# Of Disk Drives 2/2

 BBS: Inland Empire Archive
Date: 04-17-92 (22:33)             Number: 191
From: LOGAN ASHBY                  Refer#: NONE
  To: DICK DENNISON                 Recvd: NO  
Subj: # Of Disk Drives 2/2           Conf: (2) Quik_Bas

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 FUNCTION IsRemoveable%(DrvNum%)
 '| We need to test for a floppy with this method, as the truename
 '|   function will poll the hardware, and generate a crit. error
 '|   if no floppy in drive/door open
 RegsX.ax = &H4408
 RegsX.bx = DrvNum% + 1
 CALL InterruptX(&H21, RegsX, RegsX)
 IF (RegsX.Flags AND 1) THEN
         '| Could handle this error better. For now, just assume
         '|   it's not a floppy, as this code generates an error
         '|   for a Novell mapped drive.
     IsRemoveable% = FALSE
 ELSE
     IF (RegsX.ax ) THEN
         IsRemoveable% = FALSE
     ELSE
         IsRemoveable% = TRUE
     END IF
 END IF

 END FUNCTION

 SUB TrueName(DrvNum%, Logical%, Remapped$)

 DIM DrvPath AS STRING * 128
     '| The period after the backslash here avoids a Novell bug
 DrvLtr$ = CHR$(DrvNum% + 65) + ":\." + Null$

 IF (IsRemoveable%(DrvNum%)) THEN
         '| Not sure, but this is probably a bug.  I'm not sure what
         '|   will happen on systems w/ only one floppy.  Don't have
         '|   one handy to test with.
     Logical% = FALSE
     ReMappedTo$ = ""
 ELSE
     DrvPath = DrvLtr$                   '| TrueName function
     RegsX.ax = &H6000
     RegsX.di = VARPTR(DrvPath)          '| We use the same buffer
     RegsX.si = VARPTR(DrvPath)          '|   for the input and output
     RegsX.ds = VARSEG(DrvPath)
     RegsX.es = VARSEG(DrvPath)
     CALL InterruptX(&H21, RegsX, RegsX)
     DrvLtr$ = LEFT$(DrvLtr$, INSTR(DrvLtr$, ".") - 1)
     TmpPath$ = LEFT$(DrvPath, INSTR(DrvPath, Null$) - 1)
     IF ( DrvLtr$ <> TmpPath$) THEN
         Logical% = TRUE
         ReMapped$ = LEFT$(DrvPath, INSTR(DrvPath, Null$))
     ELSE
         Logical% = FALSE
         ReMapped$ = ""
     END IF
 END IF

 END SUB

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Dick, as you can see from the comments, I don't have a lot of confidence in
this code being bullet-proof.  The things I left unfixed
were because I couldn't find a way around them.  Maybe
somebody else can either come up with something better or a
way to fix this.  Hope it helps, let me know what you
think.  A good place to check for a method to do this
correctly would be Schulman's book 'Undocumented DOS'.
It's next on my book budget list, but right now 'the better
half' is threatening homicide over that very list. B-) She
seems to think eating comes before computer books. Sheesh,
some people just don't have their priorities right. <grin>


seeya,
Logan A. Ashby, QB Pilgrim  B-)

--- GoldED 2.40
 * Origin: Lurker's Lounging Point (1:398/1.2)