Category: <b>file/disk compression</b>
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<pre><b>INT 21 - Stacker - GET DEVICE DRIVER ADDRESS AND SET VOLUME NUMBER</b>

	AX = 4404h
	BL = drive number (00h = default, 01h = A:, etc.)
	CX = 0004h
	DS:DX -&gt; DWORD buffer to receive device driver address
Return: buffer filled with pointer into Stacker device driver (see <a href=../../it/50/25.html>#02550</a>):
	  driver + 19h if Stacker Anywhere controls this drive
	  driver + 1Ah if Stacker controls this drive
	  unchanged else
Notes:	in addition to returning the address of the Stacker device driver,
	  this call also sets the volume number at offset 58h in the device
	  driver (see <a href=../../it/50/25.html>#02550</a> at INT 25/AX=CDCDh)
	Stacker Anywhere does not link its built-in device driver into
	  the standard device driver chain, but it can be found via CDS/DPB
	this call can be used as an installation check for all versions of
	  Stacker and Stacker Anywhere to avoid the INT 25 call
SeeAlso: AX=4408h,AX=440Eh,AH=52h,INT 25/AX=CDCDh
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