Category: <b>no classification</b>
<br>Flags: Undocumented function<p>
<pre><b>INT 21 - PTS-DOS 6.51 & S/DOS 1.0 - DIRECT DISK WRITE</b>

	AH = 91h
	CX = FFFFh (for partitions &gt; 32 Mb)
	    DS:BX -&gt; request block (see <a href=../../it/94/40.html>#04094</a>)
	CX = sector count (for partitions &lt; 32 Mb)
	    DX = starting sector number
	    DS:BX -&gt; buffer
Return: CF set on error
	    AX error code
	CF clear on success
Note:	This function is supported by Paragon Technology Systems S/DOS 1.0
	  (and most probably by PTS-DOS 6.51, maybe even earlier).
	To access big partitions (&gt; 32 Mb), CX != FFFFh is not allowed and
	  the buffer must always be used. Otherwise, the system will return
	  error code 0207h.
	It is currently unknown if this function is also supported by
	  PhysTechSoft PTS-DOS 6.60, 6.70, or 2000.
SeeAlso: INT 21/Ah=90h"PTS",INT 25h,INT 26h
</pre>