and typically supports controlled access, version tracking, cataloging, search capabilities, and the ability to check documents in and out electronically. The open interface specification known as ODMA (Open Document Management API) enables desktop applications that support ODMA to interface with a DMS so that users can access and manage documents from within their client applications. Acronym: DMS. Also called: EDMS, electronic document management system.

Document Object Model

n. A World Wide Web Consortium specification that describes the structure of dynamic HTML and XML documents in a way that allows them to be manipulated through a Web browser. In the Document Object Model, or DOM, a document is presented as a logical structure rather than as a collection of tagged words. In essence, DOM is a means of defining a document as a treelike hierarchy of nodes in which the document is an object containing other objects, such as images and forms. Through DOM, programs and scripts can access these objects in order to change aspects such as their appearance or behavior. DOM is a vehicle for adding depth and interactivity to what would otherwise be a static Web page. Acronym: DOM.

document source

n. The plain-text HTML form of a World Wide Web document, with all tags and other markup displayed as such rather than being formatted. Also called: source, source document. See also HTML.

Document Style Semantics and Specification Language

n. An ISO standard derived from SGML that addresses the semantics of high-quality composition in a manner independent of particular formatting systems or processes. Like CSS and XSL, it can be used to format XML documents. Acronym: DSSSL. See also ISO, SGML.

document type definition n. See DTD.

DoD

n. See U.S. Department of Defense.

do-gooder virus

n. A virus or worm that has been released with the intention of correcting problems caused by other, more malicious viruses. The do-gooder virus typically looks for computers that have been compromised and then infects the system and fixes back doors and other vulnerabilities left

Microsoft Internet & Networking Dictionary

behind by the malicious program. The do-gooder virus may then use the repaired computer as a platform to infect other computers. See also anti-worm, automatic patching.

DOM

n. See Document Object Model.

domain

n. 1. In database design and management, the set of valid values for a given attribute. For example, the domain for the attribute AREA-CODE might be the list of all valid three-digit numeric telephone area codes in the United States. See also attribute (definition 1). 2. For Windows NT Advanced Server, a collection of computers that share a common domain database and security policy. Each domain has a unique name. 3. In the Internet and other networks, the highest subdivision of a domain name in a network address, which identifies the type of entity owning the address (for example, .com for commercial users or .edu for educational institutions) or the geographical location of the address (for example, .fr for France or .sg for Singapore). The domain is the last part of the address (for example, www.acm.org). See also domain name.

domain controller

n. In Windows NT, the master server that holds the directory services database that identifies all network users and resources.

domain name

n. An address of a network connection that identifies the owner of that address in a hierarchical format: server.organization.type. For example, www.whitehouse.gov identifies the Web server at the White House, which is part of the U.S. government.

domain name address

n. The address of a device connected to the Internet or any other TCP/IP network, in the hierarchical system that uses words to identify servers, organizations, and types, such as www.logos.net. See also TCP/IP.

Domain Name Server n. See DNS server.

Domain Name Service n. See DNS (definition 2).

Domain Name System

n. See DNS (definition 1).

Domain Naming System n. See DNS (definition 1).

domain slamming

n. The practice of transferring ownership of domain names from one customer to another without the permission of the first customer.

Domino

n. See Lotus Domino.

doorway page

n. A Web page that functions as a doorway into a Web site. Usually a doorway page contains keywords, which Internet search engines seek when they scan the Internet. Placing the correct keywords on a doorway page can increase the number of viewers visiting a site.

DoS

Microsoft Internet & Networking Dictionary

n. Acronym for denial of service attack. A computerized assault, usually planned, that seeks to disrupt Web access. A denial of service attack can occur in a number of forms. The most common form of attack is to overwhelm an Internet server with connection requests that cannot be completed. This causes the server to become so busy attempting to respond to the attack that it ignores legitimate requests for connections. One example of this type of attack, known as a SYN flood, inundates the server’s entry ports with false connection messages. Another, known as the Ping of Death, sends a ping command with an oversized IP packet that causes the server to freeze, crash, or restart. Other forms of denial of service attacks include the destruction or alteration of a server’s configuration data, such as router information; unauthorized access to physical components of a system; and the sending of large or invalid data that causes a system to crash or freeze. See also packet, Ping of Death, SYN flood.

dot

n. 1. In the UNIX, MS-DOS, OS/2, and other operating systems, the character that separates a file name from an extension as in TEXT.DOC (pronounced “text-dot-doc”). 2. In computer graphics and printing, a small spot combined with others in a matrix of rows and columns to form a character or a graphic element in a drawing or design. The dots forming an image on the screen are called pixels. The resolution of a display or printing device is often expressed in dots per inch (dpi). Dots are not the same as spots, which are groups of dots used in the halftoning process. 3. In an Internet address, the character that separates the different parts of the domain name, such as the entity name from the domain. See also domain (definition 3), domain name.

dot address

n. An IP address in dotted quad form. See also IP address.

dot-bomb

n. An Internet-based company or organization that has failed or downsized significantly. See also dot-commed.

dot-com

n. A company doing business primarily or entirely on the Internet. The term is derived from the top-level domain, .com, at the end of the Web addresses of commercial Web sites.

dot-commed

adj. Losing a job because of the downsizing or failure of an Internet-based company or organization. See also dot-bomb.

double posting

n. In newsgroup discussions, the practice of replying to one’s own posts. Because it may be seen as the digital equivalent to talking to one’s self, double posting is considered an undesirable practice.

Down

adj. Not functioning, in reference to computers, printers, communications lines on networks, and other such hardware.

downlink

n. The transmission of data from a communications satellite to an earth station.

download

vb. In communications, to transfer a copy of a file from a remote computer to the requesting computer by means of a modem or network.

downsample

n. To decrease the number of audio samples or pixels, by applying an operation such as averaging. Popular internet music formats, such as MP3, use downsampling to reduce file size.

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downsizing

n. In computing, the practice of moving from larger computer systems, such as mainframes and minicomputers, to smaller systems in an organization, generally to save costs and to update to newer software. The smaller systems are usually client/server systems composed of a combination of PCs, workstations, and some legacy system such as a mainframe, connected in one or more local area networks or wide area networks. See also client/server architecture.

downstream1

n. The direction in which information, such as a news feed for a newsgroup or data from an http (Web) server, is passed from one server to the next. See also newsfeed, newsgroup, server.

downstream2

adv. 1. The location of a client computer in relation to a server. 2. The direction in which data moves from the server to the client.

downstream3

adj. Refers to data that moves from a remote network to an individual computer. In some Internetrelated communications technologies, data flows more quickly downstream than upstream; cable modems, for example, can transfer data as fast as 30 Mbps downstream but support much slower rates, from 128 Kbps to around 2 Mbps, upstream. Compare upstream.

downtime

n. The amount or percentage of time a computer system or associated hardware remains nonfunctional. Although downtime can occur because hardware fails unexpectedly, it can also be a scheduled event, as when a network is shut down to allow time for maintenance.

Dreamcast

n. A console game system designed by the Sega corporation. It features a Hitachi 128-bit graphics engine with an on-board SH-4 RISC processor (operating frequency of 200 MHz 360 MIPS/1.4 GFLOPS) and a customized OS using Windows CE as its base (supporting DirectX). Game developers for the Dreamcast platform use an environment supported by Microsoft Visual Studio and refined Visual C++. See also computer game, console game. Compare GameCube, PlayStation, Xbox.

dribbleware

n. Updates, patches, and new drivers for a software product that are released one at a time, as they become available, rather than being issued together in a new version of the product. A company using the dribbleware technique might distribute new and replacement files on diskette or CD-ROM, or make them available for download through the Internet or a private network.

drill down

vb. To start at a top-level menu, directory, or Web page and pass through several intermediate menus, directories, or linked pages, until the file, page, menu command, or other item being sought is reached. Drilling down is common practice in searching for files or information on the Internet, where high-level Gopher menus and World Wide Web pages are frequently very general and become more specific at each lower level. See also Gopher, Web page.

DRM

n. Acronym for Digital Rights Management. A group of technologies developed to protect intellectual property from online piracy by controlling who can view protected content and in what form. A DRM package may allow the purchaser to view protected content, but prevent printing or forwarding. Content may also be set to expire after a set amount of time or if distributed to multiple users. DRM technology is meant to protect multiple forms of digital and analog content, and includes encryption, digital watermarking, and content tracking software.