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Radio Button

Radio buttons appear a lot in Windows applications. They are used when you have to make a choice. For example you may be asked to select which of the following age groups are you in: Under 18; 19-30; 31-40; 41-50; over 50. Each option may have a circle by it & if you click inside the circle it becomes selected ie goes from white to black. If you select a second option the first one becomes deselected - you can select only one from the list.

RAID

Redundant Array of Independent Disks

RAM

Random Access Memory

Random Access Memory

Temporary storage area that the processor uses to execute Programs & hold Data. Information is put into RAM & held there. Once the RAM becomes full information has to be removed to make space for the current task being performed. A PC with limited RAM will take a long time to perform the simplest task as the information in the RAM is constantly being replaced. RAM requires a constant electric supply to keep the information intact. Should you switch off the PC then you will lose the contents of RAM forever. Different areas of RAM include: Conventional Memory; Expanded Memory; Extended Memory; High Memory Area; Upper Memory Area. Types of RAM include: DRAM; EDO RAM; SDRAM.

rar

A 'rar' file is a type of segmented, compresed file

RAS

Remote Access Server

Read Only Memory

ROM chips cannot be written to. Therefore they contain information that never changes. All PC's have ROM chips. When the PC is switched on the Information in the ROM chip is used to test the RAM. ROM does not require a constant electric supply to keep the information intact. Information in ROM is retained should you switch the PC off.

Real Audio

Software that allows sound files to be transmitted from the Internet back to the users PC in streams. What actually happens is that the file starts playing (ie you here the music) before all of the data has been received - giving the effect of playing the sound instantaneously

Record

Files are comprised of a number of records. Each record normally has a common set of characteristics. For example at a College a particular File may contain a record of all the students. Each record could contain Student ID, Date of Birth, Year enrolled etc.

Recovery

A Back up is a duplicate copy of some data or a disk or some software that is made by the user as a safeguard against the loss of the original information. Should this happen then the information can be recovered by restoring or copying the information back from the backup.

recursive

A program routine that calls itself. Recursion occurs if a section of code contains an instruction to include another file that in itself contains instructions to include yet another file. This process must be controlled so that it does not occur indefinately.

Red/Green/Blue

Colorspace in which color monitors display text and images. HTML documents typically indicate the amount of Red, Green and Blue used to make a certain color through the use of hexadecimal values (#ffffff).

Redirect

By using particular HTML-code in a Web page, one can redirect the visitor seamlessly to another Web page.

Redundancy

Form of protection against system failures. For example, if you want to be sure that you'll always have power supply, you can set up two power supplies so that one takes over if the other one fails.

Redundant Array of Independent Disks

A technology involving 2 or more hard disks where the data is distributed based on reliability & performance.

Register

Place where CPU stores numbers while performing calculations

Remote Access Server

A PC on a network that has a number of modems attached allowing the users to connect via telephone lines.

Remote Computer

Same as Remote Terminal. Any Computer or terminal that is not on the same physical site as the computer to which it is attached. Access is normally via Modem.

Remote Terminal

Same as Computer. Any Computer or terminal that is not on the same physical site as the computer to which it is attached. Access is normally via Modem.

Replication

The sharing of computer files at multiple locations whilst maintaining an up-to-date copy of the shared file at all locations. A different copy of the file may be maintained at each location and replication ensures that all changes are reflected in all copies.

Resolution

This relates to the quality of a viewed image either on the PC Screen or printed output. For printed images the resolutions is measured in dots per inch or DPI. The higher the DPI the better the resolution.

Restore

A Back up is a duplicate copy of some data or a disk or some software that is made by the user as a safeguard against the loss of the original information. Should this happen then the information can be recovered by restoring or copying the information back from the backup.

RGB

Red-Green-Blue

Rich text Format

A file format - developed by Microsoft. Most word processors can process Rich Text Format files - the format was developed to enable documents to be transferred between application programs. Rich Text Format Files have the file extension RTF.

ROM

Read Only Memory

Root Directory

The highest point in the Directory structure at which a user can access the files. For a typical PC running this is C:.

Route

The path that data travels along moving from its starting point in a Network to its destination.

Router

A communications device that routes data between Networks.

rtf

Rich text Format