Epson Equity 286 PLUS - Manual (Page 251)

MS-DOS
Microsoft Disk Operating System. The operating system most
commonly used with your computer. See Operating
system.
Numeric keypad
The number and cursor control keys grouped to the right of the
keyboard.
Operating speed
The speed at which the central processing unit can execute
commands. The Equity 286 PLUS can run at 12 MHz or 6 MHz.
Operating system
A collection of programs (such as MS-DOS, OS/2, or Unix)
that manages a computer’s operations. The operating system
determines how programs run on the computer and supervises all
input and output.
Option card
A circuit board you install inside the computer to provide
additional capabilities, such as a modem.
Parallel
The type of interface that transmits all the bits in a byte of data
simultaneously over separate lines. See Interface and Serial.
Parameter
A qualifier added to a command that tells MS-DOS what
particular conditions to look for and specifies information such
as what data to process and where to locate or store a file.