IBM AT 5170 Technical Reference page 468

LUT. Look-up table.
m. (1) Prefix milli; 0.001. (2) Meter.
M. (1) Prefix mega; 1,000,000. (2) When referring to
computer storage capacity, 1,048,576. (1,048,576
=
2 to the
20th power.)
rnA.
Milliampere; 0.001 ampere.
machine code. The machine language used for entering text and
program instructions onto the recording medium or into storage
and which is subsequently used for processing and printout.
machine language. (1) A language that is used directly by a
machine. (2) Deprecated term for computer instruction code.
magnetic disk. (1)
A
flat circular plate with a magnetizable
surface layer on which data can be stored by magnetic recording.
(2) See also diskette.
~,
main storage. (1) Program-addressable storage from which
instructions and other data can be loaded directly into registers
for subsequent execution or processing. (2) Contrast with
auxiliary storage.
mark. A symbol or symbols that indicate the beginning or the
end of a field, of a word, of an item of data, or of a set of data
such as a file, a record, or a block.
mask. (1) A pattern of characters that is used to control the
retention or elimination of portions of another pattern of
characters. (2) To use a pattern of characters to control the
retention or elimination of portions of another pattern of
characters.
masked. Synonym for disabled.
matrix. (1) A rectangular array of elements, arranged in rows
and columns, that may be manipulated according to the rules of
Glossary-22