Epson Progression U12 - Manual (Page 203)

Operating speed
The speed at which the computer’s processor can execute
commands, usually expressed in megahertz (MHz), such as
33 MHz. See also Megahertz.
Operating system
A collection of programs that manages a computer’s
operations, such as interpreting input, managing files, and
reading and writing data to disk. The operating system (such as
MS-DOS, OS/2, or UNIX) provides the foundation for the other
programs you use and controls the usage of the hardware
resources.
Option card
A circuit board you can install inside the computer to provide
additional capabilities, such as a modem or an additional I/O
port. Option cards plug directly into the special option slots so
you do not have to alter a computer’s circuitry to enhance your
system. See also Bus.
OS/2
Operating System /2. The enhanced operating system
developed jointly by Microsoft and IBM that provides
protected mode processing and multitasking capabilities. See
also DOS, MS-DOS, and Operating system.
Parallel
The type of interface that transmits all the bits in a byte of data
simultaneously over separate wires in a cable. See also Interface
and Serial.
16 Glossary