Western Digital T13/2132-D manual Read Sectors into Memory FN 02h, Bit Description

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T13/2132-D Revision 3

June 23, 2010

8.4 Read Sectors into Memory (FN 02h)

This function shall be used to read data from the device into the host memory buffer beginning at the location specified by the contents of the ES:BX registers. If the command transfers some of the data and then returns a failure, carry is set, the buffer pointed to by ES:BX shall contain the partial data transfer, and AH shall contain an error code. When there is a partial data transfer, there is no reliable indication of what part of the data was successfully transferred. Some systems use DMA to return the data in an out-of-order fashion. This function does not have a mechanism to report what data is valid in the case of a partial transfer. In some conventional systems when a partial transfer occurs, AL contains the number of sectors transferred.

Entry

AH 02h

AL Number of sectors to read, shall be greater than 0 and less than 128 CH Low order 8 bits of the cylinder number

CL

Bit Description

7:6 high order 2 bits of the cylinder 5:0 sector number

DH Head number

DL BIOS device number

ES:BX Pointer to destination buffer in memory

Exit

Carry Clear Function completed without error

AH Shall be cleared to zero

AL Number of sectors read

ES:BX Pointer to buffer filled with read data

Carry Set Function completed with an error

AH Shall be set to the error code

AL Vendor Specific

ES:BX Pointer to buffer partially filled with read data

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

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Contents Information technology Enhanced Disk Drive 4 EDD-4 Revision June 23Working Draft Enhanced Disk Drive 4 EDD-4 Points of ContactT13/2132-D Revision 3June 23 Draft June 23 T13/2132-D RevisionAmerican National Standard T13/2132-D Revision June 23Document Status New Capabilities added to EDD-4Contents Working Draft Enhanced Disk Drive 4 EDD-4 Vii Viii Working Draft Enhanced Disk Drive 4 EDD-4 Tables Output ParametersFigures Foreword IntroductionXii 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 Symbols and abbreviations Master Boot Record MBR The first LBA on a diskConventions Abbreviation MeaningPrecedence Lists Lists overviewUnordered lists Ordered listsT13/2132-D Revision June 23 Keywords NumberingRegister and CF Contents Interrupt Services and FunctionsNumbering conventions French English This standard Bit conventionsByte Word at offset nDWord at word offset n QWord at word offset nATA string byte swapping Word Byte Character in string ATA firmware revision exampleWord Byte ValueOverview 8GB INT 13h Functions Conventional Functions Conventional Register DefinitionsRegister Description Bit DescriptionConventional Function Definitions Function a Description 8GB INT 13h Functions Overview Data StructureExtended Function Definitions Function DescriptionT13/2132-D Revision June 23 Device Address Packet Offset Fixed Disk Access Subset Fixed Disk Access Function CodeRemovable Media INT 13h Interface SubsetsEDD Support Function Code Locking and Ejecting Function CodeEnhanced Disk Drive EDD Support Subset CD/DVD Boot Overview ISO 9660 CD Layout Working Draft Enhanced Disk Drive 4 EDD-4System Area Unused Boot Methods Emulation ProcessNo Emulation Boot Floppy BootHard Drive Boot Floppy Geometries Type Cylinders Heads SectorsCD/DVD Format Boot Volume Descriptor BVDBoot Volume Descriptor T13/2132-D Revision June 23 Validation Entry Offset Type DescriptionJune 23 T13/2132-D Revision Initial/Default Entry Section Header00h Byte Header ID June 23 T13/2132-D Revision Section Entry Type DescriptionT13/2132-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 Get Disk Type FN 15h Value DescriptionSet Media Type FN 18h Park Heads FN 19h Identify Device Information FN 25h Check Extensions Present FN 41h Interface Support Bit Map DescriptionExtended Read FN 42h Extended Write FN 43h Verify Sectors FN 44h Lock/Unlock Media FN 45h Eject Removable Media FN 46h Get Device Parameters FN 48h Result BufferAscii T13/2132-D Revision June 23 Interface Path Interface Path Definitions part 1 Host Bus Type OffsetDefinition Device Path00h ATA Device 01h 02h..FFh Reserved Byte Word DWord QWord Byte Port number Device parameter table extension Offset 5 Bios use only Bios use only Offset 6 IRQ number Offset 7 READ/WRITE Multiple command block countOffset 0-1 I/O port base Offset 2-3 control port baseOffset 10-11 Bios selected hardware specific option flags Bit 7 32-bit transfer modeBit 8 Atapi device uses command packet interrupt Offset 9 PIO typeBit 13h 48-bit LBA addressing enabled June 23 T13/2132-D Revision Bits 9-10 translation typeTranslation 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 Return Boot Catalog FN 4Dh CD Command PacketSet Hardware Configuration FN 4Eh Hardware Configuration Sub-FunctionsSend Packet Command FN 50h Formatted Command Packet Offset Type DescriptionFormatted 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 Hybrid MBR boot code endeavor procedure EAXHybrid VBR boot code