To run an external command, MS-DOS must be able to locate the file containing the command’s instructions. If it cannot find the file, MS-DOS gives you an error message. If you have the Apex 100\20, all the external files are on your hard disk (drive C) in a directory named \DOS; so MS-DOS can find any external command you need.

If you have the Apex 100 (with no hard disk), you must insert the proper diskette to access an MS-DOS command. For example, if you want to use the FORMAT program, you must insert the Startup diskette in one of the diskette drives. Then you can either log onto that drive and give the FORMAT command or specify the appropriate drive when you enter the command.

For example, if the Startup diskette is in drive A and you are logged onto that drive, and you want to format a diskette that is in drive B, you could enter the command as follows:

FORMAT B:

In this case, MS-DOS looks on drive A, the default drive, for the file named FORMAT.COM and finds it there.

If you are logged onto drive B, however, you would need to enter the command like this:

A:FORMAT B:

This tells MS-LXX to look on drive A for FORMAT.COM.

Entering an MS-DOS Command

To enter an MS-DOS command, you need to type the command in the correct format. The command format provides MS-DOS with the information needed to perform a task.

3-6Using MS-DOS With Your Computer