Int 61 Fn 0004  - Banyan Vines - Get Network Drive Map                     [N]

   AX = 0004h subfn 0003h
   DS:DX -> request block (see #3075)

Return: AX = status
       0000h drive map returned in request block
Desc:  Returns a bit map indicating which drive numbers are connected to a
     file service

Note:  Only bits 0-25 are significant

See Also: AX=0004h/SF=0002h

Format of VINES Function 0004h/Subfunction 0003h request block:
Offset Size    Description (Table 3075)
 00h   WORD    0003h
 02h   DWORD   buffer for drive map (bit0=A, bit1=B, ...)