MCGA

Multi-color Graphics Array. A type of display adapter that emulates a color graphics adapter (CGA). MCGA provides two additional modes: 640 x 480 in two colors and 320 x 200 in 256 colors. See also CGA.

MDA

Monochrome Display Adapter. A type of display adapter that displays in 80 column by 25 line text mode in only one color, such as green or amber.

Megabyte (MB)

A unit used to measure storage space in a computer’s memory or on a disk. One megabyte equals 1024KB (kilobytes). See also Byte.

Megahertz (MHz)

A unit used to measure oscillation frequency, such as that of a computer’s internal clock. A megahertz is one million cycles per second.

Memory

The circuitry in your computer that stores data for possible retrieval. Memory contents are stored permanently (in ROM) or temporarily (in RAM).

Memory module

A small circuit board that contains surface-mounted memory chips. You can add memory modules to the main system board to expand your computer’s memory. Commonly called a SIMM (single inline memory module).

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