seagate ST136403LW, ST136403LC Product Manual

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Cheetah 36 Family :

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ST136403LW/LC

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Product Manual, Volume 1

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Cheetah 36 Family :

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ST136403LW/LC

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Product Manual, Volume 1

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Publication number: 83329440, Rev. B

August 1999

Seagate, Seagat e Technology, and the Seagate logo are registered trademar ks of Seagate Technology, Inc. Cheetah, SeaFAX, SeaFONE, SeaBOARD, and SeaTDD are either trademar ks or registered trademarks of Seagate Technology, Inc. or one of its subsidiaries. All other trademar ks or registered trademarks are the property of their respective owners.

Seagate reserves the right to chang e, without notice, product offerings or specifications. No part of this

publication may be reproduced in any for m without written permission of Seagat e Technology, Inc.

Revision status summary sheet

Revision Date Writer/Engineer Sheets Affected

Rev. A 06/02/99 L. Newman/D. Rus ch 1/1, v thru viii, 1-74. Class A Release. Rev. B 07/20/99 L. Newman/D. Rusch 19 and 29.

Notice. Product Manual 83329440 is Volume 1 of a two volume document with the SCSI Interface information in

the Volume 2 SC SI Interface Product Manual, par t number 7773 8479. If you need the SCSI Interface information, order the Volume 2 Interface Manual, part number

77738479.

Cheetah 36 Product Manual, Rev. B vii

Table of Contents

1.0 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2.0 Applicable standards and reference documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1 Standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1.1 Electromagnetic compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1.2 Electromagn etic susceptibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.2 Electromagn etic compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.3 Reference d ocuments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3.0 General descr iption. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3.1 Standard features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.2 Media characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.3 Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.4 Reliabili ty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3.5 Unformatted and formatted capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.6 Programmable drive capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.7 Factory installed accessories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.8 Options (factory installed). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.9 Accessories (user installed) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4.0 Performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.1 Internal drive characteristi cs (transparent to user). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.2 SCSI performance characteristics (visible to user) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.2.1 Access tim e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.2.2 Format comm and ex ecution time (minute s) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.2.3 Generalized performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4.3 Start/stop time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.4 Prefetch/m ulti-segmented cache control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

4.5 Cache operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0

4.5.1 Caching write data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.5.2 Prefetch o peration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

5.0 Reliability specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1 Error rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1.1 Environmental interference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1.2 Read errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1.3 Write erro rs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1.4 Seek errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.2 Reliability and service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5.2.1 Mean time between failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5.2.2 Field failure rate vs time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5.2.3 Preve ntive maintenan ce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.2.4 Service life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.2.5 Service philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.2.6 Service tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.2.7 Hot plugging Cheetah 36 disc drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.2.8 S.M.A.R.T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

5.2.9 Product warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

6.0 Physical/electrical specific ations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.1 AC power requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.2 DC power requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.2.1 Conduct ed noise immu nity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.2.2 Power sequenc ing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.2.3 12 V - Current profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

6.3 Power dissi pation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2

6.4 Environmental limits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

viii Cheetah 36 Product Manual, Rev. B

6.4.1 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

6.4.2 Relative humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

6.4.3 Effective altitude (sea level). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24

6.4.4 Shock and vibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

6.4.5 Air cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

6.4.6 Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

6.4.7 Electromagn etic susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

6.5 Mechanical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

7.0 Defect and error management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

7.1 Drive inte rnal defects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

7.2 Drive erro r recovery procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31

7.3 SCSI systems errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

8.0 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

8.1 Drive ID/option select header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

8.1.1 Notes for Figures 12, 13, and 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

8.1.2 Function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

8.2 Drive orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

8.3 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

8.3.1 Air flow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

8.4 Drive mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

8.5 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

9.0 Interface requiremen ts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

9.1 General description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

9.2 SCSI interface messages supported. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

9.3 SCSI interface commands suppo rted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42

9.3.1 Inquiry Vital Product data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

9.3.2 Mode Sense data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46

9.4 SCSI bus conditions and miscellaneous features support ed . . . . . . . . . . . . . . . . . . . . . . . . .48

9.5 Synchronous data trans fer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

9.5.1 Synch ronous data transfer periods supported. . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

9.5.2 REQ/ACK offset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

9.6 Physical interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

9.6.1 DC cable and connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

9.6.2 SCSI interface physical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

9.6.3 SCSI interface cable requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

9.6.4 Mating connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

9.7 Electrical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

9.7.1 Multimo de—SE and LV D alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

9.8 Terminator requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62

9.9 Terminator power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62

9.10 Disc drive SCSI timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63

9.11 Drive activity LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64

10.0 Seagate Te chnology support services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65

Cheetah 36 Product Manual, Rev. B ix

List of Figures

Figure 1. Cheetah 36 family drive (ST136403LW shown). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figure 2. Cheetah 36 family drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 3. Typical Cheetah 36 family drive +12 V current profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 4. Typical Cheetah 36 SCSI SE mode +5 V current profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figu r e 5 . Typic a l Chee tah 36 SC SI LVD m o d e +5 V curren t p r o file . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 6. DC current and power vs. input/output operations per second (single-ended mode) . . . . . . 22

Figure 7. DC current and power vs. input/output operations per second (LVD mode) . . . . . . . . . . . . . 22

Figure 8. Locations of PCBA components listed in Table 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 9. Recommended mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 10. ST136403LW mounting configuration dimens ion s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 11. ST136403LC mounting configuration dimens ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 12. J6 jumper header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 13. J5 jumper header (on LW models only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Figure 14. J2 option select header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 15. Air flow (suggested) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 16. ST136403LW drive physical interface (68-pin J1 SCSI I/O connector) . . . . . . . . . . . . . . . . . 50

Figure 17. ST136403LC drive physical interface (80-pin J1 SCSI I/O connector) . . . . . . . . . . . . . . . . . 50

Figure 18. SCSI daisy chain interface cabling for LW drives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Figure 19. Nonshielded 68 pin SCSI device connector used on LW drives . . . . . . . . . . . . . . . . . . . . . . 54

Figure 20. Nonshielded 80 pin SCSI “SCA-2” connector, used on LC drives . . . . . . . . . . . . . . . . . . . . . 55

Figure 21. LVD output signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Figure 22. Typical SE-LVD alternative tra nsmitter receiver circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Cheetah 36 Product Manual, Rev. B 1

1.0 Scope

This manual describes Seagate Technology®, Inc. Cheetah 36™ disc drives. Cheetah 36 drives support the sm all comput er system interface (SCSI) as described in the ANSI S CS I, SCSI-

2, and SCSI-3 (Fast-20 and Fast-40) interface specifications t o th e extent described in this manual. The

Interface Product Manual

other families of Seagate drives. From this point on in this product manual the reference to Cheetah 36 models is referred to as “the drive”

unless references to individual models are necessary.

(part number 77738479) describes general SCSI interface characteristics of this and

SCSI

Figure 1. Cheetah 36 family dri ve (ST136403LW shown)

Cheetah 36 Product Manual, Rev. B 3

2.0 Applicable standards and reference documentation

The drive has been developed as a system peripheral to the highest standards of design and construction. The drive depends upon its hos t equipment to provide adequate power and environment in order to ach ieve optimum performance and compliance with applicable industry a nd governmental regulations. Special attention must be given in the areas of safety, power distribution, shielding, audible noise control, and temperature regulation. In particular, the drive must be securely m ount ed in o rder to guarante e the s pecified pe rform ance c haracteristics. Mounting by bottom holes must meet the requirements of Section 8.4.

2.1 Standards

The Cheetah 36 family complies with Sea gate standards as noted in the appropriate sections of this Manual and the Seagate

The Cheetah 36 disc drive is a UL recognized com ponent per U L1950, CS A cer tified t o CSA C2 2.2 No. 950M89, and VDE certified to VDE 0805 and EN 60950 .

2.1.1 Electromagnetic compatibility

The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to use. As such the drive is supplied as a subassembly and is not subject to Subpar t B of Part 15 of the FCC Rules and Regulations nor the Radio Interference Regulations of the Canadian Department of Communications.

The design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides reasonable shielding. As such, the drive is capable of meeting the Class B limits of the FCC Rules and Regulations of the Canadian Department of Communications when properly packaged. However, it is the user’s responsibility to assure that the drive meets the appropriate EMI requirements in their system. Shielded I/O cables may be required if the enclosure does not provide adequate shielding. If the I/O cables are external to the enclosure, shielded cables should be used, with the shields grounded to the enclosure and to the host controller.

SCSI Interface Product Manual

, part number 77738479 (Vol. 2).

2.1.2 Electromagnetic susceptibility

As a component assem bly, the drive is not required to me et any suscep tibility performance requi remen ts. It is the responsibility of those integrating the dri ve within their system s to perform t hose t ests req uired and design their system to ensure that equipment operating in the same system as the drive or external to the system does not adversely affect the performance of the drive. See Section 5.1.1 and Table 2, DC power requirements.

2.2 Electromagnetic compliance

Seagate uses an independen t laboratory to confirm complia nce to the directives/standard(s) for CE Marking and C-Tick Marking. The drive was tested in a representative system for typical applications. The selected system represents the most popular characteristics for test platforms. The system configurations include:

• 486, Pentium, and PowerPC microprocessors

• 3.5-inch floppy disc drive

• Keyboard

• Monitor/display

• Printer

• External modem

• Mouse

Although the test system with this Seagate m odel com plies to the directives/standard(s), we cannot guarantee that all systems will comply. The computer manufacturer or system integrator shall confirm EMC compli ance and provide CE Marking and C-Tick Marking for their product.

Electromagnetic compliance for the European Union

If this model has the CE Marking it complies with the European Union requirements of the Electrom agnetic Compatibility Directive 89/336/EEC of 03 May 1989 as am ended by Directive 92/31/EEC of 28 A pri l 19 92 and Directive 93/68/EEC of 22 July 1993.

4 Cheetah 36 Product Manual, Rev. B

Australian C-Ti ck

If this model has the C-Tick Marking it complies with the Au stralia/New Zealand Standard AS/NZS3548 1995 and meets the Electromagnetic Compatibility (EMC) Framework requirements of Australia’s Spectrum Management Agency (SMA).

2.3 Reference documents

Cheetah 36 Installation Guide SCSI Interface Product Manual

ANSI small computer system interface (SCSI) document numbers:

X3.131-1994 SCSI-2 X3.253-1995 SCSI-3 Parallel Interface

T10/1142D Rev. 14 SPI-2 (SCSI-3 Parallel Interface version 2) SFF-8046 Specification for 80-pin connector for SCSI disk drives Package Test Specification Seagate P/N 30190-001 (under 100 lb.) Package Test Specification Seagate P/N 30191-001 (over 100 lb.) Specification, Acoustic Test Requirements, and Procedures Seagate P/N 30553-001 In case of conflict between this document and any referenced document, this document takes precedence.

Seagate P/N 83329450 Seagate P/N 77738479

Cheetah 36 Product Manual, Rev. B 5

3.0 General description

Cheetah 36 drives combine dual s tr ipe magnetoresistive (DSMR) heads, partial response/ m ax imum likelihood (PRML) read channel electronics, embedded servo technology, and a wide Ultra2 SCSI interfa ce to provide high performance, high capacity dat a storage for a variety of systems including engineering workstations, network servers, mainframes, and supercomputers.

Ultra SCSI and Ultra2 SCSI us e negotiated transfer rates. These transfer rates will occur only if your host adapter support s these data transfer rates and is com patible with the required hardware requirem ents of the I/O circui t type. T his drive a lso ope rates at S CSI-1 an d SCS I-2 da ta transfer rates for backward compa tibility with non-Ultra/Ultra2 SCSI host adapters.

Table 1 lists the features that differentiate the two Cheetah 36 models.

Table 1: Drive model number vs. differentiating features

Number

Model number

of heads I/O circuit type [1]

ST136403LW 24 Single-ended (SE) and low voltage

Number of I/O connector pins

Number of I/O data bu s bits

68 16

differential (LVD)

ST136403LC 24 Single-ended (SE) and low voltage

80 16

differential (LVD)

[1] See Section 9.6 for details and definitions. The drive records and recovers data on approxim ately 3.3-inch (84 mm) non-removeable discs. The drive supports the S mall Computer System Interface (SCSI) as described in the ANSI SCSI-2/SCSI -3

interface specifications to the extent described in this m anual (volume 1), which defines the p roduct performance characteristics of the Cheetah 36 family of drives, and th e

SCSI Interface Product Manual

(volume 2), part number 77738479, which describes the general interface characteristics of this and other families of Seagate SCSI drives.

The drive’s interface supports multiple initiators, disconnect/reconnect, self-configuring host software, and automatic features that relieve the host from the necessity of knowing the physical characteristics of the targets (logical block addressing is used).

The head and disc assembly (HDA) is sealed at the factory. Air circulates within the HDA through a nonreplaceable filter to maintain a contamination-free HDA environment.

Refer to Figure 2 for an exploded view of the drive. This exploded view is for information only—never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads, media, actuator, etc.) as this requires special facilities. The drive contains no replaceable parts. Opening the HDA voids your warranty.

Cheetah 36 drives use a dedicated landing zone at the innermost radius of the media to eliminate the possibility of destroying or degrading data by landing in the data zone. The drive automatically goes to the landing zone when power is removed.

An automatic shipping lock prevents potential damage to the heads and discs that results from movement during shipping and handling. The sh ipping lock autom atically diseng ages when power is applied t o the drive and the head load process begins.

Cheetah 36 drives decode track 0 location data from the servo data embed ded on each surface to eliminate mechanical transducer adjustments and related reliability concerns.

A high-performance actuator ass embly with a low-inertia, balanced, patented, straight-arm design provides excellent performance with minimal power dissipation.

6 Cheetah 36 Product Manual, Rev. B

Figure 2.

Cheetah 36

family drive

Cheetah 36 Product Manual, Rev. B 7

3.1 Standard features

The Cheetah 36 family has the following standard features:

• Integrated Ultra/Ultra2 SCSI controller

• Multimode SCSI drivers and receivers—single-ended (SE) and low voltage differential (LV D)

• 16 bit I/O data bus

• Asynchronous and synchronous data transfer protocol

• Firmware downloadable via SCSI interface

• Selectable even by te secto r sizes from 512 to 4,096 bytes/sector

• Programmable sector reallocation scheme

• Flawed sector reallocation at format time

• Programmable auto write and read reallocation

• Reallocation of defects on command (post format)

• Enhanced ECC correction capability up to 185 bits

• Sealed head and disc assembly

• No preventative mai ntenanc e or adjustment required

• Dedicated head landing zone

• Embedded servo design

• Self diagnostics performed when power is applied to the drive

• 1:1 Interleave

• Zoned bit recording (ZBR)

• Vertical, horizontal, or top down mounting

• Dynamic spindle brake

• 1,024 kbyte data buffer (or 4,096 kbyte option)

• Hot plug compatibility (Section 9.6.4.2 lists proper host connector needed) for “LC” model drives

• SCAM (SCSI Configured Automatically) plug-n-play level 2 compliant, factory set to level 1

3.2 Media characteristics

The media used on the drive has a diameter of approximately 3.3 inches (84 mm). The aluminum substrate is coated with a thin film magnet ic materi al, overcoated with a proprie tary prot ective layer for improved dura bility and environmental protection.

3.3 Performance

• Supports industry standard Ultra2 SCSI interface

• Programmable multi-segmentable cache buffer (see Section 3.1)

• 10,016 RPM spindle. Average latency = 2.99 ms

• Command queuing of up to 64 commands

• Background processing of queue

• Supports start and stop commands (spindle stops spinning)

3.4 Reliability

• 1,000,000 hour MTBF

• LSI circuitry

• Balanced low mass rotary voice coil actuator

• Incorporates industr y-standa rd Self-Monitori ng, Analysis and Reporting Technol ogy (S.M.A.R.T.)

• 5-year warranty

8 Cheetah 36 Product Manual, Rev. B

3.5 Unformatted a n d formatted capacities

Formatted capacity depends on the number of spare reallocation sectors reserved and the number of bytes per sector. The following table shows the standard OEM model capacities:

Formatted data block size 512 bytes/sector [1] Unformatted

ST136403 43D6720h (36.40 GB) [2] 43.2 GB

Notes.

[1] Sector size selectable at for mat time. Users having the necessary equipment may modify the data block

size before issuing a format command and obtain di fferent formatted capacities t han those listed. See Mode Select Command and Format Command in the

SCSI Interface Product Manual

, part number

77738479.

[2] User available capacity depends on spare reallocation scheme selected, the num ber of data tracks per

sparing zone, and the number of alternate sectors (LBAs) per sparing zone.

3.6 Programmable drive capacity

Using the Mode Select command, the dr ive can change its capacity to something less than maximum. See Table 5.2.1-13 in the

SCSI Interface Product Manual

, part numb er 77738479, Rev. H. Refer to the Parameter list block descriptor number of blocks field. A value of zero in the number of blocks field indicates that the drive shall not change the c apacity it is currently format ted to have. A number in the number o f blocks field that is less than the max imum number of LB As changes th e total drive capacity to the value in the block descr iptor number of blocks field. A value greater than the m aximum number of LB As is rou nded down to the maximum capacity.

3.7 Factory installed accessories

OEM Standard dr ives are shipped with t he

Cheetah 36 Installation Guide

, part number 8 3329450 (unless otherwise specified). The factory also ships with the dr ive a small bag of jumpe r plugs used for the J2, J5, and J6 option select jumper headers.

3.8 Optio ns (factory insta lled)

All customer requested options are in corporated during pr oduction or packaged at t he manufacturing facility before shipping. Some of the options available are (not an exhaustive list of possible options):

• Other capacities can be ordered depending on sparing scheme and secto r size requested.

• 4 Mbyte optional buffer size.

• Single unit shipping pack. T he drive is nor mally shipped in bulk packaging to provide max imum protection

against transit damage. Units shipped individually require additional protection as provided by the single unit shipping pack. Users planning single unit distribution should specify this option.

• The

Cheetah 36 Installation Guide

, part number 83329450, is usually included with each standard OEM

drive shipped, but extra copies may be ordered.

3.9 Accessories (user installed)

The following accessories are available. All accessories may be installed in the field.

• Single unit shipping pack.

Cheetah 36 Product Manual, Rev. B 9

4.0 Performance characteristics

4.1 Internal drive characteristics (transparent to user)

ST136403

Drive capacity 36.4 GByte (formatted, rounded off values) Read/write heads 24 Bytes/track 153,284–229,045 Bytes (average, rounded off values) Bytes/surface 1,913 Mbytes (unformatted, rounded off values) Tracks/surf ace (to tal) 9,801 Tracks (user accessible) Tracks/inch 12,580 TPI Peak bits/inch 252 KBPI Internal data rate 179-313 Mbits/sec (variable with zone) Disc rotational speed 10,016 r/min (+ Average rotational latency 2.99 msec

4.2 SCSI performance characteristics (visible to user)

The values given in Section 4.2.1 apply to all models of the Cheetah 36 fam ily unless otherwise specified. Refer to Section 9.10 and to the

SCSI Interface Product Manual

details.

0.5%)

, part number 77738 479, for additional timing

4.2.1 Access time [5]

Including cont roller overhead (without disconnect) [1] [3]

Drive level Drive level

Not Including controller overhead (without disconnect) [1] [3]

Read Write Read Write

msec msec Average – Typical [2] 6.15 6.85 5.95 6.65 Single Track – Typical [2] 0.8 1.1 0.6 0.9 Full Stroke – Typical [2] 14.2 15.2 14.0 15.0

4.2.2 Format command execution time (minutes) [1]

ST136403

Maximum (with verify) 120 Maximum (no verify) 60

4.2.3 Generalized performance chara cteris tics

Minimum sector interleave 1 to 1

Data buffer transfer rate to/from disc media (one 512-byte sector):

Min. [3]* 21.1 MByte/ s ec Avg. [3] 29.0 MB yte/ s ec Max. [3] 36.8 MByte/sec

SCSI interface data transfer rate (asynchronous):

Maximum instantaneous one byte wide 5.0 Mbytes/sec [4] Maximum instantaneous two bytes wide 10.0 Mbytes/sec [4]

Synchronous transfer rate for SCSI Fast-40 (Ultra2 SCSI):

In single-ended (SE) interface mode 5.0 to 40 Mbytes/sec In low voltage differential (LVD) interface mode 5.0 to 80 Mbytes/sec

10 Cheetah 36 Product Manual, Rev. B

Sector Sizes:

Default 512 byte user data blocks Variable 512 to 4,096 bytes per sector in even number of bytes per sector.

If n (number of bytes per sector) is odd, then n-1 will be used.

Read/write consecutive sectors on a track Yes Flaw reallocation performance impact (for flaws reallocated at format time using

the spare sectors per sparing zone reallocation scheme.) Average rotational latency 2.99 msec

Notes for Section 4.2.

[1] Execution time measured from receipt of the last Byte of the Comm and Descriptor Block (CDB) to the

request for a Status Byte Transf er to the Initiator (excluding connect/disconnect).

[2] Typical access times are meas ured under nom inal conditions of te mperature, voltage, and horizontal ori-

entation as measured on a representative sample of drives. [3] Assumes no errors and no sector has been relocated. [4] Assumes system ability to support the rates listed and no cable loss. [5] Access time = controller overhead + average seek time.

Access to data = controller overhead + average seek time + latency time.

4.3 S tar t/stop time

After DC power at nominal voltage has been applied, the drive becomes ready within 30 seconds if the Motor Start Option is disabled (i.e. the motor starts as soon as the power has been applied). If a recoverable error condition is detected during the star t sequence, the drive executes a recovery procedu re which may cause the time to become ready to exceed 30 sec onds. During spin up to read y time the drive responds to some c ommands over the SCSI interface in less than 3 seconds after application of power. Stop time is less than 30 seconds from removal of DC power.

If the Motor Start Option is enabled, the inter nal controller accept s the commands listed in the S CSI Interface Product Manual less than 3 seconds after DC power has been applied. After the Motor Start Command has been received the drive becomes ready for normal operations within 30 seconds typically (excluding an error recovery procedure). The Motor Start Command can also be used to command the drive to stop the spindle (see

SCSI Interface Product Manual

, part number 77738479).

Negligible

There is no power control switch on the drive.

4.4 Prefetch/multi-segmented cache control

The drive provides prefetch (read look-ahead) and multi-segmented cache control algorithms that in many cases can enhance system performance. “Cache” as used herein refers to the drive buffer storage space when it is used in cache operations. To select prefetch and cache features the host sends the Mode Select command with the proper values in the applicable bytes in Mode Page 08h (see number 77738479. Prefetch and cache operation are independent features from the standpoint that each is enabled and disabled independently via the Mode Select command. However, in actual operation the prefetch feature overlaps cache operation somewhat as is noted in Section 4.5.1 and 4.5.2.

All default cache and prefetch Mode parameter values (Mode Page 08h) for standard OEM versions of this drive family are given in Tables 8.

4.5 Cache operation

In general, 840 Kbytes (3, 600 kbytes of the 4,096 kbytes on units with this option) of the physica l buffer space in the drive can be used as storage space for ca che operations. The buffer can be divided into logical segments (Mode Select Page 08h, byte 13) from which data is read and to which data is written. The drive maintains a table of logical block disk m edium addresses of the dat a st ored i n each segment of the buffer. If cac he operation is enabled (RCD bit = 0 in Mode Page 08h, byte 2, bit 0. See number 77738479), data requested by the host with a Read command is retrieved from the buffer (if it is there), before any disc access is initiated. If cache operation is not enabled, the buffer (still segmented with required

SCSI Interface Product Manual,

part

Cheetah 36 Product Manual, Rev. B 11

number of segments) is still used, but only as circular bu ffe r segments during disc medium read operations (disregarding Prefetch operation for the moment). That is, the drive does not check in the buffer segments for the requested read data, but goes directly to the medium to retrieve it. The retrieved data merely passes through some buffer segment on the way to the host. On a cache miss, all data transfers t o the host are i n accordance with buffer-full ratio rules. On a cache hit the drive ignores the buffer-full ratio rules. See explanations associated with Mode page 02h (disconnect/reconnect control) in the

The following is a simplified description of a read operation with cache operation enabled:

SCSI Interface Product Manual

Case A -

1. Drive transfers to the initiator the first LB requested plus all subsequent contiguous LBs that are alre ady in

2. When the requested LB is reached that is not in any cache segment, the drive fetches it and any remaining

3. If the prefetch feature is enabled, refer to Section 4.5.2 for operation from this point.

Case B -

1. The drive fetches the requested LBs from the disc and transf ers t hem into a segment, and from there to the

2. If the prefetch feature is enabled, refer to Section 4.5.2 for operation from this point. Each buffer segment is actually a self-contained circular storage (wrap-around occurs), the length of which is

an integer number of disc medium sectors. The wrap-around capability of the individual segments greatly enhances the buffer’s overall performance as a cache storage, allowing a wide range of user selectable config- urations, which includes their use in the prefetch operation (if enabled), even when cache operation is disabled (see Section 4.5.2). The number of segm ents may be selected using the Mode Select comm and, but the size can not be directly selected. Size is selected only as a by-product of selecting the segment number specification. The size in Kbytes of each segment is not reported by the Mode Sense command page 08h, bytes 14 and

15. The value 0XFFFF is always reported. If a size specification is sent by the host in a Mode Select command (bytes 14 and 15) no new segment size is set up by the drive, and if the STRICT bit in Mode page 00h (byte 2, bit 1) is set to on e, the drive responds as it doe s for any attempt to change unchangeable pa rameters (see

SCSI Interface Product Manual,

of segments from 1 to 16. Default is three segments.

A Read command is received and the first logical block (LB) is already in cache:

the cache. This data may be in multiple segments.

requested LBs from the disc and puts them in a segment of the cache. The drive transfers the remaining requested LBs from t he cac he to the host in acco rdance with the disconnect/reconnec t sp ecification m entioned above.

A Read command requests data, the first LB of which is not in any segment of the cache:

host in accordance with the disconnect/reconnect specification referred to in case A.

part number 77738479). The drive supports operation of any integer number

4.5.1 Caching write data

Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to be written to the medium is stored in one or more segments while the drive performs the write command.

If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made available for future read cache hi ts. The sam e buffer space and segmentation is us ed as set up for read functions. The buffer segmentation scheme is set up or changed indep endently, having nothing to do with the state of RCD. When a write command is issued, if RCD=0, the cache is first checked to see if any logical blocks that are to be written are already stored in the cache from a previous read or write command. If there are, the respective cache segments are cleared. The new data is cached for subsequent Read commands.

If the number of write data logi cal blocks exceeds the size of the segment bei ng written into, when the end of the segment is reached, the data is written into the beginning of the same cache segment, overwriting the data that was written there at the beginning of the operation. However, the drive does not overwrite data that has not yet been written to the medium.

If write caching is enabled (WCE=1), then t he drive may return GOOD status on a wri te command after the data has been transferred into the cache, but before the data has been written to the medium. If an error occurs while writing the dat a to the medium, and G OOD status has already been returned, a deferred error will be generated.

The Synchronize Cache command may be used to force the drive to write all cached write data to the medium. Upon completion of a Synchronize Cache command, all data received from previous write commands will have been written to the medium.

12 Cheetah 36 Product Manual, Rev. B

Tables 8 show Mode default settings for the drives.

4.5.2 Prefetch operation

If the Prefetch feature is enabled, data in con tig uous l ogical blocks on the disc immediately beyond that which was requested by a Read command can be retrieved and stored in the buffer for immediate transfer from the buffer to the host on subsequent Read commands that request thos e logical blocks (this is tr ue even if cache operation is disabled). Though the prefetch operation uses the buffer as a cache, finding the requested data in the buffer is a prefetch hit, not a cache operation hit. Prefetch is enabled using Mode Select page 08h, byte 12, bit 5 (Disable Read Ahead - DRA bit). DRA bit = 0 enables prefetch. Since data that is prefetched replaces data already in some buffer segment(s), the host can limit the amount of prefetch data to optimize system performance. The max prefetch field (bytes 8 and 9) limits the amount of prefetch. The drive does not use the Prefetch Ceiling field (bytes 10 and 11).

During a prefetch operation, the drive crosses a cylinder boundar y t o fetch more data only if the Discontinuity (DISC) bit is set to one in bit 4 of byte 2 of Mode parameters page 08h.

Whenever prefet ch (read look-ahead) is enabled (enabled by DRA = 0), it operates under the control of ARLA (Adaptive Read Look-Ahead). If the host uses software interleave, ARLA enables prefetch of contiguous blocks from the disc when it se nses that a prefetch hit will likely oc cur, even if two consecutive read operations were not for phy sically contiguous blocks of data (e.g. “software interleave”). ARLA disables prefetch when it decides that a prefetch hit will not likely occur. If the host is not using software interleave, and if two sequential read operations are not for contiguous blocks of data, ARLA disables prefetch, but as long as sequential read operations request contiguous blocks of data, ARLA keeps prefetch enabled.

Cheetah 36 Product Manual, Rev. B 13

5.0 Reliability specifications

The following reliability specifications assume correct host/drive operational interface, including all interface timings, power supply voltages, environmental requirements and drive mounting constraints (see Section 8.4).

Seek Errors

Less than 10 in 10

Read Error Rates [1]

Recovered Data Less than 10 errors in 10 Unrecovered Data Less than 1 sector in 10

Miscorrected Data Less than 1 sector in 10 MTBF 1,000,000 hours Service Life 5 years Preventive Maintenance None required

Note.

[1] Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.

5.1 Error rates

The error rates stated in this specification assume the following:

• The drive is operated per this specification using DC power as defined in this manual (see Section 6.2).

• The drive has been formatted with the SCSI FORMAT command.

• Errors caused by media defects or host system failures are excluded from error rate computations. Refer to Section 3.2, “Media Characteristics.”

• Assume random data.

seeks

bits transferred (OEM default settings)

bits tran sferred

5.1.1 Environmental interference

When evaluating syste ms operation under conditions of Electromagnetic Interference (EMI), the perfor mance of the drive within the system shall be c onsidered acc eptable if the drive does not generate an unrecoverable condition.

An unrecoverable error, or unrecoverable condition, is defined as one that:

• Is not detected and corrected by the drive itself;

• Is not capable of being detected from the error or fault status provided through the drive or SCSI interface; or

• Is not capable of being recovered by normal drive or system recovery procedures without operator interven-

tion.

5.1.2 Read errors

Before determination or measurement of read error rates:

• The data that is to be used for measurement of read error rates must be v erifi ed as being written correctly on the m edia.

• All media defect induced errors must be excluded from error rate calculations.

5.1.3 Write errors

Write errors can occur a s a result of media defects, environmental interference, or equipment malfunction. Therefore, write errors are not predictable as a function of the number of bits passed.

If an unrecoverable write error occurs because of an equipment malfunction in the drive, the error is classified as a failure affecting MTBF. Unrecoverable write errors are those which cannot be corrected within two attempts at writing the record with a read verify after each attempt (exc luding media defects).

5.1.4 Seek errors

A seek error is defined as a failure of the dr ive to posi tion the heads to the addressed track. There shal l be no more than ten recoverable seek errors in 10

physical seek operations. After detecting an initial seek error, the drive automatically performs an error recovery process. If the error recovery process fails, a seek positioning error (15h) is reported with a Medium error (3h) or Hardware error (4h) reported in the Sense Key. This is an

14 Cheetah 36 Product Manual, Rev. B

unrecoverable seek error. Unrecoverable seek errors are classified as failures for MTBF calculations. Refer t o Section 5.1.1.2 of the

SCSI Interface Product Manual,

part number 77738479, for Request Sense information.

5.2 Reliability and service

You can enhance the reliability of Cheetah 36 disc drives by ensuring that the drive receives adequate cooling. Section 6.0 provides temperature measurement s and other information that may be used to enhance the service life of the drive. Section 8.3.1 provides recommended air-flow information.

5.2.1 Mean time between failure

The production disc dri ve shall achieve an MTBF of 1,000,000 hours w hen operated in an environment that ensures the case temperatures specified in Section 6.4.1, Table 3 are not exceeded. Short-term excursions up to the specification l imits of the operating environment will not affect MTBF performance. Continual or sustained operation at case temperatures above the values shown in Table 3 may degrade product reliability.

The MTBF target is specified as device power-on hours (POH) for all drives in se rvice per failure.

Estimated power-on operating hours in the period

MTBF per measurement period =

Number of drive failures in the period

Estimated power-on operation hours means power-up hours per disc drive times the total number of disc drives in service. Each disc drive shall have accumulated at least nine months of operation. Data shall be calculated on a rolling average base for a minimum period of six months.

MTBF is based on the following assumptions:

• 8,760 power-on hours per year.

• 250 average on/off cycles per year.

• Operations at nominal voltages.

• Systems will provide adequate cooling to ensure the case tempe ratures specified in Section 6.4.1 are not

exceeded. Drive failure means any stoppage or failure to meet defined specifications caused by drive malfunction. A S.M.A.R.T. predictive failure indicates that the drive is deteriorating to an imminent failure and is considered

an MTBF hit.

5.2.2 Field failure rate vs time

The expected field failure rate is listed below . Drive utilization will vary. An estimated range of utilization is:

• 720 power-on hours (POH) per month.

• 250 on/off cycles per year.

• Read/seek/write operation 20% of power-on hours.

• Systems will provide adequate cooling to ensure the case tempe ratures specified in Section 6.4.1 are not

exceeded.

Month 1 2,364 PPM Month 2 1,422 PPM Month 3 1,403 PPM Month 4 1,391 PPM Month 5 1,317 PPM Month 6 1,255 PPM Month 7 1,162 PPM Month 8+ 1,025 PPM

Failure rate is calculated as follows:

• No system-induced failures are counted

• Based on 1,000,000 MTBF and 720 power-on hours per month

• Month 1’s rate includes a 300 PPM installation fai lure

Cheetah 36 Product Manual, Rev. B 15

5.2.3 Preventive maintenance

No routine scheduled preventiv e maintenance shall be required.

5.2.4 Service life

The drive shall have a usef ul service life of five years. Depo t repair or replacement of major parts is perm itted during the lifetime (see Section 5.2.5).

5.2.5 Servi c e philosophy

Special equipment is required to repair the drive HDA. In order to achieve the above service life, repairs must be performed only at a proper ly equipped and st affed service and r epair facility. Troubleshooting and repair of PCBs in the field is not rec ommended, because of the extensive diagnostic equi pment required for effective servicing. Also, there are no spare parts available for this drive. Drive warranty is vo ided if the HDA is opened.

5.2.6 Service tools

No special tools are required for site installation or recommended for site maintenance. Refer to Section 5.2.5. The depot repair philosophy of the drive precludes the necessity for special tools. Field repair of the drive is not practical since there are no user purchasable parts in the drive.

5.2.7 Hot pl ugg in g C heetah 36 dis c dri v es

The ANSI SPI-2 (T10/1142D) docum ent defines the physical requirements for removal and insertion of SCSI devices on the SCSI bus. Four cases are addressed. The cases are differentiated by the state of the SCSI bus when the removal or insertion occurs.

Case 1 - All bus devices powered off during removal or insertion Case 2 - RST signal asserted continuously during removal or insertion Case 3 - Current I/O processes not allowed during insertion or removal Case 4 - Current I/O process allowed during insertion or removal, except on the device being changed

Seagate Cheetah 36 disc drives suppo rt all four hot plugging cases. Provision shall be made by the system such that a device being inserted m akes power and ground connections prior to the conne ction of any device signal contact to the bus. A device being removed shall maintain power and ground connections after the disconnection of any device signal contact from the bus (see SFF-8046, SCA-2 specification).

It is the responsibility of the systems integrator to assure that no hazards from temperature, energy, voltage, or ESD potential are presented during the hot connect/disconnect operation.

All I/O processes for the SCSI device being insert ed or removed shall be quiescent. All SCS I devices on the bus shall have receivers that conform to the SPI-2 standard.

If the device being hot plugged uses single-ended (SE) drivers and the bus is currently operating in low voltage differential (LVD) mode, then all I/O processes for all devices on the bus must be completed, and the bus quiesced, before attempting to hot plug. Following the insertion of the newly installed device, the SCSI host adapter must issue a Bus Re set, followed by a synchronous transfer negotiation. Failure to perform the SCSI Bus Reset could result in erroneous bus operations.

The SCSI bus termination and termination power source shall be external to the device being inserted or removed.

End users should not mix devices with high voltage differential (HVD) drivers and receivers and devices with SE, LVD, or multimode drivers and receivers on the same SCSI bus since the common mode voltages in the HVD environment may not be controlled to safe levels for SE and LVD devices (see ANSI SPI-2).

The disc drive spindle must come to a complete stop prior to completely rem oving the drive from the cabinet chassis. Use of the Stop Spindle command or partial withdrawal of the drive, enough to be disconnected from the power source, prior to removal are methods for insuring that this requirement is met. During drive insertion, care should be taken to avoid exceeding the limits stated in Section 6.4.4, "Shock and vibration" in this manual.

16 Cheetah 36 Product Manual, Rev. B

5.2.8 S.M.A.R.T.

S.M.A.R.T. is an acronym for Self-Monitoring Anal ysis and Re porting Techn ology. This t echnology is intended to recognize conditions that indicate a drive failure and is designed to provide sufficient warning of a failure to allow data back-up before a n actual failure occurs.

Note.

The firmware will monitor specific attributes for degradation over time but cannot predict instantaneous drive failures.

Each attribute has been selecte d to m onitor a s pecific s et of failure conditions in th e operating pe rformanc e of the drive, and the thresholds are optimized to minimize “false” and “failed” predictions.

Controllin g S.M.A.R.T.

The operating mode of S.M.A.R.T. is controlled by the DEXCPT bit and the PERF bit of the “Informational Exceptions Control Mode Page” (1Ch). The DEXCPT bit is used to enable or di sable the S.M.A.R.T. process. Setting the DEXCPT bit will disable all S.M.A.R.T. functions. When enabled, S.M.A.R.T. will collect on-line data as the drive performs normal read/write operations. When the PERF bit is set, the drive is considered to be in “On-line Mode Only” and will not perform off-line functions.

The process of measuring of f- line attributes and saving data can be forced by the RTZ command. Forcing S.M.A.R.T. will reset the timer so that the next scheduled interrupt will be two hours.

The drive can be interrogated by the host to determine the time remaining before the next scheduled measurement and data logging process will occur. This is accomplished by a log sense command to log page 0x3E. The purpose is to allow the customer to control when S.M.A.R.T. interruptions occur. As described above, forcing S.M.A.R.T by the Rezero Unit command will reset the timer.

Performance impact

S.M.A.R.T. attribute data will be saved to the disc for the purpose of recreating the events that caused a predictive failure. The drive will measure and s ave parameters once every two hours subject t o an idle period on the SCSI bus. The process of measuring off-line attribute data and saving data to the disc is uninterruptable and the maximum delay is summarized below:

Maximum processing delay

On-li ne o nly de l ay Fully enabled de lay DEXCPT = 0, PERF = 1 DEXCPT = 0, PERF = 0

S.M.A.R.T. delay times 50 milliseconds 300 milliseconds

Repor tin g c on t rol

Reporting is controlled in the Informational Exce ptions Control Page (1Ch). Sub ject to the repor ting method, the firmware will issue a 01-5D00 sens e code t o the host. The error code is preser ved through bus resets and power cycles.

Determining rate

S.M.A.R.T. monitors the rate at wh ich errors occur and sig nals a predictive failure if the rate of degraded error rate increases to an unacceptable level. To determine rate, error events are logged and compared to the num ber of total operations for a gi ven attribute. The interval defines the number of operations over which to measure the rate. The counter that keeps track of the current number of operations is referred to as the Interval Counter.

S.M.A.R.T. measures error rate, hence for each attribute the occurrence of an error is recorded. A counter keeps track of t he num ber of errors for the current interval. This counter is referred to as the Fai lure Counter.

Error rate is simply the number of errors per operation. The algorithm that S.M.A.R.T. uses to record rates of error is to set thresholds for t he number of errors and the interval. If t he number of errors exceeds the threshold before the interval expires, then the error rate is considered to be unacceptable. If the number of errors does not exceed the threshold before the interval expires, then the error rate is considered to be acceptable. In either case, the interval and failure counters are reset and the process star ts over.

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