AUTOEXEC.BAT is a special Batch File.  Each time DOS is started, it looks for a
file named AUTOEXEC.BAT in the root directory and, if found, executes it.  This
is a convenient way to have one or more commands automatically executed each
time DOS is started.

NOTE: DOS does not automatically prompt you for the date and time when it finds
an autoexec file.  You may want to include the DATE and TIME commands in your
AUTOEXEC.BAT file.
