Western Digital manual Overview, T13/2132-D Revision June 23

Page 24

T13/2132-D Revision 3

June 23, 2010

4 Overview

In the past, DOS has accessed its mass storage devices using a BIOS provided INT 13h interface. This interface was designed in the early 1980's and upgraded in the late 1980's. The maximum capacity that can be addressed by this Applications Program Interface (API) on a disk drive is 8.4 GB. The INT 13h interface, now known as the conventional INT 13h interface, uses function numbers 01h through 3Fh and is Cylinder-Head-Sector (CHS) oriented. An extended INT 13h interface has been created. The purpose of these INT 13h extensions shall be to:

a)Replace CHS addressing with Logical Block Addressing (LBA);

b)Remove the current requirement of using interrupt 41h/46h to point at the Fixed Disk Parameter Table information (see 8.20.4);

c)Make location and configuration information available to operating systems that do not use the BIOS to access mass storage devices;

d)Use data structures that apply to both IA-32 and IA-64 compatible architecture systems; and

e)Use data structures that can address media capacities for the next 20 years.

Many BIOS, Option ROM, and OS vendors have already implemented the functions defined in this document for ATA and SCSI style devices. This standard builds on EDD-3 to enable additional mass storage technologies.

DOS and other operating systems, such as Windows® 98, Windows® NT, Windows® 2000, and Windows® XP, add the capability to consistently provide the same drive letter assignments to the user. The result of this capability is that storage devices can be added to an EDD system, and the existing drive letters do not change.

Data written on media can render the media incompatible with certain drive letters when some drive letter based operating systems are used. Technologies, such as IEEE 1394-2008, blur the difference between fixed and removable media.

One of the important aspects of this standard is to allow a BIOS to describe the physical path to a device. Figure 3 shows the basic system components that are referenced by this standard.

Host Bus

(Need to know host bus type to access the

adapter/interface hardware)


							Adapter/Interface
CPU		Host Bus Bridge

							hardware
							hardware

Device

Interface Bus

I/O or Memory Bus(Need to know interface bus type to access the device)

Figure 3 — System Component Diagram

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

Image 24

Contents Information technology Enhanced Disk Drive 4 EDD-4 Revision June 23Points of Contact T13/2132-D Revision 3June 23Working Draft Enhanced Disk Drive 4 EDD-4 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 Scope BSR IncitsAmerican National Standard for Information Technology ATA8-APT ATA8-AST Normative references General Approved referencesApproved Ansi References Name References under development Other referencesReferences Under Development Name Project Number 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 SubsetsLocking and Ejecting Function Code Enhanced Disk Drive EDD Support SubsetEDD Support Function Code 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 SectorsBoot Volume Descriptor BVD Boot Volume DescriptorCD/DVD Format 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 Hybrid MBR boot Hybrid MBR boot overview GPT support for hybrid MBR boot codeAnnex a Hybrid MBR boot code Hybrid MBR boot code endeavor procedure EAXHybrid VBR boot code