INT 13 - IBM/MS INT 13 Extensions v2.1+ - SET HARDWARE CONFIGURATION

	AH = 4Eh
	AL = function
	    00h enable prefetch
	    01h disable prefetch
	    02h set maximum PIO transfer mode
	    03h set PIO mode 0
	    04h set default PIO transfer mode
	    05h enable INT 13h DMA maximum mode
	    06h disable INT 13h DMA
	DL = drive number
Return: CF clear if successful
	    AH = 00h
	    AL = status
		00h command was safe (only affected specified drive)
		01h other devices are affected
	CF set on error
	    AH = error code (see #00234)
Note:	DMA and PIO modes are mutually exclusive, so selecting DMA disables
	  PIO (for either the specified device or all devices on that
	  controller), and selecting PIO disables DMA
SeeAlso: AH=41h"INT 13 Extensions",AX=5001h"Enhanced Disk Drive"