Storing Data

All your work and programs are stored in files on your hard disk or diskettes. A data file contains information, such as words, numbers, or pictures. A program contains instructions that the computer can understand and execute.

The kind of file you create depends on the MS-DOS commands or application program you use to create it. Because each program you use may create data files in its own particular format, you are likely to encounter problems if you try to read a file with a program other than the one that created the file.

Each file must have a unique filename so that MS-DOS can find it when you need to retrieve it. The filename consists of two parts, the name and the extension.

The name can be up to eight characters in length. You can use any characters except for blank spaces and the following symbols:

“ \ / [ ] : I < > + = ; . ?

It is a good idea to choose a name that describes the contents of the file.

The extension is optional and can be up to three characters long. You can use the extension to describe the type of data contained in the file-for example, TXT for a text file. When you use an extension, separate it from the filename with a period, like this:

DATA.TXT

Many application programs automatically add extensions to the data files you create, so you don’t have to specify the extension when you name a file. Lotus 1-2-3® Release 2, for example, automatically uses the extension .WK1 for worksheet files. Microsoft Word® uses .DOC for its word processing files. Such default extensions help an application program distinguish its own data files from files created by other programs. If you have programs that use default extensions, you should avoid using those particular extensions in other contexts.

Using MS-DOS With Your Equity LT-286 5-5