If you press Enter when a command line has an error in it, you see this message:

Bad command or file name

Then MS-DOS re-displays the command prompt so you can try again. Just type the correct command line and press Enter.

Storing Data

All your work and programs are stored in files on your diskettes or hard disk. Each file must have a unique filename so you can retrieve it when you need to. The filename consists of two parts: the name and the extension.

You can choose a name up to eight characters long indicating what the file contains. The name can contain any characters or numbers except for the following:

I, \/{}:I<>+=;,.?*

The extension is optional and can be up to three characters long. It describes what type of file it is, such as a text file or program file. When you use an extension, separate it from the file name with a period. For example, an MS-DOS filename might look like this:

D A T A . T X T

Sometimes you have to further identify your files by telling MS-DOS on which drive the file is stored. To do this, you type the letter-A, B, or C-of the disk drive where the file is located, followed by a colon, and then the filename. For example:

B : D A T A . T X T

You can type the drive identifier and filename in upper- or lowercase letters. MS-DOS does not differentiate between the two, but converts everything to uppercase letters.

MS-DOS stores your files in directories. A directory contains specific information about each file stored there, such

4-4Using MS-DOS With the Equity LT