NEW EMPL.LTR

This would be rejected by MS-DOS because of the space in the filename.

Certain filename extensions have been set aside so that MS-DOS can recognize program files. These are:

COM (for COMMAND file)

E X E (for EXECUTABLE file)

BAT (for BATCH file)

Program files should always have one of these three filename extensions. Data files should never use these reserved extensions. They can, however, use any other extension.

Filename extensions are optional with data files, so you can leave them off entirely, if you want. Using filename extensions with data files allows you to have many different variations for a set of filenames. For instance, different chapters of a book might be named:

CHAPTER.001

CHAPTER.002

CHAPTER.003

and so on.

Like MS-DOS commands, filenames and extensions can be entered in either upper or lower case, but are always displayed on the screen in upper case. However, since MS-DOS converts lower case filenames into upper case, it is possible to inadvertently erase an existing file by saving a new file with a lower case name. To be safe, always make sure that you have given a unique name to each file on a disk.

Using MS-DOS With Your Computer 4-23