Int 13/AH=4Eh

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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

See Also: AH=41h"INT 13 Extensions" - AX=5001h"Enhanced Disk Drive"

Category: Disk I/O Enhancements - Int 13h - I

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