en:docs:dos:api:int21:36
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—en:docs:dos:api:int21:36 [2020/12/11 04:53] – created prokushev
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 +{{page>en:templates:dosint}}
 +
 +====== Int 21H, AH=36H ======
 +
 +===== Version =====
 +
 +2 and higher
 +
 +===== Brief =====
 +
 +GET FREE DISK SPACE
 +
 +===== Family API =====
 +
 +
 +===== Input =====
 +
 +        AH = 36h
 +        DL = drive number (00h = default, 01h = A:, etc)
 +
 +===== Return =====
 +
 + AX = FFFFh if invalid drive
 +        else
 +            AX = sectors per cluster
 +            BX = number of free clusters
 +            CX = bytes per sector
 +            DX = total clusters on drive
 +
 +===== Notes =====
 +
 +  free space on drive in bytes is AX * BX * CX
 +        total space on drive in bytes is AX * CX * DX
 +        "lost clusters" are considered to be in use
 +        according to Dave Williams' MS-DOS reference, the value in DX is
 +          incorrect for non-default drives after ASSIGN is run
 +        this function does not return proper results on CD-ROMs;
 +          use AX=4402h"CD-ROM" instead
 +        (FAT32 drive) the reported total and free space are limited to 2G-32K
 +          should they exceed that value
 +          
 +===== See also =====
 +
 + AH=1Bh,AH=1Ch,AX=4402h"CD-ROM",AX=7303h
 +
 +===== Note =====
 +
 +Text based on [[http://www.cs.cmu.edu/~ralf/files.html|Ralf Brown Interrupt List Release 61]]
 +
 +{{page>en:templates:int}}
 +
 +{{page>en:templates:fapi}}