Western Digital T13/2132-D manual Set Hardware Configuration FN 4Eh

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June 23, 2010

T13/2132-D Revision 3

8.26 Set Hardware Configuration (FN 4Eh)

The purpose of this function is to allow non-hardware-specific software to configure host adapter and devices for optimal operation. ATA channels may have two devices attached, but this function operates on a single-device basis. This shall be accommodated by the value that is returned in AL. If the host adapter supports the requested sub-function on a device basis, AL shall be cleared to 00h. If the host adapter only supports the setting on an ATA channel basis, AL shall be set to 01h. Once this function has been invoked, all subsequent INT 13h device-access functions shall use the mode specified by this invocation. This means that if "DMA Maximum" is enabled, INT 13h FN 02h shall read from the device using DMA transfers. The DMA/PIO selections are mutually exclusive. When "DMA Maximum" is enabled, "PIO Maximum" shall be disabled. If the requested mode change is not supported this function shall return with CF = 1b and AH = 01h.

Entry
	AH 4Eh
	AL	Hardware configuration sub-function (see table 29)
	DL BIOS device number
Exit
	Carry Clear	Function completed without error
		AH	Shall be cleared to zero
		AL	00h if command was safe, 01h if other devices are affected
	Carry Set	Function completed with an error
		AH	Shall be set to the error code
		Table 29 — Hardware Configuration Sub-Functions

AL			Description
0h	Enable prefetch

1h	Disable prefetch

2h	Set maximum PIO transfer mode.

3h	Set PIO mode 0.

4h	Return to default PIO transfer mode. Return the system to the PIO mode enabled by the BIOS setup
	utility.
5h	Enable INT 13h DMA maximum mode. Set the maximum rate allowed by both the host adapter and the
	device.

6h	Disable INT 13h DMA

Working Draft Enhanced Disk Drive - 4 (EDD-4)

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Contents Revision June 23 Information technology Enhanced Disk Drive 4 EDD-4Working Draft Enhanced Disk Drive 4 EDD-4 Points of ContactT13/2132-D Revision 3June 23 June 23 T13/2132-D Revision DraftT13/2132-D Revision June 23 American National StandardNew Capabilities added to EDD-4 Document StatusContents Working Draft Enhanced Disk Drive 4 EDD-4 Vii Viii Working Draft Enhanced Disk Drive 4 EDD-4 Output Parameters TablesFigures Introduction ForewordXii Working Draft Enhanced Disk Drive 4 EDD-4 American National Standard for Information Technology ScopeBSR Incits ATA8-APT ATA8-AST Approved Ansi References Name Normative references GeneralApproved references References Under Development Name Project Number References under developmentOther references June 23 T13/2132-D Revision Master Boot Record MBR The first LBA on a disk Symbols and abbreviationsConventions Abbreviation MeaningLists Lists overview PrecedenceUnordered lists Ordered listsNumbering T13/2132-D Revision June 23 KeywordsInterrupt Services and Functions Register and CF ContentsNumbering conventions French English This standard Bit conventionsWord at offset n ByteDWord at word offset n QWord at word offset nATA firmware revision example ATA string byte swapping Word Byte Character in stringWord Byte ValueOverview Conventional Register Definitions 8GB INT 13h Functions Conventional FunctionsRegister Description Bit DescriptionConventional Function Definitions Function a Description Data Structure 8GB INT 13h Functions OverviewExtended Function Definitions Function DescriptionT13/2132-D Revision June 23 Device Address Packet Offset Fixed Disk Access Function Code Fixed Disk Access SubsetRemovable Media INT 13h Interface SubsetsEDD Support Function Code Locking and Ejecting Function CodeEnhanced Disk Drive EDD Support Subset ISO 9660 CD Layout Working Draft Enhanced Disk Drive 4 EDD-4 CD/DVD Boot OverviewSystem Area Unused Emulation Process Boot MethodsFloppy Boot No Emulation BootHard Drive Boot Floppy Geometries Type Cylinders Heads SectorsCD/DVD Format Boot Volume Descriptor BVDBoot Volume Descriptor Offset Type Description T13/2132-D Revision June 23 Validation EntrySection Header June 23 T13/2132-D Revision Initial/Default Entry00h Byte Header ID Type Description June 23 T13/2132-D Revision Section EntryT13/2132-D Revision June 23 Section Entry Extension INT 13h Function Definitions Overview Reset Disk Subsystem FN 00h Get Status of Last Operation FN 01h Read Sectors into Memory FN 02h Write Sectors From Memory FN 03h Verify Sectors FN 04h Get Drive Parameters FN 08h Read Buffer FN 0Eh Write Buffer FN 0Fh Value Description Get Disk Type FN 15hSet Media Type FN 18h Park Heads FN 19h Identify Device Information FN 25h Interface Support Bit Map Description Check Extensions Present FN 41hExtended Read FN 42h Extended Write FN 43h Verify Sectors FN 44h Lock/Unlock Media FN 45h Eject Removable Media FN 46h Result Buffer Get Device Parameters FN 48hAscii Interface Path Definitions part 1 Host Bus Type Offset T13/2132-D Revision June 23 Interface PathDevice Path Definition00h ATA Device 01h 02h..FFh Reserved Byte Word DWord QWord Byte Port number Device parameter table extension Offset 7 READ/WRITE Multiple command block count Offset 5 Bios use only Bios use only Offset 6 IRQ numberOffset 0-1 I/O port base Offset 2-3 control port baseBit 7 32-bit transfer mode Offset 10-11 Bios selected hardware specific option flagsBit 8 Atapi device uses command packet interrupt Offset 9 PIO typeJune 23 T13/2132-D Revision Bits 9-10 translation type Bit 13h 48-bit LBA addressing enabledTranslation Type Bits Description Bit 11 Ultra DMAGet Extended Media Change Status FN 49h Initiate Disk Emulation FN 4Ah Value Emulation Working Draft Enhanced Disk Drive 4 EDD-4 Terminate Disk Emulation FN 4Bh Initiate Disk Emulation & Boot FN 4Ch CD Command Packet Return Boot Catalog FN 4DhHardware Configuration Sub-Functions Set Hardware Configuration FN 4EhFormatted Command Packet Offset Type Description Send Packet Command FN 50hFormatted Protocol Specific Data T13/2132-D Revision June 23 Output Parameters Security Protocol Commands FN 51h INT 15h Removable Media Eject Annex a Hybrid MBR boot Hybrid MBR boot overviewGPT support for hybrid MBR boot code Hybrid MBR boot code EAX Hybrid MBR boot code endeavor procedureHybrid VBR boot code