Extension

A suffix of up to three characters that can be added to a filename.

External command

An MS-DOS command that is stored in a program file. The FORMAT command, for example, is stored in the file FORMAT.COM. To perform an external command, MS-DOS must be able to find the appropriate program file. External commands are distinguished from internal commands (such as DIR or ERASE), which are not stored in separate program files.

File

A group of related pieces of information (sometimes called records, or entries) stored together on a disk. Text files consist of words and sentences. Program files consist of code and are used by computers to perform instructions.

Filename

A name of up to eight characters that MS-DOS uses to identify a file.

Floppy disk

See Diskette.

Format

To prepare a new disk (or erase an old one) so that it can store information. Formatting a disk divides it into tracks and sectors and creates addressable locations on it.

Graphics

Lines, angles, curves, and other non-alphanumeric data.

Gray-scale mode

The mapping of colors to shades of gray on the LCD screen. In mode 0, all colors are displayed as black or white. In modes 1 and 2, colors are mapped to preset shades of gray. Mode 3 is user- definable; any color may be mapped to any shade of gray. Use the setup program (Chapter 2) to define mode 3. Use keyboard DIP switches 2 and 3 (Chapter 1) to select a gray-scale mode.

8 G l o s s a r y