Epson 486SX - Manual (Page 214)

A small device that connects two pins on an option card, a disk
drive, or the main system board to activate a particular function.
Key disk
A diskette containing a copy-protected program that must
remain in the diskette drive while you are using the program.
Kilobyte (KB)
A unit used to measure storage space in a computer’s memory
or on a disk. One kilobyte equals 1024 bytes.
LIM 4.0 EMS
Version 4.0 of the Lotus/Intel/Microsoft Expanded Memory
Specification-a protocol that allows certain application
programs to use memory that MS-DOS cannot use.
Main system board
The board built into your computer containing the circuitry the
computer requires to operate.
Math coprocessor
A microprocessor that enables the computer to process certain
mathematical calculations and display graphic images faster.
In this computer, the 50 MHz model includes a built-in math
coprocessor and the 25 MHz model can be upgraded with an
80487SX chip with built-in math coprocessor.
MCGA
Monochrome/Color Graphics Adapter. A type of display
adapter that controls either a monochrome or color graphics
monitor.
10 Glossary