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,
Over Drive processor
An optional microprocessor chip that doubles the internal processing speed of the microprocessor and includes a
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.
Parameter
A qualifier added to a command that tells your operating system what data to process, where it should locate or store a file, or how it should operate. See also Switch.
Parity
A method used to verify the accuracy of data transmissions by making the total of the number of l’s in a group of bits odd (odd parity), even (even parity), or none (no parity).
16 Glossary