XT-4000S Product Specification and OEM Technical Manual Document 1014995 Revision B July 1989 REVISION RECORD Revision Date Published Revised Contents 01 April 1988 Preliminary Release (originally released as revision A) 02 May 1988 Preliminary Release 03 July 1988 Preliminary Release A-1 August 1988 Formal Release A-1 (Adden 1) February 1989 Formal Release A-1 (Adden 2) April 1989 Formal Release B July 1989 Formal Release B (Adden 1) January 1990 Formal Release Document No: 1014995 WARRANTY Maxtor warrants the XT-4000S Family of disk drives against defects in materials and workmanship for a period of twelve months, for the original purchaser. Direct any questions regarding the warranty to your Maxtor Sales Representative. Maxtor maintains Customer Service Centers for the repair/reconditioning of all Maxtor products. Direct all requests for repair to the Maxtor Service Center in San Jose. This assures you of the fastest possible service. REGULATORY APPROVALS UL Recognition obtained: File Number E87276(s) CSA Certification obtained: File Number LR54048-6 VDE Recognition obtained: File Number 41296G Address comments concerning this manual to: Maxtor Corporation Technical Publications 211 River Oaks Parkway San Jose, California 95134-1913 Telephone: (408) 432-1700 Telex: 171074 FAX: (408) 434-6469 Technical Data Restrictions In case of sale to or use of units by DoD, use, duplication or disclosure of any software, firmware or related documentation is subject to restrictions stated in paragraph (c) (1) (ii) of the Rights in Technical Data and Computer Software clause at DFAR 252.227-7013. For Civilian Agencies: Use, reproduction, or disclosure of the software and related documentation is subject to restrictions set forth in FAR 52.227-19. Unpublished rights reserved under the copyright laws of the United States. Maxtor Corporation, 211 River Oaks Parkway, San Jose, CA 95134. Copyright Notice This manual and all material contained in it are copyrighted. The manual may not be copied, in whole or in part, without the written consent of Maxtor Corporation. The contents of thismanual may be revised without prior notice. © Copyright 1988 by Maxtor Corporation, San Jose, California, USA. All rights reserved PREFACE Maxtor reserves the right to make changes and/or improvements to its products without incurring any obligation to incorporate such changes or improvements in units previously sold or shipped. Maxtor publishes descriptive Brochures and Data Sheets, an OEM Manual, and a Quick Reference Guide for each product line. In addition, important changes to a product are conveyed in the form of a Technical Bulletin sent to all product customers of record. Changes that affect the content of any manual recovered by publishing addenda or revisions to the affected manual. XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS PREFACE.....................................................V 1.0..............................................INTRODUCTION 1 1.1.....................................General Description 1 1.2......................................Key Drive Features 2 1.3.................................Key Controller Features 3 1.4......................Summary of Supported SCSI Commands 5 2.0.....................................SPECIFICATION SUMMARY 7 2.1..............................Performance Specifications 7 2.2...............................Functional Specifications 8 2.3............................Environmental Specifications 9 2.4.................................Physical Specifications 9 2.5..............................Reliability Specifications 10 2.6.......................Error Rates at the SCSI Interface 10 2.7...................................DC Power Requirements 11 2.8...............................Standards and Regulations 11 3.0................................FUNCTIONAL CHARACTERISTICS 13 3.1.............................General Theory of Operation 13 3.2......Read/Write Control and SCSI Controller Electronics 13 3.3.........................................Drive Mechanism 14 Doc 1014995, Rev B ix Maxtor Corporation Doc 1014995, Rev B ix Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 3.4...................................Air Filtration System 14 3.5..............................Head Positioning Mechanism 15 3.6..............................Read/Write Heads and Disks 16 3.7.................................Track and Sector Format 17 3.8..........................................SCSI Interface 17 3.8.1....................Initiator-Target Configurations 17 3.8.2..............Logical/Electrical Signal Definitions 19 3.8.3......................Pin Assignments and Connector 20 3.9..............................Electrical Power Interface 23 3.9.1..................................Power-Up Sequence 23 3.9.2....................................Power Connector 24 3.9.3...................................Ground Connector 25 3.10..............................Mounting and Installation 25 3.11...............................................Shipping 28 4.0...................................USER SELECTABLE OPTIONS 29 4.1.......................................SCSI ID Selection 32 4.2..................................Drive Power Up Options 32 4.3..............................Terminator Power Selection 33 4.4....................................Write Protect Option 34 4.5...........................................Parity Option 34 4.6...........................................Other Jumpers 34 4.7.............................................Sector Size 35 4.8...................................Interface Termination 35 4.9.....................................Auxiliary Connector 36 Doc 1014995, Rev B x Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 5.0...................................LOGICAL CHARACTERISTICS 39 5.1..................................Power Up and BUS RESET 39 5.1.1.................................Self-Test Sequence 39 5.1.2............................Initialization Sequence 40 5.1.3.................................Self Configuration 41 5.1.4...........................UNIT ATTENTION Condition 41 5.2........................................Buffering Scheme 41 6.0..................................SCSI PHASES AND MESSAGES 43 6.1..........................................BUS FREE Phase 44 6.2.......................................ARBITRATION Phase 45 6.3.........................................SELECTION Phase 45 6.4.......................................RESELECTION Phase 46 6.5.............................Information Transfer Phases 47 6.5.1..................Asynchronous Information Transfer 48 6.5.2..........................Synchronous Data Transfer 48 6.5.3......................................COMMAND Phase 49 6.5.4........................DATA IN and DATA OUT Phases 50 6.5.5.......................................STATUS Phase 50 6.5.6......................................MESSAGE Phase 52 6.6...........................................SCSI Messages 52 6.6.1...................................MESSAGE IN Phase 52 6.6.2..................................MESSAGE OUT Phase 53 6.6.3.............................COMMAND COMPLETE (00h) 53 6.6.4............................SAVE DATA POINTER (02h) 54 Doc 1014995, Rev B xi Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 6.6.5.............................RESTORE POINTERS (03h) 54 6.6.6...................................DISCONNECT (04h) 54 6.6.7.....................INITIATOR DETECTED ERROR (05h) 54 6.6.8........................................ABORT (06h) 55 6.6.9...............................MESSAGE REJECT (07h) 55 6.6.10................................NO OPERATION (08h) 55 6.6.11........................MESSAGE PARITY ERROR (09h) 55 6.6.12.....................LINKED COMMAND COMPLETE (0Ah) 56 6.6.13.........LINKED COMMAND COMPLETE (WITH FLAG) (0Bh) 56 6.6.14............................BUS DEVICE RESET (0Ch) 56 6.6.15................................IDENTIFY (C0h/80h) 56 6.6.16...SYNCHRONOUS DATA TRANSFER REQUEST Message (01h) 57 6.7........................................Error Conditions 59 6.7.1.....................MESSAGE OUT Phase Parity Error 59 6.7.2.........................COMMAND Phase Parity Error 60 6.7.3........................DATA OUT Phase Parity Error 60 6.7.4...........................Initiator Detected Error 60 6.7.5...................................REJECTED Message 61 6.7.6.....................Initiator MESSAGE PARITY ERROR 62 6.7.7...............................RESELECTION Time-Out 62 6.7.8.........................Internal Controller Errors 62 7.0.................................SCSI COMMAND DESCRIPTIONS 61 7.1...................................SCSI Command Overview 61 7.2.............................................FORMAT UNIT 66 Doc 1014995, Rev B xii Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.2.1.............................Defect List Management 67 7.2.2....................................SCSI Deviations 68 7.2.3.................................Command Parameters 68 7.2.4.......................................Format Modes 70 7.2.5..............................Initiator Defect List 75 A..................................D List Block Format 76 B.......................D List Bytes from Index Format 77 C........................D List Physical Sector Format 78 7.2.6...................................Error Conditions 80 7.3.................................................INQUIRY 82 7.3.1....................................SCSI Deviations 82 7.3.2.................................Command Parameters 82 7.3.3........................................Data Format 83 7.4.............................................MODE SELECT 87 7.4.1....................................SCSI Deviations 88 7.4.2.................................Command Parameters 88 7.4.3..............................Parameter List Format 89 A.........................Parameter List Header Format 89 B...............Parameter List Block Descriptor Format 90 C...................................Page Header Format 91 7.4.4.....................Error Recovery Parameters Page 92 7.4.5..........................Disconnect-Reconnect Page 99 7.4.6.................................Format Device Page 100 7.4.7..........Rigid Disk Drive Geometry Parameters Page 103 7.4.8.......................................Caching Page 105 Doc 1014995, Rev B xiii Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.4.9..........................Maxtor Drive Control Page 107 7.4.10...........................Read-Ahead Control Page 109 7.4.11..................................Error Conditions 110 7.5..............................................MODE SENSE 112 7.5.1....................................SCSI Deviations 113 7.5.2.................................Command Parameters 113 7.5.3..............................Parameter List Format 115 A.........................Parameter List Header Format 116 B...............Parameter List Block Descriptor Format 117 C...................................Page Header Format 118 7.5.4.....................Error Recovery Parameters Page 118 7.5.5...............Disconnect/Reconnect Parameters Page 121 7.5.6........Direct-Access Device Format Parameters Page 123 7.5.7..........Rigid Disk Drive Geometry Parameters Page 126 7.5.8.......................................Caching Page 128 7.5.9..........................Maxtor Drive Control Page 130 7.5.10................Read-Ahead Control Parameters Page 132 7.5.11..................................Error Conditions 133 7.6....................................................READ 134 7.6.1....................................SCSI Deviations 134 7.6.2.................................Command Parameters 134 7.6.3...................................Error Conditions 135 7.7.........................................READ (EXTENDED) 136 7.7.1....................................SCSI Deviations 136 7.7.2.................................Command Parameters 136 Doc 1014995, Rev B xiv Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.7.3...................................Error Conditions 137 7.8.............................................READ BUFFER 138 7.8.1....................................SCSI Deviations 138 7.8.2.................................Command Parameters 138 7.8.3......................................Command Usage 139 7.8.4........................................Data Format 139 7.8.5...................................Error Conditions 140 7.9...........................................READ CAPACITY 141 7.9.1....................................SCSI Deviations 141 7.9.2.................................Command Parameters 141 7.9.3........................................Data Format 142 7.9.4...................................Error Conditions 143 7.10.......................................READ DEFECT LIST 144 7.10.1...................................SCSI Deviations 144 7.10.2................................Command Parameters 144 7.10.3............................................Header 146 7.10.4......................................Block Format 147 7.10.5...........................Bytes from Index Format 148 7.10.6............................Physical Sector Format 149 7.10.7..................................Error Conditions 150 7.11..............................................READ LONG 151 7.11.1...................................SCSI Deviations 151 7.11.2................................Command Parameters 151 7.11.3..................................Error Conditions 152 7.12.....................................READ LONG (SCSI-2) 153 Doc 1014995, Rev B xv Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.13.........................READ MANUFACTURERS DEFECT LIST 155 7.13.1...................................SCSI Deviations 155 7.13.2................................Command Parameters 155 7.13.3.......................................Data Format 156 7.14.........................................REASSIGN BLOCK 158 7.14.1...................................SCSI Deviations 158 7.14.2................................Command Parameters 158 7.14.3................................Defect List Format 159 7.14.4..................................Error Conditions 160 7.15.............................RECEIVE DIAGNOSTIC RESULTS 161 7.15.1...................................SCSI Deviations 161 7.15.2................................Command Parameters 161 7.15.3.......................................Data Format 162 7.15.4..................................Error Conditions 162 7.16...........................................RELEASE UNIT 163 7.16.1...................................SCSI Deviations 163 7.16.2................................Command Parameters 163 7.16.3..................................Error Conditions 164 7.17..........................................REQUEST SENSE 165 7.17.1...................................SCSI Deviations 165 7.17.2................................Command Parameters 165 7.17.3.......................................Data Format 166 A........................Nonextended Sense Data Format 167 B...........................Extended Sense Data Format 167 C..........................................Sense Codes 173 Doc 1014995, Rev B xvi Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.17.4..................................Error Conditions 177 7.18...........................................RESERVE UNIT 178 7.18.1...................................SCSI Deviations 178 7.18.2................................Command Parameters 178 7.18.3..................................Error Conditions 179 7.19............................................REZERO UNIT 180 7.19.1...................................SCSI Deviations 180 7.19.2................................Command Parameters 180 7.20...................................................SEEK 181 7.20.1...................................SCSI Deviations 181 7.20.2................................Command Parameters 181 7.20.3..................................Error Conditions 182 7.21........................................SEEK (EXTENDED) 183 7.21.1...................................SCSI Deviations 183 7.21.2................................Command Parameters 183 7.21.3..................................Error Conditions 184 7.22........................................SEND DIAGNOSTIC 185 7.22.1...................................SCSI Deviations 185 7.22.2................................Command Parameters 185 7.22.3..................................Error Conditions 187 7.22.4.......................................Subcommands 188 A..........................GET DRIVE STATUS Subcommand 188 B........................PASS DRIVE COMMAND Subcommand 190 C...............................READ HEADER Subcommand 193 7.23........................................START/STOP UNIT 196 Doc 1014995, Rev B xvii Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.23.1...................................SCSI Deviations 196 7.23.2................................Command Parameters 196 7.23.3..................................Error Conditions 197 7.24........................................TEST UNIT READY 198 7.24.1...................................SCSI Deviations 198 7.24.2................................Command Parameters 198 7.24.3..................................Error Conditions 198 7.25.................................................VERIFY 199 7.25.1...................................SCSI Deviations 199 7.25.2................................Command Parameters 199 7.25.3..................................Error Conditions 200 7.26..................................................WRITE 201 7.26.1...................................SCSI Deviations 201 7.26.2................................Command Parameters 201 7.26.3..................................Error Conditions 202 7.27.......................................WRITE (EXTENDED) 203 7.27.1...................................SCSI Deviations 203 7.27.2................................Command Parameters 203 7.27.3..................................Error Conditions 204 7.28.......................................WRITE AND VERIFY 205 7.28.1...................................SCSI Deviations 205 7.28.2................................Command Parameters 205 7.29...........................................WRITE BUFFER 207 7.29.1...................................SCSI Deviations 207 7.29.2................................Command Parameters 207 Doc 1014995, Rev B xviii Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual TABLE OF CONTENTS 7.29.3.......................................Data Format 208 7.29.4..................................Error Conditions 209 7.30.............................................WRITE LONG 210 7.30.1...................................SCSI Deviations 210 7.30.2................................Command Parameters 210 7.30.3..................................Error Conditions 211 7.31....................................WRITE LONG (SCSI-2) 212 APPENDIX A: DISCONNECT/RECONNECT CONDITIONS..............215 APPENDIX B: DEFECT MANAGEMENT............................217 Reassignment Sequences..................................218 Cylinder-Oriented Reassignment Sequence..............218 Track-Oriented Reassignment Sequence.................220 Drive-Oriented Reassignment Sequence.................220 Host Defect Management Sequence......................221 Defect Management Assumptions and Statistics............221 APPENDIX C: CDB BIT DEFINITIONS..........................225 APPENDIX D: UNITS OF MEASURE.............................227 APPENDIX E: BUFFER RATIO APPLICATIONS....................229 What are the Buffer Ratios?.............................229 What are the Performance Benefits from Buffer Ratios?...229 Buffer Full Ratio.......................................229 Buffer Empty Ratio......................................231 What value should be used for the Buffer Ratios?........231 APPENDIX F: THE READ-AHEAD FEATURE.......................233 What is Read-Ahead?.....................................233 How Does it Work?.......................................233 Key Read-Ahead Parameters...............................235 Controlling the Read-Ahead Feature......................236 Read Algorithm..........................................236 Read-Ahead Performance..................................237 GLOSSARY..................................................239 Doc 1014995, Rev B xix Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual FIGURES XT-4000S Product Specification & OEM Technical Manual FIGURES Figure 3o1..............................Air Filtration System 15 Figure 3o2.........................Head Positioning Mechanism 16 Figure 3o3.......................................Track Format 17 Figure 3o4........................Typical SCSI Configurations 18 Figure 3o5............Connector Locations, Rear View of Drive 22 Figure 3o6...............................SCSI Cable Connector 23 Figure 3o7...................Motor Start Current Requirements 24 Figure 3o8.......................................J3 Connector 25 Figure 3o9.............Mechanical Outline, Top and Side Views 26 Figure 3o10................Mechanical Outline, Isometric View 27 Figure 3o11...............................Removable Faceplate 28 Figure 4o1.........................................PCB Layout 29 Figure 4o2..................................Fab #3 PCB Layout 30 Figure 4o2A.................................Fab #6 PCB Layout 31 Figure 6o1..............Signal Sequence Chart for SCSI Phases 44 Figure 7o1...............Flow Chart of Automatic Reallocation 95 Figure Eo1.......Data Transfer Rate Without Buffer Full Ratio 230 Figure Eo2..........Data Transfer Rate With Buffer Full Ratio 231 Figure Fo1................Sequential Reads without Read-Ahead 234 XT-4000S Product Specification & OEM Technical Manual TABLES XT-4000S Product Specification & OEM Technical Manual TABLES Table 2o1..........................Performance Specifications 7 Table 2o2...........................Functional Specifications 8 Table 2o3................................Environmental Limits 9 Table 2o4.................................Physical Dimensions 9 Table 2o5..........................Reliability Specifications 10 Table 2o6.........................................Error Rates 10 Table 2o7...............................DC Power Requirements 11 Table 3o1...........................Connector Pin Assignments 21 Table 4o1.....................................SCSI ID Jumpers 32 Table 4o2.........................Summary of Power-Up Options 33 Table 4o3................Other Jumper Pin Assignments, Fab #1 34 Table 4o4................Other Jumper Pin Assignments, Fab #3 35 Table 4o5.................Auxiliary Connector Pin Assignments 36 Table 4o6.............Remote SCSI ID Programming Combinations 37 Table 6o1........................Signal States and Bus Phases 43 Table 6o2.....................................SCSI Bus Timing 47 Table 6o3.........................................Status Byte 50 Table 6o4........................................Status Codes 51 Table 6o5.......................................Message Codes 52 Table 6o6..............................IDENTIFY Message Codes 57 Table 6o7.......SYNCHRONOUS DATA TRANSFER REQUEST Byte Values 58 Table 6o8....Drive Responses to the SYNCHRONOUS DATA TRANSFER REQUEST Message............................................58 Table 7o1.....................Typical CDB for 6-Byte Commands 61 XT-4000S Product Specification & OEM Technical Manual TABLES Table 7o2....................Typical CDB for 10-Byte Commands62 Table 7o3...........................CDB Operation Code Format 63 Table 7o4.................................CDB Operation Codes 63 Table 7o5........................................Control Byte 64 Table 7o6.....................................FORMAT UNIT CDB 69 Table 7o7......................FORMAT UNIT Defect List Header 71 Table 7o8...................Initialization Pattern Descriptor 72 Table 7o9.....................Initialization Pattern Modifier 73 Table 7o10........................Initialization Pattern Type 73 Table 7o11.....................FORMAT UNIT Drive Format Modes 75 Table 7o12.........................FORMAT UNIT D List Formats 76 Table 7o13.....FORMAT UNIT Defect Descriptor(s), Block Format 77 Table 7o14.FORMAT UNIT Defect Descriptor(s), Bytes from Index Format 78 Table 7o15..FORMAT UNIT Defect Descriptor(s), Physical Sector Format 79 Table 7o16........................................INQUIRY CDB 82 Table 7o17..............................INQUIRY Response Data 84 Table 7o18................................MODE SELECT Command 88 Table 7o19..................MODE SELECT Parameter List Header 90 Table 7o20.MODE SELECT Parameter List Block Descriptor Format 91 Table 7o21.............................MODE SELECT Page Codes 92 Table 7o22..................Error Recovery Page (Page Code 1) 93 Table 7o23...................MODE SELECT Error Recovery Modes 98 Table 7o24..........................Disconnect-Reconnect Page 99 Table 7o25.................................Format Device Page 101 Table 7o26...MODE SELECT Rigid Disk Drive Geometry Parameters (Page Code 4).............................................104 XT-4000S Product Specification & OEM Technical Manual TABLES Table 7o27.......................................Caching Page 106 Table 7o28..........................Maxtor Drive Control Page 107 Table 7o29............Read-Ahead Control Page (Page Code 38h) 109 Table 7o30.................................MODE SENSE Command 113 Table 7o31.....................MODE SENSE Page Control Fields 114 Table 7o32..............................MODE SENSE Page Codes 115 Table 7o33...................MODE SENSE Parameter List Header 116 Table 7o34..MODE SENSE Parameter List Block Descriptor Format 117 Table 7o35..................MODE SENSE Page Header Page Codes 118 Table 7o36.MODE SENSE Error Recovery Parameters (Page Code 1) 119 Table 7o37.MODE SENSE Disconnect/Reconnect Control Parameters (Page Code 2).............................................122 Table 7o38..MODE SENSE Direct-Access Device Format Parameters (Page Code 3).............................................124 Table 7o39....MODE SENSE Rigid Disk Drive Geometry Parameters (Page Code 4).............................................127 Table 7o40.................MODE SENSE Default Number of Heads 128 Table 7o41.......................................Caching Page 129 Table 7o42..........................Maxtor Drive Control Page 130 Table 7o43......Read-Ahead Control Parameters (Page Code 38h) 132 Table 7o44...........................................READ CDB 134 Table 7o45................................READ (EXTENDED) CDB 136 Table 7o46....................................READ BUFFER CDB 138 Table 7o47.................................READ BUFFER Header 140 Table 7o48..................................READ CAPACITY CDB 142 Table 7o49..........................READ CAPACITY Data Format 143 Table 7o50...............................READ DEFECT LIST CDB 144 Table 7o51...............READ DEFECT LIST Defect List Formats 146 XT-4000S Product Specification & OEM Technical Manual TABLES Table 7o52............................READ DEFECT LIST Header 147 Table 7o53READ DEFECT LIST Defect Descriptor(s), Block Format 148 Table 7o54..READ DEFECT LIST Defect Descriptor(s), Bytes from Index Format..............................................149 Table 7o55....READ DEFECT LIST Defect Descriptor(s), Physical Sector Format.............................................150 Table 7o56......................................READ LONG CDB 152 Table 7o57..................................READ LONG Command 153 Table 7o58.................READ MANUFACTURERS DEFECT LIST CDB 156 Table 7o59..READ MANUFACTURERS DEFECT LIST Defect Descriptors Returned Format...........................................157 Table 7o60.................................REASSIGN BLOCK CDB 159 Table 7o61..................REASSIGN BLOCK Defect List Header 159 Table 7o62................REASSIGN BLOCK Defect Descriptor(s) 160 Table 7o63.....................RECEIVE DIAGNOSTIC RESULTS CDB 161 Table 7o64...................................RELEASE UNIT CDB 163 Table 7o65..................................REQUEST SENSE CDB 166 Table 7o66........REQUEST SENSE Nonextended Sense Data Format 167 Table 7o67.........................Extended Sense Data Format 168 Table 7o68................................Field Pointer Bytes 170 Table 7o69...........................Actual Retry Count Bytes 170 Table 7o70...................Format Progress Indication Bytes 171 Table 7o71.............REQUEST SENSE Extended Sense Key Codes 172 Table 7o72.............................Additional Sense Codes 174 Table 7o73...................................RESERVE UNIT CDB 179 Table 7o74....................................REZERO UNIT CDB 180 Table 7o75...........................................SEEK CDB 181Table 7o76................................SEEK (EXTENDED) CDB 184 XT-4000S Product Specification & OEM Technical Manual TABLES Table 7o77................................SEND DIAGNOSTIC CDB 186 Table 7o78............SEND DIAGNOSTIC Drive Self-Test Options 187 Table 7o79.........GET DRIVE STATUS Subcommand Parameter List 188 Table 7o80.......................GET DRIVE STATUS Data Format 189 Table 7o81.............GET DRIVE STATUS Command Status Values 190 Table 7o82.......PASS DRIVE COMMAND Subcommand Parameter List 191 Table 7o83..............PASS DRIVE COMMAND Status Data Format 192 Table 7o84...........PASS DRIVE COMMAND Command Status Values 192 Table 7o85...PASS DRIVE COMMAND Standard Status Response Bits 193 Table 7o86..............READ HEADER Subcommand Parameter List 194 Table 7o87............................READ HEADER Data Format 194 Table 7o88................TRANSLATE Subcommand parameter List 195 Table 7o89..............................TRANSLATE Data Format 195 Table 7o90................................START/STOP UNIT CDB 196 Table 7o91................................TEST UNIT READY CDB 198 Table 7o92.........................................VERIFY CDB 199 Table 7o93..........................................WRITE CDB 201 Table 7o94...............................WRITE (EXTENDED) CDB 203 Table 7o95...............................WRITE AND VERIFY CDB 205 Table 7o96...................................WRITE BUFFER CDB 208 Table 7o97......................Combined Header and Data Mode 209 Table 7o98.....................................WRITE LONG CDB 211 Table 7o99.................................WRITE LONG Command 212Table Bo1........................Defect Management Selections 218 Table Bo2.....................Spares Versus Capacity, XT-4380 222 XT-4000S Product Specification & OEM Technical Manual TABLES Table Bo3.....................Spares Versus Capacity, XT-4170 223 Table Eo1.................................Buffer Ratio Values 232 Table Fo1......................................READ Algorithm 236 XT-4000S Product Specification & OEM Technical Manual TABLES XT-4000S Product Specification & OEM Technical Manual 1.0 INTRODUCTION 1.1 GENERAL DESCRIPTION The XT-4000S| Family disk drives are low cost, high capacity, high performance, random access storage devices which use nonremovable 5.25 inch disks as storage media. Each disk surface employs one moveable head to access the data tracks. The total unformatted capacity of these drives ranges from 179 to 384 megabytes. The drives include the Small Computer System Interface (SCSI) controller embedded in the drive electronics. Some of the resulting benefits of having an integrated controller include the elimination of a separate controller printed circuit board (PCB), reduction in the number of associated cables, and elimination of the controller-specific power supply. Low cost and high performance are achieved through the use of a rotary voice coil actuator and a closed loop servo system using a dedicated servo surface. The innovative MAXTORQ| rotary voice coil actuator provides performance usually achieved only with larger, higher powered linear actuators. The closed loop servo system and dedicated servo surface combine to allow state of the art recording densities (1,070 tracks per inch, 21,064 bits per inch) in a 5.25 inch package. High capacity is achieved by a balanced combination of high areal recording density, run-length limited (RLL) data encoding techniques, and high density packaging techniques. Maxtor's advanced MAXPAK| electronic packaging techniques use miniature surface-mounted devices to allow all electronic circuitry to fit on one PCB. Advanced flexures and heads allow closer spacing of disks, and therefore allow a higher number of disks in a 5.25 inch package. Maxtor's unique integrated drive motor/spindle design allows a deeper head disk assembly (HDA) casting than conventional designs, thus permitting eight disks to be used. The drive's electrical interface is compatible with the ANSI SCSI standard X3.131-1986, plus the Common Command Set (CCS) requirements. Size and mounting conform to the industry standard 5.25 inch form factor for floppy and Winchester disk drives, and the same direct current (DC) voltages and connectors are used. XT-4000S Product Specification & OEM Technical Manual 1.2 KEY DRIVE FEATURES FEATURE BENEFITS o Storage capacity of 179 Ideal for multiuser to 384 megabytes systems and graphics (unformatted) workstations o Single PCB High reliability, ease of maintenance o Rotary voice coil Fast, accurate head actuator and closed loop positioning servo system o Separate microprocessor- Fast access times, high controlled servo reliability, and high density packaging o Thin film metallic media Higher bit density and resolution, plus improved durability o Automatic actuator lock, High reliability, data with dedicated head protected from mechanical landing and shipping shock zone o Brushless DC spindle Maximum storage capacity motor inside hub o Separate microprocessor- Precise speed control controlled spindle motor under all load conditions o Dynamic braking during Minimum head/disk contact power down cycle time during spindown cycle o Industry standard DC Ease of integration power supply requirements (no alternating current (AC) power required) o Industry standard Ease of integration physical size and mounting XT-4000S Product Specification & OEM Manual 1.3 KEY CONTROLLER FEATURES FEATURE BENEFITS o Sophisticated, hardware- Minimum time on SCSI bus; based control of SCSI Maximum bus use protocol o Up to 4.8 megabytes per Maximum SCSI bus use second data transfer rate, in either asynchronous or synchronous mode o Synchronous offsets up Provides for high to 15 bytes performance on long cables o High performance buffer Simultaneous data manager transfers from disk to buffer and buffer to initiator o In-line sector sparing Maintains high performance over life of drive, even after numerous reassignments o Cylinder-oriented defect Maximizes formatted management capacity available to system o Programmable cylinder No slipped revolutions skewing when crossing cylinder boundaries o 45 kilobytes dual ported Maintains maximum SCSI bus first-in, first-out transfer rate buffer; two full tracks capacity o Hardware head switching No head skewing required to prevent slipped revolutions due to software overhead o Programmable Flexibility; more alternates/zones available capacity o Dedicated microprocessor SCSI bus unaffected by for SCSI drive interface functions, such as SEEK XT-4000S Product Specification & OEM Manual o Error map on disk Automatic defect deallocation during format; no manual entry FEATURE BENEFITS o ANSI SCSI Standard Compatibility; ease of X3.131-1986 Level 2 integration conformance o Full implementation of Availability of options CCS revision 4B and industry compatibility o Programmable 48 bit High data integrity error correction code (ECC). o Programmable automatic Flexibility and high data retry on READ errors integrity o Interleave of 1:1 Maximum data throughput supported o Full Optimum SCSI bus disconnect/reconnect performance capability o Sector sizes User flexibility; system programmable from 180 to compatibility 4,096 bytes o SCSI implementation Ease of integration and compatible with all upgrade Maxtor Winchester and optical drives XT-4000S Product Specification & OEM Manual XT-4000S Product Specification & OEM Manual 1.4 SUMMARY OF SUPPORTED SCSI COMMANDS The commands supported by the drive are listed and discussed in Section 7.0, SCSI Command Descriptions. For more information on Group 0 and Group 1 commands for direct-access devices, see the reference documents below: o ANSI X3.131-1986, SCSI, American National Standards Institute, Inc., June 23, 1986. o X3T9.2/85-52 Rev 4.B CCS, June 23, 1986, a document of the American Standards Committee. XT-4000S Product Specification & OEM Manual XT-4000S Product Specification & OEM Technical Manual XT-4000S Product Specification & OEM Technical Manual XT-4000S Product Specification & OEM Technical Manual 2.0 SPECIFICATION SUMMARY 2.1 PERFORMANCE SPECIFICATIONS Table 2o1 Performance Specifications 2.2 FUNCTIONAL SPECIFICATIONS Table 2o2 Functional Specifications 2.3 ENVIRONMENTAL SPECIFICATIONS Table 2o3 Environmental Limits 2.4 PHYSICAL SPECIFICATIONS Table 2o4 Physical Dimensions 2.5 RELIABILITY SPECIFICATIONS Table 2o5 Reliability Specifications XT-4000S Product Specification & OEM Technical Manual 2.6 ERROR RATES AT THE SCSI INTERFACE Table 2o6 Error Rates 2.7 DC POWER REQUIREMENTS Table 2o7 DC Power Requirements 2.8 STANDARDS AND REGULATIONS The Maxtor XT-4000S Family disk drives satisfy the following standards and regulations: UNDERWRITERS LABORATORIES (UL) = United States safety; UL 478, Standard for Safety, Electronic Processing Units and Systems. CANADIAN STANDARDS ASSOCIATION (CSA) = Canadian safety; CSA C22.2 No. 220, 1986, Information Processing and Business Equipment (Consumer and Commercial Products). VERBAND DEUTSCHER ELECTROTECHNIKER (VDE) = German safety; VDE 0806/8.81, Safety of Office Appliances and Business Equipment. INTERNATIONAL ELECTROTECHNICAL COMMISSION (IEC) = International safety commission; IEC 950 (formerly 380), Safety of Information Technology Equipment. FEDERAL COMMUNICATIONS COMMISSION (FCC) = United States radiation emissions; Part 15, Subpart J, Class B Consumer Computing Devices. CAUTION: Connections between equipment must be made with shielded cables, and a shielded power cord must be used to connect AC power to the unit. CAUTION: This equipment generates and uses radio frequency energy, and may cause interference to radio and television reception if not installed and used in XT-4000S Product Specification & OEM Technical Manual strict accordance with the instructions in this manual . The drive has been tested and found to comply with the limits for a Class B computing device, in accordance with the specifications in Subpart J of Part 15 of FCC Rules, which are designed to provide reasonable protection against radio and television reception interference in a residential installation. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference using one or more of the following measures: o reorient the receiving antenna o reorient the computer with respect to the receiver o move the computer away from the receiver o plug the computer into a different outlet, so that the computer and receiver are on different branch circuits If necessary, consult the dealer, or an experience radio/television technician, for additional suggestions. You may find the FCC booklet How to Identify and Resolve Radio TV Interference Problems helpful. This booklet is available from the United States Government Printing Office, Washington, D.C., 20402, stock number 004-000-00345-4. Maxtor is not responsible for any radio or television interference caused by unauthorized modifications to the drive. It is the responsibility of the user to correct such interference. XT-4000S Product Specification & OEM Technical Manual XT-4000S Product Specification & OEM Technical Manual Doc 1014995, Rev B 1 Maxtor Corporation Doc 1014995, Rev B 1 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 3.0 FUNCTIONAL CHARACTERISTICS 3.1 GENERAL THEORY OF OPERATION The disk drive consists of read/write, control, and interface electronics, read/write heads, a servo head, a head positioning actuator, a disk drive motor/spindle, media, and an air filtration system. The components perform the following functions: o interpret and generate control signals o position the heads over the desired track o read and write data o provide automatic error correction to the data o provide a contamination-free environment o provide a controller to interact with the initiator o maintain precise spindle rotation speed 3.2 READ/WRITE CONTROL AND SCSI CONTROLLER ELECTRONICS All the disk drive and controller electronics are packaged on a single PCB. This PCB, which includes three microprocessors, performs the following disk drive functions: o data separation o reading/writing of data o index detection o head positioning o head selection o disk drive selection o fault detection o track zero detection o recalibration to track zero on power up o track position counter o power and speed control for spindle disk drive motor o braking for the spindle disk drive motor o disk drive up-to-speed indication o reduced write current on the inner tracks o monitoring for WRITE FAULT conditions o control of all internal timing o generation of SEEK COMPLETE signals o RLL encoding/decoding The PCB performs the following controller functions: o error detection and correction Doc 1014995, Rev B 2 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual o SCSI bus disconnect/reconnect functions o SCSI bus arbitration o defect handling o data transfer o automatic retries o data buffering o command linking o sector formatting 3.3 DRIVE MECHANISM The HDA is a sealed subassembly containing the mechanical portion of the disk drive. A brushless DC disk drive motor contained within the spindle hub rotates the spindle and is controlled by a dedicated microprocessor. The motor and spindle are dynamically balanced to ensure a low vibration level, and dynamic braking is used to quickly stop the spindle motor when power is removed. The HDA is shock mounted to minimize vibration through the frame. The frame is the mechanical assembly holding the HDA and PCB. 3.4 AIR FILTRATION SYSTEM The disks and read/write heads are assembled in a Class 100 environment and then sealed within the HDA. The HDA contains an absolute filter, mounted inside the casting, to provide constant internal air filtration (see Figure 3o1, Air Filtration System). A second absolute filter, located on the HDA top cover, permits pressure equalization between internal and ambient air. Figure 3o1 Air Filtration System 3.5 HEAD POSITIONING MECHANISM The read/write heads are mounted on a head/arm assembly, which is then mounted on a ball bearing supported shaft (see F, Head Positioning Mechanism). The voice coil, an integral part of the head/arm assembly, lies inside the magnet housing when installed in the disk drive. Current from the power amplifier, controlled by the servo system, induces a magnetic field in the voice coil which either aids or opposes Doc 1014995, Rev B 3 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual the field around the permanent magnets. This reaction causes the voice coil to move within the magnetic field. Because the head/arm assemblies are connected to the voice coil, voice coil movement is transferred, through the pivot point, directly to the heads, to position them over the desired cylinder. Figure 3o2 Head Positioning Mechanism Actuator movement is controlled by the servo feedback signal from the servo head. The servo information is prewritten at the factory and is used as a control signal for the actuator to provide track crossing signals during a seek operation, track following signals during on cylinder operation, and timing information, such as index and servo clock. The servo information also provides the timing to divide a track into sectors used for data storage. The servo control system has a dedicated microprocessor for fast, optimized performance. 3.6 READ/WRITE HEADS AND DISKS The disk drive employs state of the art sliders and flexures. The configuration of the sliders and flexures provides improved aerodynamic stability, superior head/disk compliance, and a higher signal-to- noise ratio. The disk media uses thin metallic film, deposited on 130 millimeter diameter aluminum substrates. The coating formulation, together with the low load force/low mass heads, permits highly reliable contact start/stop operation. The nickel-cobalt metallic film yields high amplitude signals, and very high resolution performance, compared to conventional oxide coated media. It also provides a highly abrasion and impact resistant surface, decreasing the potential for damage caused by shock and vibration. Data on each of the data surfaces is read by one read/write head; each head accesses 1,224 physical tracks. There is one surface dedicated to servo information in each disk drive. Doc 1014995, Rev B 4 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 3.7 TRACK AND SECTOR FORMAT The standard track format is organized into numbered data segments, or sectors (see Figure 3o3, Track Format). The sectors are addressed via the logical block address (LBA) in the SCSI commands. The method of encoding is 2, 7 RLL. Figure 3o3 Track Format 3.8 SCSI INTERFACE 3.8.1 Initiator-Target Configurations The SCSI initiator interface offers a number of unique advantages, facilitating the interconnection of the disk drive with one (or more) computer systems. Unlike traditional microcomputer disk interfaces, such as ST506, SCSI supports multiple peripherals and different peripheral types, all operating on the same bus structure. Figure 3o4, Typical SCSI Configurations, shows examples of typical configurations. Figure 3o4 Typical SCSI Configurations The disk drive also supports multiple initiator configurations consistent with the established arbitration cycle outlined in the SCSI standards. Configuration changes are made by SCSI address jumpers, which are set when the disk drive is installed in the system (jumper settings are discussed in Section 4.0, User Selectable Options). The SCSI implementation used in the disk drive is intended to facilitate high-speed data transfer between the initiator and the drive. Interconnection between the initiator system(s) and the drive is via a fifty- pin ribbon cable, and uses the single-ended alternative, which allows up to 6 meters of cable length. Doc 1014995, Rev B 5 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 3.8.2 Logical/Electrical Signal Definitions The SCSI bus uses eighteen signals. Nine signals are for the 8-bit data bus, with one data parity bit; the other nine signals are the SCSI control lines, which coordinate bus accesses for transfers of commands, data, status, and messages. The interface signals are listed below; refer to the SCSI standard for further details. Pin assignments of the connector are provided in section 3.8.3, Pin Assignments and Connector. Across the SCSI bus all initiator signals are low-true. The signals are asserted, or active, at 0 to 0.4 volts DC, and negated, or inactive, at 2.5 to 5.25 volts DC. This low-true logic is indicated by the negative sign which precedes the signal name. -RST The -RST (reset) signal is an OR-tied signal asserted by the initiator, causing the disk drive to do a "hard" RESET, self configure, and return to the IDLE condition. This signal is normally used during a power-up sequence. The -RST pulse should be at least 25 microseconds wide. -SEL The -SEL (select) signal is asserted by the initiator, along with the disk drive's SCSI ID bit (zero through seven), causing the drive to be selected. The -SEL line must be negated by the initiator after the drive asserts the - BSY line in response to a proper selection. The signal can be asserted by the arbiter (initiator or disk drive) in the ARBITRATION phase. The signal is also asserted by the disk drive during the RESELECTION phase. -BSY The -BSY (busy) signal is an OR-tied signal asserted by the disk drive, indicating that the bus is being used. It is also asserted by the arbiter during the ARBITRATION phase and by the initiator and the disk drive during the RESELECTION phase. -C/D Assertion of the -C/D (control/data) signal by the disk drive indicates that command, status, or message information is to be transferred on the data bus. Negation of this line indicates that data is to be transferred on the data bus. Doc 1014995, Rev B 6 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual -I/O When the -I/O (input/output) signal is asserted by the disk drive it indicates that information is transferred to the initiator from the disk drive. Negation of the signal indicates that information is transferred to the disk drive from the initiator. Note that IN means toward the initiator. -REQ When asserted by the disk drive, the -REQ (request) signal indicates that a byte is to be transferred on the data bus. -REQ is negated following assertion of the -ACK line by the initiator. -ACK The -ACK (acknowledge) signal is asserted by the initiator, following assertion of the -REQ line, to indicate data has been accepted by the initiator, or that data is ready to be transferred from the initiator to the disk drive. -ACK is negated following negation of the -REQ line. -ATN The -ATN (attention) signal is asserted by the initiator to indicate the ATTENTION condition, which is a request for the disk drive to enter the MESSAGE OUT phase. -MSG The -MSG (message) signal is asserted by the disk drive during one of the message phases. Messages may be either IN or OUT, depending on the state of the -I/O signal. -DB (7-0, P) The eight bidirectional data bus lines (DB 7-0) and parity line (DBP) are used to transfer 8 bit parallel data to/from the initiator. Bit seven is the most significant bit. Bits zero through seven are also used as SCSI ID bits during the ARBITRATION, SELECTION and RESELECTION phases. Data bus parity (DBP) is odd. 3.8.3 Pin Assignments and Connector The disk drive communicates with an initiator system via a fifty-pin connector, J1. The logical/electrical configuration of the SCSI connector is given in Table 3o1, Connector Pin Assignments. Note that the minus sign (-) indicates low-true logic, and that all odd- numbered pins are return (ground) pins for the associated even-numbered pins, except for pin twenty- Doc 1014995, Rev B 7 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual five, which is not connected. Pin one is located on the end of J1 closest to the DC power connector, J3. (See Figure 3o5, Connector Locations, Rear View of Drive.) Table 3o1 Connector Pin Assignments Figure 3o5 Connector Locations, Rear View of Drive Connection to J1 is via a nonshielded fifty-conductor connector, consisting of two rows of twenty-five female contacts on 0.1 inch centers. Figure 3o6, SCSI Cable Connector, shows the configuration and dimensions of a suitable mating connector. Recommended strain-relief connectors are AMP part number 1-499506-2, or Dupont part number 669002 (66900-250). Use of a keyed connector is recommended. Figure 3o6 SCSI Cable Connector 3.9 ELECTRICAL POWER INTERFACE This section describes the power-up sequence for the disk drive, and the two connectors associated with the electrical power interface. These connectors are the power connector, J3, and the ground connector, J4. 3.9.1 Power-Up Sequence DC power (+5 volts and +12 volts) may be supplied in any order. Both power supplies must be present, and within the tolerances of the power sensing circuit, before the motor will spin up. Typical current draw during power up is shown in Figure 3o7, Motor Start Doc 1014995, Rev B 8 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual Current Requirements. When the spindle reaches full speed, the actuator lock automatically disengages. The disk drive performs automatic SEEK calibration during start up for optimum SEEK performance. The disk drive executes its recalibration sequence whenever power is applied or the START STOP UNIT command is received. You may delay starting the spindle motor, to minimize power surges in multidrive configurations, by using the jumper options (see section 4.2, Drive Power-Up Options). The two jumpers controlling the disk drive power up-options are also covered in this section. Figure 3o7 Motor Start Current Requirements 3.9.2 Power Connector The DC power connector,J3 (shown in Figure 3o8, J3 Connector) is a four-pin AMP MATE-N-LOCK connector, part number 3505430-1. The recommended mating connector is AMP part number 1-480424-0, using AMP pins part number 350078-4 (strip) or part number 61173-4 (loose piece). J3 pins are numbered and assigned as shown in Figure 3o8. Figure 3o5, Connector Locations, Rear View of Drive, shows the location of J3 on the disk drive. Figure 3o8 J3 Connector 3.9.3 Ground Connector The DC logic ground connector at the back of the HDA, J4, is a Faston-type connector, AMP part number 61761- 2. (See Figure 3o5.) The recommended mating connector is AMP part number 62187-1. If wire is used, the hole in J4 will accommodate a maximum wire size of 18 AWG. This ground is optional. The frame of the disk drive is insulated from the HDA and the DC logic ground. The frame is electrically Doc 1014995, Rev B 9 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual connected to the computer system chassis when mounted in a computer system. Normally the chassis, and hence the frame of the drive, is at earth ground. 3.10 MOUNTING AND INSTALLATION The disk drive may be mounted in any orientation. In any final mounting configuration, ensure that the operation of the three shock mounts, which isolate the HDA from the frame, is not restricted. Certain switching power supplies may emanate electrical noise, which can degrade the specified read error rate. For best results, orient the disk drive so that the PCB assembly is not adjacent to these noise sources. Eight mounting holes, four on the bottom and two on each side, are provided for mounting the disk drive into an enclosure. The size and location of these holes, shown in Figure 3o9, Mechanical Outline, Top and Side Views, are identical to industry standards. Overall height, width, and depth, along with other key dimensions, are shown in Figure 3o9, and Figure 3o10, Mechanical Outline, Isometric. Figure 3o9 Mechanical Outline, Top and Side Views Figure 3o10 Mechanical Outline, Isometric View The faceplate may be removed in installations that do not require it. Remove the two E-Rings and unplug the light-emitting diode (LED) cable from the PCB, as shown in Figure 3o11, Removable Faceplate. Figure 3o11 Removable Faceplate Doc 1014995, Rev B 10 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 3.11 SHIPPING At power down, the heads are automatically positioned over the nondata, dedicated landing zone on each disk surface. The automatic shipping lock solenoid is also engaged at this time. Maxtor ships the disk drive in single and multipack shipping containers. Users can ship the disk drive installed when the nonoperating shock and vibration limits are not exceeded. Doc 1014995, Rev B 11 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 4.0 USER SELECTABLE OPTIONS Jumper locations for Fab #1 (part numbers 1015664, 1015377, and 1014207) are identified in Figure 4o1, PCB Layout. Figure 4o1 PCB Layout Jumper locations for Fab #3 (part numbers 1018353 and 1018359) are identified in Figure 4o2, Fab #3 PCB Layout. Figure 4o2 Fab #3 PCB Layout Doc 1014995, Rev B 44 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual Jumper locations for Fab #6 PCB (part number 1019822) are identified in Figure 4o2A, Fab #6 PCB Layout. Figure 4o2A Fab #6 PCB Layout 4.1 SCSI ID SELECTION SCSI ID jumpers (JP35 through JP37) are provided to configure each drive with a SCSI device ID for use in multiple SCSI device configurations. Table 4o1, SCSI ID Jumpers, is a reference table for the jumper configuration, ID, and priority on the SCSI bus. An ID of seven is the highest priority in a multidevice configuration, and is usually used for the initiator. Table 4o1 SCSI ID Jumpers The drive is shipped from the factory with a SCSI ID of six. This assures that sufficient jumpers are available for any address except seven, which is usually reserved for the host system. The SCSI ID can also be set remotely through the auxiliary connector, as mentioned in Section 4.9, Auxiliary Connector. The SCSI ID jumpers must be removed for this option and any shorting required for a selected SCSI ID is done outside the drive. 4.2 DRIVE POWER UP OPTIONS In order to allow for system power supply constraints, which may require minimizing surge current when powering up multiple drives, three modes of start up sequencing are provided (see Table 4o2, Summary of Power Up Options). Doc 1014995, Rev B 45 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual Table 4o2 Summary of Power-Up Options Start by ID Sequence: With both JP14 and JP38 out, the drive delays spinup for approximately 11 to 13 seconds times the SCSI ID. This allows for power up sequencing. A RESET condition results in the drive delaying its spinup according to its SCSI ID. Wait for Start Command: With JP14 out and JP38 in, the drive does not spin up until the initiator issues a START STOP UNIT command with the start bit equal to one. Start When Power Applied: When JP14 is in and JP38 is out, the motor starts as soon as power is applied. The drive is shipped in this configuration. NOTE: If the drive has JP14 in and JP38 out, it does not respond to a START/STOP UNIT command. 4.3 TERMINATOR POWER SELECTION Power to the terminators may come internally from the drive, or externally from the SCSI bus. If JP41 is in, the terminator power is internal, from the drive. If JP34 is in, the terminator power is external, from the SCSI bus. With both JP41 and JP34 in, terminator power is provided from the drive and to the SCSI bus. Hence, the drive is at one end of the SCSI bus with terminators in place and is also supplying terminator power for the device at the other end of the SCSI bus (see Figure 3o4, Typical SCSI Configurations). Additional discussion of the termination of the SCSI bus and location of the drive on the bus is presented in Section 4.8, Interface Termination. As shipped, JP41 is in and the drive supplies power to the terminators. JP34 is out. 4.4 WRITE PROTECT OPTION The write protect jumper, JP18, is used to protect the data written to the drive. When the jumper is in, data cannot be written on the drive; only READ operations can be executed. Installation of JP18 grounds the Doc 1014995, Rev B 46 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual remote write protect line, J2-7, forcing WRITE PROTECT on, and prevents remote control through J2-7 on the ten-pin connector. As shipped from the factory, JP18 is out, allowing normal reading/writing, or optional remote control through the J2 connector. See Section 4.9, Auxiliary Connector, for details of the J2 connector. 4.5 PARITY OPTION The parity jumper, JP40, enables (in) or disables (out) odd parity detection in the drive. Odd parity is always generated by the drive and provided to the SCSI bus. The drive is shipped with JP40 in, enabling parity detection. 4.6 OTHER JUMPERS Other jumper positions are not user selectable and are shipped as indicated in Table 4o3 and Table 4o4, Other Jumper Pin Assignments. The user should avoid changing these jumpers, or improper operation may occur. Table 4o3 Other Jumper Pin Assignments, Fab #1 Table 4o4 Other Jumper Pin Assignments, Fab #3 NOTE: Positions JP1, JP2, JP3, JP8, JP9, JP32 and JP33 are eliminated in the Fab #6 PCB. 4.7 SECTOR SIZE The drive is shipped from the factory formatted with 512 byte sectors. Configuration parameters are default values in all optional cases. It is recommended that users reformat the drive with the user's sector size, Doc 1014995, Rev B 47 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual using the P list, and the user's configuration parameters. 4.8 INTERFACE TERMINATION SCSI devices require proper interface termination. The first device and the last physical, not SCSI ID, device on the daisy chain SCSI bus must be terminated (see Figure 3o4, Typical SCSI Configurations). Remove the terminators from any devices in between. For instance, if the drive is in the middle of the string, remove its terminators. The disk drive terminators are shown in Figure 4o1, PCB Layout and Figure 4o2, Fab #3 PCB Layout. Pin one is on the end of the terminator that is marked with a dot in Figure 12, PCB Layout. The orientation of the terminator in the PCB is also shown. RN17 through RN19 all look like the side view inset in the figure. Note that the hole/solder pad for pin one has a square outline, whereas all others have a round outline. Pin one is oriented toward the power connector, J3. NOTE: All terminator packs (RN17 through RN19) must be oriented with the dot toward J3 for the drive to work properly. As shipped, interface signal lines are terminated with three removable 220/330 ohm resistor network packs. The devices driving the drive inputs should be open collector devices capable of sinking at least 48 milliamps at a voltage level of less than 0.5 volts DC (7438 or equivalent). Devices receiving the drive outputs should be of SCHMITT trigger type to improve noise immunity, 74LS14, 74LS240, or equivalent. The initiator should not load the bus with more than one standard low power Schotky transistor-transistor logic (LSTTL) input load per line, and should terminate all signals with 220/330 ohm terminators. 4.9 AUXILIARY CONNECTOR Connector J2 in Figure 3o5, Connector Locations, Rear View of Drive, is an auxiliary connector providing remote control of write protect and SCSI ID, and ability to carry the LED signal beyond the drive. The Doc 1014995, Rev B 48 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual auxiliary connector is a Berg 68451-121, ten-pin part. The mating connector is a 3M 3473-6010 part. Pin assignments are as in Table 4o5, Auxiliary Connector Pin Assignments (also see Figure 3o5, Connector Locations, Rear View of Drive). Table 4o5 Auxiliary Connector Pin Assignments When pin seven is connected to ground, the drive is protected from writing, regardless of commands sent to the drive via the SCSI interface. The write protect signal may also be connected to an LED whose (+) terminal is tied to a voltage source, so that the LED is illuminated when the pin is grounded and the drive is in write protect mode. For remote write protect, JP18 must be removed (see Section 4.4, Write Protect Option). When an LED is connected to pin one (+) and pin five (- ), that LED functions in the same manner as the LED which is mounted on the drive's front faceplate. This is typically used in cases where the drive is mounted in a position where the drive's LED is not visible and the faceplate is removed. Pin three is not present so that users can key the mating connector. Pin three of the mating connector should be blocked for this purpose. The SCSI ID of the drive may be programmed remotely by selectively connecting pins six, eight, and ten to ground, or leaving them open. The various combinations are shown in Table 4o6, Remote SCSI ID Programming Combinations. Table 4o6 Remote SCSI ID Programming Combinations SCSI ID jumpers (JP35 through JP37) must be removed for the remote SCSI ID option. Doc 1014995, Rev B 49 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual XT-4000S Product Specification & OEM Technical Manual Doc 1014995, Rev B 51 Maxtor Corporation Doc 1014995, Rev B 51 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 5.0 LOGICAL CHARACTERISTICS The following information is based on the ANSI SCSI standard (X3.131-1986), and the Common Command Set (CCS). For more information, refer to these publications. 5.1 POWER UP AND BUS RESET The following sections describe the sequence of events during drive self-test and initialization sequences. The self-test sequence occurs before the initialization sequence. 5.1.1 Self-Test Sequence The self-test sequence is executed upon drive power up. The self-test sequence verifies the integrity of the hardware. This test is not an exhaustive hardware diagnostic, but checks the major components for full function. The drive does not respond to SELECTION for the first 250 milliseconds of the self-test. After 250 milliseconds have elapsed, the drive responds to SELECTION with a BUSY status for 2 to 3 seconds: this time is spent completing the remaining self-test sequences, initializing the SCSI circuitry, and enabling the SCSI interrupts. After the self-test is complete and the interface circuitry is initialized (approximately 3 seconds), the drive responds to SELECTION with CHECK CONDITION status and the appropriate sense data (i.e., UNIT ATTENTION, POWER ON/RESET condition). The self-test sequence consists of the following events: o Hardware Reset Test - This routine tests the microprocessor, buffer controller, disk formatter, and SCSI reset latch for the proper power up condition. If any of these tests fail, the drive can only be reset by a POWER UP condition. o Microprocessor Test - This routine tests the microprocessor's internal memory, timers, and register bank switching for proper operation. o Erasable Programmable Read Only Memory (EPROM) Checksum Test - This routine performs a checksum calculation on the controller firmware EPROM and compares it against the checksum stored in the EPROM. Doc 1014995, Rev B 52 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual o Buffer Controller Test - This routine tests the buffer controller for proper operation. All the registers are tested and the chip is engaged to access random-access memory (RAM). o Dynamic RAM Test - This routine tests the dynamic RAM by writing and reading different patterns to memory. In addition, the buffer controller is tested for proper refresh operation and parity detection. This test also tests the memory parity interrupt. o Disk Formatter Test - This routine tests the disk formatter chip by writing and reading all possible patterns to each of the disk formatter chip registers. After the registers are tested, the interrupts are tested to ensure that the formatter chip generates an interrupt when a command completes. o SCSI Controller Test - This routine tests the SCSI controller chip by executing the chip diagnostic command. After the diagnostic test completes, the interrupts are tested to ensure that the SCSI chip generates an interrupt when a command completes. Finally, the registers are tested by writing and reading all possible patterns to each of the SCSI controller chip registers. If any portion of the self-test fails, except the hardware reset test, the drive can be reset by a SCSI bus RESET condition or a power up RESET condition. The failure of the hardware reset test is considered a catastrophic failure and the controller can only be reset from such a failure by a power up RESET condition. 5.1.2 Initialization Sequence The initialization sequence is executed for any one of the following three reasons: o a POWER UP condition occurs o the SCSI bus -RST signal is asserted o a BUS DEVICE RESET message (on the SCSI bus) is received After a successful initialization, the first command from each initiator is terminated with CHECK CONDITION status. The sense data is set to UNIT ATTENTION/POWER ON, RESET, or BUS DEVICE RESET OCCURRED. Until the drive has spun up, any command sent by an initiator which requires a ready drive for GOOD Doc 1014995, Rev B 53 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual completion status, is terminated with CHECK CONDITION status. The sense data is set to DRIVE NOT READY. Commands that may complete with GOOD status prior to the drive being ready are REQUEST SENSE, INQUIRY, RESERVE UNIT, RELEASE UNIT, START STOP UNIT, READ BUFFER, and WRITE BUFFER. Note that the INQUIRY command results in the general model designation (XT-4000S) being returned prior to the drive being READY. Afterwards, the specific model number is returned. After a RESET CONDITION occurs, the first command sent by the initiator that causes a medium access loads the saved mode parameters into the current mode parameters. 5.1.3 Self Configuration When the drive powers up or a RESET CONDITION occurs, it configures itself from the parameters and information saved on the medium from the previous format operation. This includes the model number returned in the INQUIRY command and the mode parameters. Refer to 7.4 MODE SELECT, and 7.5 MODE SENSE later in this manual, which describe the mode parameters. 5.1.4 UNIT ATTENTION Condition A UNIT ATTENTION condition is generated for each initiator whenever the drive has been reset (by a BUS DEVICE RESET message or a RESET condition), or when the mode parameters have been changed by other initiators. The UNIT ATTENTION condition persists for each initiator until that initiator issues any command other than INQUIRY. The generation of a UNIT ATTENTION condition supercedes any pending sense data. If an INQUIRY command is received from an initiator with a pending UNIT ATTENTION condition, the last UNIT ATTENTION generated condition is reported. The drive returns the INQUIRY data and does not clear the UNIT ATTENTION condition. 5.2 BUFFERING SCHEME The drive has 64 kilobytes of RAM. The drive uses 4 kilobytes of RAM for a scratchpad, 16 kilobytes of RAM Doc 1014995, Rev B 54 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual for a write buffer and 45,056 bytes of RAM for a data buffer. The drive will use the data buffer for read-ahead cache if this feature is enabled. The drive will use the data buffer for write operations if the transfer length exceeds 16 kilobytes. Normally, the drive uses the split buffering, that is, separate buffers for write operations (write buffer) and read operations (data buffer) to optimize throughput. This is particularly advantageous in systems that perform extensive read-modify-write processes. The buffer controller is dual parted, allowing simultaneous transfers to and from the initiator and the medium. Doc 1014995, Rev B 55 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual XT-4000S Product Specification & OEM Technical Manual Doc 1014995, Rev B 1 Maxtor Corporation Doc 1014995, Rev B 1 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.0 SCSI PHASES AND MESSAGES The condition on the SCSI bus can be divided into eight distinct phases: BUS FREE phase ARBITRATION phase SELECTION phase RESELECTION phase COMMAND phase \ DATA phase \ These phases are collectively termed the STATUS phase / Information Transfer phases. MESSAGE phase / The various phases are defined by the state of the SCSI bus signals -SEL, -BSY, -MSG, -C/D, -I/O, -REQ, and -ACK (see Table 6o1, Signal States and Bus Phases). The SCSI bus can never be in more than one phase at a time. Figure 6o1, Signal Sequence Chart for SCSI Phases, shows the signal sequence of the eight phases. See the figure while reading the following sections. NOTE: The condition of the control lines for information transfer is valid only when the SCSI bus - REQ signal is asserted; therefore, the disk drive is not "in a phase" unless the --REQ signal is asserted. Table 6o1 Signal States and Bus Phases Figure 6o1 Signal Sequence Chart for SCSI Phases 6.1 BUS FREE PHASE The BUS FREE phase is used to indicate that no SCSI device is actively using the SCSI bus, and that it is available for subsequent users. The BUS FREE phase occurs when the drive releases -BSY following a RESET condition or certain message phases (i.e., COMMAND COMPLETE and DISCONNECT). Doc 1014995, Rev B 2 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.2 ARBITRATION PHASE The ARBITRATION phase allows one SCSI device to gain control of the SCSI bus so that it can assume the role of an initiator or target (drive). The arbitrating device waits for the BUS FREE phase to occur. It then asserts its own SCSI ID bit and -BSY. The arbitrating device then examines the data bus. If a higher priority SCSI ID bit exists on the data bus, the arbitrating device loses arbitration and releases -BSY and the data bus. Otherwise, the arbitrating device wins arbitration and asserts -SEL. NOTE: Implementation of the ARBITRATION phase is a system option. Systems that do not implement this option can have only one initiator. The ARBITRATION phase is required for systems that use the disconnect/reconnect feature. 6.3 SELECTION PHASE If the initiator wins arbitration, it enters the SELECTION phase by continuing to assert its own initiator SCSI ID bit and asserting the drive's SCSI ID bit. The initiator then negates -BSY (-SEL remains asserted by the initiator). If the initiator expects the drive to disconnect/reconnect, the initiator must assert the -ATN line prior to the negation of -BSY. If the initiator does not support arbitration, then the SELECTION phase is entered from the BUS FREE phase. The initiator asserts only the disk drive's SCSI ID bit and asserts -SEL. During the SELECTION phase, the drive maintains a negated -I/O line so that the SELECTION phase may be distinguished from the RESELECTION phase. The drive determines that it has been selected by detecting its SCSI ID bit asserted on the bus (as determined by the ID jumpers, see 4.1 SCSI ID Selection earlier in this manual). If more than two IDs are asserted on the data bus, or parity is enabled and bad parity is detected, the drive does not respond to the SELECTION phase. The drive asserts -BSY after detecting that it has been selected. At this point, the initiator must negate - SEL and may remove the IDs from the data bus. Doc 1014995, Rev B 3 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.4 RESELECTION PHASE After disconnecting to free the bus for other activity, the drive reconnects when it is ready to transfer data or status across the bus. The drive arbitrates for the bus and, if it wins, reselects the initiator. The RESELECTION phase is similar to the SELECTION phase, except that the -I/O signal line is asserted. The drive asserts its own SCSI ID bit and the SCSI ID bit of the initiator which is being reselected. The drive releases -BSY (-BSY was already asserted during arbitration) and continues to assert -SEL. The initiator detects that it has been selected and responds by asserting -BSY. The drive detects that the -BSY signal is now true and responds by also asserting -BSY (at this point, both the initiator and the drive are holding the -BSY signal low). The drive then releases -SEL and the initiator responds by releasing - BSY (-BSY is still being asserted by the drive). See Figure 6o1, Signal Sequence Chart for SCSI Phases. After reselecting the initiator, the drive sends an IDENTIFY message to identify itself to the initiator. If the initiator does not respond to the reselection within a selection time-out delay (see Table 6o2, SCSI Bus Timing), the drive releases the bus and then rearbitrates for the bus, trying to reselect the initiator. It does this up to 255 times, or until the initiator responds or the drive is reset. NOTE: The drive does not disconnect if, during the SELECTION phase, the initiator does not set its initiator SCSI device ID on the bus and if the initiator does not send an IDENTIFY message out (with bit six asserted) to the drive. Table 6o2 SCSI Bus Timing 6.5 INFORMATION TRANSFER PHASES The -C/D, -I/O, and -MSG signals are used to distinguish between the different information transfer phases (COMMAND, DATA, STATUS, and MESSAGE). The drive controls these three signals, and, therefore, controls all changes from one phase to another. The initiator Doc 1014995, Rev B 4 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual can request a MESSAGE OUT phase by asserting -ATN, and the drive can cause a BUS FREE phase by negating/releasing -SEL and -BSY (and all other SCSI bus signals). The information transfer phases use one or more -REQ/- ACK handshakes to control the information transfer. Each -REQ/-ACK handshake allows the transfer of one byte of information. During the information transfer phases, -BSY remains true and -SEL remains false. Additionally, during the information transfer phases, the drive continuously envelopes the -REQ/-ACK handshake(s) with -C/D, -I/O, and -MSG in such a manner that these control signals are valid for a bus settle delay (see Table 6o2, SCSI Bus Timing) before the assertion of -REQ of the first handshake, and remain valid until the negation of -ACK at the end of the last handshake. 6.5.1 Asynchronous Information Transfer The drive controls the direction of information transfer by means of the -I/O signal. When -I/O is true, information is transferred from the drive to the initiator. When -I/O is false, information is transferred from the initiator to the drive. If -I/O is true (transfer to the initiator), the drive first asserts -DB (7-0, P) to their desired values, delays at least one deskew delay, plus a cable skew delay (see Table 6o2, SCSI Bus Timing), and then asserts -REQ. -DB (7-0, P) remain valid until -ACK is true at the drive. The initiator reads -DB (7-0, P) after -REQ is true, then signals its acceptance of the data by asserting -ACK. When -ACK becomes true at the drive, the drive may change or release -DB (7-0, P), and negates -REQ. After -REQ is false, the initiator then negates -ACK. After -ACK is false, the drive may continue the transfer by asserting -DB (7-0, P) and - REQ as described above. If -I/O is false (transfer to the drive), the drive requests information by asserting -REQ. The initiator drives -DB (7-0, P) to their desired values, delays at least one deskew delay, plus a cable skew delay (see Table 6o2, SCSI Bus Timing), and asserts -ACK. The initiator continues to drive -DB (7-0, P) until -REQ is false. When -ACK becomes true at the drive, the drive reads -DB (7-0, P) and then negates -REQ. When -REQ becomes false at the initiator, the initiator may Doc 1014995, Rev B 5 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual change or release -DB (7-0, P), and negates -ACK. The drive may continue the transfer by asserting -REQ as described above. 6.5.2 Synchronous Data Transfer Synchronous data transfer is optional, and may be used only if previously agreed to by the initiator and drive through the message system (see 6.6.16 SYNCHRONOUS DATA TRANSFER REQUEST Message later in this chapter). The messages determine the use of synchronous mode by the initiator and the drive, and establish a -REQ/-ACK offset and a transfer period. The synchronous mode, once established, remains in effect for all DATA phases until a RESET condition or power cycle occurs, or until one of the devices elects to modify the agreement. The -REQ/-ACK offset specifies the maximum number of - REQ pulses that can be sent by the target in advance of the number of -ACK pulses received from the initiator, thereby establishing a pacing mechanism. If the number of -REQ pulses exceeds the number of -ACK pulses by the -REQ/-ACK offset, the drive does not assert -REQ until the next -ACK pulse is received. A requirement for successful completion of the DATA phase is that the number of -ACK and -REQ pulses be equal. The transfer period specifies the minimum time allowed between leading edges of successive -REQ and -ACK pulses. The drive asserts the -REQ signal for a minimum of one assertion period. The drive waits at least the greater of a transfer period from the last transition of -REQ to true, or the minimum of a negation period from the last transition of -REQ to false before the disk drive asserts the -REQ signal. The initiator sends one pulse of the -ACK signal for each -REQ pulse received. The initiator asserts the - ACK signal for a minimum of one assertion period. The initiator waits at least the greater of a transfer period from the last transition of -ACK to true, or for a minimum of a negation period from the last transition of -ACK to false, before the initiator asserts the -ACK signal. If -I/O is true (transfer to the initiator), the drive first asserts -DB (7-0, P) to their desired values, waits at least one deskew delay, plus one cable skew Doc 1014995, Rev B 6 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual delay (see Table 6o2, SCSI Bus Timing), and then asserts -REQ. -DB (7+0, P) are held valid for a minimum of one deskew delay, plus one cable skew delay, plus one hold time (see Table 6o2) after the assertion of -REQ. The drive asserts -REQ for a minimum of one assertion period. The drive may then negate -REQ and change or release -DB (7-0, P). The initiator reads the value on -DB (7-0, P) within one hold time of the transition of -REQ to true. The initiator then responds with a -ACK pulse. If -I/O is false (transfer to the drive), the initiator transfers 1 byte for each -REQ pulse received. After receiving a -REQ pulse, the initiator first asserts -DB (7-0, P) to the desired value, delays at least one deskew delay, plus one cable skew delay (see Table 6o2, SCSI Bus Timing), and then asserts -ACK. The initiator holds -DB (7-0, P) valid for at least one deskew delay, plus one cable skew delay, plus one hold time (see Table 6o2) after the assertion of -ACK. The initiator asserts -ACK for a minimum of one assertion period. The initiator may then negate -ACK and may change or release -DB (7-0, P). The drive reads the value of -DB (7-0, P) within one hold time of the transition of -ACK to true. 6.5.3 COMMAND Phase After being selected and processing the IDENTIFY message, if any, the drive normally switches to the COMMAND phase. The 6 or 10 bytes of command information (command descriptor block, or CDB) are transferred from the initiator to the drive. If enabled, parity is checked on each command byte. If bad parity is detected, the command is aborted. The drive switches to the STATUS phase, returns CHECK CONDITION status, and sets the sense data to ABORTED COMMAND/PARITY ERROR for that initiator. The drive then switches to the MESSAGE phase, returns a COMMAND COMPLETE message, and goes to the BUS FREE phase. After each command byte transfer, the -ATN bit is checked; if the -ATN line is active the drive switches to the MESSAGE OUT phase and receives and then acts on the message. Doc 1014995, Rev B 7 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.5.4 DATA IN and DATA OUT Phases In commands that require a DATA phase (READ, WRITE, MODE SELECT, etc.), the drive enters a DATA phase. During the DATA IN phase, data is transferred from the drive to the initiator. During the DATA OUT phase, data is transferred from the initiator to the drive. If bus parity is enabled and bad parity is detected, the command is aborted. The controller switches to the STATUS phase, returns CHECK CONDITION status, and sets the sense data to ABORTED COMMAND/PARITY ERROR for that initiator. The drive then switches to the MESSAGE phase, returns a COMMAND COMPLETE message, and goes to the BUS FREE phase. After each block, or group of blocks, is transferred, the -ATN bit is checked; if set, the disk drive switches to the MESSAGE phase to receive, and then act on, the message. 6.5.5 STATUS Phase After completing any command (successfully or unsuccessfully, as indicated by the status byte), the drive switches to the STATUS phase and returns the status byte to the initiator. The drive also switches to the STATUS phase for reporting a BUSY, INTERMEDIATE- GOOD, or RESERVATION CONFLICT status. The drive does not go to the STATUS phase if it is cleared by a BUS DEVICE RESET or ABORT message, or by a "hard" RESET condition. Following the STATUS phase, the drive enters the MESSAGE phase. The format of the status byte containing the command completion information is defined in Table 6o3, Status Byte. Table 6o3 Status Byte The reserved bits are set aside for future standardization and is always set to zero. The status code field is used to specify the status of the completed command. Table 6o4, Status Codes, gives Doc 1014995, Rev B 8 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual the bit values for the status codes returned by the disk drive. Table 6o4 Status Codes Descriptions of the status codes are given below: GOOD - This status byte indicates that the operation completed as expected. CHECK CONDITION - Any error, exception, or abnormal condition, that causes sense data to be set causes a CHECK CONDITION status. The REQUEST SENSE command should be issued following a CHECK CONDITION status to determine the condition. NOTE: If any command other than REQUEST SENSE or INQUIRY is issued following a CHECK CONDITION, the sense data is lost. BUSY - The drive returns this status whenever it is unable to accept a command. For example, the drive returns this status when it is busy doing self-tests and self configuration after being powered up or reset, or if the drive is busy executing a previously received command. INTERMEDIATE-GOOD - This status is returned for every command in a series of linked commands (except the last command), unless an error, exception, or abnormal condition, causes a CHECK CONDITION status or a RESERVATION CONFLICT status to be set. If the INTERMEDIATE-GOOD status is not returned, the chain of linked commands is broken; no further commands in the series are executed. RESERVATION CONFLICT - This status is returned whenever an initiator attempts to access a drive that is reserved by another initiator. 6.5.6 MESSAGE Phase The MESSAGE phase is used to transfer information about exception conditions between the initiator and the drive. The MESSAGE IN and MESSAGE OUT phases are Doc 1014995, Rev B 9 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual discussed below, followed by descriptions of the SCSI messages. Message codes supported by the drive are shown in Table 6o5, Message Codes. Table 6o5 Message Codes 6.6 SCSI MESSAGES 6.6.1 MESSAGE IN Phase During the MESSAGE IN phase, a message is transferred from the drive to the initiator. The drive may enter this phase at any time. 6.6.2 MESSAGE OUT Phase During the MESSAGE OUT phase, a message is transferred from the initiator to the drive. The initiator requests that the drive enter the MESSAGE OUT phase by asserting the -ATN line. The drive frequently monitors the -ATN line and enters the MESSAGE OUT phase at its earliest convenience in response to the initiator's assertion of -ATN. After being selected, the drive sets the control lines in preparation for the MESSAGE OUT phase. If the initiator has -ATN asserted, the drive requests a message from the initiator by asserting -REQ. The first message is expected to be an IDENTIFY message, but the drive also accepts a BUS DEVICE RESET, or an ABORT message. If any other message is received the drive goes to the BUS FREE phase. (See 6.6.16 SYNCHRONOUS DATA TRANSFER REQUEST Message later in this chapter for additional information.) If, during the selection, the initiator does not assert its ID on the bus, the drive does not examine the -ATN signal. The drive assumes the initiator cannot support any message except COMMAND COMPLETE, and does not support DISCONNECT-RECONNECT. The drive also assumes the initiator ID is zero, and saves any status for that initiator as initiator zero. Doc 1014995, Rev B 10 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual NOTE: If the initiator expects the drive to disconnect-reconnect, then a MESSAGE OUT phase (the IDENTIFY message with bit six true) must occur immediately following a SELECTION phase which had both the initiator's, and the drive's, SCSI device ID asserted on the bus. 6.6.3 COMMAND COMPLETE (00h) The COMMAND COMPLETE message is sent from the drive to the initiator to indicate that the execution of a command (or a series of linked commands) has terminated, and that valid status has been sent to the initiator. After sending this message successfully, the drive goes to the BUS FREE phase by releasing - BSY, unless the initiator sets the -ATN line. NOTE: The command may or may not have been executed successfully, as indicated in the status. If the initiator rejects this message with a MESSAGE REJECT message, the drive goes to the BUS FREE phase and does not consider this an error. 6.6.4 SAVE DATA POINTER (02h) When doing disconnects, the SAVE DATA POINTER message is sent before every DISCONNECT message . If the initiator rejects this message with a MESSAGE REJECT message, the drive does not disconnect. 6.6.5 RESTORE POINTERS (03h) The RESTORE POINTERS message is sent from the drive to the initiator. The message acts to restore to the active state the most recently saved pointers for the currently attached logical unit. Pointers to the command, data, and status locations for the logical unit are restored to the active pointers. Command and status pointers are restored to the beginning of the present command and status areas. The data pointer is restored to the value at the beginning of the data area, or to the value at the point at which the last SAVE DATA POINTERS message occurred for that logical unit. If the initiator rejects this message with a MESSAGE REJECT message, the drive immediately terminates the present command with a CHECK CONDITION status and sets Doc 1014995, Rev B 11 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual the sense data to HARDWARE ERROR/MESSAGE REJECT ERROR (04h, 43h) for that initiator. When the drive reselects the initiator, the IDENTIFY message implies that the initiator should restore its pointers. Therefore, this message is not normally used in reselection. 6.6.6 DISCONNECT (04h) This message is sent by the drive to inform the initiator that the present physical path is about to be broken (the drive plans to disconnect by releasing - BSY), but that a later reconnect is required in order to complete the current operation. This message does not cause the initiator to save the data pointer. If the initiator rejects this message with a MESSAGE REJECT message, the drive does not disconnect. 6.6.7 INITIATOR DETECTED ERROR (05h) The INITIATOR DETECTED ERROR message is issued by an initiator to inform the drive that an error has occurred during an operation. This message should be sent by the initiator when a parity error is detected. 6.6.8 ABORT (06h) The ABORT message is sent from the initiator to the drive to clear the present operation. All pending data and status for the issuing initiator is cleared from the drive, and the drive goes to the BUS FREE phase. Pending data and status for other initiators is not cleared. No status or ending message is sent for the operation. It is not an error to issue this message to a logical unit that is not currently performing an operation for the initiator. 6.6.9 MESSAGE REJECT (07h) The MESSAGE REJECT message is sent from either the initiator or the drive to indicate that the last message received was inappropriate or has not been implemented. To create a MESSAGE REJECT message the initiator asserts -ATN prior to releasing -ACK; the handshake of Doc 1014995, Rev B 12 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual the message is then rejected. When the drive sends this message it changes to the MESSAGE IN phase and sends this message prior to requesting additional message bytes from the initiator. This provides an interlock so that the initiator can determine which message is rejected. If the initiator responds to this message with a MESSAGE REJECT message, the drive immediately terminates the present command with a CHECK CONDITION status and sets the sense data to HARDWARE ERROR/MESSAGE ERROR (04h, 43h) for that initiator. 6.6.10 NO OPERATION (08h) The initiator sends the NO OPERATION message when it has no valid message for the drive request. The drive receives and ignores this message. 6.6.11 MESSAGE PARITY ERROR (09h) The initiator sends a MESSAGE PARITY ERROR message to indicate a parity error on one or more bytes of the last message sent from the drive. The initiator asserts -ATN prior to releasing -ACK for the last byte of the message in error, so that the drive knows which message is in error. The drive resends the message. If the Message Parity Error is received again, the drive goes to the BUS FREE phase and aborts the current command for that initiator. No further reconnection is attempted, and neither STATUS nor COMMAND COMPLETE messages are returned for the command. The sense data is set to ABORTED COMMAND/SCSI PARITY ERROR (04h, 47h) for that initiator. 6.6.12 LINKED COMMAND COMPLETE (0Ah) The LINKED COMMAND COMPLETE message is sent to the initiator to indicate that the execution of a linked command has completed and that the status has been sent. If the initiator responds with a MESSAGE REJECT message, the drive goes to the BUS FREE phase and does not execute the next command. The sense data is set to HARDWARE ERROR/MESSAGE ERROR (04h, 43h) for that initiator. Doc 1014995, Rev B 13 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.6.13 LINKED COMMAND COMPLETE (WITH FLAG) (0Bh) The LINKED COMMAND COMPLETE (WITH FLAG) message is sent to the initiator to indicate that the execution of a linked command (with the flag bit set to one) has completed and that the status has been sent. If the initiator responds with a MESSAGE REJECT message, the drive goes to the BUS FREE phase and does not execute the next command. The sense data is set to HARDWARE ERROR/MESSAGE ERROR (04h, 43h). 6.6.14 BUS DEVICE RESET (0Ch) An initiator may send the BUS DEVICE RESET message to the drive to clear all current commands on that SCSI device. The drive clears all commands, goes through its initial power up checks, its self configuration, and goes to the BUS FREE condition ("hard" RESET). 6.6.15 IDENTIFY (C0h/80h) The IDENTIFY message is sent by an initiator after it selects a drive. It is sent by the drive as the first message after a reconnection. In addition, this message specifies that the sender supports some or all of the optional messages. The bits in Table 6o6, IDENTIFY Message Codes, show that the only truly changeable bit is bit six; therefore, the command can have only two values: C0h if the disconnect/reconnect feature is supported, or 80h if the disconnect/reconnect feature is not supported. Table 6o6 IDENTIFY Message Codes If the initiator responds to this message with a MESSAGE REJECT message, the drive immediately terminates the present command with a CHECK CONDITION status and sets the sense key/error code to HARDWARE ERROR/Message Reject Error (04h, 43h) for that initiator. NOTE: The drive does not disconnect if, during the SELECTION phase, the initiator does not set its initiator SCSI device ID on the bus, and if the Doc 1014995, Rev B 14 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual initiator does not send an IDENTIFY message out (with bit six set) to the drive. 6.6.16 SYNCHRONOUS DATA TRANSFER REQUEST Message (01h) The drive can, optionally, perform synchronous data transfers, as discussed in 6.5.2 Synchronous Data Transfer earlier in this chapter. A pair of SYNCHRONOUS DATA TRANSFER REQUEST messages (see Table 6o7 SYNCHRONOUS DATA TRANSFER REQUEST Byte Values) are exchanged between an initiator and the drive under the following conditions: o a SCSI device that supports synchronous data transfer recognizes it has not communicated with the other SCSI device since receiving the last "hard" RESET o A SCSI device that supports synchronous data transfer recognizes it has not communicated with the other SCSI device since receiving a BUS DEVICE RESET message SCSI devices may also exchange messages to establish synchronous data transfer when requested to do so. The messages exchanged establish the transfer period and the -REQ/-ACK offset. Table 6o7 SYNCHRONOUS DATA TRANSFER REQUEST Byte Values The transfer period is defined as the minimum time between the leading edge of a -REQ pulse and of its corresponding -ACK pulse. The -REQ/-ACK offset is defined as the maximum number of -REQ pulses that may be outstanding before the corresponding -ACK pulse is received at the drive. A -REQ/-ACK offset value of zero indicates asynchronous mode; a value of 0Fh yields the maximum number of outstanding -REQ pulses supported (fifteen). If the initiator recognizes that negotiation is required, it asserts -ATN and, if the drive implements message transfers, sends a SYNCHRONOUS DATA TRANSFER REQUEST message, specifying the -REQ/-ACK offset and minimum transfer period. The -REQ/-ACK offset is Doc 1014995, Rev B 15 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual chosen to meet the data handling requirements of the target, while the minimum transfer period is chosen to meet the data handling requirements of the initiator. The drive responds in any of the ways outlined in Table 6o8, Drive Responses to the SYNCHRONOUS DATA TRANSFER REQUEST Message. Table 6o8 Drive Responses to the SYNCHRONOUS DATA TRANSFER REQUEST Message The implied agreement remains in effect until a BUS DEVICE RESET message is received, a "hard" RESET condition occurs, or until one of the two SCSI devices elects to modify the agreement. Renegotiation at every selection is not recommended since a significant performance impact is likely. The default mode of data transfer is asynchronous. The default mode is entered at power on, after a BUS DEVICE RESET message, or after a "hard" RESET condition. The SYNCHRONOUS DATA TRANSFER REQUEST message exchange can only take place following a SELECTION phase that includes the SCSI IDs for both the initiator and the target. Violation of this rule may make data transfer impossible owing to disagreements among SCSI devices about the data transfer mode. 6.7 ERROR CONDITIONS Under several error conditions, the drive changes the phase to BUS FREE without correctly terminating the command (i.e., no DISCONNECT or COMMAND COMPLETE message is sent). The drive clears all information regarding the command, except sense data (if any), and does not attempt to reconnect, or in any other way terminate, the command. The initiator must assume that this is a catastrophic failure and return the error to the system software. Sense data may or may not be valid when this condition occurs. If the initiator issues a REQUEST SENSE command and the returned sense key and additional sense code are not zero, the sense data is valid. Doc 1014995, Rev B 16 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.7.1 MESSAGE OUT Phase Parity Error If the drive detects a parity error during the MESSAGE OUT phase it retries the MESSAGE OUT phase once using the following sequence: 1. Continue the -REQ/-ACK handshake until the initiator negates -ATN (receives all of the message bytes). 2. Instruct the initiator to resend all of the message bytes sent during the previous MESSAGE OUT phase by not changing the phase and asserting -REQ. 3. The initiator then resends all of the previous message bytes. If, after one retry, the message is still not received correctly, the drive processes the error using one of the following sequences: o If an IDENTIFY message is not received, the drive immediately goes to the BUS FREE phase. No sense data code information is set for this type of error. o If an IDENTIFY message is received, the drive terminates the present command with a CHECK CONDITION status and sets the sense data to ABORTED COMMAND/SCSI PARITY ERROR (0Bh/47h). This error does not prevent the initiator from retrying the command. 6.7.2 COMMAND Phase Parity Error When the drive detects a parity error during the COMMAND phase, it retries the COMMAND phase one time using the following sequence: 1. Send the initiator a RESTORE POINTERS message to reset the pointers to the start of the command. 2. Attempt to receive the entire command again. If, after one retry, the command is still not received successfully, the drive aborts the command using one of the following sequences: o If the initiator does not send an IDENTIFY message, the drive immediately goes to the BUS FREE phase. No sense data information is sent for this type of error. Doc 1014995, Rev B 17 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual o If the drive receives an IDENTIFY message, it terminates the command with a CHECK CONDITION status and sets the sense data to ABORTED COMMAND/SCSI PARITY ERROR (0Bh/47h). This error does not prevent the initiator form retrying the command. 6.7.3 DATA OUT Phase Parity Error If the drive detects a parity error during the DATA OUT phase, it terminates the command with a CHECK CONDITION status, and sets the sense data to ABORTED COMMAND/SCSI PARITY ERROR(0Bh/47h). This error does not prevent the initiator from retrying the command. 6.7.4 Initiator Detected Error If the drive receives an initiator detected error message at any time during the command, except during the STATUS phase or COMMAND COMPLETE message, it terminates the current command with a CHECK CONDITION status and sets the sense data to ABORTED COMMAND/INITIATOR DETECTED ERROR MESSAGE RECEIVED(0Bh/48h). This error does not prevent the initiator from retrying the command. If the initiator sends an initiator detected error message immediately after the STATUS phase, the drive sends a RESTORE POINTERS message and resends the status. If the initiator sends another initiator detected error message in response to the resent status, the drive immediately goes to the BUS FREE phase. The sense data is set to ABORTED COMMAND/INITIATOR DETECTED ERROR MESSAGE RECEIVED(0Bh/48h). This error does not prevent the initiator from retrying the command. If the initiator sends an initiator detected error message immediately after the COMMAND COMPLETE message is sent, the drive immediately goes to the BUS FREE phase. The sense data is set to ABORTED COMMAND/INITIATOR DETECTED ERROR MESSAGE RECEIVED(0Bh/48h). This error does not prevent the initiator from retrying the command. 6.7.5 REJECTED Message When the drive receives a MESSAGE REJECT message from the initiator, it resends the original message. If the Doc 1014995, Rev B 18 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual message is rejected again, the drive takes one of the following actions, based on which message was rejected: o COMMAND COMPLETE - If the rejected message is a COMMAND COMPLETE message, the disk drive goes to the BUS FREE phase and does not consider this an error. o DISCONNECT - If the rejected message is a DISCONNECT message, the drive does not disconnect from the initiator and continues the current command. This condition does not preclude the drive from attempting to disconnect at a later time. NOTE: The drive does not send a DISCONNECT message to an initiator which does not support the disconnect/reconnect option. o IDENTIFY (Reconnect) - If the rejected message is an IDENTIFY message, the drive immediately goes to the BUS FREE phase and aborts the current SCSI command. No further reconnection is attempted, and no STATUS or COMMAND COMPLETE message is sent for the command. The sense data is set to HARDWARE ERROR/MESSAGE ERROR(04h/43h). o LINKED COMMAND COMPLETE - If the rejected message is a LINKED COMMAND COMPLETE message, the drive immediately goes to the BUS FREE phase and does not read the next command in the linked list. The sense data is set to HARDWARE ERROR/MESSAGE ERROR(04h/43h). o MESSAGE REJECT - If the rejected message is a MESSAGE REJECT message, the drive immediately terminates the present command with a CHECK CONDITION status and sets the sense data to HARDWARE ERROR/ MESSAGE ERROR (04h/43h). o RESTORE POINTERS - Since the RESTORE POINTERS message is only used in an error recovery or retry situation, if the rejected message is a RESTORE POINTERS message, the drive aborts the recovery or retry attempt, assumes the error is unrecoverable, and completes the command according to the error condition. o SAVE DATA POINTER - The drive assumes the initiator does not support this message and does not attempt to disconnect from the bus during this command. Doc 1014995, Rev B 19 Maxtor Corporation XT-4000S Product Specification & OEM Technical Manual 6.7.6 Initiator MESSAGE PARITY ERROR When the drive receives a MESSAGE PARITY ERROR message from the initiator, it retries the operation by resending the original message. If the message cannot be sent successfully, the drive immediately goes to the BUS FREE phase and aborts the current SCSI command. No further reconnection is attempted and no STATUS or COMMAND COMPLETE message is returned for the command. The sense data is set to ABORTED COMMAND/SCSI PARITY ERROR (0Bh/47h). 6.7.7 RESELECTION Time-Out When the drive attempts to reselect the initiator and the initiator does not respond within a sele