Int 7F Fn 24  - Alloy Ntnx, Mw386 - Attach Or Release Drive For Low-level  [N]

   AH = 24h
   CL = function
       00h attach
       01h release
   CH = drive (0=A:,1=B:,etc)

Return: AX = status
       00h successful
       01h invalid request
       02h already attached
       03h not attached
       04h lock table full

Note:  only drives on the current machine may be attached