Specifies the maximum number of drives you can access. You can use this command only in your CONFIG.SYS file.
The value you specify represents the last valid drive the operating system is to recognize.
Default setting If you do not use the LASTDRIVE command, the default value is the letter following the last one in use.
Effect on memory The operating system allocates a data structure in memory for each drive specified by LASTDRIVE, so you should not specify more drives than are necessary.
To set the last drive to M, giving your computer access to 13 drives, you would include in your CONFIG.SYS file: