eee)a pplitati
`PeeteTL:
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`rasae ADDISON-WESLEY
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`a ’DISKINCLUDED 4
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`OLYMPUS EX. 1006- 1/312
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`OLYMPUS EX. 1006 - 1/312
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`—— @ ———
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`The
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`SCSI Bus
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`and
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`The
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`SCSI Bus
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`and
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`IDE Interface
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`Protocols, Applications and Programming
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`Sd
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`Friedhelm Schmidt
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`Translated by
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`J. Michael Schultz
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`TransTech Translations
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`A.
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`ADDISON-WESLEY
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`PUBLISHING
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`COMPANY
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`Wokingham, England * Reading, Massachusetts * Mento Park, California « New York
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`Tokyo * Madrid * San Juan © Milan * Paris « Mexico City.* Seoul « Taipei
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`OLYMPUS EX.1006- 3/312
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`OLYMPUS EX. 1006 - 3/312
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`TK 7EqS
`"afeS>
`MERCER
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`© 1995Addison-Wesley PublishersLtd.
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`© 1995 Addison-Wesley Publishing CompanyInc.
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`Translated from the German edition SCS-Bus und IDE-Schnittstelle
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`published by Addison-Wesley (Deutschland) GmbH.
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`All rights reserved. No part of this publication may be reproduced,stored in a retrieval
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`system, or transmitted in any form or by any means, electronic, mechanical,
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`photocopying, recording or otherwise, without prior written permission of the
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`publisher.
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`The programsin this book have been included for their instructional value. They have
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`been tested with care but are not guaranteed for any particular purpose. The publisher
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`does not offer any warranties or representations nor doesit accept any liabilities with
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`respect to the programs.
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`Manyof the designations used by manufacturers andsellers to distinguish their
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`products are claimed as trademarks. Addison-Wesley has made every attempt to
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`supply trademark information about manufacturers and their products mentioned in
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`this book.
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`Cover designed by Designers & Partners, Oxford
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`and printed by The Riverside Printing Co. (Reading) Ltd.
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`Typeset by VAP Group, Kidlington, Oxon.
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`Printed and boundin GreatBritain at T.J. Press (Padstow) Ltd, Padstow, Cornwall
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`First printed 1995
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`ISBN 0-201-42284-0
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`British Library Cataloguing in Publication Data
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`A catalogue record for this book is available from the British Library.
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`Library of Congress Cataloging-in-Publication Data
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`Schmidt. Friedhelm
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`(SCSI-Bus und [DE-Schnittstelle. English)
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`The SCSI bus and IDEinterface/Friedhelm Schmidt; translated by
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`Michael Schultz.
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`Pp. cm.
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`Includes index.
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`ISBN 0-201-42284-0
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`__1, SCSI (Computer bus)
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`TK7895-B87536 1995
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`004. 6°2--dc20
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`2. IDE (Standard)
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`I. Title
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`94-23813
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`cIP
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`AESOF ConCae
`FEB 1 9 1995
`cory
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`ciP
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`OLYMPUS EX.1006 - 4/312
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`OLYMPUS EX. 1006 - 4/312
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`Preface
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`The SCSI bus and IDE interface are without question the two most important
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`interfaces for computer peripherals in use today. The IDE hard disk interface is
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`found almost exclusively in the world of IBM PC compatibles. The SCSI bus, on
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`the other hand, is designed not only for hard drives butalso for tape drives, CD-
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`ROM,scanners, and printers. Almost all modern computers, from PCs to work-
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`stations io mainframes, are equipped with a SCSI interface.
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`Both SCSI and IDE are ANSI standards. However, aside from the actual
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`ANSI documentation, there exists almost no additional reference material to
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`either specification. The purposeof this bookis to fill that void with a clear, con-
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`cise description of both interfaces. The essential terminology is introduced,
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`while the commands and protocols are broken down in full. In the interest of
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`economy the less important details and options have been omitted in certain
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`cases. Often a specific section in the ANSI documentation will be cited for easy |
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`cross-referencing. After reading this book you should be in the position to easily
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`understand relevant technical documentation, including the ANSIspecifications
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`themselves.
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`First and foremost, a thorough introduction to the terminology is in
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`order. Especially with respect to SCSI, there is a deluge of terms and definitions —
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`that are used nowhere else or are used differently than in other computer
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`domains. These keywords, which include signal names and interface com-
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`mands, are typeset in small capital letters, for examyple FORMAT UNIT.
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`This book is intended for readers with a broad range of technical back-
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`grounds and interests. Those working on the design of mass storage devices, for
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`example, will find the protocol descriptions extremely useful. Readers writing soft-
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`ware or device drivers may have other interests. They will find the hardware
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`descriptions, such as that of the physical organization of a disk drive, very helpful.
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`This book is not meantto replace the ANSI documentation. On the other
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`hand, those specifications are not meant to explain the technology, rather to
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`defineit. It is very difficult to find your way around in the original documenta-
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`tion without an understanding of the subject matter. The book’s thorough, in-
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`depth descriptions, along with index and glossary, make it the perfect tutor for
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`IDE and SCSI, as well as a helpful guide to the ANSIliterature.
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`Friedhelm Schmidt
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`February 1993
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`OLYMPUS EX.1006 - 5/312
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`HUAWEI EX. 1006 - 5/312
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`OLYMPUS EX. 1006 - 5/312
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`

`

`Contents
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`Preface
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`PartI
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`Introduction
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`1 Computers and peripherals
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`1.1 Massstorage
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`1.2
`Peripheral interfaces
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`2 Traditional peripheral interfaces
`The RS-232 serial interface
`2.1
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`2.2
`The Centronics printer interface
`2.3 Hard disks and their interfaces
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`2.4
`ST506
`2.5
`ESDI
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`3 Computer buses
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`Characteristics of buses
`3.1
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`3.2
`Specialized buses
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`Part II The IDE interface
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`4 Background
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`4.1
`The origin of IDE
`4.2 Overview
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`4.3. Outlook
`4.4 Documentation
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`The physical IDE interface
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`Theelectrical interface
`5.1
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`5.2
`Timing specifications
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`IDE protocol
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`6.1
`The register model of the IDE controller
`6.2 Command execution
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`6.3
`Power-up or hardware reset
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`Part III
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`9
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`Contenis
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`The model of an IDE disk drive
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`7.1 Organization of the medium
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`7.2 Defect management
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`7.3
`The sector buffer
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`Power conditions
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`IDE commands
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`8.1 Mandatory commands
`8.2 Optional commands
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`The SCSI bus
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`Background
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`9.1
`The evolution of SCSI
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`92 Overview
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`9.3 Outlook
`9.4 Documentation
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`SCSI hardware
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`10.1 SCSE configurations
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`10,2 SCSI signals
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`10.3 Cables and connectors
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`10.4 Single-ended SCSI
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`10.5 Differential SCSI
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`10.6 SCSI bus phases
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`10.7 Synchronoustransfers and Fast SCSI
`10.8 Wide SCSI
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`SCSI busprotocol
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`11.1 The message system
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`I/O processes
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`11.3 SCSI pointers
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`11.4 Disconnect-reconnect: freeing the bus
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`11.5 Transfer options
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`11.6 Tagged queues
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`11.7 Termination of I/O processes
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`11.8 Error handling in the message system
`11.9 Asynchronous eventnotification
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`SCSI commands
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`12.1 The SCSI target model
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`42.2. Commanddescriptor blocks
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`12.3 Commandsfor all SCSI devices
`12.4 Mode parameter pagesforall device classes
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`vili
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`13. Direct access devices
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`13.1 The model of a SCSI disk drive
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`13.2. Hard disk commands-
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`13.3 Mode parameter pages for disk drives
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`Tape drives
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`14.1 The model of a SCSI tape drive
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`14.2. Commandsfor tape devices
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`14.3 Mode parameters for tape devices
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`Printers
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`15.1 The model of a SCSI printer
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`15.2 Printer commands
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`15.3 Mode parameters for printers
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`Scanners
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`16.1 The model of a SCSI scanner
`16.2 Scanner commands
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`16.3 Mode parameters for scanners
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`Processor devices
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`17.4. The model of a SCSI processor device
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`17.2. Commandsfor processor devices
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`18 Communications devices
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`18.1 The model of a SCSI communications device
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`18.2. Commands for SCSI communications devices
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`18.3 Mode parameter pages for communications devices
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`19 Optical storage and WORMdrives
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`19.1 The SCSI modelof optical storage
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`19.2. Commandsfor optical storage and WORM drives
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`19.3 Mode parameters for optical storage
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`20 CD-ROM
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`20.1 The model of a SCSI CD-ROM drive
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`20.2 Commands for CD-ROM
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`20.3 Audio commands for CD-ROM
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`20.4 Mode parameters for CD-ROMs
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`21 Medium-changer devices
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`21.1 The model of a SCSI medium-changer device
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`21.2 Commands for medium-changers
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`21.3 Mode parameter pages for medium-changers
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`22 The SCSI monitor program
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`23
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`24
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`25
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`«©6Software interfaces
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`23.1 The concept of ASPI
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`23.2 SCSI request blocks
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`23.3 ASPIinitialization and function calls
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`Test equipment
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`24.1 SCSI analyzers
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`24.2 SCSI emulators
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`24.3 Examples from industry
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`SCSI protocol chips
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`25,1 The NCR 5385
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`25.2 Target applications: EMULEX ESP200
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`25.3 PC host adapters: FUTURE DOMAIN TMC-950
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`Appendix A|
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`SCSI commands (by opcode)
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`Appendix B
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`SCSI commands(alphabetically)
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`Appendix C
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`SCSI sense codes
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`Appendix D The SCSI bulletin board
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`Appendix E
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`Source code for SCANSCSLPAS
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`Glossary
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`Index
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`Contents
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`ix
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`247
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`248
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`248
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`253
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`257
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`257
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`259
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`263
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`HUAWEI EX. 1006 - 10/312
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`

`

`Part I
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`Introduction
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`1 Computers and peripherals
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`2 Traditional peripheral interfaces
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`3 Computer buses
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`OLYMPUS EX. 1006 - 12/312
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`

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`1 Computers and peripherals
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`A computer can be broken down into a number of interdependent functional
`blocks. The most importantof these are the central processing unit (CPU), main
`memory,
`input/output (I/O) and mass storage. The CPU executes the
`instructions of a program, which, along with the necessary data, mustreside in
`main memory at execution time. Therefore, before a program can be run it must
`be loaded into main memory from mass storage. The data to be processed by the
`program comeseither from mass storage or from an input device such as the
`keyboard. The CPU accesses memory atleast once for each program step in order
`to read the corresponding machine instructions. In fact, several accesses are
`usually necessary to read and write data. For this reason the CPU and memory
`are very tightly coupled: access is uncomplicated and, aboveall, fast.
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`[3
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`Tape drive a
`convoller
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`Figure 1.1 Computer system with peripheral devices.
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`In contrast to memory, I/O devices and massstorage are located further
`from the CPU, hence the name‘peripherals’ (Figure 1.1). Access to such devices
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`3
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`4
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`SCS! Bus and IDE Interface
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`is slower and more complicated. Communication with the peripherals is
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`accomplished using an interface such as SCSI or IDE. On the other end of the
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`interface is a controller, which in turn communicates with the CPU and memory.
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`1.1 Mass storage
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`A mass storage device is capable of storing data many times the size of main
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`memory. In addition, information stored here is nonvolatile: when the device is
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`turned off the data remains intact.
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`Hard disks Disk drivesor hard disks store information by writing it onto rotating disks. The
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`information is divided up into blocks of fixed length, each of which can be
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`accessed relatively quickly, typically around 30 milliseconds (ms). For this
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`reason. hard disks are also referred to as random access mass storage devices.
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`Among the different types of mass storage devices are hard disks, exchangeable
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`medium. drives, diskettes, optical disks and CD-ROM.
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`In contrast to hard disks, tape devices (or tape drives) write data sequentially
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`onto magnetic tape. The length of time needed to access a specific block of
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`information depends on which position is presently underneath the read/write
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`head.If it is necessary to rewind or fast forward the tape a very long distance, a
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`tape access can take as long as several minutes. Tape drives ave also known as
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`sequential mass storage devices. Among these are the traditional reel-to-reel
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`drives, cassette drives, drives that use video cassettes for recording and 4mm
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`digital audio tape (DAT)drives.
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`W/O devices Under the heading I/O devices are the monitor and keyboard used for
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`communication between the user and the computer. Further examples of output
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`devices are printers, plotters and even speakers used for outputting speech.
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`Among the many input devices are mice, analog to digital converters, scanners
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`and microphones used in speech recognition.
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`Network connections also fall into this category. This is especially so
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`today where massstorage is often replaced by a file server across a network.
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`Computers with no mass storage of their own are called diskless workstations.
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`Miscellaneous
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`devices
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`There are many more devices that exchange data with computers, although one
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`hardly refers to a computer controlled lathe or a music synthesizer as a
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`computer peripheral. Nevertheless,
`they function as peripherals and
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`communicate with the computer using I/O.
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`OLYMPUS EX. 1006 - 14/312
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`

`
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`Computers and peripherals
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`5
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`1.2 Peripheral interfaces
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`Peripheral devices are connected fo computer systems via interfaces. The
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`the
`abstract model of a peripheral interface is made up of many layers,
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`boundaries of which are not alwaysclear, especially for older interfaces.It is also
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`true that some layers are omitted in certain interface definitions. In this book I
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`adhere to a model with four layers for the SCSI interface, as was agreed upon by
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`the American National Standards Institute (ANSI) committee for the first time
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`for SCSI-3. Thestrata of layers are designed bottom up. All low level layers are
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`mandatory for the implementation of an interface. An uppermost layer,
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`however, can be omitted in some cases. A high level interface refers to the case
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`whereall possible levels have been implemented.
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`Among those things defined in the lowest level are cable and connector
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`types. Also defined are the signal voltages and the current requirements of the
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`drivers. Finally, the timing and coordination of all of the signals of the bus are
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`described here. This lowest level is referred to as the physical interface.
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`Directly above the physical layer resides the protocol layer. The protocol
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`of an interface contains, for example, information about the difference between
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`data bytes and command bytes and about the exchange of messages between
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`devices. If corrupted data is to be corrected through the use of error correction,
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`this is described in the interface protocol.
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`On top of the protocol layer lies the peripheral device model. Here the
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`behavior of devices to be connected to the interface is described. These
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`descriptions can be very detailed and precise. The SCSI bus is an example of.
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`such a detailed model, where in addition to the characteristics of general
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`defined.
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`Finally, some interfaces go so far as to define which commands must be
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`understood by the interface devices. The command set builds upon the device
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`model and represents the fourth layer of the interface.
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`The term ‘interface’ always refers to all implemented layers in their
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`entirety. There are distinct peripheralinterfaces defined using the same physical
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`level but a unique protocollevel. It is also possible for a single interface to allow
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`for different options in the physicallevel.
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`The interface used for printers is a good example of a four-layer
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`interface. Figure 1.2 makes the relationships among the layers clear. The two
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`lower levels are covered by the Centronics interface. This parallel interface
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`contains the definition of the physical and protocol layers. The particular printer
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`model in Figure 1.2 is a page printer. This means that the printer constructs an
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`entire page in internal memory before printingit. In contrast to line printers, the
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`lines of a page can be sentin any order as long as a page boundary is not crossed.
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`However, once a page is printed it is impossibleto retrieve it in order to make
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`changes.
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`The page description language PostScript is an excellent example of a
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`large and complex commandset. It is built upon the page printer model and
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`makes it possible to output text as well as various graphic elements. These
`elements can be positioned freely on the current page. Naturally, there are other
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`OLYMPUS EX. 1006 - 15/312
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`HUAWEI EX. 1006 - 15/312
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`OLYMPUS EX. 1006 - 15/312
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`

`

`
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`6
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`SCSI Bus and IDE interface
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`Command set
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`PostScript
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`Device model
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`Printer
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`Protocol
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`Physical
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`votes Centronics...-.-.--
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`Figure 1.2 Layers of a printerinterface.
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`such page formatting languages written for the page printer model. This makes
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`the division between device and language very intuitive.
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`As you can see, this interface is complete in that it contains all four
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`interface layers. If you purchase a printer with such an interface, it makes no.
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`difference which brand name you choose. Aslong asit is true to the interface
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`specification it will work with any computer also equipped with the printer
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`interface. However, if you were to omit even only the uppermostlayer of the
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`specification, then the interface description would be incomplete. It would still
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`be possible to connect up. the printer, but whether it would function properly
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`would be a matter of luck.
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`The IDE interface and the SCSI bus are likewise complete interface
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`definitions. Before getting. to these, however, I would like to introduce in
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`Chapter 2 a few classic examples of peripheral interfaces. For the most part their
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`definitions contain only the lowerlayers of the interface model. This chapter will
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`help to underscore the difference between traditional interfaces on the one hand
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`and the complete IDE and SCSI interfaces on the other.
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`OLYMPUS EX. 1006 - 16/312
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`

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`2 Traditional peripheral
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`interfaces
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`This chapter will help to familiarize you with several classic peripheral inter-
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`faces of the computer industry. As with the printer interface outlined in Chapter
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`1, these will be described within the framework of the layered interface model.
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`These descriptions are by no means comprehensive; complete specifications
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`would turn this book into several volumes.
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`I have two goals in mind in presenting these interfaces. First of all, the
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`interfaces are very simple; they will allow you to become acquainted with inter-
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`face characteristics that are valid for all interfaces, including computer buses.
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`Secondly, to a certain degree these specifications are the forerunners of competi-
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`tion to the IDE and SCSI bus interfaces. A background in the moretraditional
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`interfaces will make it much easier to evaluate and understand their modern
`descendants, the main topic of this book.
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`2.1 The RS-232 serial interface
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`RS-232C is the most widely used serial interface. ‘Serial’ means that the data is
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`transferred one bit at a time across a single connection. RS-232C is used mainly
`for the connection of computer terminals and printers. Nonetheless,it is also
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`appropriate for the exchange of data between computers, Machine tools and
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`measurement instruments are frequently connected to computers using RS-
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`232C. Understandably, it is not a device specific interface. RS-232C is the respon-
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`sibility of the Electronic Industries Association (ETA).
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`The specification for RS-232C contains the physical layer and hardware
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`protocol. In addition, there are software protocols, of which only a few build on
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`top of the RS-232 hardware protocol. This leads to an uncommonsituation with
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`RS-232C andotherserial interfaces - not all applications use all of the signals.
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`Frequently cables are used that conduct only a few of the defined signals,a sit-
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`uation thatwould be unthinkable for IDE or SCSI. I concentrate here on a varia-
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`tion of the interface using only three signals, which I call mini-RS-232,
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`

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`8
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`SCS/ Bus and IDE Interface
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`The physical Mini-R5-232 establishes a bidirectional point-to-point connection between
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`interface equipment. Each direction has its own data signal andasingle groundsignalis
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`shared. The data signals are called TD (transmit data) and RD (receive data).
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`Whentwodevices are coupled to each other, these signals are crossed suchthat
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`the TD of one device connects to the RD of the other (Figure 2.1).
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`Start bit
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`8 Data bits
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`on
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`Receive data
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`Receive data
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`Figure 2.1. Physical interface: mini-RS-232.
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`The connector chosen by the EIA standardis the 25-pin DB25, Other con-
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`nectors, however, are frequently employed, such as the DB9 for the IBM AT or
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`the RJ11 telephone connector used in various minicomputers.
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`Onthe signallines, a logical 1 is represented by a voltage between +5 V
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`and +15 V, and the receiver recognizes anything above +3 V as such. Likewise,
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`logical 0 is represented by a signal voltage between —-5 V and —15 V. Again, the
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`receiver recognizes any signal below —3 V as such.
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`Data transfer takes place serially, character by character. The characters
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`are further broken downintobits, which are sent acrossthe line one by one. On
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`the other end, the receiver then assembles the bits back into characters. The
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`numberof bits per character lies between five and eight; eightis precisely what
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`is needed to transfer one byte. The data bits are preceded bya start bit and fol-
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`lowed bya stop bit. In addition, a parity bit may be sentfor error detection. The
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`transfer rate: can range between 75 and 115 000 bits per second (baud), and a
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`cable alone cannot compensate for different transfer rates; the devices must be
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`set at the same speed otherwise no exchange of data can take place.
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`Now comesa rather confusing point: this method of transfer over the
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`serial interface is called asynchronous even thoughthe data is sent and received
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`relative to a clock. Among otherserial interfaces the term ‘synchronous’is used
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`whenevera clock is involved. For RS-232C, however, the transfer is referred to
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`as asynchronous becausethe clocks are nottied to each other. The RS-232C spec-
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`ification includessignals that allow the sender and the receiver to use the same
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`clock for data transfer. When these signals are employed the data transfer is
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`OLYMPUS EX. 1006 - 18/312
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`HUAWEI EX. 1006 - 18/312
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`OLYMPUS EX. 1006 - 18/312
`
`

`

`Traditional peripheralinterfaces
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`9
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`referred to as synchronous. True asynchronous transfer uses control signals to
`exchange data. This point, among others, will be madeclear in Section 2.2.
`As a rule of thumb, when thinking about data throughput you can con-
`sider a byte or character to be 10 bits (one stop, one start and eightdata bits).
`Whenthefastest transfer rate possible is employed, namely 115 000 bits per sec-
`ond, the maximum throughput is approximately 11.5 Kbytes per second.
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`The protocol Mini-RS-232 has no protocol of its own. However, there is a protocolthat is often
`used with the interface, called the XON/XOFFprotocol (Figure 2.2). It works in
`the following way. When the receiving device is no longer able to take on data
`from the sender, it sends a special character, an XOFF byte,to indicate this, Later,
`whenit is ready to continue receiving data, it sends an XONbytetotell the
`sender to proceed. This protocolis in no wayerror proof — characters are some-
`times lost. In addition, the protocol cannot be used for bidirectional transfer of
`binary data. The reasonfor this restriction is simple: for text data only a subset
`of the possible bytes is sent over the interface, those corresponding to letters,
`numbers, and symbols. This leaves room for a numberof special characters, of
`which XON and XOFF are examples. When, on the other hand, binary data is
`transferred, the data is not restricted to certain characters; any binary pattern
`may occur. In this situation there is no room for the special characters and the
`XON/XOFFprotocol is unusable. For connecting monitors and printers, how-
`ever, the protocolis actually very practical,
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`po
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`ffisf[rstfal|
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`melsit{tf|
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`XON
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`Printer
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`XOFF
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`Figure 2.2 XON/XOFFprotocol.
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`An example of a higher level protocol for the transfer of binary data(file
`transfer) is Kermit. This public domain program can be used at no cost for non-
`commercial purposes. A number of computer manufacturers have also devel-
`oped their own internal protocols built on top of RS-232.
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`Commands
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`There are no commands special to the RS-232 interface. As RS-232 was devel-
`oped, commands were designed for specific devices apart from the interface.
`SCSI is amongthe first interfaces to define universal commandsets for whole
`device classes.
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`Nevertheless, some commandsets have been designed for use with RS-
`232. Examples are page formatting languages for printers, such as PostScript.
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`OLYMPUS EX.1006 - 19/312
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`OLYMPUS EX. 1006 - 19/312
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`

`

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`10
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`SCS! Bus and IDE Interface
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`Summary As you can see, an interface that builds on top of RS-232 has many possible vari-
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`ations. The complete description of.my printer-PC interface would be: RS-232 at
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`9600 baud, 1 stop bit, no parity, XON/XOFF protocol, PostScript. If I were to
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`change a parameterfor only the printer or only the PC, for example by not send-
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`ing PostScript or starting to use a parity bit, nothing would print. Although
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`mini-RS-232 appears to be simple (only three wires), there are almost an
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`uncountable number of ways in which the connection can fail. What is missing
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`is a protocol that allows the devices to agree upon the available options.
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`Although RS-232 has given a good portion of frustration to just about everyone
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`who has worked withit, it nonetheless has the decided advantage that it exists
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`on ever