Category: <b>BIOS</b>
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<pre><b>INT 13 - DISK - WRITE DISK SECTOR(S)</b>

	AH = 03h
	AL = number of sectors to write (must be nonzero)
	CH = low eight bits of cylinder number
	CL = sector number 1-63 (bits 0-5)
	     high two bits of cylinder (bits 6-7, hard disk only)
	DH = head number
	DL = drive number (bit 7 set for hard disk)
	ES:BX -&gt; data buffer
Return: CF set on error
	CF clear if successful
	AH = status (see <a href=../../it/34/2.html>#00234</a>)
	AL = number of sectors transferred
	      (only valid if CF set for some BIOSes)
Notes:	errors on a floppy may be due to the motor failing to spin up quickly
	  enough; the write should be retried at least three times, resetting
	  the disk with AH=00h between attempts
	most BIOSes support "multitrack" writes, where the value in AL
	  exceeds the number of sectors remaining on the track, in which
	  case any additional sectors are written beginning at sector 1 on
	  the following head in the same cylinder; the CONFIG.SYS command
	  MULTITRACK can be used to force DOS to split disk accesses which
	  would wrap across a track boundary into two separate calls
	the IBM AT BIOS and many other BIOSes use only the low four bits of
	  DH (head number) since the WD-1003 controller which is the standard
	  AT controller (and the controller that IDE emulates) only supports
	  16 heads
	AWARD AT BIOS and AMI 386sx BIOS have been extended to handle more
	  than 1024 cylinders by placing bits 10 and 11 of the cylinder number
	  into bits 6 and 7 of DH
	under Windows95, an application must issue a physical volume lock on
	  the drive via INT 21/AX=440Dh before it can successfully write to
	  the disk with this function
SeeAlso: AH=02h,AH=0Bh,AH=07h"V10DISK.SYS",AH=22h"PS/1",AH=43h"IBM"
SeeAlso: INT 21/AX=440Dh"DOS 3.2+",INT 4D/AH=03h
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