Category: <b>DOS kernel</b>
<br>Flags: Undocumented function<p>
<pre><b>INT 21 - DOS 4.0+ internal - GET/SET DISK SERIAL NUMBER</b>

	AH = 69h
	AL = subfunction
	    00h get serial number
	    01h set serial number
	BL = drive (0=default, 1=A, 2=B, etc)
	BH = info level (00h only for DOS; OS/2 allows other levels)
	DS:DX -&gt; disk info (see <a href=../../it/66/17.html>#01766</a>)
Return: CF set on error
	    AX = error code (see <a href=../../it/80/16.html>#01680</a> at AH=59h/BX=0000h)
	CF clear if successful
	    AX destroyed
	    (AL = 00h) buffer filled with appropriate values from extended BPB
	    (AL = 01h) extended BPB on disk set to values from buffer
Notes:	does not generate a critical error; all errors are returned in AX
	error 0005h given if no extended BPB on disk
	does not work on network drives (error 0001h)
	buffer after first two bytes is exact copy of bytes 27h thru 3Dh of
	  extended BPB on disk
	this function is supported under Novell NetWare versions 2.0A through
	  3.11; the returned serial number is the one a DIR would display,
	  the volume label is the NetWare volume label, and the file system
	  is set to "FAT16".
	this function is not supported by Novell DOS 7 through Update 13, but
	  Personal NetWare 1.0 and Update 15 do support this function
	the serial number is computed from the current date and time when the
	  disk is created; the first part is the sum of the seconds/hundredths
	  and month/day, the second part is the sum of the hours/minutes and
	  year
	the volume label which is read or set is the one stored in the extended
	  BPB on disks formatted with DOS 4.0+, rather than the special root
	  directory entry used by the DIR command in COMMAND.COM (use AH=11h
	  to find that volume label)
SeeAlso: AX=440Dh"DOS 3.2+"

</pre>