INT 13 - HARD DISK - PSIBM PS/2, any model/1 and newer PS/2IBM PS/2, any model - READ MULTIPLE DISK SECTORS
	AH = 21h
	AL = number of sectors to write
	CH = low byte of 12-bit cylinder number
	CL = starting sector (bits 0-5) and bits 8-9 of cylinder (bits 6-7)
	DH = head number (bits 0-5) and bits 10-11 of cylinder (bits 6-7)
	DL = drive number (80h,81h)
	ES:BX -> buffer for data to be read
Return: CF clear if successful
	    ES:BX buffer filled
	CF set on error
	AH = status (see #00234 at AH=01h)
Desc:	read from the disk using the Multiple Block mode available on newer
	  IDE(Integrated Drive Electronics) A type of disk drive interface which essentially extends the PCIBM PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself.	 See also ESDI. drives and some hard disk controllers, which generates an
	  interrupt only after the end of transferring a group of sectors
	  rather than after each sector
Notes:	must call AH=24h"PSIBM PS/2, any model/1" before using this function
	input values in CL and DH are not range-checked
	the byte at address 0040h:0074h is set to the status of the operation
SeeAlso: AH=02h,AH=22h"PSIBM PS/2, any model/1",AH=23h"PSIBM PS/2, any model/1",AH=24h"PSIBM PS/2, any model/1"