- PC - Buzz - 1 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z *

---

DA = Destination Address

A six octet value uniquely identifying an endpoint which is sent in IEEE LAN frame headers to indicate frame destination.
> MAC

---

DAC = Discretionary Access Control

Defined in C2 - implemented in Windows NT where users own objects.
The ability to provide different types of access to different users.
Means of restricting access to objects based on the identity and need-to-know of users and/or groups to which the object belongs. Controls are discretionary in the sense that a subject with a certain access permission is capable of passing that permission (directly or indirectly) to any other subject.
> MAC, profile

 

DAC = Digital to Analog Converter

a device (usually a single chip) that converts digital data into analog signals. Modems require a DAC to convert data to analog signals that can be carried by telephone wires. Video adapters also require DACs, called RAMDACs, to convert digital data to analog signals that the monitor can process.

---

DACS = Digital Access and Cross-Connect System

A digital switching device for routing T-1 lines and DS-0 portions of lines, among multiple T-1 ports.

---

Damgaard

Producenter af finans- og bogholderi-systemet Concorde, som nu er fusioneret med det tilsvarende system Navision - og opkøbt af Microsoft.

>DANMAX

---

DANMAX

Damgaards første PC-økonomiprogram i 1983
> Concorde, Damgaard

---

DAO = Data Access Object (DataAdgangsObjekt)

I databaseprogrammet Microsoft Access: Det objekt, der repræsenterer strukturen i databasen, og de data, objektet indeholder. I Visual Basic kan du anvende DAO-objekter til at oprette eller ændre tabeller og forespørgsler, til at sikre databasen eller til at få adgang til data fra eksterne datakilder. Du kan også anvende DAO-objekter til at arbejde med de data, der er gemt i databasen ved hjælp af programkode.
>ADO, ODBC

---

DAP = Directory Access Protocol

> LDAP

---

DARPA = Defence Advanced Research Projects Agency

= ARPA fra ca 1985 til 1993 - udviklede satellit og radio netværk som blev tilsluttet ARPAnet. Udviklede TCP/IP.

---

DAT = Digital Audio Tape

> DDS, DLT

---

database

> DBMS, RDBMS

hierakisk - forældre/børn system

netværks-

> DBTG database

relations-

- En samling af relaterede, navngivne tabeller.
> Access, IBM database, Informix, Ingres, Sybase, Oracle, Paradox
> SQL

---

datakommunikation

Enhver form for datatransport - fx vha elektriske signaler - mellem to terminaler, som er forbundet med en 'datakanal'. OSI er en systematisk model for datakommunikation.
>datatransmission

---

Datapak

Pakkekoblet datanet i nordiske lande - benytter protokollen X.25.

---

datatransmission

Datatransport via en datakanal.
parallel datatransmission : overførsel af flere bits samtidigt - bruges især internt i datamaskiner - og til korte eksterne forbindelser fx til printer.
seriel datatransmission : overførsel af én bit ad gangen - bruges især til transmission over længere afstande - fx via netværkskabler og telefonlinjer.
>datakommunikation

---

Datex

Kredsløbkoblet datanet i nordiske lande - benytter protokollen X.21.

---

DBA = Dynamic Bandwidth Allocation

A process that optimizes overall network efficiency by automatically increasing or decreasing the bandwidth of a channel to accommodate changes in data flow from end-user equipment.

---

DBMS = DataBase Management System

> Database, ODBC, RDBMS

---

DBTG = the DataBase Task Group

under den amerikanske standardiseringskomité - udviklede netværksdatabasen i slutningen af 1960'erne
DBTG database - netværksdatabase (= CODASYL database) med et meget ordrigt og engelsk-lignende programmeringssprog (ligesom COBOL)

---

DCE = Data Communicating Equipment, Data-Communications Equipment

- In RS232 communications, a device implementing the interface and handshaking of a data communications device (such as a modem).
The equipment that enables a DTE to communicate over a telephone line or data circuit. The DCE establishes, maintains, and terminates a connection, and performs the conversions necessary for communications. In RS-232, designation as either DCE or DTE determines the signaling role in handshaking

---

DCE = Distributed Computing Environment

> X.500

---

DCOM = Distributed Component Object Model

in Windows NT 4 and 98. For communication between component of a DCOM-enabled distributed application.
Previously called Network OLE

---

DCS = Digital Access Cross-Connect Switch

A digital switching device for routing time slots among multiple E1/T1 ports.

---

DCS = Digital Cross Connect System

(1) An electronic switching node that enables circuits to be cross-connected.
(2) An electronic cross-connect which has access to the lower-rate channels in higher-rate multiplexed signals and can electronically rearrange (cross-connect) those channels.

---

DDE = Dynamic Data Exchange

Introduceret i Windows 2 - til kommunikation mellem Windows-programmer.
A message protocol for transferring data between two Windows applications while they are running.
> IPC, OLE

---

DDF = Dansk DataForening

Varetager PC-kørekort

www.ddf.dk

---

DDN = Defense Data Network

udviklet fra ARPAnet - ca 1975
> Milnet

---

DDR SDRAM = Double Data Rate SDRAM

[whatis] : DDR SDRAM is synchronous dynamic RAM (SDRAM) that can theoretically improve memory clock speed to at least 200 MHz. It activates output on both the rising and falling edge of the system clock rather than on just the rising edge, potentially doubling output. It's expected that a number of Socket 7 chipset makers will support this form of SDRAM.

---

DDS = Digital Data Storage

U.S. private data transmission network, established in 1974 by AT&T and based on AT&T's Dataphone data service. DDS is a digital overlay network built on the existing loop and trunking network.
> DAT

---

DEA = Data Encryption Algorithm

specielt den algoritme som benyttes i DES

---

DEC = Digital Equipment Corporation

= Digital
DEC Alpha - a CPU used in high-end graphics (3D-CAD, Animation etc)
DEC VAX - a mini computer

---

DECT = Digital Enhanced Cordless Phone

En europæisk standard for digitale trådløse telefoner - med flere funktioner end analoge - fx en indbygget telefonbog. DECT bruger det frie 2.4 GHz bånd, ligesom Bluetooth, Wireless LAN og mikrobølgeovne - der er derfor mulighed for støj.

---

DELNI = Digital Equipment Local Network Interconnect

ethernet repeater
> DEMPR, MTU

---

DEMPR = Digital Equipment Multiport Repeater

ethernet repeater
> DELNI

---

DES = Data Encryption Standard

One of the most widely used data encryption techniques.

 

DES = Destination End Station

An ATM termination point which is the destination for ATM messages of a connection and is used as a reference point for ABR services.

---

Deschutes

> Pentium II

---

Deutsche Telekom

tysk telekommunikations-selskab, som er Europas største internetudbyder

www.telekom.de/english/

---

DHCP = Dynamic Host Configuration Protocol

tildeler automatisk unik IP-adresse til hver PC ved log-on til nettet
En computer på netværket skal fungere som DHCP-server med ansvar for tildelingen af IP-adresser. DHCP-serveren har fast IP-adresse
Understøttet af Windows NT Server 3.5-(ikke win95/98)
> DNS, TCP/IP, WINS

---

DHTML = Dynamic HTML

Før Internet Explorer 4 og Netscape Navigator 4 kunne scripts kun ændre HTML-sidens indhold og udseende mens den blev indlæst - derefter var siden statisk.
Med Dynamisk HTML, som understøttes fra version 4 af IE og NN, kan siden ændre udseenede mens den vises - fx som respons på hændelser, som brugeren udløser ved fx klik med musen.

DHTML er ikke et kodesprog (som fx HTML) men en samling web-teknikker, som gør web-siderne interaktive og dynamiske. DHTML består af:

• HTML - de grundlæggende koder
• Style Sheets (CSS) - koder som kan formatere sidens elementer
• Scripts - programkode som bl.a. kan reagere på hændelser
• Document Object Model (DOM) - alle sidens (dokumentets) elementer som navngivne objekter - som kan ændres med scripts

 
DHTML tillader scripts at opdatere HTML-koden efter at den er blevt indlæst i browserens hukommelse.
NB: Den HTML-kode, som kan ses med Vis - Kilde, er uændret!

 

www.microsoft.com/workshop/author/dhtml/
developer.netscape.com/library/documentation/communicator/dynhtml/

---

Diatel

Danmarks største on-line service

---

DIB = Device Independent Bitmap

'Enhedsuafhængig bitmap'.

[FOLDOC]: An image format in which the sequence and depth of pixels in the file is not specifically related to their layout in any particular device. This allows any device dependent bitmap (DDB) image to be converted to or DIB format without loss of information, and this can then later be converted to other DDB formats for, e.g., printing or display. Rather than requiring converters from each DDB format to all other formats, only converters to and from DIB are needed.

DIB images are normally transferred in metafiles, bmp files, and the clipboard.

Transferring colour bitmaps from one device to another was not possible in versions of Microsoft Windows earlier than 3.0. Application programs can build DIB images without any interaction with Windows. If Windows lacks a drawing primitive, the application can simulate it directly into the DIB instead of using the existing graphics device interface (GDI) primitives. Unfortunately, under Windows versions 3.0 and 3.1, GDI cannot perform output operations directly to a DIB.

Conversion between DIB and DDB is performed by the device driver. Where the driver does not have this facility, the conversion is performed by GDI but only in monochrome. DIBs are slower to use than device dependent bitmaps due to the conversions required.

http://www.geocities.com/SiliconValley/2151/dibs.html

---

DIFO = Dansk Internet Forum

er en forening, som har til opgave at fastlægge de overordnede mål og midler for den danske del af internettet herunder fastlæggelse af regler for administration af og tvister om domænenavne under .DK

http://www.difo.dk/

---

digital

Datatransmission, hvor data repræsenteres af bits (med værdien 0 eller 1). Benyttes fx i computere og i (lokale) netværk.

Sammenlign >analog.
>modem

---

Digital Certificates

A virtual security document which ensures the association between the user's public key and the user's identity and security privileges.

---

Digital Signatures

www.zdnet.com/pcmag/issues/1507/pcmg0090.htm : Jeff Prosise (PC Magazine April 9, 1996) - Digital Signatures: How They Work

---

DIMM = Dual In-Line Memory Module

RAM modul for 64-bit data bus (PCI/Pentium systems) - one is enough.
168-pin edge connector.
[whatis] : A DIMM is a double SIMM (single in-line memory module). Like a SIMM, it's a module containing one or several random access memory (RAM) chips on a small circuit board with pins that connect it to the computer motherboard. A SIMM typically has a 32 data bit (36 bits counting parity bits) path to the computer that requires a 72-pin connector. For synchronous dynamic RAM (SDRAM) chips, which have a 64 data bit connection to the computer, SIMMs must be installed in in-line pairs (since each supports a 32 bit path). A single DIMM can be used instead. A DIMM has a 168-pin connector and supports 64-bit data transfer. It is considered likely that future computers will standardize on the DIMM.

---

DIN = Deutche Industrie Norme, Deutche Institut für Normung

Tysk standardorganisation.

www2.din.de

---

DIP = Dual Inline Package

On/Off kontakt - DIP Switch

---

Direct3D

Standard Microsoft API for 3D-grafik - en del af DirectX
> OpenGL

---

directory service

En dynamisk netværksdatabase, der indeholder oplysninger om alle tilgængelige ressourcer på netværket (evt flere LAN forbundet i et WAN)
> NDS, ADS

---

DirectDraw

Standard Microsoft API for 2D-grafik - en del af DirectX

---

DirectX

Multimedie systemudvidelser (API) til Windows 95/98 og NT 4/2000

bombay.npac.syr.edu/fms/directx/index.htm

> Direct3D, DirectDraw

---

DISA = Data Interchange Standards Association

The premier association for electronic commerce - a not-for-profit organization that supports the development and use of electronic data interchange standards in electronic commerce.
> EDI

www.disa.org

---

DISA = Direct Inward System Access

A feature found on some PBX systems

---

diskussionsgrupper

> nyhedsgrupper

---

DIT = Directory Information Tree

> X.500

---

DIX = Digital (DEC), Intel, Xerox

Specified Ethernet II
DIX connector = AUI connector in 10base-5

---

DIX = Danish Internet eXchange

Drives af UNI*C - her er tilkoblet Sektornettet og flere Internetleverandører

---

DLC = Data Link Control

A Microsoft communications protocol for Windows clients that supports terminal connections to IBM mainframes and AS/400 minis. HP printers that are attached via the network using HP's JetDirect internal print servers may optionally use or even require this protocol. > SDLC
DLC is installed on the print-server.
The data link layer protocol (layer 2) that is used in IBM's SNA networking. The SNA layer responsible for transmission of data between two nodes over a physical link. Used by Microsoft SNA Server.
En data link protokol som opfører sig som en transport protokol - kan ikke bruges til deling af filer og printere.
Understøttet af Windows 98

 

[whatis]: DLC (Data Link Control) is the service provided by the Data Link Layer of function defined in the Open Systems Interconnection (OSI) model for network communication. The Data Link Layer is responsible for providing reliable data transfer across one physical link (or telecommunications path) within the network. Some of its primary functions include defining frames, performing error detection or correction on those frames, and performing flow control (to prevent a fast sender from overwhelming a slow receiver).
Many point-to-point protocols exist at the Data Link Layer including High-level Data Link Control (HDLC), Synchronous Data Link Control (SDLC), Link Access Procedure Balanced (LAPB), and Advanced Data Communications Control Procedure (ADCCP). All of these protocols are very similar in nature and are found in older networks (such as X.25 networks). In the Internet, one of two point-to-point protocols are used at this layer: Serial Line Internet Protocol (SLIP) or Point-to-Point Protocol (PPP) with PPP being the newer, approved standard. All of these protocols are used in point-to-point connections such as those on Metropolitan Area Network (MAN) or Wide Area Network (WAN) backbones or when we dial our Internet service provider (ISP) from home using a modem.
In local area networks (LANs) where connections are multipoint rather than point-to-point and require more line-sharing management, the Data Link Layer is divided into two sublayers: the Logical Link Control (LLC) sublayer and the Media Access Control (MAC) sublayer. The LLC protocol performs many of the same functions as the point-to-point data link control protocols described above. The MAC protocols support methods of sharing the line among a number of computers. Among the most widely used MAC protocols are Ethernet (IEEE 802.3), Token Bus (IEEE 802.4), and Token Ring (IEEE 802.5) and their derivatives.

---

DLCI = Data Link Connection Identifier

A value in frame relay that identifies a logical connection.

---

DLL = Dynamic Link Library

Fil (.DLL) med biblioteksrutiner, som kun indlæses i RAM, når der er brug for dem.

http://www.dlldump.com/ : DLL File Archive - Download DLL files

---

DLR = Dansk Landbrugs Realkreditfond

 

---

DLSw = Data Link Switching

A reliable means of transporting SNA and NetBIOS traffic in a multiprotocol router network using IP encapsulation. Defined in RFC 1434 and RFC 1795.

---

DLT = Digital Linear Tape

> DAT

---

DLT = DRAM Lead-off Timing

in RAM access

---

DLT = Data Location Transparency

RPC

---

DMA = Direct Memory Access

DMA controller: manage DMA I/O
DMA channel: a hardware circuit enabling a device to access RAM without involving the CPU
> AGP, ISA, Ultra-DMA
8 channels (0-7) common assignments:
channel 0 or 4: DRAM refresh
channel 2: Floppy drive DMA support

---

DMI = Desktop Management Interface

in Windows 98

---

DMZ = DeMilitarized Zone

[Webopedia] A Demilitarized Zone is used by a company that wants to host its own Internet services without sacrificing unauthorized access to its private network. The DMZ sits between the Internet and an internal network's line of defense, usually some combination of firewalls and bastion hosts. Typically, the DMZ contains devices accessible to Internet traffic, such as Web (HTTP ) servers, FTP servers, SMTP (e-mail) servers and DNS servers.

---

DNA = Distributed Network Applications

Element i fremtidige Windows-versioners arkitektur, som kan danne rammen om DNS-løsninger.
Med DNA vil man kunne afvikle enhver applikation, som er tilgængelig på netværket.
DNA er implementeret i Windows 2000 Server.

---

DNS = Digital Nervous System

Centralt begreb i Microsofts vision for fremtidens IT-løsninger med hurtig 'reaktionsevne':
- nødvendige informationer kan leveres på ethvert tidspunkt og ethvert sted.
- nye muligheder kan udnyttes hurtigt.
>DNA

 

DNS = Domain Naming System, Domain Name System, Domain Name Server, Domain Name Service

Oversætter Internettets domæne-navne til IP-adresser.
Benytter IP-port 53.
 

http://www.rhyshaden.com/dns.htm

---

DOD = Department Of Defence

US
> C2, NSA

---

DOLAP = Database OLAP

A database OLAP refers to a relational DBMS that is designed to host OLAP structures and perform OLAP calculations.

---

DOM = Document Object Model

- beskriver hvordan forskellige objekter i browseren og på websiden er organiseret og navngivet.
- styrer hvilke objekter og egenskaber der kan ændres og hvilke værdier der er acceptable.
>DHTML
 
The document object model (DOM) is a simple, heirarchical naming system that makes all of the objects in the page, such as images, forms, and even CSS properties, accessible to scripting languages like JavaScript.
The DOM is a specification under development by the W3C. It will allow all elements of a Web page--graphics, text, headlines, styles, and so on--to be manipulated and acted on by programs and scripting languages (such as JavaScript and VBScript). For example, the DOM makes it possible to define each individual letter on a Web page as an object, and then to assign separate qualities such as color, size, and style to each letter.
The DOM is one of the core technologies that make up DHTML, along with Cascading Style Sheets (CSS), traditional HTML, and scripting languages.
 

http://www.w3.org/DOM/
http://xml.coverpages.org/dom.html

---

Domain, Domæne
 

1: i Windows netværk

Gruppe af computere, som tilhører samme arbejdsgruppe, hvor adgangen til netværkets ressourcer styres af en 'domain controller' (server), som vedligeholder en database med oplysninger om alle brugere, adgangskoder og rettigheder i domænet.
>PDC, BDC
 

2: i internetværk

Gruppe af netværk - administreret af en organisation, en insitution, et universitet, ...
> DNS, Host Adress, URL, Webserver
> broadcast domain
 

Domain Name, Domænenavn

Unikt navn - tildelt af InterNIC - knyttet til en bestemt IP adresse.
Fx 'microsoft.com' eller 'tietgen.dk'
>DIFO
 

Registrering af domæne-navne: Ledige domæne-navne kan købes på Internettet - i Danmark på fx

www.dandomain.dk
www.digiweb.dk
www.dk-hostmaster.dk
www.enavn.dk
www.gratisdns.dk

- her kan man også checke om et domæne er ledigt - og evt hvem der ejer domænet.
se også whois.

> webhotel
 

Domæne-navnet består af to dele adskilt med et punktum:
- første del kan vælges frit (men uden æ, ø, å og mellemrum).
- anden del - 'domæne klassen' ('Top Level Domain') - angiver et land eller (i USA) organisationstypen for ejeren af domænet.
 

Top Level Domain, Domain class

.com	: US commercial
.edu	: US educational
.dk	: Danmark
.se	: Sverige
.de	: Tyskland

- der er mange flere - se listen domain class
>IANA

http://www.norid.no/domenenavnbaser/domreg.html
http://www.dk-hostmaster.dk/dkhostcms/bs?action=cmsview&pageid=153&language=da& : Landekoder

 

Subdomain

Et Fuldt Kvalificeret Domænenavn (FQDN) består af subdomæne + domænenavn:
fx 'www.dr.dk' eller 'hjem.get2net.dk'

www			: subdomæne
	dr.dk		: domæne navn
		dk	: domæne klasse (Top Level Domain)

 

Ejeren af et domæne kan tilføje et eller flere frit valgte fornavne (subdomæner), som knytter domænenavnet til en bestemt (mappe på en) webserver (webhotel). Det mest benyttede subdomæne er 'www', fordi det er let at huske.
 

fx 'vejret.tv2.dk'
subdomæne : vejret
domæne : tv2.dk

PC - Software - DOS