Glossary of Terms - P

This is a unit of data, which is typically a part of a file, that has been prepared for transmission across a network, usually the internet.

A 25-pin port on a PC that uses eight wires to transfer one byte of data at a time at speeds up to 100KBps (kilobytes per second) and is used mainly for connecting printers.

Peripheral Component Interconnect. The most common bus design for motherboards and expansion slots.

Printer Control Language. A language developed by HP to control its LaserJet printers and supported by virtually all printer manufacturers. It consists of commands called "escape sequences" that programs use to tell the printer about the number of copies to print, the resolution and page formatting.

A small network of PCs that do not use a central server. Each user can decide what resources on their PC they wish to share.

On flat-panel displays it's the pixel pitch that determines how many dots can be displayed on the screen. The lower the pixel pitch, the more dots will be used to build up an image.

Circular discs within a hard drive on which data is stored. Typically 3.5in diameter.

Sometimes shortened to PnP, this is a standard which allows a PC to automatically recognise when compatible devices, such as printers or monitors, are connected to it. Previously, it was necessary for the user to inform the PC that new hardware had been attached in order to get the device in question working.

Point of Presence. The location of the nearest node for an ISP, this is the number you dial to connect to the internet. A POP necessarily has a unique internet protocol address.

Post Office Protocol

Power On Self Test. The first process a PC runs when it is switched on that checks the memory, processor, graphics and so forth are all functioning. A series of beeps indicate if errors are found - one beep usually means that all is well.

Page description language developed by Adobe Systems that describes each element as a vector pair, rather than telling the printer where to place each dot of ink or toner. It is more suited to graphics printing and has wider application than PCL as it can produce better output quality at higher print resolutions.

A server that sits between your browser and a web server. The proxy server intercepts all requests by your web server and checks that it doesn't have the requested web page stored on its hard disk. If it has, the proxy server returns the requested web page from its hard disk. Proxy servers help to speed up internet access and can also be used to filter out requests for unsuitable web pages.