C

Command Line
The line on the display screen where a command is expected. Generally, the command line is the line that contains the most recently displayed command prompt .

Cache
Pronounced "cash", a special high-speed area in memory used to store the contents of frequently accessed areas of memory. Other devices, like disks, may also have a cache for storing information fo fast access.

CD-ROM
Compact Disc-Read-Only Memory. A type of optical disk capable of storing large amounts of data -- up to 1GB, although the most common size is 650MB (megabytes). A single CD-ROM has the storage capacity of 700 floppy disks, enough memory to store about 300,000 pages of text.

Com Port
The name commonly used to describe a serial communications port. Mice, modems, and printers are commonly connected to com ports.

Control Characters
These are characters that can be used to control system behavior when pressed in combination with the control key on the keyboard. For example Control-C can be used to stop a process.

CPU
The Central Processing Unit is the brains of the computer. Sometimes referred to simply as the processor or central processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a computer system.

Cursor
A special symbol, that signifies where the next character will be displayed on the screen. If you are running a graphics-based program, the cursor may appear as a small arrow, called a pointer. (The terms cursor and pointer are often used interchangeably.) In text processing, a cursor sometimes appears as an I-beam pointer. Programs that support a mouse may use two cursors: a text cursor, which indicates where characters from the keyboard will be entered, and a mouse cursor for selecting items with the mouse.