'===========================================================================
' Subject: LIST OF DRIVES                     Date: 01-01-90 (00:00)       
'  Author: Larry Stone                        Code: QB, PDS                
'  Origin: FidoNet QUIK_BAS Echo            Packet: DISK.ABC
'===========================================================================
' > In QuickBASIC, how do I obtain a list of all active drives (except
' > diskette drives).  In other words, the C drive and any Novell
' > network drives.

DEFINT A-Z

'$INCLUDE: 'qbx.bi'

DECLARE FUNCTION FDList$ ()
DECLARE FUNCTION HDList$ (FloppyList$)

'***********************************************************************
'* FUNCTION FDList$
'*
'* PURPOSE
'*    PEEKs at the BIOS Equipment Word to return a list of floppy
'*    drives installed on the system.
'*
'* CREDIT(S)
'*    Larry Stone, based on a routine published in MicroHelp's BUG
'*    Newsletter, 1/1/90.
'*
'*    Modified to use fixed-length strings.
'***********************************************************************
FUNCTION FDList$ STATIC
   DEF SEG = 0
   FD% = PEEK(&H410) \ 64 + 1                'How many FDs installed?
   DEF SEG                                   'Restore DGROUP
   FD$ = SPACE$(FD%)

   FOR N% = 1 TO FD%                         'Place these letters into
      MID$(FD$, N%, 1) = CHR$(64 + N%)       '  FD$
   NEXT

   FDList$ = FD$                             'Return value
   FD$ = ""
END FUNCTION

'***********************************************************************
'* FUNCTION HDList$
'*
'* PURPOSE
'*    Uses DOS ISR 21H, Function 44H, Subfunction 09H (Is Drive Remote)
'*    to return a list of valid, local hard drives.
'*
'* CREDIT(S)
'*    Larry Stone, based on a routine published in MicroHelp's BUG
'*    Newsletter, 1/1/90.
'*
'*    Modified to use fixed-length strings.
'***********************************************************************
FUNCTION HDList$ (FloppyList$)
   DIM IRegs AS RegType, ORegs AS RegType

   FloppyList$ = FDList$                     'Get floppy drive list
   FDs% = LEN(FloppyList$)                   'How many drives found?

   HD% = FDs% + 1 + ABS(FD% = 1)             'If only 1 FD, first is C:
   HD$ = SPACE$(HD%)

   FOR BL% = HD% TO 26                       'Check possible hard drives
      IRegs.ax = &H4409                      'Set up call
      IRegs.bx = BL%                         'Drive letter in BL
      Interrupt &H21, IRegs, ORegs           'Call DOS

      IF (ORegs.flags AND 1) THEN            'Check carry flag
         EXIT FOR
      END IF

      MID$(HD$, HD%, 1) = CHR$(64 + ORegs.bx)'Add the letter
   NEXT

   HDList$ = HD$                             'Return value
   HD$ = ""
END FUNCTION