1、INCITS TR-27-2001Information Technology Address Offset Reserved Area Boot MethodReaffirmed as INCITS TR-27-2001 (R2006)Reaffirmed as INCITS TR-27-2001 (R2006)NCITS TR-27-2001NCITS Technical ReportInformation Technology Address Offset Reserved Area Boot MethodSecretariatInformation Technology Industr
2、y CouncilAbstractThis technical report describes a method of booting an operating system from a reserved area onATA/ATAPI devices, using an Address Offset Set Features Function.Reaffirmed as INCITS TR-27-2001 (R2006)This Technical Report is one in a series produced by the National Committee forInfor
3、mation Technology Standards (NCITS). The secretariat for NCITS is held bythe Information Technology Industry Council (ITI), 1250 Eye Street, NW, Suite 200,Washington, DC 20005.As a by-product of the standards development process and the resources ofknowledge devoted to it, NCITS from time to time pr
4、oduces Technical Reports.Such Technical Reports are not standards, nor are they intended to be used assuch.NCITS Technical Reports are produced in some cases to disseminate thetechnical and logical concepts reflected in standards already published or underdevelopment. In other cases, they derive fro
5、m studies in areas where it is foundpremature to develop a standard due to a still changing technology, orinappropriate to develop a rigorous standard due to the existence of a number ofviable options, the choice of which depends on the users particular requirements.These Technical Reports, thus, pr
6、ovide guidelines, the use of which can result ingreater consistency and coherence of information processing systems.When the draft Technical Report is completed, the Technical Committee approvalprocess is the same as for a draft standard. Processing by NCITS is also similar tothat for a draft standa
7、rd.CAUTION: The developers of this Technical Report have requested that holdersof patents that may be required for the implementation of the Technical Report,disclose such patents to the publisher. However, neither the developers nor thepublisher have undertaken a patent search in order to identify
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9、 by the developer or the publisher in respect to any Technical Report itprocesses. No representation is made or implied that licenses are not required toavoid infringement in the use of this Technical Report.NCITSTechnicalReportSeriesPublished byAmerican National Standards Institute25 West 43rd Stre
10、et, New York, New York 10036Copyright 2001 by Information Technology Industry Council (ITI)All rights reservedNo part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without prior written permission of the publisher.Printed in the United States of Ame
11、ricaPATENTSTATEMENTReaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page iContents Page1. Scope .12. Definitions, abbreviations, and conventions .22.1 Definitions and abbreviations .22.2 Conventions .23. Address Offset Mode operation33.1 Enable/Disable Address Offset Mode .33.2 IDENTIFY D
12、EVICE .33.3 SET MAX ADDRESS34. Booting from the reserved area using Address Offset .5Figures Page1 The effect of Address Offset on addressing4Annex PageA Bibliography.6Reaffirmed as INCITS TR-27-2001 (R2006)Page ii Foreword This technical report describes the Set Features Address Offset feature and
13、the method of booting an operating system from the reserved area using the Address Offset feature. This technical report was developed by T13 during 1999/2000. The approval process started in 2000. This document is not an American National Standard and the material contained herein is not normative
14、in nature. Comments on the content of this document should be sent to the NCITS Secretariat, Information Technology Industry Council, 1250 Eye Street, NW (Suite 200), Washington, DC 20005. This technical report was processed and approved for submittal to ANSI by Accredited Standards Committee on Nat
15、ional Committee for Information Technology Standards, NCITS. Committee approval of the technical report does not necessarily imply that all committee members voted for approval. Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page iiiSubcommittee T13 on ATA Interfaces, that developed thi
16、s standard, had the following members:Gene Milligan, ChairmanPete McLean, Vice-ChairmanKent Pryor, SecretaryPaul Anderson, Editor Andre Hedrick,Larry Barras, Tasuku Kasebayashi,Amy Barton, Hale Landis,Tim Bradshaw, Raymond Liu,Darrin Bulik, Ming Louie,Litko Chan, Ian Morrell,Ben Chang, Masataka Ogaw
17、a,Dan Colegrove, Ron Roberts,Tom Colligan, Matt Rooke,David Dickson, Curtis Stevens,Greg Elkins, Tim Thompson,Mark Evans, Kanting Tsai,Phil Gardner, Quang Vuong,Tony Goodfellow, Aaron Wilson,Robert Griswold, Anthony Yang,Tom Hanan,Ken Bovatsek Alternate, Leroy Leach Alternate,Andy Chen Alternate, We
18、n Lin Alternate,Renee Depew Alternate, James McGrath Alternate,Richard Harcourt Alternate, Kha Nguyen Alternate,Naoto Kawakubo Alternate, Marc Noblitt Alternate,Lawrence Lamers Alternate, Darrell Redford AlternateYogi Schaffner Alternate, Chi Wang Alternate,Paresh Sheth Alternate, Graeme Weston-Lewi
19、s Alternate,Tokuyuki Totani Alternate, Sam Wong Alternate,Tri Van Alternate,The T13 ad hoc had the following additional participants:Mahmoud Assaf, Akil Houston,Marc Bombet, Mike Jaskowiak,Mike Christensen, Niek Lambert,Michael Eschmann, Russell Leidich,Stephen Finch, Raymond Liu,Jon Haines, Bill Mc
20、Ferrin,Jonathan Hanmann, Lynn McQueen,Adge Hawes, Jeff Wolford,Eorge Hefner Joseph YoungJeroen Heuvelman,Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page ivIntroductionThis technical report encompasses the following:Clause 1 describes the scope.Clause 2 provides definitions, abbrevia
21、tions, and conventions used within this technical report.Clause 3 describes the operation of the Set Features Address Offset feature.Clause 4 describes booting from the reserved area using the Address Offset feature.Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page 1NCITS TR nn-yyNati
22、onal Committee for Information Technology Standards (NCITS)Technical Report Address Offset Reserved Area Boot Method1. ScopeThis technical report assumes that the reader is familiar with the conventional Int 13h interface, and the basicoperation of ATA devices. This technical report describes the Ad
23、dress Offset feature and the method of booting anoperating system from a reserved area using the Address Offset feature.NCITS TR-27-2001Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page 22. Definitions, abbreviations, and conventions2.1 Definitions and abbreviations2.1.1 user area: Th
24、e range of device addresses accessible by read and write commands.2.1.2 reserved area: The range of device addresses not accessible by read and write commands after a SET MAXcommand has been used to reduce the size of the user area.2.1.3 set max pointer: The set max pointer is the lowest addressable
25、 sector of the reserved area.2.2 ConventionsLowercase is used for words having the normal English meaning. Certain words and terms used in this standardhave a specific meaning beyond the normal English meaning. these words and terms are defined either in clause 2or in the text where they first appea
26、r.The names of abbreviations, commands, fields, and acronyms used as signal names are in all uppercase (e.g.,IDENTIFY DEVICE).2.2.1 PrecedenceIf there is a conflict between text, figures, and tables, the precedence shall be tables, figures, then text.2.2.2 ListsOrdered lists, those lists describing
27、a sequence, are of the form:a)b)c)Unordered lists are of the form:1)2)3)NCITS TR-27-2001NCITS TR-27-2001Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page 33. Address Offset Mode operation3.1 Enable/Disable Address Offset ModeIn devices that support the Address Offset feature, the SET
28、FEATURES subcommand 09h Enable Address OffsetMode, offsets address Cylinder 0, Head 0, Sector 1, LBA 0, to the start of the non-volatile protected area establishedusing the SET MAX ADDRESS Command.The Address Offset condition is cleared by the SET FEATURES subcommand 89h Disable Address Offset Mode,
29、 ahardware reset or a power-on reset.If Reverting to Power on Defaults has been enabled by a SET FEATURES command, it is cleared by software resetas well.Upon entering the Address Offset mode the capacity of the drive returned in the Identify device data is the size of theformer protected area. A su
30、bsequent SET MAX ADDRESS command using the address returned by the READNATIVE MAX ADDRESS command allows access to the entire drive. Addresses wrap so the entire drive remainsaddressable (see figure 1).If a non-volatile reserved area has not been established before the device receives a SET FEATURES
31、 EnableAddress Offset Mode command, the command fails with Abort error status.The Disable Address Offset Mode removes the address offset and sets the size of the drive reported by theIDENTIFY DEVICE command back to the size specified in the last non-volatile SET MAX ADDRESS command.3.2 IDENTIFY DEVI
32、CEIDENTIFY DEVICE word 83 bit 07, if set to one, indicates the device supports the Address Offset Mode. IDENTIFYDEVICE word 86 bit 07, if set to one, indicates the device is in Address Offset Mode.3.3 SET MAX ADDRESSIssuing the SET MAX ADDRESS command with bit 0 in the Sector Count register set to o
33、ne is not valid when thedevice is in Address Offset Mode.NCITS TR-27-2001Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page 4LBA (M-R+1) LBA MLBA (M-R)LBA 0User accessiblearea(former reservedarea)Reserved area(former user accessible area)LBA MLBA RLBA 0User accessible area Reserved are
34、aBefore SET FEATURES Enable Address Offset ModeA reserved area has been created using a non-volatile SET MAX ADDRESS command:After SET FEATURES Enable Address Offset ModeThe former reserved area is now the user accessible area. The former user accessiblearea is now the reserved area.After a SET MAX
35、ADDRESS command using the value returned by READ NATIVEMAX ADDRESS:LBA MLBA 0User accessible areaAfter a SET FEATURES Disable Address Offset Mode, software reset, hardware reset,or power-on reset:LBA MLBA RLBA 0User accessible area Reserved areaFigure 1 - The effect of address offset on addressingNC
36、ITS TR-27-2001Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page 54. Booting from the reserved area using Address OffsetComputer systems perform initial code loading (booting) by reading from a predefined address on a disk drive. TheAddress Offset feature allows a second operating syst
37、em to be booted from the reserved area on a drive by changingthe location of LBA 0 instead of modifying the BIOS to begin the boot process from an alternate starting address.To boot an alternate operating system the BIOS:a) Issues a SET FEATURES Address Offset command to the disk driveb) Checks to s
38、ee that it the SET FEATURES Address Offset command was completed successfully.c) Executes the normal boot process.NCITS TR-27-2001Reaffirmed as INCITS TR-27-2001 (R2006)T13/1407DT Revision 5Page 6Annex A(informative)BibliographyAT Attachment Interface with Packet Interface Extensions (ATA/ATAPI-4), ANSI X3.317-1999IBM Personal Computer AT Technical Reference, IBM Boca Raton, FL, 1984IBM Personal System/2 and Personal Computer BIOS Interface Technical Reference, S68X-2341 and S10G-6467.NCITS TR-27-2001Reaffirmed as INCITS TR-27-2001 (R2006)
