seagate SCSI INTERFACE Manual

SCSI Interface

Ultra 320 Ultra 160

Product Manual, Volume 2

SCSI Interface

Ultra 320 Ultra 160

Product Manual, Volume 2

Publication number: 75789509, Rev. C

February 2004

Seagate and Seagate Technology are registered trademar ks of Seagate Technology LLC. SeaTools, SeaFONE, SeaB OARD, SeaTDD, and the Wave logo are registe red trademarks or trademarks of Sea gate Technology LLC . Other pr oduct name s are re gistered tr ademarks or trademarks of their owners.

Seagate reserves the right to ch ange, witho ut notice, product offerings or spec ifications . No

part of this publication may be reproduc ed in any form w ithout wr itte n per mi ssio n of Seagate

Technology LLC.

Revision status summary sheet

Revision Date Sheets Affected

A Issue 01/31/2000 D. Ashby/G. Houlder 1/1, v thru viii, 1 thru 338. Rev. B 04/22/2002 L. Newman/G. Houlder 1/1, v thru xvi, 1 thru 364. Rev. C 02/13/2004 K. Schweiss/G. Holder 39, 83, 86, 94, 115, 123, 135-140,

Sheets Affected

141, 174, 202, 207, 210, 224-225, 227-228, 230, 232, 236, 238, 249, 252, 253, 255, 258, 260, 267, 280, 313, 325-326, 331-338, 345, 348, 351, 354-361, and 363.

Table of Contents

1.0 Interface requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 How to use this interface manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1.1 Scope of SCSI standards. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.1.2 Applicable standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2 General interface description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.2.1 Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.2.2 Keywords. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1.3 Physical interface characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

1.4 Summary of SCSI commands and messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

2.0 SCSI bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.1 SCSI bus signals overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

2.1.1 Drive select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.1.2 Signal values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.2 Signal states . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.2.1 SE signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.2.2 LVD signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2.3 OR-tied signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

2.4 Signal sources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

2.5 SCSI bus timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

2.5.1 Arbitration delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.5.2 ATN transmit setup time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.5.3 ATN receive setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.5.4 Bus clear delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.5.5 Bus free delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

2.5.6 Bus set delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.7 Bus settle delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.8 Cable skew delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.9 Chip noise in receiver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.10 Clock jitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.11 De-skewed data valid window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.12 Flow control receive hold time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.13 Flow control receive setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.14 Flow control transmit hold time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.5.15 Flow control transmit setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.16 pCRC receive hold time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.17 pCRC receive setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.18 pCRC transmit hold time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.19 pCRC transmit setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.20 Data release delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.21 DIFFSENS voltage filter time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.22 Physical disconnection delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.23 Power on to selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.24 QAS arbitration delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2.5.25 QAS assertion delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.26 QAS release delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.27 QAS non-data phase REQ(ACK) period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.28 Receive assertion period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.29 Receive hold time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.30 Receive internal hold time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.31 Receive internal setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.32 Receive negation period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.5.33 Receive setup time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

SCSI Interface Product Manual, Rev. C (Draft 03) v

2.5.34 Receive REQ(ACK) period tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.5.35 Receive REQ assertion period with P_CRCA transitioning . . . . . . . . . . . . . . . . . . 33

2.5.36 Receive REQ negation period with P_CRCA transitioning. . . . . . . . . . . . . . . . . . . 33

2.5.37 Receive skew compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.5.38 Receiver amplitude time skew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.5.39 REQ(ACK) period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.5.40 Reset delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

2.5.41 Reset hold time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.42 Reset to selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.43 Residual skew error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.44 Selection abort time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.45 Selection timeout delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.46 Signal timing skew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.47 Skew correction range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.48 Strobe offset tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.49 System deskew delay. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.5.50 System noise at launch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.51 System noise at receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.52 Time asymmetry. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.53 Transmit assertion period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.54 Transmit hold time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.55 Transmit ISI compensation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.56 Transmit negation period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.57 Transmit setup time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.58 Transmit REQ(ACK) period tolerance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

2.5.59 Transmit REQ assertion period with P_CRCA transitioning. . . . . . . . . . . . . . . . . . 36

2.5.60 Transmit REQ negation period with P_CRCA transitioning . . . . . . . . . . . . . . . . . . 36

2.5.61 Transmitter skew . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.5.62 Transmitter time asymmetry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.6 Measurement points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.6.1 SE Fast-5 and Fast-10 measurement points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.6.2 SE Fast-20 measurement points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

2.6.3 LVD measurement points. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.7 Clocking methods for data transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.8 Paced transfer on a SCSI bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

2.9 Data transfer modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.9.1 Asynchronous transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.9.2 Synchronous transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.9.3 Paced transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.10 ST DATA phase parallel transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.11 DT DATA phase parallel transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.11.1 Data group transfers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

2.11.2 Information unit transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2.12 Negotiation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

2.12.1 Negotiation algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

2.12.2 When to negotiate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

2.12.3 Negotiable fields. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

2.12.4 Transfer agreements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

2.12.5 Transfer period factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

2.12.6 REQ/ACK offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

2.12.7 Transfer width exponent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

2.12.8 Protocol options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

2.12.8.1 IU_REQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

2.12.8.2 DT_REQ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

2.12.8.3 QAS_REQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

vi SCSI Interface Product Manual, Rev. C (Draft 03)

2.12.8.4 HOLD_MCS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

2.12.8.5 WR_FLOW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.12.8.6 RD_STRM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.12.8.7 RTI (Retain Training Information) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.12.8.8 PCOMP_EN. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

2.12.9 Negotiable field combinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

2.12.10 Message restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

2.12.11 Negotiation message sequences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

3.0 Logical characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

3.1 SCSI bus phases overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

3.1.1 BUS FREE phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

3.1.1.1 Unexpected and expected bus free phases. . . . . . . . . . . . . . . . . . . . . 53

3.1.1.2 Expected bus free phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

3.1.2 Arbitration and QAS overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

3.1.2.1 Normal ARBITRATION phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

3.1.2.2 QAS protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

3.1.2.3 QAS phase overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

3.2 SELECTION phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

3.2.1 Selection overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

3.2.1.1 Selection using attention condition . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

3.2.1.1.1 Starting the SELECTION phase when using

attention condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

3.2.1.1.2 Information unit transfers disabled . . . . . . . . . . . . . . . 58

3.2.1.1.3 Information unit transfers enabled. . . . . . . . . . . . . . . . 58

3.2.1.1.4 Selection using attention condition timeout

procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

3.2.1.2 Selection without using attention condition . . . . . . . . . . . . . . . . . . . . . 59

3.2.1.2.1 Information unit transfers disabled or enabled . . . . . . 59

3.2.1.2.2 Selection without using attenti on condi tion

time-out procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3.3 RESELECTION phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3.3.1 RESELECTION phase overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3.3.2 Physical reconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

3.3.3 Physical reconnection timeout procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

3.4 SCSI bus fairness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

3.5 Information transfer phases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

3.5.1 Asynchronous transfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3.5.2 Synchronous transfer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3.5.2.1 ST synchronous data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3.5.2.2 DT synchronous transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

3.5.2.2.1 Information unit transfer . . . . . . . . . . . . . . . . . . . . . . . 64

3.5.2.2.2 Data group data field transfer . . . . . . . . . . . . . . . . . . . 66

3.5.3 Paced transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

3.5.3.1 Paced transfer training pattern. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

3.5.3.1.1 DT DATA IN phase training pattern. . . . . . . . . . . . . . . 71

3.5.3.1.2 DT DATA OUT phase training pattern. . . . . . . . . . . . . 72

3.5.3.2 P1 data valid/invalid state transitions. . . . . . . . . . . . . . . . . . . . . . . . . . 73

3.5.3.2.1 Starting pacing transfers at end of training pattern . . . 74

3.5.3.2.2 Starting pacing transfers with no training pattern . . . . 74

3.5.3.2.3 Ending pacing transfers. . . . . . . . . . . . . . . . . . . . . . . . 75

3.5.3.3 Paced information unit transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

3.5.3.4 Deskewing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

3.5.4 Wide transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

3.6 COMMAND phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

SCSI Interface Product Manual, Rev. C (Draft 03) vii

3.6.1 COMMAND phase description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

3.6.2 COMMAND phase exception condition handling . . . . . . . . . . . . . . . . . . . . . . . . . . 77

3.7 DATA phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

3.7.1 DATA phase overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

3.7.2 DT DATA IN phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.7.3 DT DATA OUT phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.7.4 ST DATA IN phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.7.5 ST DATA OUT phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.8 STATUS phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.8.1 STATUS phase description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.8.2 STATUS phase exception condition handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.9 MESSAGE phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.9.1 MESSAGE phase overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

3.9.2 MESSAGE IN phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

3.9.2.1 MESSAGE IN phase exception condition handling . . . . . . . . . . . . . . . 79

3.9.3 MESSAGE OUT phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

3.9.3.1 MESSAGE OUT phase exception condition handling . . . . . . . . . . . . . 79

3.10 Signal restrictions between phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

3.11 SCSI bus phase sequences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

3.11.1 SCSI bus phase sequences overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

3.11.2 Phase sequences for physical reconnection and selection using attention

condition with information unit transfers disabled. . . . . . . . . . . . . . . . . . . . . . . . . . 81

3.11.3 Phase sequences for selection without using attention condition with

information unit transfers disabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

3.11.4 Phase sequences for physical reconnection or selection without using

attention condition with information unit transfers enabled. . . . . . . . . . . . . . . . . . . 83

3.11.5 Phase sequences for physical selection using attention condition with

information unit transfers enabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

3.12 Data bus protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

3.12.1 Data bus protection overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

3.12.2 ST data bus protection using parity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

3.12.3 DT data bus protection using CRC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

3.12.3.1 DT data bus protection using CRC overview . . . . . . . . . . . . . . . . . . . . 85

3.12.3.2 Error detection capabilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

3.12.3.3 Order of bytes in the CRC field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

4.0 Message system specification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

4.1 General message protocols and formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

4.2 Message formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

4.2.1 One-byte messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

4.2.2 Two-byte messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

4.2.3 Extended messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

4.3 Message categories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

4.3.1 LINK CONTROL MESSAGES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

4.3.2 DISCONNECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

4.3.3 IDENTIFY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

4.3.4 IGNORE WIDE RESIDUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

4.3.5 INITIATOR DETECTED ERROR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

4.3.6 LINKED COMMAND COMPLETE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

4.3.7 MESSAGE PARITY ERROR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

4.3.8 MESSAGE REJECT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

4.3.9 MODIFY DATA POINTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

4.3.10 MODIFY BIDIRECTIONAL DATA POINTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

4.3.11 NO OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

4.3.12 PARALLEL PROTOCOL REQUEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

viii SCSI Interface Product Manual, Rev. C (Draft 03)

4.3.12.1 PARALLEL PROTOCOL REQUEST . . . . . . . . . . . . . . . . . . . . . . . . . . 99

4.3.13 QAS REQUEST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

4.3.14 RESTORE POINTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

4.3.15 SAVE DATA POINTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

4.3.16 SYNCHRONOUS DATA TRANSFER REQUEST . . . . . . . . . . . . . . . . . . . . . . . . 101

4.3.16.1 Target initiated SDTR negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

4.3.16.2 Initiator initiated SDTR negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . 103

4.3.17 TASK COMPLETE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

4.3.18 WIDE DATA TRANSFER REQUEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

4.3.18.1 Target initiated WDTR negotiation. . . . . . . . . . . . . . . . . . . . . . . . . . . 106

4.3.18.2 Initiator initiated Wide Data Transfer Request (WDTR) negotiation . 106

4.4 Task attribute messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

4.4.1 Task attribute message overview and codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

4.4.2 ACA (AUTO CONTINGENT ALLEGIANCE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

4.4.3 HEAD OF QUEUE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

4.4.4 ORDERED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

4.4.5 SIMPLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

4.5 Task management messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

4.5.1 Task management message codes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

4.5.2 ABORT TASK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

4.5.3 ABORT TASK SET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

4.5.4 CLEAR ACA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

4.5.5 CLEAR TASK SET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

4.5.6 LOGICAL UNIT RESET. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

4.5.7 TARGET RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

5.0 Miscellaneous SCSI bus characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

5.1 Attention condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

5.2 Bus reset condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

5.3 Hard reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

5.4 Reset events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.4.1 Bus reset event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.4.2 Power on reset event. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.4.3 Target reset event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.4.4 Transceiver mode change reset event. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.5 Asynchronous condition recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

5.5.1 SCSI pointers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

5.5.2 Active pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

5.5.3 Saved pointers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116

5.6 Command processing considerations and exception conditions. . . . . . . . . . . . . . . . . . . . . 117

5.6.1 Command processing considerations and exception conditions overview . . . . . 117

5.6.2 Asynchronous event notification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117

5.6.3 Incorrect initiator connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

5.6.4 Unexpected RESELECTION phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

6.0 SPI information units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

6.1 Information unit transfer logical operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119

6.2 SPI information units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

6.2.1 SPI command information unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

6.2.2 SPI L_Q information unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

6.2.3 SPI data information unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

6.2.4 SPI data stream information unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

6.2.5 SPI status information unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

7.0 SCSI commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.1 Command implementation requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

SCSI Interface Product Manual, Rev. C (Draft 03) ix

7.1.1 Reserved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

7.2 Command Descriptor Block (CDB) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

7.2.1 Fixed and variable length Command Descriptor Block formats . . . . . . . . . . . . . . 136

7.3 Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

7.3.1 Status precedence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143

7.4 Command examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

7.4.1 Single command example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

7.4.2 Disconnect example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

7.5 Timing examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

7.6 Command processing considerations and exception conditions . . . . . . . . . . . . . . . . . . . . . 146

7.6.1 Auto Contingent Allegiance or Contingent Allegiance . . . . . . . . . . . . . . . . . . . . . 146

7.6.1.1 Logical Unit response to Auto Contingent Allegiance or

Contingent Allegiance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

7.6.1.2 Clearing an Auto Contingent Allegiance condition. . . . . . . . . . . . . . . 147

7.6.2 Overlapped commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

7.6.3 Incorrect logical unit selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

7.6.4 Sense data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

7.6.4.1 Asynchronous Event Reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

7.6.4.2 Autosense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

7.6.5 Unexpected RESELECTION phase. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

7.6.6 Unit Attention condition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150

7.6.7 Target hard reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

7.6.8 Logical unit reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

7.7 Queued tasks (formerly “queued I/O processes”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

7.7.1 Untagged task queuing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7.7.2 Tagged task queuing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152

7.8 Parameter rounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

7.9 Programmable operating definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

7.10 Incorrect initiator connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154

8.0 Command descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

8.1 CHANGE DEFINITION command (40h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

8.2 COMPARE command (39h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

8.3 COPY command (18h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

8.4 COPY AND VERIFY command (3Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

8.5 FORMAT UNIT command (04h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

8.5.1 FORMAT UNIT parameter definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

8.5.2 FORMAT UNIT parameter list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

8.5.2.1 Defect List header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164

8.5.2.2 Initialization Pattern Descriptor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

8.5.2.3 Defect List formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168

8.6 INQUIRY command (12h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170

8.6.1 Drive standard INQUIRY data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

8.6.2 SCSI Parallel Interface (SPI) specific INQUIRY data. . . . . . . . . . . . . . . . . . . . . . 179

8.6.3 Vital Product Data pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

8.6.4 Command support data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

8.6.5 Vital product data parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

8.6.5.1 ASCII Implemented Operating Definition page . . . . . . . . . . . . . . . . . 183

8.6.5.2 ASCII Information page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

8.6.5.3 Device Identification page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184

8.6.5.4 Supported Vital Product Data pages . . . . . . . . . . . . . . . . . . . . . . . . . 189

8.6.5.5 Unit Serial Number page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190

8.6.6 Firmware Numbers page (C0h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

8.6.7 Date Code page (C1h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193

8.6.8 Jumper Settings page (C2h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

x SCSI Interface Product Manual, Rev. C (Draft 03)

8.6.9 Device Behavior page (C3h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

8.7 LOCK UNLOCK CACHE (10) command (36h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

8.8 LOCK UNLOCK CACHE (16) command (92h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

8.9 LOG SELECT command (4Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200

8.10 LOG SENSE command (4Dh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203

8.10.1 Initiator page (0Fh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

8.10.2 Buffer Over-run/Under-run page (01h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210

8.10.3 Cache Statistics page (37h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211

8.10.4 Error Counter pages (WRITE, READ, READ REVERSE and VERIFY, 02h,

03h, 04h, and 05h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212

8.10.5 Factory Log page (3Eh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

8.10.6 Informational Exceptions log page (2Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213

8.10.7 Last n Deferred Errors or Asynchronous Events page (0Bh). . . . . . . . . . . . . . . . 215

8.10.8 Last n error events page (07h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215

8.10.9 Protocol Specific Port Log page (xxh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216

8.10.9.1 Relative target port identifier format. . . . . . . . . . . . . . . . . . . . . . . . . . 217

8.10.10 Non-Medium Error page (06h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217

8.10.11 Self-Test Results Log page (10h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218

8.10.12 Start-Stop Cycle Counter page (0Eh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221

8.10.13 Supported Log pages (00h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224

8.10.14 Temperature page (0Dh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225

8.11 MODE SELECT (6) command (15h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

8.11.1 MODE SELECT (6) parameter list. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

8.11.2 MODE SELECT (6) page descriptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

8.12 MODE SELECT (10) command (55h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

8.12.1 MODE SELECT (10) parameter list. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232

8.13 MODE SENSE (6) command (1Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235

8.13.1 MODE SENSE page descriptor header. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

8.13.2 Unit Attention parameters page (00h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 240

8.13.3 Error Recovery page (01h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242

8.13.4 Disconnect/Reconnect Control page (02h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245

8.13.5 Format Parameters page (03h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248

8.13.6 Rigid Drive Geometry Parameters page (04h). . . . . . . . . . . . . . . . . . . . . . . . . . . 251

8.13.7 Verify Error Recovery page (07h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 254

8.13.8 Caching Parameters page (08h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 257

8.13.9 Control Mode page (0Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

8.13.10 Notch page (0Ch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264

8.13.11 Power Condition page (1Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266

8.13.12 Xor Control Mode page (10h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267

8.13.13 Vital product data (VPD) parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

8.13.13.1 VPD parameters overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

8.13.13.2 Block Limits VPD page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 269

8.13.14 Port Control Mode page (19h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271

8.13.14.1 Margin control subpage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272

8.13.14.2 Saved training configuration values subpage . . . . . . . . . . . . . . . . . . 274

8.13.14.3 Negotiated settings subpage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

8.13.14.4 Report transfer capabilities subpage . . . . . . . . . . . . . . . . . . . . . . . . 277

8.13.15 Informational Exceptions Control page (1Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . 278

8.14 MODE SENSE (10) command (5Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281

8.15 MOVE MEDIUM command (A7h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284

8.16 PERSISTENT RESERVE IN command (5Eh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

8.16.1 PERSISTENT RESERVE IN parameter data for READ Keys . . . . . . . . . . . . . . . 286

8.16.2 PERSISTENT RESERVE IN parameter data for READ Reservations . . . . . . . . 287

8.16.3 PERSISTENT RESERVE IN parameter data for REPORT CAPABILITIES . . . . 291

8.17 PERSISTENT RESERVE OUT command (5Fh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 292

SCSI Interface Product Manual, Rev. C (Draft 03) xi

8.17.1 PERSISTENT RESERVE OUT parameter list . . . . . . . . . . . . . . . . . . . . . . . . . . . 294

8.18 PREFETCH (10) command (34h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297

8.19 PREFETCH (16) command (90H) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299

8.20 PREVENT/ALLOW MEDIUM REMOVAL command (1Eh) . . . . . . . . . . . . . . . . . . . . . . . . . 300

8.21 READ (6) command (08h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

8.22 READ (10) command (28h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303

8.23 READ (12) command (A8h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305

8.24 READ (16) command (88h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307

8.25 READ BUFFER command (3Ch). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309

8.25.1 Read Combined Descriptor Header and Data mode (0000b) . . . . . . . . . . . . . . . 310

8.25.2 READ DATA mode (0010b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

8.25.3 READ BUFFER Descriptor mode (0011b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310

8.25.4 Read Data from Echo Buffer mode (1010b). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311

8.25.5 Echo Buffer Descriptor mode (1011b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 312

8.26 READ CAPACITY (10) command (25h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313

8.27 READ CAPACITY (16) command (9Eh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315

8.28 READ DEFECT DATA (10) command (37h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 317

8.29 READ DEFECT DATA (12) command (B7h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 319

8.30 READ ELEMENT STATUS command (B4h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321

8.31 READ LONG command (3Eh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322

8.32 REASSIGN BLOCKS command (07h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 324

8.32.1 REASSIGN BLOCKS defect list. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325

8.33 RECEIVE DIAGNOSTIC RESULTS command (1Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 326

8.33.1 Supported Diagnostic Pages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

8.33.2 Translate Address page (40h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 328

8.34 RELEASE (6) command (17h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

8.35 RELEASE (10) command (57h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330

8.36 REPORT DEVICE IDENTIFIER command (A3h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331

8.37 REPORT LUNS command (A0h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333

8.38 REQUEST SENSE command (03h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336

8.38.1 Sense Key Specific field. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339

8.38.1.1 Current errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

8.38.1.2 Deferred errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341

8.38.2 Sense Key and Sense Code descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 343

8.38.3 Additional Sense and Additional Sense Qualifier codes. . . . . . . . . . . . . . . . . . . . 344

8.39 RESERVE (6) command (16h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.40 RESERVE (10) command (56h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.41 REZERO UNIT command (01h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.42 SEARCH DATA EQUAL command (31h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.43 SEARCH DATA HIGH command (30h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.44 SEARCH DATA LOW command (32h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.45 SEEK (6) command (0Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348

8.46 SEEK EXTENDED command (2Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349

8.47 SEND DIAGNOSTIC command (1Dh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350

8.47.1 Supported Diagnostic page—SEND DIAGNOSTIC . . . . . . . . . . . . . . . . . . . . . . . 352

8.47.2 Translate Address page—SEND DIAGNOSTIC . . . . . . . . . . . . . . . . . . . . . . . . . 353

8.48 SET DEVICE IDENTIFIER command (A4h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 354

8.49 SET LIMITS command (33h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 355

8.50 START/STOP UNIT command (1Bh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356

8.51 SYNCHRONIZE CACHE (10) command (35h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 357

8.52 SYNCHRONIZE CACHE (16) command (91h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358

8.53 TEST UNIT READY command (00h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360

8.54 VERIFY (10) command (2Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361

8.55 VERIFY (12) command (AFh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363

8.56 VERIFY (16) command (8Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365

xii SCSI Interface Product Manual, Rev. C (Draft 03)

8.57 WRITE (6) command (0Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367

8.58 WRITE (10) command (2Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369

8.59 WRITE (12) command (AAh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371

8.60 WRITE (16) command (8Ah). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373

8.61 WRITE AND VERIFY (10) command (2Eh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 375

8.62 WRITE AND VERIFY (12) command (AEh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377

8.63 WRITE AND VERIFY (16) command (8Eh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379

8.64 WRITE BUFFER command (3Bh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381

8.64.1 Combined header and data mode (0000b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

8.64.2 vendor-specific mode (0001b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

8.64.3 Data mode (0010b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382

8.64.4 Download microcode mode (0100b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383

8.64.5 Download microcode and save mode (0101b). . . . . . . . . . . . . . . . . . . . . . . . . . . 383

8.64.6 Download microcode with offsets (0110b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383

8.64.7 Download microcode with offsets and save mode (0111b) . . . . . . . . . . . . . . . . . 384

8.64.8 Write data to echo buffer (1010b) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385

8.65 WRITE LONG command (3Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386

8.66 WRITE SAME (10) command (41h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387

8.67 WRITE SAME (16) command (93h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388

8.68 Xor commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389

8.69 XDREAD (10) command (52h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390

8.70 XDREAD (32) command (7Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391

8.71 XDWRITE (10) command (50h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

8.72 XDWRITE (32) command (7Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394

8.73 XDWRITEREAD (10) command (53h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396

8.74 XDWRITEREAD (32) command (7Fh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397

8.75 XPWRITE (10) command (51h). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399

8.76 XPWRITE (32) command (7Fh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 400

9.0 Drive features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

9.1 S.M.A.R.T. system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

9.2 Self-test operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

9.2.1 Default self-test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

9.2.2 The short and extended self-tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403

9.2.3 Self-test modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

9.2.3.1 Foreground mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

9.2.3.2 Background mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404

9.2.3.3 Elements common to foreground and background self-test modes. . 405

9.3 Alternate error detection for the asynchronous information phases (AIP)—Command,

Message, and Status. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406

9.3.1 Error detection for asynchronous information phases . . . . . . . . . . . . . . . . . . . . . 406

9.3.2 Protection code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 406

9.3.2.1 Covered signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407

9.3.2.2 Code description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408

9.3.2.3 Error detection properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408

9.3.3 Protection code usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409

9.3.3.1 Protection code transmission. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409

9.3.3.2 Enabling protection code checking . . . . . . . . . . . . . . . . . . . . . . . . . . 409

9.3.3.3 Disabling protection code checking . . . . . . . . . . . . . . . . . . . . . . . . . . 409

9.3.4 Parity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409

9.3.5 Error handling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 409

9.4 Removal and insertion of SCSI devices (popularly known as “hot plugging”) . . . . . . . . . . . 410

9.4.1 Removal and insertion of SCSI devices overview . . . . . . . . . . . . . . . . . . . . . . . . 410

9.4.2 Case 1—Power off during removal or insertion . . . . . . . . . . . . . . . . . . . . . . . . . . 410

9.4.3 Case 2—RST signal asserted continuously during removal or insertion . . . . . . . 410

SCSI Interface Product Manual, Rev. C (Draft 03) xiii

9.4.4 Case 3—Current I/O processes not allowed during insertion or removal. . . . . . . 410

9.4.5 Case 4—Current I/O process allowed during insertion or removal . . . . . . . . . . . 411

9.5 SPI-3 to SCSI-2 terminology mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412

10.0 Seagate Technology support services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413

xiv SCSI Interface Product Manual, Rev. C (Draft 03)

List of Figures

Figure 1. Functional scope of SCSI standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Figure 2. SCSI client-server model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 3. Voltage and current definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 4. LVD Signaling sense . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Figure 5. ST latching data vs. DT latching data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 6. ST synchronous transfer example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 7. DT synchronous transfer example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 8. Paced transfer example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 9. Example of a SCSI bus with paced transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 10. Use of P1 to establish data valid and data invalid states . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 11. Phase sequences for physical reconnection and selection using attention condition

with information unit transfers disabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Figure 12. Phase sequences for selection without using attention condition with information unit

transfers disabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Figure 13. Phase sequences for physical reconnection or selection without using attention

condition/with information unit transfers enabled. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Figure 14. Phase sequences for selection with attention condition/physical reconnection and

information unit transfers enabled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Figure 15. SPI information unit sequence during initial connection . . . . . . . . . . . . . . . . . . . . . . . . . . . 120

Figure 16. SPI information unit sequence during data type transfers. . . . . . . . . . . . . . . . . . . . . . . . . . 121

Figure 17. SPI information unit sequence during data stream type transfers. . . . . . . . . . . . . . . . . . . . 122

Figure 18. SPI information unit sequence during status transfers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Figure 19. Single command example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Figure 20. Disconnect example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145

Figure 21. Protection code generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 408

SCSI Interface Product Manual, Rev. C xv

xvi SCSI Interface Product Manual, Rev. C

1.0 Interface requirements

1.1 How to use this interface manual

This manual provides a description of the SCSI1 interface protocol an d some general timing informa tion as implemented by Seagate products. The features described in this manual are typically referred to as “Ultra160 SCSI” or “Ultra320 S CSI” features. Each individual drive’s Product Manual, Volume 1, for the various SCS I interface products contains additional and more detailed information on protocol, features su pported, timing, and electrical/mechanical aspects of how the SCSI interface is implemented by that product.

This manual provides a ge neral, tuto rial-t ype des cripti on of the ANSI SCSI (for merly c alled SC SI-3) s ystem. It is not intended to give all of the kin ds of details needed t o design/implemen t a SCSI system o r product. For information about SCSI interface details not included herein or in Volume 1, refer to the standards listed in Section 1.1.1.

Note. The individual drive’s Produc t Manual, Volume 1, has tables that specify which SCSI features the

drive implements, what the defa ult parameters are for the vario us features they impleme nt, which parameters are changeable, and which are not.

The combination of t h is s pe ci fic ati on tog ethe r with the de tails in the ind iv id ual dri ve ’s Produ ct Manual, Volume 1, provides a description of how a particular product implements the SCSI I/O system. This specification is Volume 2 of a set of manuals that is made up of an individual drive’s Product Manual, Volume 1, and this manual. The older Ultra2 SCS I Interface P roduct Manual, Volume 2, part number 7 7738479 , applies to Seagate products that implement ol der versions of the S CSI interface (SCSI-1/ SCSI-2). This new S CSI Interface Product Manual, Volume 2, part number 75789509, is referenced by newer individual drive’s Product Manuals, Volume 1, representing Seagate produ cts that support Ultra160 or Ultra320 SCSI feat ures and other new features, such as packetized information transfer (SPI information units), data group transfers, paced transfers, increased CRC protection, etc.

1.Unless required for clarity, “SCSI” is now used instead of “SCSI-3.”

SCSI Interface Product Manual, Rev. C 1

1.1.1 Scope of SCSI standards

Figure 1 uses a representative set of specifications to show the functional partitions and the relationships among SCSI standards applicable to drives covered by this product manual.

SCSI Block

Commands (SBC)

Commands

SCSI Primary

Commands (SPC)

SCSI

Interlocked

Protocol

SCSI Architecture Model (SAM)

Figure 1. Functional scope of SCSI standards

and

SCSI

Parallel

Interface (SPI-3)

SCSI

Fibre Channel

Protocol (FCP)

Fibre Channel

Physical and Signaling

Interface (FC-PH)

Protocols

Common Access Method (CAM)

Interconnects

2 SCSI Interface Product Manual, Rev. C

The functional areas define the scope of each standard as follows:

• SCSI Architecture Mode l: Define s the SCSI sy stem s model , the functio nal partitioni ng of the SCSI standard set and requirements applicable to all SCSI implementations and implementation standards.

• Commands: Implementation standards which define classes including a device model for each class. These standards specify the r equired comm ands and beha vior that is comm on to all devic es or unique to a gi ven class of devices and prescribe the rules to be followed by a SCSI initiator port when sending commands to a device.

• Common Access Method: Implementation standard which defines a host architecture and set of services for device access.

• Protocols: Implementation standards which define the rules for exchanging information so that different SCSI devices can communicate.

• Interconnects: Implementation standards which define the electrical and signaling rules essential for devices to interoperate over a given physical interconnect.

The diagram of Figure 1 shows how the standards listed below fit within each category . The standards included in the diagram are meant to serve as examples and may not reflect the full set of standards currently in force.

1.1.2 Applicable standards

The following ANSI standa rds should be refe renced for more de tails about SCSI syste m standards of operation:

• SCSI Architecture Model-2 (SAM-2), T10/1157D

• SCSI Enclosure Services Command Set (SES), T10/1212D

• SCSI Block Commands (SBC-2), T10/1417-D

• SCSI Primary Commands-3 (SPC-3), T10/1416-D

• SCSI Enhanced Parallel Interface (EPI), T10/1143D

• SCSI Parallel Interface (SPI-4), T10/1365D

• SCSI Medium Changer Commands (SMC), T10/999D

• SCSI Controller Command Set-2 (SCC-2), T10/1225D

• SCSI Stream Device Command Set (SSC), T10/997D

• SCSI Enclosure Services (SES), T10/1212D

1.2 General interface description

This SCSI Interfac e Product Manual d escribes the Seag ate Technology, Inc. subset of th e SCSI ( Small Computer Systems Interface) as implemented on the Seagate-built drives. The interface is compatible with the SCSI Interface Specifications listed in S ection 1.1.2 . The drives covered by this product ma nual are classi fied as “Intelligent” peripherals.

The Seagate SCS I interface describe d herei n consists o f a 9 or 18 bit bidirectio nal data bus (includ es bits for parity checking and enabli ng CRC p ro tec tio n), plus 9 con trol signals. The SCSI interfac e sup ports mul ti ple in itiators, disconne ct/reconnect, self-configu ring host so ftware, automatic features that relieve the host from the necessity of know ing the ph ys i cal a rchi tec tur e of the target (log ic al bl ock addressing is us ed ), and some other miscellaneous feat ures .

The SCSI physical inte rface uses either s ingle-ended drivers and receivers or low vol tage differential drivers and receivers an d uses asynchronous or synchronous communication protocols. The bus i nterface transfer rate for asynchronous or syn chronous is given in ind ividual drive ’s Product Manual , Volume 1. The bus protocol supports multiple i nitiators, disconnect /reconnect, additiona l messages plus 6-byte, 10- byte, 12-byte, 16byte and variable length Command Descriptor Blocks.

SCSI Interface Product Manual, Rev. C 3

Unless specified othe rwise in th e individual drive’s Product Manual, Volume 1, the drive is always a S CSI target port, and never a SCS I initiator port. For certain com man ds, whi ch may or may not be supported by a particular drive model, the drive must act as a S CSI initiator port, but does not othe rwise do so. For purposes of this specification, “drive” may be substituted for the word “target” wherever “target” appears.

In the event of a conflict between this document and ANSI SCSI documents, the requirements of the ANSI documents shall apply.

Note. In this revision, some new terminology is introduced as taken from the ANSI specifications. In many

instances, the broader scope terms such as “initiator” and “target” are not used, but rather the more specific terms “initiator” and “target” appear. In Figure 2, it can be seen that several “initiators” from a single initiato r may have one or mo re tasks in queue with se veral “targets” in a singl e target. A drive could be a S CSI target port or it could be one of the targets as part of some larg er entity. When reading the description, one needs to be able to put the drive of interest in the proper context in terms of what is shown in Figure 2. For a proper understanding of the operation of the SCSI protocol, the terms in the SCSI architectural model as described in ANSI specification T10/1157D (SAM-2) should be well understood before r eading operatio n descriptions in any SCSI document. Although a Glossary of terms is provided herein, the definitions may not be adequate for some. The SAM-2 specification gives a more detailed understanding of some of the new SCSI terminology

Logical

Unit

Application

Client

Device Service Request

Device Service Response

Device Server

Task Management Request

Task Management Response

Initiator

Figure 2. SCSI client-server model

Task

Manager

Target

1.2.1 Glossary aborted command—A SCSI command that has been ended by aborting the task created to execute it. ACA—Auto Contingent Allegiance (see below). ACA command—A command performed by a task with the ACA attribute. See Section 4.4.2. initiator—An object that i s the source of SCS I commands. An o bject in this se nse is not a tangible piec e of

hardware, but may be a s ing le num er ic para mete r, such as a logic al un it n umb er, or a complex enti ty tha t per forms a set of operations or services on behalf of another object (see ANSI SAM-2, T10/1157D).

asynchronous event notification—A procedure used by targets to notify initiato rs of even ts that occur whe n a pending task does not exist for that initiator.

asynchronous transfer—An information transfer that uses the REQ/ACK handshake with an offset of zero. auto contingent allegiance—One of the conditions of a task set following the return of a CHECK CONDITION

status. See Section 4.4.2.

4 SCSI Interface Product Manual, Rev. C

blocked (task state)—The state of a task that is prevented from completing due to an ACA condition. blocking boundary—A task set boundary deno ting a set of condi tions that in hibit tasks ou tside the bou nda ry

from entering the Enabled state.

byte—An 8-bit construct. call—The act of invoking a procedure. client-server—A relationship established between a pair of distributed objects where one (the client) requests

the other (the server) to perform some operation or unit of work on the client’s behalf (see ANSI standard SAM-2, T10/1157D).

client—An object that requests a service from a server. command—A request describing a unit of work to be performed by a target. command descriptor block—A structure used to communicate a command from an initiator to a target. Com-

mand structures of 6, 10, 12, or 16 bytes are used, but a new v ariable length co mmand s truct ure has rec ently been introduced.

completed command—A command that has ende d by retur ni ng a status and s ervi ce resp ons e of Task Complete or Linked Command Complete.

completed task—A task that has ended by r eturning a status and service r esponse of Task Complete. The actual events comprising the Task Complete response are protocol specific.

confirmation—A response returned to an object, which signals the completion of a service request. confirmed service—A service av ai lab le at th e p ro toc ol s er v ice interface, which req uires co nfi rm ati on of com-

pletion. The confirm ed s ervi ce consists of the request and co nfi rm ati on steps and optionally the indic atio n an d response steps.

contingent allegiance—An optional condition of a task set following the return of a CHECK CONDITION status. A detailed definition of contingent allegiance may be found in Section 4.4.2.

control mode page—The mode page that identifies the sett ings of several target behavior s that may be of interest to an initiat or or may b e changed by an initiator. The complete de finition of the Control mode page is found in Section 8.13.9.

current task—A task that is in the process of sending messages, sending status, transferring data, or transferring command data to or from the initiator.

cyclic redundancy chec k (CRC)—An error detec ting code used to detect the validi ty of data that has been transferred during the current data group.

data field—The portion of a data group that contains data bytes. data group—A sequence of data bytes and the f our pCRC bytes during a DT D ATA IN PHASE or a DT DATA

OUT PHASE that starts at the first byte of the DT DATA phase or at the first byte after the last pCRC byte. data group transfer—Parallel transfers that t ransfer d ata and pCRC i nform ation us ing only data gro ups. The

last four bytes of a data group transfer contain CRC information over the whole data group. destination device—The SCSI device to which a service delivery transaction is addressed. See source

device. target—An object within the logical unit which executes SCSI tasks according to the rules for task manage-

ment described in clause 7 of ANSI SAM-2 document, T10/1157D. device service request—A request, submitted by an initiator, conveying a SCSI command to a target.

SCSI Interface Product Manual, Rev. C 5

device service response—The response returned to an initiator by a target on completion of a SCSI command.

differential—A signalling alternative that empl oys di fferential (tw o com pleme ntary signals ) drivers and rec eivers to improve signal-to-noise ratios and increase maximum cable lengths.

disconnect—The action that occurs when a SCSI devi c e releas es con tr ol of the SCS I bus, all owi ng it to go to the BUS FREE PHASE.

domain—An I/O system consistin g of a set of SCSI dev ices tha t inter act with one anoth er by mean s of a service delivery subsystem.

dormant (task state)—The state of a task that is prevented from starting execution due to the presence of certain other tasks in the task set.

double transition (DT)—The latching of data on both the assertion edge and the negated edge of the REQ or ACK signals.

driver—The circuitry used to control the state of the bus. enabled (task state)—The state of a task th at m ay comp lete at any time. Alterna tiv el y, the state of a task that

is waiting to receive the next command in a series of linked commands.

ended command—A command that has completed or aborted. exception condition—Any event that causes a SC SI d evice to e nter an auto co ntinge nt alle gian ce or c ontin-

gent allegiance condition.

faulted initiator—The initiator to which a Command Terminated or CHECK CONDITION status was returned. faulted task set—A task set that contained a faulting task. faulting command—A command that completed with a status of Check Condition or Command Terminated. faulting task—A task that has completed with a status of Check Condition or Command Terminated. function complete—A logical unit response indicating that a task management function has finished. The

actual events comprising this response are protocol specific. hard reset—a SC SI target port respo nse to a reset event o r a S CSI target port Rese t in which the target per-

forms the operations described in Section 7.6.7.

implementation—The physical realization of an object. implementation-specific—A requireme nt or feature tha t is define d in a SCSI s tandard but whose i mplemen-

tation may be specified by the system integrator or vendor. implementation option—An option whose actualization within an imple mentation is at the discretion of the

implementor.

indication—The second step in a four-step confirmed service reply to a request. information unit tr ansfer—Pa rallel tran sfers that transfe r data, status, commands, task attribut es, task man-

agement information, acrid, and nexus information using only SPI information units. initial connection—The result of a physical connect. It exists from the assertion of the BSY signal in a

SELECTION PHASE until the next BUS FREE PHASE or the next QAS REQUEST message. initiator—A SCSI device containing initiators which originate device service and task management requests to

be processed by a SCSI target port SCSI device. interconnect—The electrical media (including connectors and passive loads) used to connect the TERM-

PWR, terminators, and SCSI devices in a SCSI bus.

6 SCSI Interface Product Manual, Rev. C

interconnect subsys tem —One or more physical in terc onne cts whi ch appear as a single path for the tra ns fer of information between SCSI device s in a domai n.

intersymbol interference (ISI)—The effect of adjacent symbols on the symbol currently being received. in transit—Information that has been sent to a remote object but not yet received. I/O operation—An operation defin ed by an u nlink ed SCS I com mand, a seri es of li nked S CSI c ommand s or a

task management function. I/O process—An I/O process consists of one initial connection or, if information units are enabled, the

establishment of a nexus, and a zero o r more physic al or l ogical r econne ction all per taining to a s ingle task or a group of tasks. An I/O process beg ins with the es tabli shmen t of a nex us . If the SPI inform ati on un it trans fe rs are disabled, an I/O pr ocess no rmally end s with a C ommand Com plete mes sage. If info rmation u nit transfe rs are enabled, an I/O process ends with a SPI L_Q info rmati on un it wit h the ty pe fi el d set to status an d the Data Length field set to zero.

I T nexus—A nexus that exists between a SCSI initiator port and a SCSI target port. I T L nexus—A nexus that exists between a SCSI initiator port, a SCSI target port, and a logical unit. This rela-

tionship replaces the prior I T nexus. I T L Q nexus—A nexus between a SCS I initiator por t, a SCSI target port, a logi cal unit, and a queue tag fol-

lowing the successful receipt of one of the queue tag message s. This relationship replaces the prior I T L nexus.

iuCRC protection—The use of CRC to detect DT DATA PHASE data transmission errors during parallel transfers. Contains CRC information covering all bytes transmitted in a SPI information unit.

layer—A subdivision of the architecture constituted by subsystems of the same rank. linked CDB—A CDB with the link bit in the control byte set to one. linked command—One in a series of SCSI comman ds execu ted by a si ngle task, whic h coll ectiv ely make up

a discrete I/O operati on. In such a series, ea ch co mmand has the same task identifier, and all except t he last have the link bit in the CDB control byte set to one.

logical connect—Establishes an I_T_L_Q nexus using SPI L_Q information units. logical disconnect—Reduces the current I_T_L_Q nexus to an I_T nexus. logical reconnect—Reestablishes an I_T_L_Q nexus from an I_T nexus using SPI L_Q information units. logical unit—a SCSI target port-reside nt entity which implements a device model and exec utes SCSI com-

mands sent by an initiator.

logical unit number—A 64-bit identifier for a logical unit. logical unit option—An option pertaining to a logical unit, whose actualization is at the discretion of the logical

unit implementor.

lower level protocol—A protocol used to carry the information representing upper level protocol transactions. mandatory—The referenced item is required to claim compliance with a standard. media information—Informatio n store d within a SCSI d evice whic h is n on-volatil e (retained through a po wer

cycle) and accessible to a SCSI initiator port through the execution of SCSI commands. multidrop—A characteristic of the SCSI bu s that allo ws SCSI devices to be connecte d to the SCSI bu s with-

out disrupting the electrical path between the terminators. multimode single-ended (MSE)—A signalling alternative for multimode SCSI devices that employs MSE driv-

ers and receivers to allow multimode SCSI devices to operate when SE SCSI devices are present on the bus.

SCSI Interface Product Manual, Rev. C 7

nexus—A relat ionship between a SCSI initia tor port and a SCSI target port, lo gical unit, or queue tag that begins with an ini tia l co nne ction and ends with the completion of the associated I/O pr oces s. T hi s rel ati ons hi p is formed as the result of a task.

object—An architectural abstraction or “container” that encapsulates data types, services, or other objects that are related in some way.

odd parity—Odd logical parity, where the parity bit is dri ve n an d v erifi ed to b e th at v al ue that mak es th e nu mber of assertions o n the asso ciated data byte p lus the parity bit eq ual to an o dd num ber (1, 3, 5, 7, or 9). See parity bit. If an even number of asserted bits are detected at the receiver, a parity error occurs.

paced transfer—Parallel transfers that transfer information using pacing. pacing—Use of the ACK or REQ signal as a contin uously runni ng clock i n combinati on with the P 1 signal t o

indicate when data is valid.

packetized—A method of transferring information using SPI information units. See object. pad field—The portion of a data group that contains pad information. parallel protocol request—Messages use d to ne got iate a sy nchr on ous data trans fer agree men t, a wi de da ta

transfer agreement, and set the protocol options between two SCSI devices. par i t y b i t —A bi t associ ated with a byte that is used to detect th e presence of an od d number of asser ted bits

within the byte. The parity bit is driven such that the number of logical ones in the byte plus the parity bit is odd.

pCRC field—The portion of a data group that contains pCRC information. pCRC protection—The use of pCRC to detect DT DATA PHASE. peer-to-peer protocol service—A service used by an upper level protocol implem entation to exchange infor -

mation with its peer.

peer entities—Entities within the same (protocol) layer. pending task—A task that is not a current task. physical interconnect—A single physical pathway for the transfer of informat ion between SCS I devices in a

domain. physical reconnect—Th e act of resumi ng a nexus to continue a task. A S CSI target port i nitiates a phys ical

reconnect when conditions are appropriate for the physical bus to transfer data associated with a nexus between a SCSI initiator port and a SCSI target port.

physical reconnection—The result of a physical reconn ec t that ex ists from the asserti on of the BS Y signal in a SELECTION or RESEL ECTION PHASE. A physical reconnection e nds with the BUS FREE PHASE (see Section 3.1.1) or a QAS REQUEST message (see Section 4.3.13).

port—Synonymous with “service delivery port.” A single attachment to a SCSI bus from a SCSI device. procedure—An operation that can be invoked through an external calling interface. protocol—The rules governing the conten t and exchange of informatio n passed between distributed obje cts

through the service delivery subsystem.

protocol option—An option whose definition within a SCSI protocol standard is discretionary. protocol service confirmation—A signal fr om the lower level pro tocol service lay er notif ying the up per l ayer

that a protocol service request has completed. protocol service indication—A signal from the lower level protocol service layer notifying the upper level that

a protocol transaction has occurred.

8 SCSI Interface Product Manual, Rev. C

protocol service request—A call to the lo wer le ve l protoc ol s er vic e l ay er to begin a protocol ser vi ce tran sa ction.

protocol service response—A reply from the upper level protocol layer in response to a protocol service indication.

quick arbitration and selection process (QAS)—Quicker than the normal arbitrati on and s electio n pro cess. Implementation is optional for SCSI devices.

queue—The arrangement of tasks within a task set, usually according to the temporal order in which they were created. See task set.

queue tag—The parameter associated with a task that uni que ly id enti fi es it f ro m ot her tagged tasks for a log ical unit from the same initiator.

receiver—A client or server that is the recipient of a service delivery transaction. reference model—A standard model used to specif y sys tem requi remen ts in an i mplem entation- indepe ndent

manner.

request—A transaction invoking a service. request-response transaction—An interaction between a pa ir of d istributed , cooper ating ob jects, co nsisting

of a request for service submitted to an object followed by a response conveying the result. request-confirmation transaction—An interaction between a pair of cooperating objects, consisting of a

request for service submitted to an object followed by a response for the object confirming request completion. reset event—A protocol-specific event which may trigger a hard reset response from a SCSI device as

described in Section 5.3.

response—A transaction conveying the result of a request. SCSI application layer—The proto cols and procedures tha t implement or invoke S CSI commands and task

management functions by using services provided by a SCSI protocol layer. SCSI device—A device that contains at le ast one SCSI port and the means to connec t its drivers and receiv-

ers to the bus.

SCSI device identifier—An address by which a SCSI device is referenced within a domain. SCSI I/O system—An I/O system, cons isting of two or more SCSI devices, a SCSI i nterconnect a nd a SCSI

protocol, which collectively interact to perform SCSI I/O operations. SCSI protocol layer—The protocol and services used by a SCSI application layer to transport data represent-

ing a SCSI application protocol transaction.

sender—A client or server that originates a service delivery transaction. server—A SCSI object that performs a service on behalf of a client. service—Any operation or function performed by a SCSI object, which can be invoked by other SCSI objects. service delivery failure —Any non-recoverable error causing t he corruption or loss of one or more ser vice

delivery transactions while in transit. service delivery po rt—A device-residen t interface used by the initiato r, target or task manager to ente r and

retrieve requests and responses from the service delivery subsystem. Synonymous with “port.” service delivery subsy stem—That part of a SCSI I/ O system which transmits serv ice requests to a logical

unit or target and returns logical unit or target responses to a SCSI initiator port. service delivery transaction—A request or response sent through the service delivery subsystem.

SCSI Interface Product Manual, Rev. C 9

signal—(n) A detectable asynchro nous event possibly accompanied by descriptive data and parameters. (v) The act of generating such an event.

single transition (ST)—The latching of data only on the assertion edge of the REQ or ACK signals. source device—The SCSI device from which a service delivery transaction originates. See destination devic e. SPI information unit—Data structures that encapsulate data, status, command, task attributes , iuCRC, and

nexus information into various formats. SPI L_Q information unit—The SPI L_Q in for ma tio n unit (see Section 6.2. 2, tables 48 and 49) contains L_Q

nexus (Logical unit—Q tag relationship) information for the information unit that follows, the type of information unit that follows, and the length of information unit that follows. A SPI L_Q information unit shall precede all SPI command information units, SPI multiple command in formation units, SPI data information u nits, SPI status information units, and the first of an uninterrupted sequence of SPI data stream information units.

subsystem—An element in a hierarchically part itioned system which i nteracts directly only wi th elements in the next higher division or the next lower division of that system.

suspended information—Information stored within a logical unit that is not available to any pending tasks. target—A SCSI device which receives SCSI com mands and directs such command s to one or more logical

units for execution. task—An object withi n the logical unit representing the wor k associated with a command or group of lin ked

commands. A task consists of one initial connection and zero or more physical or logical reconnections, all pertaining to the task.

task abort event—An event or condition indic ating that the task has been aborted by means of a task m anagement function.

task address—a SCSI initiator port iden tifies a task to a SCSI target port usi ng a Task Addres s. The Task Address object repr esen ts either a Tagged Task Address or an Untagged Task Address without regard for the tagged or untagged nature o f the Task. A Tagged Task Address is composed of a Log ical Unit Ide ntifie r and a Tag. An Untagged Task Address is composed of a Logical Unit Identifier.

task completion event—An event or condition indicating that the task has end ed with a ser vice response o f Task Complete.

task ended event—An event or condition indicating that the task has completed or aborted. task management function—A t ask manager service which can be invoked by an initiator to affect the execu-

tion of one or more tasks. task management request—A request submitted by an initiator, invoking a task management fun ction to be

executed by a task manager. task management response—The response returned to an initia tor by a task manager on comple tion of a

task management request.

task manager—A server within the target which executes task management functions. task set—A group of tasks within a SCSI target port devi ce, whose interac tion is dependent on the queuing

and auto contingent allegiance rules of Section 7.6.1.

task slot—Resources within the logical unit that may be used to contain a task. task tags—A Tag is a field containing up to 64 bits that is a component of a Tagged Task Identifier. A SCSI ini-

tiator port assigns tag values in each Tagged Task Identifier in a way that ensures that the identifier uniqueness requirements stated in ANSI SAM-2, T10/1157D, Section 4.9, are met.

10 SCSI Interface Product Manual, Rev. C

third-party command—A SCSI command whic h re quire s a l ogi ca l uni t wit hin the target dev ice to as su me th e initiator role and send a SCSI command to a SCSI target port device.

transaction—A cooperative interaction between two objects, involving the exchange of information or the execution of some service by one object on behalf of the other.

transfer period—The negotiated time between edges of RE Q or ACK that latch data. For ST, the transfer period is measured from assertion edge of the REQ or ACK signal to the next assertion edge of the signal. For DT, the transfer period is measured from a transition edge of the REQ or ACK signal to the next transition edge of the signal.

unconfirmed protocol service—A service available at the protocol service interface, which does not result in a completion confirmation.

unlinked command—A SCSI command having the link bit set to zero in the CDB control byte. upper level protocol—An application-specif ic protocol execute d through services provided by a lower level

protocol.

1.2.2 Keywords

Several keywords are used to differentiate between different levels of requirements and optionality, as follows:

vendor-specific—Specification of the referenced item is determined by the device vendor. protocol-specific—Implementation of the referenced item is de fined by a SCSI protocol standard (se e Sec-

tion 1.1.1.)

expected—A keyword used to describe the behavior of the models specified by this standard. invalid—A keyword us ed to desc ribe an ille gal or u nsupp orted bit, by te, word, field , or c ode v alue. Receipt o f

an invalid bit, byte, word, field, or code value shall be reported as an error.

mandatory—A keyword indicating items required to be implemented as defined by this standard. may—A keyword that indicates flexibility of choice with no implied preference (equivalent to “may or may not”). may not—Keywords that indi cates flexibilit y of choice with no i mplied preference (equivalent to “ may or may

not”). obsolete—A keyword indicating items that were defined in prior SCSI standard s but ha ve be en remo ve d f rom

this standard. option, optional—Keywords that describe features which are not required to be implemented by this stan-

dard. However, if any optional feature defined by the standard is implemented, it shall be implemented as defined by the standard.

reserved—A key word referring to bits, bytes, words, fields, and code values that are set aside for future standardization. Their us e and interpretation may b e specified by fu ture extensions to this or other standards. A reserved bit, byte, word, or field sh all be s et to zero, or in acco rdanc e with a fu ture exten sion to this standard . Recipients are not required to check rese rved bits, bytes , word s, or fiel ds for ze ro val ues. Rece ip t of reser ved code values in defined fields shall be treated as an error.

shall—A keyword i ndicating a m andatory re quirement. De signers a re required to impleme nt all such mandatory requirements to ensure interoperability with other standard conformant products.

should—A keyword indicating flexibility of choice with a strongly preferred alternative. Equivalent to the phrase “it is recommended.”

SCSI Interface Product Manual, Rev. C 11

1.3 Physical interface characteristics

The physical interface characteristics (cables, connectors, ele ctrical descriptions, termination requirements, etc.) for the drives cover ed by this Interfac e Manual are found in each indivi dual drive’s Product Manual, Volume 1, since these features are not the same for all drives.

12 SCSI Interface Product Manual, Rev. C

+ 436 hidden pages