Specifications

From the A> prompt, try the command:
The computer will respond:
Press ENTER after you insert the diskette into the drive, then
the system prompt will be:
If you have a dual floppy disk drive system, the second, or “B”
drive is now the system default drive, as indicated by the new
system prompt. If performed on a single drive computer system,
this command will still change the system prompt to B >, even
though there is only one physical drive present.
The BIOS “pretends” there are two disk drives present. It
routes all commands intended for the B drive back to the A
drive.
Using MS-DOS With Your Computer
4-11