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Daemon

A dormant background process on a Web server (in a UNIX environment), waiting to perform tasks. Well-known daemons are the sendmail daemon and the HTTP daemon.

dat

A file type that contains data to be used by an application program. DAT Files have a File extension of DAT. It has nothing to do with DISS file and DAT file

Data

The content of a File, e.g. the information contained within a Spreadsheet, the contents of the Records on a Database

Database

A collection of Data organized & designed for easy access. A collection of customer names & addresses may form the content of a database.

Data Transfer Rate

The speed at which data can be read from the hard disk & delivered to the processor

Defragmentation

When you save a data file to your hard disk, the operating system will try and store the complete contents of the file to the same section of the hard disk. Once the disk starts to become full, this process becomes impossible to achieve & the operating system splits the contents of the file over sections of the disks - the files become fragmented. Defragmentation is a utility that you can run over your hard disk to put the defragmented files back together.

Design

The look, feel, and structure of a web site. It is the synergy and synthesis of three aspects:sensory, conceptual, and reactive.

Desktop Management Interface

Software for managing the PC's within a network from a central PC.

Device Driver

Software that allows the PC to talk to hardware devices such as the printer & the Mouse. If you buy a new Printer it will come complete with a Disk containing the necessary Device Drivers.

DHCP

Dynamic Host Configuration Protocol

Dialog Box

A box displayed on your PC screen by a program including a message normally indicating that something is about to happen or has just happened. The dialog box requires the user to respond to the message before continuing with what it is about to do - normally the response is in the form of a Yes or No & based on the answer the program will carry out the next step or stop what it is doing. An example of this could be within an Email program - you read a message that has been sent to you & you decide to delete the message. After clicking on the delete button a dialog box containing the message "Are you sure you want to remove this message from your PC ? Yes or No" may be displayed.

Dial Up Connection

A temporary connection between two computers via a telephone line normally using a modem - the most common method used to access the Internet

Digital Video Disk

New Disk Technology. Digital Video Disks can hold over 4 Gigabytes of information - these are predicted to eventually supersede CD's.

Digital Video Disk Read Only Media

Digital Video Disks that can only be read.

DIMMS

Dual In-line Memory Modules

Directory

A directory is catalog for files stored on the Hard disk of a PC; a mechanism to group the files so that the user is not overwhelmed by a one huge long list of all the files stored on the hard disk. All the filenames belonging to a particular project, for example, might be kept together in one directory. The topmost directory is called the root directory; the directories within a directory are called sub directories. Example: C:WINDOWSSYSTEM. In this Example "C:" is the Root Directory, "C:WINDOWS" is referred to as the WINDOWS directory & "C:WINDOWSSYSTEM" is referred to as the SYSTEM directory. This directory is a subdirectory of "C:WINDOWS". Windows 95 refers to directories as Folders

Direct Memory Access

A DMA channel is used to transmit data at a high speed between an I/O device & the PC's memory - without involving the microprocessor.

Direct X

Software used by windows to allow application programs direct access to the sound & graphics hardware - very popular in computer games that take full advantage of the PC's Multimedia capabilities.

Diskette

Another name for a 3.5 inch Floppy Disk.

Disk drive

The hardware that performs the basic operations on the hard disk - including rotating the disk & reading/writing data to the disk.

Disk Operating System

It oversees such operations as disk input and output, video support, keyboard control, and many internal functions related to program execution and file maintenance.

Dithering

An undesirable effect that occurs when an image is displayed at a lower resolution than the resolution at which it was created.

dll

Dynamic Link Library

DMA

Direct Memory Access

DMA

Direct Memory Access

DMI

Desktop Management Interface

DNS

Domain Name Server [Service];

Domain Name System

How the Internet links together the thousands of Networks. The DNS is utilized whenever you send an Email or access a particular Web Page. Each computer on the Internet has a one of more Domain Names such as "fredbloggs.co.uk". The .co indicates a commercial organization & the .uk indicates that the computer is in the United Kingdom. Standard conventions used in Domain Names include: ac - Educational institution: co - Commercial organization: com - Commercial organization: edu - Educational institution: gov - Non military government organizations: int - International Organizations: mil - Military government organizations: net - Networks; org - non profit organization. u will also see these codes in URL's such as "homepages.enterprise.net/jenko/index.htm". These DNS converts the Domain Names to a unique number known as an IP address (the IP stands for Internet Protocol). You will often see the IP address displayed by your Web Browser when you are connecting to a particular computer.

DOS

Disk Operating System

Dots Per Inch

A measure of the quality of the output from a printer - the greater the number of DPI the better the printer.

Dot Pitch

A measure of the space between pixels displayed on the monitor.

Download

To copy files from another computer to your own PC via a network or using a modem.

DPI

Dots Per Inch

Drag

An action performed using the mouse. Hold down the left hand mouse button & move the mouse. Many windows applications allow the use of the drag option - in particular to move files between different directories

Drag and drop

This term relates to a GUI (Graphical User Interface). You can drag a file by clicking its icon with the left-hand mouse button depressed & moving the mouse pointer - the file is dragged along. When you let go of the file pointer the icon is released or dropped. You can use this technique to move a file between directories.

DRAM

Dynamic Random Access Memory

Dual In-line Memory Modules

Memory chips which are soldered onto plugs that slot into sockets on the Motherboard of the PC - makes fitting memory much easier than it use to be. They have 168 pins in two rows. See SIMMs

Dump

A special way of saving a file to disk from computer memory; what you take when you go to the can [take a dump]

DVD

Digital Video Disk.

DVDROM

Digital Video Disk Read Only Media

Dynamic

Something that occurs as and when it is needed - the word is used frequently in PC terminology. Examples include DLL (dynamic link library) and DRAM (dynamic RAM).

Dynamic Host Configuration Protocol

A standard method for assigning IP addresses automatically to the devices on a TCP/IP network. As a new device connects, the DHCP server assigns an IP address from a list of available addresses. The device retains this IP address for the duration of the session - once the device disconnects the IP address becomes available for use again.

Dynamic HTML - DHTML

Allows a Web page to change after it's loaded into the browser --there doesn't have to be any communication with the Web server for an update.

Dynamic Link Library

A library of program subroutines that can be shared amongst several different Application Programs - a concept which is extensively used under Windows. Windows programmers do not have to re-invent the wheel each time they want to do something common such as undo the last command or highlight a line of text.

Dynamic Random Access Memory

It is a type of RAM capable of speeds of about 40MHz. Superseded by EDO RAM.