Int 2F Fn 4A11  - Dblspace.bin - "getextrainfo" - Determine Number Of Dis  [d]

   AX = 4A11h
   BX = 0009h
   DL = compressed drive number (0=A:)

Return: AX = status (see also AX=4A11h/BX=0001h)
       0000h successful
       CL = number of DISK_UNIT structures allocated
           (see AX=4A11h/BX=0005h)

See Also: AX=4A11h/BX=0000h,AX=4A11h/BX=0008h