MS-DOS

Microsoft Disk Operating System. The operating system that comes with your computer. See Operating system.

Numeric keypad

The number keys grouped to the right of the keyboard.

Operating speed

The speed at which the central processing unit can execute commands. Also called execution speed. The Apex can run at

4.77MHz or 10 MHz.

operating system

A collection of programs (such as MS-DOS) 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, a hard disk controller, or a mouse.

Parallel

The type of interface that transmits data in groups of bits. See Interface and Serial.

Parameter

A qualifier added to a command that tells the computer what particular conditions to look for.

Parent directory

The directory immediately above a given directory in the directory tree. In pathnames, the parent directory is represented by the symbol .. (two periods).

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