Category: <b>DOS kernel</b>
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<pre><b>INT 21 - DOS 2+ - GET FREE DISK SPACE</b>

	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
SeeAlso: AH=1Bh,AH=1Ch,AX=4402h"CD-ROM",AX=7303h
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