INT 2F - CD-ROM - READ VTOC                                                     
	AX = 1505h
	ES:BX -> 2048-byte buffer
	CX = drive number (0=A:)
	DX = sector index (0=first volume descriptor,1=second,...)
Return: CF set on error
	    AX = error code (15=invalid drive,21=not ready)
	CF clear if successful
	    AX = volume descriptor type (1=standard,FFh=terminator,0=other)
Note:	This function was not supported by Novell DOS 7 NWCDEX prior to the
	  08/16/94 update