# M

This glossary is far from complete. We are constantly adding computing terms.


MacOS
The operating system used by Apple computers.

mail server

mailbox
The file where your incoming e-mail messages are stored.

mainframe
A more powerful computer, often used as a server on large networks. One of the main types of computer, along with minicomputer, microcomputer and supercomputer.

MB: megabyte
Normally used to signify 220 bytes (1048576) when referring to memory or storage space.

memory
A storage area needed by a computer which is found on certain silicon chips. ROM and RAM chips are examples of memory chips.

megahertz (MHz)
One million cycles per second, the unit used to measure the speed of the internal clock of a computer. The clock controls the speed of the pulses. The performance of a computer will largely depend upon the 'clock speed' and chip design of the CPU.

modem
this stands for MODulator/DEModulator. A modem is used to convert data from the computer so that it can be transmitted along a telephone line, and vice versa.

monitor
The screen, connected to a computer, on which data is displayed.

mouse
An input device which controls the screen pointer or cursor.

MS-DOS
Microsoft Disc Operating System. This was a common operating system before Windows became the operating system for Microsoft PCs. Some of its feature can still be accessed from the command line in Windows.

multimedia
The combination of different forms of presentation such as graphics, sound, animation and video.