Epson LT-286 - Manual (Page 86)

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