Mac

Short for Macintosh. General term used to describe any computer designed for the Apple Macintosh GUI and the Motorola processor architecture. See PC.

Macintosh OS

Abbreviation for Macintosh Operating System. The point-and-click GUI that controls Macintosh computers. The Macintosh OS utilizes pull-down menus and icons to allow users to easily open programs and organize files. Also known as Mac OS. See GUI, Microsoft Windows and operating system.

Macintosh PICT

Graphic file format common to Macintosh applications.

Marquee

Moving dotted-line outline that makes up masks and selection areas in image editing programs.

Mask

In image editing programs, a tool that allows the user to select portions of an image and apply changes only to the selected portions. A mask is also used when cropping an image to select the areas to be cropped.

Megabyte

Amount of stored data equal to 1,024 kilobytes. There are 1,024 megabytes in a gigabyte. Also written as M or MB. See byte, kilobyte and gigabyte.

Memory

1. Device in a computer for storing and retrieving information which assists with the processing of data and applications. RAM memory is attached to the motherboard as a set of semiconductor storage units. 2. Generic reference to any data storage device, such as a hard disk or floppy disk.

Menu Bar

In a GUI, a bar across the top of a program window that contains common and specialized pull-down menus such as File, Edit, etc.

MHz

Abbreviation for megahertz. Frequency roughly equal to 1 million cycles per second. MHz is commonly used to rate the speed of computer processors. The higher the MHz, the faster the processor.

Microsoft Windows

The point-and-click GUI developed by Microsoft in 1983. Windows utilizes pull-down menus and icons to allow users to easily open programs and organize files. Windows 3.1 and 3.11 were simply shells that ran on top of MS-DOS. Windows 95, 98 and NT are self-contained operating systems. Commonly known simply as Windows. See GUI, Macintosh OS and operating system.

Micro-stepping Motor

Small, low-power electric motor used in electronic devices capable of moving in very small, precise increments, or "steps."

Midtones

In an image, the range of tones between light and dark.

Millimeter

Unit of measure. One inch equals 25.40 millimeters.

Mirror

1. Piece of glass with silver backing used to reflect images. 2. In a flatbed scanner, a mirror is mounted on the carriage to reflect images to the rear-mounted CCD.

Modem

Abbreviated term for modulator/demodulator. Electronic device that allows a computer to send and receive data via a standard telephone line. Modems use digital-to-analog converters to send data, and analog-to-digital converters to receive it.

Moiré

Unattractive pattern on an image from scanning a halftone. Halftone prints are the kinds found in newspapers and magazines. See descreen.

Monitor

Electronic display used with a computer. Monitors use a cathode-ray tube, like a television, but have better resolution. Some monitors use liquid crystal displays.

Motherboard

1. Main circuit board of a computer system where all of the essential electronic components are located. The processor, RAM, expansion sockets and disk drive controllers are all connected to the motherboard. 2. General term used to describe the main circuit board of any piece of electronic equipment.

Mouse

Common input device used along with a GUI to select items on screen by clicking them. The bottom of a mouse has a ball, which spins either optic or electric sensors as it moves. These sensors translate this into the movement of a mouse-pointer arrow on the GUI screen. Selecting items in a GUI are done by single or double-clicking the buttons on the mouse. See click, double-click and GUI.

MS-DOS

Acronym for Microsoft Disk Operating System. A single-task operating system that used typed commands to open files, run applications, etc. Introduced in 1981 by Microsoft Corporation.

Multitasking

The ability of certain operating systems to allow multiple programs to run simultaneously so that the user may switch between one or more tasks.

Mustek

Taiwan-based manufacturer of imaging devices founded in 1988. Mustek is an international company with offices in Taiwan, Japan, Germany and the United States.