One batch file that you may find particularly useful is called AUTOEXEC.BAT. Every time you turn on your computer, MS-DOS looks for the AUTOEXEC.BAT file and automatically executes each of the commands in the file.

When you install MS-DOS, it creates an AUTOEXEC.BAT file for you. To modify the file or replace it with a new one, you can use the COPY or EDLIN command, a text editor, or a word processing program that can save a file as text-only. Be sure to name the file AUTOEXEC.BAT and store it in the root directory of the hard disk or diskette from which you load MS-DOS.

See your MS-DOS manual for more information about creating and using batch files.

Changing the Processor Speed

Your computer’s processor can operate at two speeds: high and low. High speed is 25 MHz or 50 MHz (depending on your model) and low speed simulates an 8 MHz processor speed. At high speed, the computer can access memory faster than at low speed. The default setting is high speed unless you changed it in Setup to low or to change automatically.

Note

When your computer is operating at high speed, the TURBO light on the front panel is on. It is off when the computer is operating at low speed.

You should use high speed for almost everything you do because your programs will work faster. However, certain application programs have specific timing requirements and can run only at the slower speed. See your software manual to determine if this is the case.

4-2 Enhancing System Operations