Format of parameter block for functions 41h, 61h:
Offset	Size	Description	)
 00h	BYTE	special functions (reserved, must be zero)
 01h	WORD	number of disk head
 03h	WORD	number of disk cylinder
 05h	WORD	number of first sector to read/write
 07h	WORD	number of sectors
 09h	DWORD	transfer address
Note:	under Windows95, a volume must be locked (see AX=440Dh/CX=084Bh) in
	  order to perform direct accesses such as track reads and writes
	  with this IOCTL function