Glossary of computer terms

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A - D

ADB	Apple Desktop Bus. The method of connecting input devices such as keyboards and mice to pre-G4 versions of Apple Macintosh computers.
Application	A software program that runs on a computer, e.g. web browsers, e-mail programs, word processors, games and utilities.
Byte	The unit of measurement of a single character in a computer's memory. 1,000 bytes = 1KB (kilobyte).
CD-R	Compact Disc Recordable. A blank CD that can be written onto by a CD burner, whether recording audio (which can be played back by most CD players) or computer data (e.g. backing up your files). Once information has been burned onto a CD-R, it cannot be altered or erased like the data on a hard drive (although most burning software allows you to burn the information in multiple "sessions" until the disc is full. CD-RWs, on the other hand, can be erased and completely re-recorded.
CD-ROM	Compact Disc Read-Only Memory. A CD that can be read by a computer. "Read-only" means that the data cannot be altered or erased.
CD-RW	Compact Disc Re-Writable. A blank CD that can be written onto by a CD burner, but unlike CD-R's, the data can be erased and more data written. However, erasing and re-recording data may effect the reliability of the disc, so CD-Rs are batter for long-term backups
CPU	The Central Processing Unit, also known as the processor, is the 'brain' of a computer, handling all the processes and calculations.
CRT	Cathode Ray Tube monitor. These are traditional computer monitors which use the same technology as TV, and are much bulkier than newer LCD monitors. CRT displays are still generally used by graphics professionals because of their vibrant and accurate color, but the quality of LCD displays are now such that they are well on their way to replacing CRT monitors in both the consumer and professional markets.
Cache	(Pronounced "cash") There are various types of caches but they all serve the same purpose - storing recently-used information in a place where it can be accessed extremely fast, e.g. a Web browser like Internet Explorer uses a browser cache to store the text and images of recently visted Web sites, or a disk cache stores information you have recently read from your hard disk in the computer's RAM.
DVD+R	Digital Versatile Disc Recordable. DVD+R discs can be used to record data. Single-sided, single-layer DVD+R discs can store 4.7GB of data, double-layer discs can store 8.5GB, and double-sided DVD-Rs can store 9.4GB. The DVD+R format is not quite as common as the DVD-R format, but is still supported by most current DVD players and DVD-ROM drives. Drives that can read both DVD+R and DVD-R discs are often referred to as DVD±R drives.
DVD+RW	Digital Versatile Disc Rewritable. A DVD+RW is like a DVD+R, but can be erased and rewritten. They can hold 4.7GB of data and do not come in double-sided or double-layer versions like DVD+Rs do, and your DVD burner needs to support the DVD+RW format.
DVD-R	Digital Versatile Disc Recordable. DVD+R discs can be used to record data, which cannot be written over. A basic single-sided, single-layer DVD-R disc can store 4.7GB of data. Double-layer discs can store 8.5GB, while double-sided DVD-Rs can store 9.4GB. DVD-R is the most common format of writable DVDs, and most DVD players and DVD-ROM drives can read DVD-R discs.
DVD-RAM	Digital Versatile Disc Random Access Memory. DVD-RAMs are writable DVDs, which can also be erased and rewritten. However, they only work when placed in an enclosing cartridge, meaning they won't fit in most standard DVD players or DVD-ROM drives.
DVD-RW	Digital Versatile Disc Rewritable. A DVD-RW is like a DVD-R but can be erased and written to again. DVD-RWs can hold 4.7GB of data and do not come in double-layered or double-sided versions like DVD-Rs do. To record data onto a DVD-RW disc, you'll need a DVD burner that supports the DVD-RW format.
Driver	A small file that contains information the computer needs to recognise and control various hardware devices, e.g. if you buy a printer, it will probably come with a CD containing a printer driver that you will need to install onto your computer.

E - Z

Firewire / FW	A method of connecting a computer to various peripherals, e.g. digital video cameras, hard drives, audio interfaces, MP3 players. Firewire is considerably faster than USB.
GB	Gigabyte (= 1,000MB). A measurement of disk / memory size, commonly abbreviated in speech as "gig". Hard drives are generally anything from 40GB - 2,000GB (2TB)
GHz	Gigahertz (= 1,000MHz).
Hard Drive	Where all computer data (e.g. your computer's operating system or your own files) is physically stored. All computers come with a built-in drive, and you can also buy an external unit for extra storage space, which is then linked to your computer via USB or Firewire.
KB	Kilobyte (= 1,000bytes). A measurement of disk / memory size, commonly abbreviated in speech as "k". Most small files on your computer are measured in kilobytes, e.g. a typical image can be about 100KB.
LCD	Liquid Crystal Display monitor. Flat screen monitors weighing much less than (and using less power than) CRT monitors.
MB	Megabyte (= 1,000KB). A measurement of disk / memory size, commonly abbreviated in speech as "meg". Large computer files are typically measured in megabytes, e.g. a high-quality JPEG photo taken directly from a digital camera can take up about 3MB of space. CDs can hold up to 700MB.
MHz	Megahertz. One MHz equals one million cycles per second and is used to measure transmission speeds of electronic devices, particularly the speed of a computer's processor.
Operating System / OS	The software in every computer that communicates with computer hardware on the most basic level. PC's come with Microsoft Windows (current version Windows XP), while Apple Macs have the Mac OS (current version OSX).
PCI	Peripheral Component Interconnect. A way of linking various external hardware to a computer. Most add-on cards such as SCSI, Firewire and USB controllers use a PCI connection. PCI slots are found at the back of computers and are about 3.5" long and about 0.5" high.
Peripheral	Any external device that provides input and/or output for the computer, e.g. keyboard, mouse, monitor, printer, external hard drive.
RAM	Random Access Memory. RAM is a small amount of temporary memory in a computer. When a program is opened, it gets loaded from the hard drive into the RAM, as reading data from RAM is faster than reading data from the hard drive. Generally speaking, the more RAM you have installed on your computer, the more efficient / faster it will be.
RPM	Revolutions Per Minute. Hard drives are made up of a number of disks which contain the actual code that makes up all the data stored on a computer. These disks spin rapidly (typically at 5400 or 7200 RPM) to enable superfast access.
TB	Terabyte (= 1,000GB). A measurement of disk / memory size. The biggest hard drives available are measured in terabytes.
TFT	TFT monitors are a variant of Liquid Crystal Display which use Thin-Film Transistor technology to improve image quality.
USB	Universal Serial Bus. The most common method of connecting a computer to various peripherals, e.g. keyboards, mice, game controllers, printers, scanners, printers, digital cameras.
Windows	Microsoft's operating system, which is pre-installed on most PC's.