Drive space

 BBS: Inland Empire Archive
Date: 09-22-93 (18:51)             Number: 46
From: ANDY THOMAS                  Refer#: NONE
  To: GARY BLYDENBURGH              Recvd: NO  
Subj: Drive space                    Conf: (2) Quik_Bas

 GB> Under OS/2 I get negative numbers under DOS it works fine.

 Oh, I didn't realize that was the "problem" you were having.
 In that case, you're doing everything right!
 Your math is just getting confused because of the way QB stores
 integers. The following code gets the drive space and includes
 corrections to avoid the negative numbers (up to 2
 gigabytes)....

 '>>> Page 1 of DRIVE.BAS begins here. TYPE:BAS
 TYPE regtype
  Ax AS INTEGER
  Bx AS INTEGER
  Cx AS INTEGER
  dx AS INTEGER
  bp AS INTEGER
  si AS INTEGER
  di AS INTEGER
  flags AS INTEGER
  DS AS INTEGER
  es AS INTEGER
 END TYPE

  DIM SHARED Inreg AS regtype, Outreg AS regtype

  CLS
  DEFINT A-Z
  Use$ = "&##########"
  Drive$ = "C"
  Drive% = ASC(UCASE$(Drive$)) - 64

  Inreg.Ax = &H3600
  Inreg.dx = Drive%
  CALL interrupt(&H21, Inreg, Outreg)
  IF NOT (Outreg.Ax AND &HFFFF) THEN
    SectorsPerCluster& = Outreg.Ax
    BytesPerSector& = Outreg.Cx

    ' The following computations are necessary to
    ' transform signed integers to positive long
    ' integers. DX and BX will usually be greater
    ' than the maximum positive integer of 32767.

    TotalClusters&=((((Outreg.dx AND &HFF00) / 256) AND &HFF) *_
   256&) + (Outreg.dx AND &HFF)
    FreeClusters&=((((Outreg.Bx AND &HFF00) / 256) AND &HFF) *_
   256&) + (Outreg.Bx AND &HFF)

    TotalCapacity& = TotalClusters& * SectorsPerCluster& *_
   BytesPerSector&
    FreeCapacity& = FreeClusters& * SectorsPerCluster& *_
   BytesPerSector&

    PRINT "Drive:"; Drive$
    PRINT "Sectors/Cluster:"; SectorsPerCluster&
    PRINT "Bytes/Sector:"; BytesPerSector&
    PRINT "Total number of clusters:"; TotalClusters&
    PRINT USING Use$; "Total drive capacity:"; TotalCapacity&
    PRINT USING Use$; " Free drive capacity:"; FreeCapacity&
    ' Note: due to the use of long signed integers this

    ' program will report a negative drive capacity for
    ' drives over 2 gigabytes.
  ELSE
    PRINT "Error - drive invalid"
  END IF

  '>>> Page 1 of DRIVE.BASends here. Last page.


 Write back if you've got any questions....
 -Andy                In San Francisco, CA on 09/22/93 @ 18:56


 * RM 1.2 00593 * Cat philosophy:  When in doubt, cop an attitude.

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