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EK-THZ02-SG-A01

May 1983

212 pages

Original

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Document:	THZ02/THZ27 Magnetic Tape Owner's Manual
Order Number:	EK-THZ02-SG
Revision:	A01
Pages:	212
Original Filename:

OCR Text

THZ02/THZ27 Magnetic Tape
Owner’s Manual
Order Number: EK–THZ02–SG.A01

Digital Equipment Corporation

July, 1993
The information in this document is subject to change without notice and should not be construed
as a commitment by Digital Equipment Corporation. Digital Equipment Corporation assumes no
responsibility for any errors that may appear in this document.
Restricted Rights: Use, duplication, or disclosure by the U.S. Government is subject to restrictions
as set forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software
clause at DFARS 252.227-7013.
© Digital Equipment Corporation 1993.
All Rights Reserved.
Printed in U.S.A.
FCC NOTICE: The equipment described in this manual generates, uses, and may emit radio
frequency energy. The equipment has been type tested and found to comply with the limits for
a Class A computing device pursuant to Part 15 of FCC Rules, which are designed to provide
reasonable protection against such radio frequency interference when operated in a commercial
environment. Operation of this equipment in a residential area may cause interference, in which
case the user at his own expense may be required to take measures to correct the interference.
The following are trademarks of Digital Equipment Corporation: CompacTape, TK, and the
DIGITAL logo.
IBM is a registered trademark and AS/400 is a trademark of International Business Machines
Corporation.
UNIX is a registered trademark of UNIX System Laboratories, Inc.

This document was prepared using VAX DOCUMENT, Version 2.1.

Contents
1 Overview of THZ02/THZ27 Subsystem
2 THZ02 Controller Hardware
2.1
2.2
2.2.1
2.2.2
2.2.3
2.2.4

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Controller Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCSI Interface and Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Write Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Read Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Protection and Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–1
2–2
2–2
2–2
2–5
2–5

3 Installation
3.1
3.2
3.2.1

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCSI ID Switch Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3–1
3–1
3–1

4 Tape Drive Operation
4.1
Power-On Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2
Front Panel Indicators and Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3
Front Panel Lights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.1
OK To Lift Handle Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.2
Tape In Use Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3
Write Protect Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.1
Write Protect Light On Steady . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.3.2
Write Protect Light Blinking . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.4
Use Cleaning Tape Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.5
All Four Lights Flashing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.6
Tape In Use and Write Protect Lights Flashing . . . . . . . . . . . . . . . . . .
4.3.7
Power On Light Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3.8
Unload Button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.4
Write Protect Switch on Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5
Cleaning Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.1
Cleaning Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.2
Cartridge Insert/Release Handle . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.3
CompacTape III Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.4
Loading the Tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5.5
Unloading the Tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4–1
4–2
4–3
4–3
4–3
4–3
4–3
4–3
4–4
4–4
4–4
4–5
4–5
4–5
4–6
4–6
4–6
4–7
4–8
4–9

iii

5 Media Loader Operation
5.1
5.2
5.3
5.3.1
5.3.2
5.4
5.5
5.5.1
5.5.2
5.5.3
5.5.4
5.6
5.6.1
5.6.2
5.6.3
5.6.4

Introduction to The Media Loader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-On Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mode Select Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Service Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operator Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Slot Select, Load/Unload, and Eject Button Functions . . . . . . . . . . . . . . . .
Selecting a Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loading the Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unloading the Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Opening the Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Magazine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inserting a Cartridge into the Front of the Magazine . . . . . . . . . . . . .
Removing a Cartridge from the Magazine . . . . . . . . . . . . . . . . . . . . . .
Removing the Magazine from the Receiver . . . . . . . . . . . . . . . . . . . . .
Installing the Magazine into the Receiver . . . . . . . . . . . . . . . . . . . . . .

5–1
5–1
5–2
5–2
5–4
5–4
5–5
5–5
5–6
5–6
5–6
5–7
5–7
5–9
5–10
5–10

6 SCSI Interface
6.1
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2
General SCSI Bus Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.1
Data Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.2
Initiator/Target Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.3
SCSI IDs And Logical Unit Numbers . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.4
Unit Attention Condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.5
Behavior Around Power-On and SCSI Bus Reset . . . . . . . . . . . . . . . . .
6.2.6
Data Cache and Tape Write Interaction . . . . . . . . . . . . . . . . . . . . . . . .
6.2.7
Other SCSI Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.8
Bus Phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.9
ATTENTION Signal Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.2.10
STATUS Phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.3
SCSI Message System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4
Tape Drive SCSI Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.1
Control Byte — Flag and Link Bits . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2
Summary of Supported Sequential-Access Device Commands . . . . . . .
6.4.2.1
ERASE (19h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.2
INQUIRY (12h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.2.1
INQUIRY — SCSI II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.2.2
INQUIRY — 8mm Emulation . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.2.3
INQUIRY — AS400 Attachment . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.3
LOAD-UNLOAD (1Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.4
LOCATE (2Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.5
LOG SELECT (4Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.5.1
Operation of LOG SELECT . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.6
LOG SENSE (4Dh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.7
MODE SELECT (15h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.7.1
MODE SELECT — SCSI II . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.7.2
MODE SELECT — 8mm Emulation . . . . . . . . . . . . . . . . . . . .
6.4.2.7.3
MODE SELECT — AS400 Attachment . . . . . . . . . . . . . . . . . .
6.4.2.8
MODE SENSE (1Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.8.1
MODE SENSE — SCSI II . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.8.2
MODE SENSE — 8mm Emulation . . . . . . . . . . . . . . . . . . . . .
6.4.2.8.3
MODE SENSE — AS400 Attachment . . . . . . . . . . . . . . . . . . .
iv

6–1
6–1
6–1
6–1
6–2
6–2
6–3
6–3
6–4
6–4
6–4
6–4
6–6
6–10
6–10
6–11
6–12
6–12
6–13
6–19
6–22
6–25
6–26
6–27
6–28
6–31
6–36
6–37
6–48
6–54
6–66
6–66
6–76
6–79

6.4.2.9
PREVENT/ALLOW MEDIUM REMOVAL (1Eh) . . . . . . . . . . . . . .
6.4.2.10
READ (08h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.11
READ BLOCK LIMITS (05h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.12
READ BUFFER (3Ch) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.12.1
Combined Header and Data Mode . . . . . . . . . . . . . . . . . . . . . .
6.4.2.12.2
Data Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.12.3
Descriptor Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.13
READ POSITION (34h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.13.1
READ POSITION Data Format . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.14
RECEIVE DIAGNOSTICS RESULTS (1Ch) . . . . . . . . . . . . . . . . .
6.4.2.15
RELEASE UNIT (17h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.15.1
Medium Changer Considerations . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.16
REQUEST SENSE (03h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.16.1
REQUEST SENSE — SCSI II . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.16.2
REQUEST SENSE — 8mm Emulation . . . . . . . . . . . . . . . . . .
6.4.2.16.3
REQUEST SENSE — AS400 Attachment . . . . . . . . . . . . . . . .
6.4.2.17
RESERVE UNIT (16h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.17.1
Medium Changer Considerations . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.18
REWIND (01h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.19
SEND DIAGNOSTIC (1Dh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.20
SPACE (11h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.21
TEST UNIT READY (00h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.21.1
Medium Changer Considerations . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.22
VERIFY (13h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.23
WRITE (0Ah) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.24
WRITE BUFFER (3Bh) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.24.1
Header and Data Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.24.2
Write Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.24.3
Download Microcode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.24.4
Download Microcode and Save . . . . . . . . . . . . . . . . . . . . . . . . .
6.4.2.25
WRITE FILEMARKS (10h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5
Supported SCSI-2 Medium Changer Device Commands . . . . . . . . . . . . . .
6.5.1
INITIALIZE ELEMENT STATUS (07h) . . . . . . . . . . . . . . . . . . . . . . . .
6.5.2
READ ELEMENT STATUS (B8h) . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5.2.1
Element Status Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5.2.2
Medium Transport Element Status Page . . . . . . . . . . . . . . . . . . . .
6.5.2.3
Storage Element Status Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5.2.4
Data Transfer Element Status Page . . . . . . . . . . . . . . . . . . . . . . . .
6.5.3
MODE SENSE/SELECT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5.3.1
Device Capabilities Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.5.3.2
Element Address Assignment Page . . . . . . . . . . . . . . . . . . . . . . . .
6.5.3.3
Transport Geometry Parameters Page . . . . . . . . . . . . . . . . . . . . . .
6.5.4
MOVE MEDIUM (A5h) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–88
6–89
6–91
6–92
6–93
6–93
6–93
6–94
6–95
6–96
6–97
6–97
6–98
6–98
6–105
6–111
6–117
6–118
6–118
6–119
6–120
6–122
6–122
6–123
6–124
6–126
6–127
6–127
6–127
6–127
6–128
6–129
6–130
6–131
6–132
6–133
6–134
6–136
6–138
6–138
6–139
6–140
6–141

7 Firmware Update Procedure (From Tape)
7.1
THZ02 Firmware Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2
Creating a "Firmware Update Tape" . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.1
On UNIX Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3
Firmware Update Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.1
Updating the Firmware on THZ02 (Drive Only Configuration) . . . . . .
7.3.1.1
Interpreting the Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.3.2
Updating the Firmware on THZ27 Loader Configuration . . . . . . . . . .
7.3.2.1
Interpreting the Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7–1
7–2
7–2
7–2
7–2
7–3
7–4
7–5

8 Diagnostics
8.1
Test Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.2
Resident Power-On Self-Test (POST) Diagnostics . . . . . . . . . . . . . . . . . . .
8.2.1
Failure Action . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3
Microdiagnostic Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3.1
Microdiagnostic Test Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3.1.1
Level 1 Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.3.1.2
Level 2 Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

8–1
8–2
8–2
8–3
8–3
8–3
8–3

9 Technical Specifications
9.1
9.1.1
9.1.2
9.1.3
9.1.4
9.2
9.3
9.3.1
9.3.2
9.3.3
9.4
9.4.1
9.4.2
9.4.3
9.5
9.5.1
9.5.2
9.6
9.7
9.7.1
9.7.2
9.7.3
9.7.4
9.7.5
9.7.6
9.7.7
9.7.8
9.8
9.8.1
9.8.2
9.8.3
9.9

Index

Physical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Top View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Side View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Isometric View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Performance Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nominal Tape Tension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Timing Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ27 Media Loader Timing Characteristics . . . . . . . . . . . . . . . . . . .
Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Tabletop Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . .
THZ27 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Environmental Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Temperature and Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Vibration and Shock Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electromagnetic Interference Susceptibility . . . . . . . . . . . . . . . . . . . . . . . .
Electromagnetic Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conducted Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiated Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Magnetic Radiated Susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Radiated Susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Conducted Susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESD Failure Level Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Acoustic Noise Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regulatory Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electromagnetic Emission Requirements . . . . . . . . . . . . . . . . . . . . . . .
Shipping Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drive Reliability Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9–1
9–1
9–2
9–3
9–4
9–5
9–5
9–5
9–5
9–6
9–6
9–6
9–6
9–6
9–7
9–7
9–8
9–9
9–10
9–10
9–10
9–11
9–11
9–11
9–12
9–12
9–13
9–13
9–13
9–13
9–14
9–14

Figures
2–1
2–2
2–3
3–1
3–2
4–1
4–2
4–3
5–1
5–2
5–3
5–4
5–5
6–1
6–2
6–3
6–4
6–5
6–6
6–7
6–8
6–9
6–10
6–11
6–12
6–13
6–14
6–15
6–16
6–17
6–18
6–19
6–20
6–21
6–22
6–23
6–24
6–25
6–26
6–27
6–28
6–29
6–30
6–31
6–32

THZ02 Controller Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rewrites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Data Path Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCSI ID Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear Panel Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tape Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loading the Tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unloading the Tape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ27 Operator Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Write-Protect Switch on a Cartridge . . . . . . . . . . . . . . . . . . . . . . . . . .
Inserting a Cartridge into the Magazine . . . . . . . . . . . . . . . . . . . . . . .
Removing a Cartridge from the Front of the Magazine . . . . . . . . . . . .
Receiver Opened . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Extended Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SDTR Extended Message Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ERASE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INQUIRY CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inquiry Response Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inquiry Vendor Unique Bytes Definition . . . . . . . . . . . . . . . . . . . . . . .
Supported Vital Product Data Pages page . . . . . . . . . . . . . . . . . . . . . .
Unit Serial Number Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Firmware Build Information Page — VU . . . . . . . . . . . . . . . . . . . . . . .
INQUIRY CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inquiry Response Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inquiry Vendor Unique Bytes Definition . . . . . . . . . . . . . . . . . . . . . . .
INQUIRY CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inquiry Response Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Inquiry Vendor Unique Bytes Definition . . . . . . . . . . . . . . . . . . . . . . .
LOAD-UNLOAD CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOCATE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOG SELECT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOG Page Control Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Read/Write Error Log Select Page Format . . . . . . . . . . . . . . . . . . . . . .
LOG SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOG Page Control Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LOG SENSE Pages Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parameter Codes Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supported Pages Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Read/Write Error Log SENSE Page Format . . . . . . . . . . . . . . . . . . . . .
Threshold Met Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mode Select Parameter List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE/SELECT Pages Supported . . . . . . . . . . . . . . . . . . . . . .
Device Configuration Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnect/Reconnect Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . .

2–1
2–4
2–5
3–2
3–2
4–7
4–8
4–9
5–3
5–7
5–8
5–9
5–11
6–8
6–10
6–12
6–13
6–14
6–16
6–17
6–17
6–18
6–19
6–20
6–21
6–22
6–23
6–24
6–25
6–26
6–27
6–28
6–29
6–31
6–32
6–32
6–33
6–34
6–34
6–36
6–37
6–38
6–39
6–40
6–42

vii

6–33
6–34
6–35
6–36
6–37
6–38
6–39
6–40
6–41
6–42
6–43
6–44
6–45
6–46
6–47
6–48
6–49
6–50
6–51
6–52
6–53
6–54
6–55
6–56
6–57
6–58
6–59
6–60
6–61
6–62
6–63
6–64
6–65
6–66
6–67
6–68
6–69
6–70
6–71
6–72
6–73
6–74
6–75
6–76
6–77
6–78
6–79
viii

Medium Partition Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Error Recovery Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Format . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Example 1 . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Example 2 . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT Block Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT Page Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Format . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Example 1 . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Example 2 . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mode Select Parameter List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE/SELECT Pages Supported . . . . . . . . . . . . . . . . . . . . . .
Device Configuration Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnect/Reconnect Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . .
Medium Partition Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Error Recovery Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Format . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Example 1 . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Example 2 . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Page Control Definition . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Block Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Page Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Pages Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Configuration Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnect/Reconnect Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . .
Medium Partition Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Error Recovery Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Block Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Page Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Page Control Definition . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Block Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Page Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SENSE Pages Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Configuration Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Disconnect/Reconnect Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . .
Medium Partition Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Error Recovery Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PREVENT/ALLOW MEDIUM REMOVAL CDB . . . . . . . . . . . . . . . . . .

6–43
6–44
6–45
6–46
6–47
6–48
6–49
6–49
6–49
6–51
6–52
6–53
6–54
6–55
6–57
6–58
6–60
6–61
6–62
6–63
6–64
6–65
6–66
6–67
6–68
6–68
6–68
6–70
6–71
6–73
6–74
6–75
6–76
6–77
6–77
6–77
6–79
6–79
6–80
6–80
6–80
6–82
6–83
6–85
6–86
6–87
6–88

6–80
6–81
6–82
6–83
6–84
6–85
6–86
6–87
6–88
6–89
6–90
6–91
6–92
6–93
6–94
6–95
6–96
6–97
6–98
6–99
6–100
6–101
6–102
6–103
6–104
6–105
6–106
6–107
6–108
6–109
6–110
6–111
6–112
6–113
6–114
6–115
6–116
6–117
6–118
6–119
9–1
9–2
9–3
9–4

READ CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ BLOCK LIMITS CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ BLOCK LIMITS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ BUFFER CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ BUFFER Modes Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ BUFFER Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ BUFFER Descriptor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ POSITION CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
READ POSITION Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RECEIVE DIAGNOSTICS RESULTS CDB . . . . . . . . . . . . . . . . . . . . .
Receive Diagnostic Result Data Format . . . . . . . . . . . . . . . . . . . . . . . .
RELEASE UNIT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REQUEST SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REQUEST SENSE Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REQUEST SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REQUEST SENSE Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REQUEST SENSE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REQUEST SENSE Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
RESERVE UNIT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
REWIND CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SEND DIAGNOSTIC CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPACE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SPACE Code Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TEST UNIT READY CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VERIFY CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
WRITE CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
WRITE BUFFER CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
WRITE BUFFER Modes Supported . . . . . . . . . . . . . . . . . . . . . . . . . . .
WRITE FILEMARKS CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
INITIALIZE ELEMENT STATUS CDB . . . . . . . . . . . . . . . . . . . . . . . .
READ ELEMENT STATUS CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Element Type Code Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Element Status Data Header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Medium Transport Element Status Page . . . . . . . . . . . . . . . . . . . . . . .
Storage Element Status Page . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Data Transfer Element Status Page . . . . . . . . . . . . . . . . . . . . . . . . . . .
Device Capabilities Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Element Address Assignment Page Format . . . . . . . . . . . . . . . . . . . . .
Transport Geometry Page Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MOVE MEDIUM CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Front View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Top View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Side View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Isometric View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6–89
6–91
6–91
6–92
6–92
6–93
6–93
6–94
6–95
6–96
6–96
6–97
6–98
6–99
6–105
6–106
6–111
6–112
6–117
6–118
6–119
6–120
6–120
6–122
6–123
6–124
6–126
6–126
6–128
6–130
6–131
6–131
6–132
6–133
6–134
6–136
6–138
6–139
6–140
6–141
9–1
9–2
9–3
9–4

Tables
4–1
5–1
6–1
6–2
6–3
6–4
6–5
6–6
6–7
6–8
6–9
6–10
6–11
6–12
6–13
6–14
6–15
6–16
6–17
6–18
6–19
6–20
6–21
6–22
9–1
9–2
9–3
9–4
9–5
9–6
9–7
9–8
9–9
9–10
9–11
9–12
9–13
9–14
9–15
9–16
9–17
9–18
9–19

Front Panel Indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ27 Operator Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supported SCSI Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Supported SCSI Commands . . . . . . . . . . . . . . . . . . . . . . . . . . .
INQUIRY Command Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MODE SELECT Command Sections . . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Parameters . . . . . . . . . . . . . . . . . . . . . .
Changeable Mode Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Parameters . . . . . . . . . . . . . . . . . . . . . .
Changeable Mode Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
EEROM Vendor Unique Page Parameters . . . . . . . . . . . . . . . . . . . . . .
Changeable Mode Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mode Sense Command Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Request Sense Command Sections . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sense Keys Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Sense Codes/Qualifiers Used . . . . . . . . . . . . . . . . . . . . . . . .
Sense Keys Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Sense Codes/Qualifiers Used . . . . . . . . . . . . . . . . . . . . . . . .
Sense Keys Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Sense Codes/Qualifiers Used . . . . . . . . . . . . . . . . . . . . . . . .
Sense Keys Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additional Sense Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SCSI-2 Medium Changer Commands . . . . . . . . . . . . . . . . . . . . . . . . . .
Medium Changer Element Addresses . . . . . . . . . . . . . . . . . . . . . . . . .
Size, Depth, Mounting Holes, Weight . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ02 Timing Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
THZ27 Media Loader Timing Characteristics . . . . . . . . . . . . . . . . . . .
THZ02 Power Requirements (±5%) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power-On Ranges — No Tape Loaded (Unpacked — 72 Hours) . . . . . .
Storage Ranges (Unpacked or Packed) . . . . . . . . . . . . . . . . . . . . . . . . .
Shipment Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating Vibration Requirements (Within Specification — No
Damage) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nonoperating Vibration Requirements (Unpacked — No damage) . . . .
Operating Shock Requirements (Within Specification — No
Damage) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Nonoperating Shock Requirements (Unpacked — No Damage) . . . . . .
Low Frequency, Magnetic Fields, 10 to 3000 kHz . . . . . . . . . . . . . . . .
High Frequency, Electric Fields, 1 to 1000 MHz . . . . . . . . . . . . . . . . .
Fast Transient (Bursts) for Power and Data Cables . . . . . . . . . . . . . . .
High Energy Transient Voltage for Power Cables . . . . . . . . . . . . . . . .
Low-Level Conducted Interference . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ESD Failure Level Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shipping Requirements (Repetitive Synchronous Motion) . . . . . . . . . .

4–2
5–4
6–6
6–11
6–12
6–36
6–45
6–48
6–51
6–54
6–63
6–66
6–66
6–98
6–101
6–102
6–108
6–108
6–114
6–114
6–119
6–120
6–129
6–129
9–5
9–5
9–6
9–6
9–7
9–7
9–8
9–8
9–9
9–9
9–9
9–9
9–11
9–11
9–12
9–12
9–12
9–12
9–14

9–20
9–21
9–22

Vibration Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Physical Drop Test Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reliability Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9–14
9–14
9–14

1
Overview of THZ02/THZ27 Subsystem
Product Features
•

High performance/high capacity
512 kB read/write data cache
1.1 MB/sec raw transfer rate when streaming
800 kB/sec data transfer rate when streaming
5.0 MB/sec data rate on SCSI bus (synchronous mode)
6.0 GB cartridge capacity (42 GB with media loader)
Fast reposition time (less than 1.3 seconds)

•

Extensive data integrity/recovery features
Custom 64-bit CRC on each 2k of data on media
Powerful custom Reed Solomon ECC (designed for tape)
End-to-end EDC on data (onto media and back),
overlapped with parity from the SCSI bus
Parity checking on data cache memory
Undetected errors < 1 in 10 E+30 bits
Unrecovered read errors < 1 in 10 E+17 bits
Cache "Water Marking" to minimize drive start-stops, thus increasing
drive, head and media life

•

Interconnect flexibility
Available three types of firmware to be either:
*

Compliant with SCSI-2 requirements or

Provide 8mm emulation or

Provide attachment to the IBM AS/400.

8-bit wide SCSI data path
Both single ended and differential implementations
Optional remote panel for SCSI ID selection
•

Firmware update capability using flash EEPROM technology:
Customer can do the update
Allows inexpensive fixing of bugs
Allows inexpensive product enhancements

Overview of THZ02/THZ27 Subsystem 1–1

Overview of THZ02/THZ27 Subsystem

•

Extensive embedded diagnostic self-test software
Automatic determination of need for head cleaning
Extensive built-in diagnostics
LEDs for indication of POST failure/success, and command traffic
Errors recorded in EEPROM for later analysis at repair sites

•

General Details
NCR 53C96 SCSI controller chip used for the SCSI interface.
Based on a 68020 microprocessor
Most subsystem code is written in ’C’
4K blocking factor on tape:
*

Increases user-data rate to tape

Decreases uP power needed to manage data/command traffic

Record sizes from 1 up to 256k bytes supported

1–2 Overview of THZ02/THZ27 Subsystem

2
THZ02 Controller Hardware
This section describes the THZ02 controller hardware. The main hardware areas
are listed and some of the assumptions in the hardware design discussed and its
operation explained.

2.1 Overview
Figure 2–1 THZ02 Controller Block Diagram

15 MHz
68020 uP

16 x 32k
"Local"
RAM

16 x 128k
Code
Flash ROMs

GPSP4
chip

SCSI
Bus

8 x 2k
EEPROM

53C96
chip

Data

Path

EZ
gate array
chip

Media
Loader
Port
Drive
Port

512 kbytes
DRAM

The THZ02 controller connects to the SCSI bus via a standard 50 pin SCSI
connector. Using synchronous data transfer mode, it can sustain a 5 MB/sec
data rate on the SCSI interconnect. Along with an efficient message system, this
minimizes the bus bandwidth required for a THZ02 subsystem, allowing more
SCSI devices to share the same bus — assuming an efficient host adapter. To
support streaming, the host adapter must efficiently process the SCSI protocol,
and data transfers must be fast enough to offset SCSI bus overhead and activity
on the bus by other devices.
To maintain streaming operation, the controller formats data from the SCSI bus
and supplies it to the drive at the rate of about 800 kB/sec of initiator data. For
every eight 4k blocks of data from the bus, the controller generates two 4k blocks
of Reed Solomon ECC information. Together, this brings the raw data rate at the
drive to over 1 MB/second.
To maintain this transfer rate, the controller uses a 68020 microprocessor. To aid
the 68020, the NCR 53C96 chip is used for SCSI bus protocol handling. Two gate
arrays have been developed to help control the data paths and format the data.
Finally, the THZ02 has a sizable data buffer to minimize or eliminate latencies
added by drive repositions when the host is not able to maintain the average 800
kB/sec data transfer rate.
THZ02 Controller Hardware 2–1

THZ02 Controller Hardware
2.1 Overview
The controller consists of the following sections.
•

68020 microprocessor subsystem:
256 kB of firmware flash EEPROM
64 kB SRAM for data structures
2 kB EEPROM for configurable parameters

•

SCSI interface:
NCR 53C96 SCSI controller chip
Synchronous and asynchronous data transfers supported
Differential and single-ended SCSI bus options

•

Cache and drive interface:
SCSI, formatter and ECC (EZ) gate array
512 kB formatter/ECC buffer RAM, with parity
GPSP4 gate array:
2 channel drive I/O interface
Drive communication port
Media loader communication port
Remote panel inputs

2.2 Controller Theory of Operation
2.2.1 SCSI Interface and Memory
All SCSI commands and responses are initiated by the 68020 through the NCR
53C96 chip. Messages and commands are copied out and into the 53C96 chip
directly. Data transfers are carried out between the 53C96 and the EZ chips
directly, under DMA control.
The blocking factor of the device is 4k. This means that internally the data
is managed in units of 4k, and does not affect or limit the block size used by
initiators. However, data is stored in units of 4k on the media, and blocks that
are not an integral multiple of 4k will cause capacity and throughput reductions.

2.2.2 Write Operation
Command Handling
The SCSI protocol controller automatically handles selection, message out, and
command transfers. The uP decodes the command, validates it, and if memory
is available will begin transferring data without a disconnect. Otherwise, if the
command is valid and disconnect privilege is granted, a disconnect message will
be sent and the bus released. When memory is available, a reconnection to the
initiator (if needed) will be done.

2–2 THZ02 Controller Hardware

THZ02 Controller Hardware
2.2 Controller Theory of Operation
Data Transfer into EZ RAM
Data will be transferred in units of 4k bytes, except for the remainder bytes of
blocks that are not an integral multiple of 4k. Disconnections (if allowed) will
be done based on the value of the maximum burst size mode parameter, and
the availability of buffer memory. Disconnections will always be on a 4k byte
boundary.
As the data is transferred in, the hardware checks the SCSI bus parity (unless
parity checking is disabled via the controller or remote panel switch package
switch defined for this purpose), and stores the data and parity into DRAM buffer
memory. At the same time, the EZ gate array calculates an XOR-rotate type EDC
on the data which is also stored in DRAM. This EDC is eventually written onto
the media, and verified as part of the read-after-write checking, and again during
read operations.
If a bus parity error is detected during Data Out, the THZ02 will immediately
stop the transfer, issue a Restore Pointers message, and restart the transfer from
the point defined by the last Save Data Pointer message. To allow this, Save Data
Pointer messages will be sent to the initiator at strategic points in the transfer
(but always on a 4k boundary).
After the data is transferred, if caching is enabled, the Status byte and Command
Complete message byte are sent immediately and the bus released. Otherwise,
the Save Data Pointer and Disconnect messages are sent and the bus released.
When the block is written onto media, a reconnection will be done to report the
outcome of the operation.
Formatting, Generation of ECC and Transfer to Tape
Once these 2056 byte buffers are constructed in FECC memory, the control field
information can be created and attached to the end of each buffer. The 68020 will
format the control field information in local memory and then append it to the
2056 byte data blocks in FECC memory making the physical tape block size equal
to 2076. This is done just before the blocks are written to tape since some fields
in the control information change very dynamically depending on rewrite retries.
As each of these buffers or blocks are formatted, the 68020 will program the
GPSP3 to start requesting the transfer of the blocks to tape via the FECC gate
array. As the FECC gate array fetches the data words for the GPSP3, it will also
feed them to the Reed Solomon generator which is being done concurrent with the
write operation. That reduces the memory bandwidth requirements on the FECC
memory.
This process of requesting data, generating ECC and writing data to tape
continues for the entire 2076 block length. At the end of the transfer, the GPSP3
will interrupt the 68020 so that it can set up the next set of pointers to start
writing the next block and calculate the ECC. After eight 4k tape blocks have
been written to tape, the two 4k ECC blocks will be ready to be written.

THZ02 Controller Hardware 2–3

THZ02 Controller Hardware
2.2 Controller Theory of Operation
Error Recovery During Writes
At the same time a block is being written to tape the previous block is being read.
At the CRC check time, the GPSP3 will interrupt the 68020 so that status can be
checked. If a block on either track is bad, it will be rewritten without stopping
the tape. Because the drive is a streaming tape drive, rewrites are done in line
on the fly. What this means is that if we have written block A and start writing
block B, the read after write of A will not be complete until B is already started.
If A is determined to be bad by the CRC (or EDC check) results, then 68020 has
to modify a bit in the control field of block B (the "K" bit) so the controller knows
to ignore it later during a read, and finish writing B. The controller then has to
rewrite A and B again until the read after write of A is correct.
This process of rewrites continues for every block written until the read after
write of that block is correct. If however the rewrite count defined in controller
software is exceeded then, the controller will stop the tape, backup to the
beginning of the rewrite sequence, and start all over again. This entire sequence
is repeated for up to the "Over-Write" retries value. If still not successful a hard
write error will then be reported. Also at the CRC check time the EDC that was
generated by the Swift gate array is checked by the GPSP3. The writing and
checking of the EDC on tape gives the controller end to end checking on its data
path to minimize otherwise undetected errors.
Because the rewrite of blocks affect the Reed Solomon calculation due to the fact
that writes are linked directly to the Reed Solomon generator, the software in
the controller has to retain multiple copies of the Reed Solomon calculation and
only use the copies that were generated by blocks that had good read after write
status. The following figure illustrates the rewrite of block A.
Figure 2–2 Rewrites

WRITE

...

Set K bit in Control Field
at end of block B before
it is written
READ AFTER WRITE

...

BAD CRC

2–4 THZ02 Controller Hardware

(ignore
CRC)

GOOD CRC GOOD CRC GOOD CRC

THZ02 Controller Hardware
2.2 Controller Theory of Operation
2.2.3 Read Operation
This is similar to write command handling. After the READ command is
validated, buffer memory is checked to see if enough data is there to satisfy the
command. If so, no disconnect is performed, the correct data is located and the
transfer started. Otherwise a disconnect is executed until the data is located or
read off the tape.
When the transfer is complete, if the requested block size matches the size of the
block read off the tape, Status and Command Complete are returned immediately.
If there is an error or exception case (for example due to a block size "mismatch"),
a disconnect may be performed, with a later reconnection to report the status of
the operation.
If the initiator asserts the ATN signal during the Data In, the THZ02 will stop
almost immediately, and go to Message Out. If an Initiator Detected Error
message is received, a Restore Pointers message will be sent, and the transfer
restarted from the point at which a Save Data Pointer message was last sent.

2.2.4 Data Protection and Recovery
The THZ02 has full end-to-end data protection. As shown in the following figure,
as the data comes onto the controller (and bus transmission errors checked
for), the 53C96 chip checks and passes parity to the EZ chip, which builds a
16 bit XOR-rotate type EDC for each 512 bytes of data as it writes the data
into EZ controlled memory. This word of EDC is appended to the data in RAM,
and is then considered as part of the data during all subsequent data handling
operations. While stored in controller cache memory, the data is also protected
with byte parity by the hardware. When the data is DMAed to the drive’s write
circuity, a 64 bit CRC is generated on the data and EDC, which is also written
onto the media. The read-after-write that occurs immediately after writing
checks both the CRC and EDC. This allows detection of data corruptions that
might occur on the controller at the time data is written, instead of later, during
a critical restore operation.
Figure 2–3 THZ02 Data Path Protection
.
SCSI .
BUS
tape
.
.
.
.
.
53C96

.
XOR−Rotate
EDC generation

.
. Parity Protection

.
.
.
.
EDC re−Checked
. Parity
Passed thru

. while in DRAM
.
.
.
(Read)
.

by EZ

.
.

.
.
CRC Added

onto

.
.
.
.
. Read or
.
Read−After−Wr: .
. EDC & CRC
. Checked
.
by GPSP4

During a read, the EDC and CRC are again both checked. In addition, block
format information is also checked. If any error or inconsistency is detected,
the Reed-Solomon correction algorithm is applied using ECC blocks that were
generated and stored on the tape during the write process. There are two 4k
ECC blocks for every eight 4k data blocks (each 4k is divided into two 2k blocks
that go on different channels in parallel) and up to 4 of the 2k data blocks can be
recreated which helps give the THZ02 its very low unrecovered error rate.

THZ02 Controller Hardware 2–5

THZ02 Controller Hardware
2.2 Controller Theory of Operation
If too many 2k blocks are in error, the tape is stopped and reread retries
performed and correction done if appropriate. Once the data has been recovered,
and is sent over the SCSI bus, the EZ chip again checks the EDC word on each
512 bytes of data. In the unlikely case that the EDC check fails, the controller
will abort the data transfer and flag an error to the host.
Retries will be performed in this case using the data in memory and the Restore
Pointers mechanism, but the chances of success are small since the error is most
likely due to a corrupted buffer. Fortunately the chance of this type of error is
extremely low.

2–6 THZ02 Controller Hardware

3
Installation
This chapter provides information for installing, configuring and operating the
THZ02 tape drive.

3.1 Installation
Note
The SCSI (small computer system interface) bus must be terminated at
both ends of the bus, and at least one device must supply terminator
power.

The THZ02 controller module has sockets for the termination resistor packs.
Note that there are two positions labeled on the etch: NO TERM and TERM.
If the THZ02 is the last device on the bus, and external termination of the cables
is not going to be done, you should ensure that the three resistor packs are
placed in the TERM position. (The NO TERM position is a holding place for the
resistor packs.)
You can configure the THZ02 to supply TERM PWR on the bus by moving the
TERM PWR jumper on the controller from NO PWR to PWR.
Be sure the resistors are in the NO TERM position if you use external
termination.

3.2 Configuration
Select the SCSI ID by using the three rightmost switches on the controller. These
switches specify an encoded value from 0 to 7. The left switch disables checking
for parity on the SCSI bus by the tape unit, and should be done for systems that
do not generate parity.

3.2.1 SCSI ID Switch Settings
Use Figure 3–1 to determine the SCSI ID switch settings. Switch 2 is the most
significant bit (MSB) and switch 4 is the least significant bit (LSB): Refer to
Figure 3–2 for details of physical switch location on the tabletop box.

Installation 3–1

Installation
3.2 Configuration
Figure 3–1 SCSI ID Selection

SCSI ID

Switch 2

Switch 3

Switch 4

Off

Figure 3–2 Rear Panel Switches

OFF

SCSI ID LSB

SCSI ID

SCSI ID MSB

DISABLE
PARITY
REMOTE PANEL
SHR-TZ86-04

3–2 Installation

4
Tape Drive Operation
4.1 Power-On Self-Test
The power-on self-test (POST) includes:
•

Diagnostic LED test

•

68020 microprocessor register and instruction test

•

Local RAM test

•

NCR 53C96 chip test

•

EZ gate array test

•

GPSP4 gate array test

•

Cache (EZ) RAM test

•

Flash code ROM test

•

Timer and other tests

POST completes and the subsystem responds normally to all commands within
5 seconds. However, it may take longer for the media to be made ready. After a
bus reset, the tape drive responds within a bus selection timeout period or less.

Tape Drive Operation 4–1

Tape Drive Operation
4.2 Front Panel Indicators and Controls

4.2 Front Panel Indicators and Controls
The front panel consists of the following indicators and controls:
•

Indicators
Write Protected
Tape in Use
Use Cleaning Tape
Operate Handle
Beeper

•

Controls
Unload button
Cartridge insert/release handle

Table 4–1 Front Panel Indicators
Label
Write Protected
Tape in Use
Use Cleaning Tape

Operate Handle

Beeper

4–2 Tape Drive Operation

State

Purpose

Tape is write protected

Off

Tape is write enabled

Blinking

Tape is moving

Tape is loaded and ready for use

Drive heads need cleaning or the tape is bad

Off

Cleaning is complete or cleaning is
unnecessary

Operate the cartridge insert/release handle

Off

Do not operate the cartridge insert/release
handle

Sounds when you can operate the cartridge
insert/release handle

Tape Drive Operation
4.3 Front Panel Lights

4.3 Front Panel Lights
4.3.1 OK To Lift Handle Light
When the OK To Lift Handle light is on by itself, it is okay to operate the handle.
Do not attempt to open the handle if the OK To Lift Handle light is not on.
If the OK To Lift Handle light flashes by itself, this indicates that the cartridge
leader may be bad. Raise the handle and extract the cartridge. Carefully open
the door of the cartridge, and check to see if the loop on the cartridge leader is
visible. If it is not visible or the leader appears to be broken or mispositioned,
replace the cartridge.

4.3.2 Tape In Use Light
The Tape In Use light indicates that a tape is in use or the drive is initializing. If
the Tape In Use light stays on, then the tape is stopped. If the Tape In Use light
is flashing, then the tape is moving or the drive is initializing.

4.3.3 Write Protect Light
4.3.3.1 Write Protect Light On Steady
If the Write Protect light is on steady, it indicates that the tape is write protected
(recorded data is protected). If the Write Protect light is on steady, then one or
more of the following conditions is true:
•

The write protect switch on the cartridge is set.

•

The cartridge is software write protected from the host.

•

The cartridge has TK50 or TK70 calibration tracks written on it. (TK50 and
TK70 cartridges can be read by a THZ02 but not written).

4.3.3.2 Write Protect Light Blinking
If the drive is unloaded, the handle closed, and the Write Protect light is blinking
by itself, the drive is in the initial stage of code update mode. See Chapter 7 for a
more detailed description of code update mode.

Tape Drive Operation 4–3

Tape Drive Operation
4.3 Front Panel Lights
4.3.4 Use Cleaning Tape Light
The front panel Use Cleaning Tape light is turned on or off following calibration.
The light is turned on for the following reasons:
•

For TX85 media, the noise is measured for all four channels while the tape
is stopped and while the tape is erasing. The difference between the moving
noise and stopped noise is compared to the 2f amplitude. If this ration of
noise to signal exceeds a given level for any of the four channels, then the Use
Cleaning Tape light is turned on.

•

For TX85 media, if the resolution is less than a given minimum for any of the
four channels, then the Use Cleaning Tape light is turned on.

•

For TX70/50 media, if the VCG for any of the four channels is 0, this means
that the calibration procedure was unable to set the gain high enough. This
may indicate a dirty head, and the Use Cleaning Tape light is turned on.

•

For TX70/50 media, if the 1f amplitude is less than a given minimum, then
the Use Cleaning Tape light is turned on.

•

For any media, if the calculated tape tension is greater than a given
maximum or less than a given minimum, then the Use Cleaning Tape
light is turned on.

The Use Cleaning Tape light will also be turned off after a cleaning cartridge has
been used. Note that if the cartridge is ’used up’, the Use Cleaning Light will not
be turned off after the cleaning cartridge has been used.

4.3.5 All Four Lights Flashing
All four lights will flash constantly when the drive is in an error condition. You
may try to reinitialize the drive and unload the tape by pressing the unload
button. All three lights will briefly turn on and the drive will try to reinitialize.

4.3.6 Tape In Use and Write Protect Lights Flashing
If both the Tape In Use and Write Protect lights are flashing, this indicates that
the drive is in code update mode. See Chapter 7 for a more detailed description
of code update mode.

4–4 Tape Drive Operation

Tape Drive Operation
4.3 Front Panel Lights
4.3.7 Power On Light Sequence
All four front panel lights will turn on sequentially when the drive is powered up
(top to bottom). All four lights will remain on for a few seconds while the drive
goes through power-on self-test (POST). After POST is complete, the Tape In
Use light will flash slowly and the other three lights will turn off while the drive
initializes.
After initialization, the drive will be in one of the four states listed below:
•

If no cartridge is present, the amber light will turn off, the green light will
turn on, the handle will be unlatched, and the drive will beep. It is now okay
to raise the handle and insert a cartridge.

•

If a cartridge is present and the handle is down, the drive will load the
cartridge. When the amber light stops flashing and stays on, then the drive is
ready for use.

•

If a cartridge is present but the handle is up (not recommended), the amber
light will turn off and the green light will turn on. The handle should then be
lowered and the cartridge will load.

•

If the drive detects an error condition, then all four lights will flash
repeatedly. You may try to unload the tape and reinitialize the drive by
pressing the unload button. The four lights will stop flashing and the drive
will try to reinitialize as just described.

4.3.8 Unload Button
The unload button is used primarily to indicate that the user wants to unload the
tape. When the user pushes the unload button, the THZ02 waits until an active
write to tape is completed before beginning the unload sequence.
If the drive is in error state (all four front panel lights flashing), pushing the
unload button will cause the drive to reset and unload the tape if possible.

4.4 Write Protect Switch on Cartridge
If the user changes the state of the cartridge write protect switch, the drive will
turn on the write protect LED immediately. However, if the drive is currently
writing to the tape, the write protect will not take effect until the current write is
completed.

Tape Drive Operation 4–5

Tape Drive Operation
4.5 Cleaning Cartridge

4.5 Cleaning Cartridge
4.5.1 Cleaning Algorithm
When the drive detects that a cleaning cartridge has been loaded the drive will
initiate the cleaning algorithm. Note that the cleaning algorithm will occur
regardless of whether the cleaning light is on.
•

Tape motion is started and the head is moved to the bottom stop and then up
a given number of steps. Tape motion is stopped.

•

Tape motion is started and the head is scanned through an area of tape where
previous cleaning (and writing) may have taken place. A/D samples are taken
as the head is stepped up. The maximum and minimum A/D samples for each
channel are stored. When the head has finished stepping and the tape has
moved a certain distance, tape motion is stopped. If the difference between
the maximum and minimum signal amplitudes is less than a given threshold,
then it is assumed that the tape has not been written on and is fresh. This is
because, as described in more detail below, a number of ’tracks’ are written on
the cleaning tape each time it is used. When it is read, there will be areas of
no signal and areas of strong signal.

•

If is determined that the area of tape being scanned has been written, then
the above procedure is continued on the next area of tape until an unwritten
area is found or until the diameter of the supply cartridge is less than a given
diameter indicating that the cartridge is used up.

•

Once a clean area of tape has been found, a number of passes are made over
the tape while writing a 1f frequency with VCWs set to a nominal value. On
each pass the head is moved a number of steps.

•

After the last pass, the Use Cleaning Tape light is turned off.
If the drive was unable to find an unwritten area of tape (tape is used up),
then the Use Cleaning Tape light will not be turned off.

•

After cleaning is complete, the THZ02 will unload the tape.

The Unload button rewinds the tape and unloads the tape from the drive back
to the cartridge. The tape must be completely rewound and unloaded into the
cartridge before you remove the cartridge from the drive.

4.5.2 Cartridge Insert/Release Handle
Operate the cartridge insert/release handle only when the Operate Handle
indicator is on, and the momentary beep sounds.

4–6 Tape Drive Operation

Tape Drive Operation
4.5 Cleaning Cartridge
4.5.3 CompacTape III Cartridge
The CompacTape III is a 4-inch, gray plastic, cartridge containing 1100 feet of 1/2
inch magnetic metal particle tape.
The medium is a CompacTape III half-inch cartridge or ANSI-compatible
equivalent. It is written and read using the interchange format as proposed
in ANSI X3B5/91-227.
Figure 4–1 Tape Cartridge

ORANGE
INDICATOR

m
Co

e
ap

III

WRITEPROTECT
SWITCH

WRITEENABLED

WRITEPROTECTED
SHR_X1020C_89

The CompacTape III has a write-protect switch to prevent accidental erasure
of data. When you slide the switch to the left and the small orange rectangle
is visible, data cannot be written to the tape. The arrow (beneath the orange
rectangle and over the two lines on the write-protect switch) lets you know that
data cannot be written to the tape.
On the right side of the write-protect switch is another symbol: an arrow over
one line. This symbol indicates that if you slide the write-protect switch to the
right, data can be written to the tape.

Tape Drive Operation 4–7

Tape Drive Operation
4.5 Cleaning Cartridge
4.5.4 Loading the Tape
Note
The directions for loading a cartridge into, and unloading a cartridge from
the drive, are printed on the front of the drive.

To load a tape, refer to these steps:
1. Pull the cartridge insert/release handle open when the green light is on
steadily.
2. Insert the cartridge.
3. Push the cartridge into the drive.
4. Push the handle closed.
The green light turns off and the yellow light blinks to show that the cartridge
is loaded. When the tape is at the BOT marker, the yellow indicator turns on
steadily. The tape is now ready for use.
Figure 4–2 Loading the Tape

SHR-0256-87
SHR_X1093_89_CPG

4–8 Tape Drive Operation

Tape Drive Operation
4.5 Cleaning Cartridge
4.5.5 Unloading the Tape
To unload a tape, follow these steps:
1. Press the Unload button.
2. Pull the cartridge insert/release handle open to eject the cartridge when the
green light turns on and the beeper sounds.
3. Remove the cartridge.
4. Push the handle closed.
Figure 4–3 Unloading the Tape

SHR-0257-87
SHR_X1049_89_CPG

Tape Drive Operation 4–9

5
Media Loader Operation
This chapter explains THZ27 subsystem operation:
•

Power-on process

•

Mode Select key modes

•

Operator control panel (OCP) indicator functions

•

Slot Select, Load/Unload, and Eject button functions

•

Magazine cartridge insertion and removal

5.1 Introduction to The Media Loader
The media loader option is a half-rack form factor packaging of the THZ02 and a
media loader that services the drive and a 7-cartridge magazine.
The media loader is controlled by the same SCSI target controller board as the
tape drive. The loader is presented as an SCSI-2 medium changer device on LUN
1 (the tape drive is always LUN 0) if the controller detects its presence on power
up.
The SCSI-2 medium changer commands allow random access to the media stored
in the magazine slots. In addition, sequential access of the media is supported
automatically in auto-loading mode. Auto-loading is implemented as a side-effect
of the SCSI UNLOAD command. If an UNLOAD is specified, and a media loader
is present, after winding the tape back into the cartridge and moving it from the
drive to the magazine slot it came from, the cartridge in the next slot is moved
from the magazine into the drive and made ready. If the next slot is empty, or the
cartridge unloaded was for the last slot in the magazine, the drive is left empty.

5.2 Power-On Process
When the THZ27 subsystem powers on, all of the indicators on the operator
control panel (OCP) light within 15 seconds. The power-on self-test, or POST,
is initializing the subsystem. When POST completes successfully, all OCP
indicators, including the Magazine Fault and Loader Fault indicators, turn off —
except for Power On.
Note
If the Magazine Fault or Loader Fault indicator remains on, POST has
detected an error.

Media Loader Operation 5–1

Media Loader Operation
5.2 Power-On Process
The elevator scans the magazine to determine which slots contain cartridges. If
the subsystem has a magazine with a cartridge in slot 0, and no cartridge is in
the drive, these indicators should be on:
Power On
Eject
Load/Unload
Slot Select
Slot 0

5.3 Mode Select Key
The Mode Select key (Figure 5–1) can lock the loader transfer assembly into the
enclosure, as well as lock the receiver closed. It has four modes: OCP Disabled,
Automatic, Manual, and Service. The OCP Disabled, Automatic, and Manual
modes are for operational use; the Service mode is for head cleaning and servicing
procedures.

5.3.1 Operating Modes
The following modes are for operational use:
•

OCP Disabled — When the magazine is inserted into the receiver and the
receiver is closed, the loader transfer assembly scans the magazine. The first
cartridge in the magazine automatically loads into the drive. Operations stop
if you are copying data to tape and either the storage capacity of the last tape
cartridge is exceeded, or no tape cartridge is in the next sequential slot in the
magazine.
To lock the THZ27 subsystem into the enclosure and lock the receiver, set the
Mode Select key to OCP Disabled mode. The OCP pushbuttons are disabled.

•

Automatic — This mode is the default, or normal, mode of the THZ27
subsystem. It automatically loads and unloads cartridges as necessary during
backup procedures. Operations stop if you are copying data to tape and either
the storage capacity of the last tape cartridge is exceeded, or no tape cartridge
is in the next sequential slot in the magazine.
To lock the THZ27 subsystem into its normal operating position in the
enclosure but leave the receiver unlocked, set the Mode Select key to
Automatic mode. The receiver can be opened; all OCP pushbuttons are
enabled.

•

Manual — Automatic loading and unloading of cartridges does not occur
in this mode; rather, you must press the Load/Unload button to move each
cartridge. This mode is most useful for, but not restricted to, copying specific
files to or from tape.
To lock the THZ27 subsystem into the enclosure, set the Mode Select key
to Manual mode. The receiver is unlocked and can be opened; all OCP
pushbuttons are on.
Note
During Manual mode, the cartridge returns to the magazine, but the
current Slot Select indicator does not advance forward to the next
available cartridge.

5–2 Media Loader Operation

Media Loader Operation
5.3 Mode Select Key
Figure 5–1 THZ27 Operator Control Panel

O PERAT O R CO NT RO L PANEL

Eject

Load/Unload

MOD E S E LE C T KEY

BUTTON
AND
INDICATOR
AREA

Slot Select
OCP
DISABLED

0
AUTOMATIC
MODE

Power On

OCP LABEL
CURRENT
SLOT
INDICATORS
0-6

Write
Protected
Tape In Use

MANUAL
MODE

Use
Cleaning Tape

SERVICE
MODE

Magazine
Fault
Loader Fault

Eject

DSSI NODE
ID LABEL
(TF867 ONLY)

Load/Unload

Slot Select

0
Power On
Write
Protected

Write Protect
Load Fault

Tape In Use
Use
Cleaning Tape

Magazine
Fault
Loader Fault

5
4

40% REDUCTION

SHR_X1025E_91

Media Loader Operation 5–3

Media Loader Operation
5.3 Mode Select Key
5.3.2 Service Mode
Service mode is for performing head cleaning by manually loading the
CleaningTape III and for performing servicing procedures.
To unlock the THZ27 subsystem from its enclosure and remove it from its normal
operating position, set the Mode Select key to Service mode. The receiver is
unlocked and can be opened.

5.4 Operator Control Panel
The THZ27 operator control panel (OCP) has 3 OCP pushbuttons and 16
indicators that are used with the Mode Select key (Table 5–1). See Section 5.3 for
information on the Mode Select key and its functions. See Section 5.5 for more
details on button and indicator operations.
Table 5–1 THZ27 Operator Control Panel
Button/Indicator

Color

Function

Eject button

–

Opens the receiver, allowing access to the
magazine for removal and insertion of
cartridges. Also used to unload the tape from
the drive to the magazine.

Eject indicator

Green

Indicates a magazine fault, and that you can
press the Eject button to unload cartridges
from the drive to the magazine and to open the
receiver.

Load/Unload button

–

Loads the currently selected cartridge into the
tape drive. Unloads the cartridge currently in
the tape drive. Resets the subsystem if there
is a loader fault.

Load/Unload indicator

Green

Indicates that you can press the Load/Unload
button.

Slot Select button

–

Increments the current slot indicator to the
next slot.

Slot Select indicator

Green

Indicates that you can press the Slot Select
button. Pressing this button moves the current
slot indicator to the next slot.

Power On indicator

Green

Indicates the THZ27 magazine tape subsystem
is in a known good power state (ac and dc
voltages are within tolerance).

Write Protected indicator

Orange

When on, indicates that the cartridge currently
in the drive is write-protected by one of these
methods:
•

Setting the write-protect switch to writeprotect

•

Using software write-protect qualifiers

When off, indicates that the current cartridge
is write-enabled.
(continued on next page)

5–4 Media Loader Operation

Media Loader Operation
5.4 Operator Control Panel
Table 5–1 (Cont.) THZ27 Operator Control Panel
Button/Indicator

Color

Function

Tape In Use indicator

Yellow

Indicates tape drive activity as follows:

Use Cleaning Tape indicator

Orange

•

Slow blinking indicates tape is rewinding.

•

Rapid blinking indicates tape is reading or
writing.

•

When on steadily, indicates that a
cartridge is in the drive and the tape
is not moving.

•

When off, indicates that no cartridge is in
the drive.

Indicates that the read/write head needs
cleaning.

Magazine Fault indicator

Red

Indicates a magazine failure.

Loader Fault indicator

Red

Indicates a loader transfer assembly error or
drive error.

Current slot indicators 0–6

Green

Identifies the current slot (see Slot Select
button). Each current slot indicator blinks
when its corresponding cartridge moves to or
from the drive. Also used with the Magazine
Fault or Loader Fault indicator to show the
type of fault.

5.5 Slot Select, Load/Unload, and Eject Button Functions
The Slot Select, Load/Unload and Eject buttons are OCP pushbuttons. They
contain a green indicator, and they are operable only when their corresponding
indicators are on.
Note
The Load/Unload button has three functions: load, unload, and reset. If
there is a loader fault and the Loader Fault indicator is on, press the
Load/Unload button to reset the THZ27 subsystem.

5.5.1 Selecting a Cartridge
Use the Slot Select button to select a cartridge; press this button to advance the
slot indicator light to the next available slot. After a successful initialization, the
THZ27 subsystem automatically selects slot 0 and the Slot Select button becomes
active. The Load/Unload and Eject indicators remain on during the slot selection.

Media Loader Operation 5–5

Media Loader Operation
5.5 Slot Select, Load/Unload, and Eject Button Functions
5.5.2 Loading the Cartridge
Press the Load/Unload button to load the cartridge into the drive. This action
causes the Select Slot, Load/Unload, and Eject indicators to turn off, and the
elevator to move to the selected slot, indicated by the light. The cartridge is then
removed from the magazine and placed in the elevator. The elevator moves to the
drive position and inserts the cartridge into the drive. The indicators remain off
until the tape has loaded to the beginning of the tape (BOT). After the cartridge
is loaded into the drive, the Eject and Load/Unload indicators turn on, and the
corresponding buttons are enabled. The Slot Select indicator remains off.

5.5.3 Unloading the Cartridge
Caution
Do not press the Load/Unload button until backup or other tape
operations are stopped at the terminal. Doing so can result in operation
failure and drive unavailability.

When you press the Load/Unload button, the Select Slot, Load/Unload, and Eject
indicators turn off, and the cartridge unloads from the drive into the magazine.
However, automatic operation now stops and the Select Slot operation does not
increment. The indicators turn on once the cartridge is returned to the magazine.
The Load/Unload indicator must be on before you press the button to load or
unload a cartridge. If the Loader Fault indicator is on, showing a malfunction,
press the Load/Unload button to reset the subsystem and try to clear the error.

5.5.4 Opening the Receiver
The Eject button opens the receiver for insertion or removal of the magazine. It
is disabled when the Mode Select key is in the OCP Disabled position. The Eject
button can also be used to unload a tape from the drive.
Note
When a cartridge is not in the drive, the Slot Select, Load/Unload, and
Eject indicators are on before any operation begins. Pressing the Eject
button causes all indicators to turn off. The elevator then returns to its
home position and the receiver opens.
When a cartridge is in the drive, the Eject and Load/Unload indicators
are on before the operation begins. When you press the Eject button, both
indicators turn off, and the cartridge unloads from the drive and moves
back into the magazine. The receiver then opens to allow access to the
magazine.
In both situations, once the receiver is closed again, a magazine scan
begins, and the indicators turn back on when the scan is complete.

5–6 Media Loader Operation

Media Loader Operation
5.6 Magazine

5.6 Magazine
The front of the magazine has numbers, 0 through 6, that indicate the number of
the slot.
Note
Insert and remove all cartridges at the front of the magazine.

5.6.1 Inserting a Cartridge into the Front of the Magazine
To simplify cartridge insertion, place the magazine on a flat surface with the
slots facing you (Figure 5–3). Each slot is numbered — to ensure that you are
inserting the cartridge correctly in the front of the magazine. Usually, cartridges
are inserted into consecutive slots.
To insert a cartridge into the magazine:
1. Grasp the cartridge with the CompacTape III label facing up and the writeprotect switch facing you (Figure 5–2).
2. Set the cartridge’s write-protect switch to the desired position. If you want
to write on the tape, slide the switch to the right (orange indicator is not
visible). If you want to write-protect the tape, slide the switch to the left
(orange indicator is visible).
3. Insert the cartridge (Figure 5–3) by pushing it into the slot until you hear a
click. A small metal tab holds the cartridge in place.
Figure 5–2 Write-Protect Switch on a Cartridge

ORANGE
INDICATOR

p
om

I
pe

WRITEPROTECT
SWITCH

WRITEENABLED

WRITEPROTECTED
SHR_X1020C_89

Media Loader Operation 5–7

Media Loader Operation
5.6 Magazine
Figure 5–3 Inserting a Cartridge into the Magazine
BACK OF
MAGAZINE

p
om

III

5
5

NOTE: Push tape in
until a click is heard

SLOT
NUMBERS
0-6

FRONT OF
MAGAZINE

SHR_X1021_89

5–8 Media Loader Operation

Media Loader Operation
5.6 Magazine
5.6.2 Removing a Cartridge from the Magazine
To remove a cartridge from the magazine, press the cartridge (Figure 5–4) at
the front of the magazine until you hear a click; then release. The slot uses a
spring-release action. When you press the cartridge in all the way, it pops out.
Note
Never apply labels to the top or bottom of tape cartridges. Doing so can
cause cartridge jams in the THZ27 subsystem. Use the space on the front
of the cartridge for labels.

Figure 5–4 Removing a Cartridge from the Front of the Magazine
BACK OF
MAGAZINE

NOTE: Push tape in
until a click is heard

m
Co

Co
1

4
4

5
5

SLOT
NUMBERS
0-6

FRONT OF
MAGAZINE

SHR_X1022_89

Media Loader Operation 5–9

Media Loader Operation
5.6 Magazine
5.6.3 Removing the Magazine from the Receiver
To remove the magazine from the receiver, first be sure that:
1. The Power On indicator is on (Figure 5–1).
2. The tape drive is unloaded.
3. The Eject indicator is on. (It must be on before you can press the Eject
button.)
Then:
1. Press the Eject button (Figure 5–1) to open the receiver.
2. Grasp the receiver after it opens (Figure 5–5), and gently pull it forward to
access the magazine.
3. Grasp the magazine’s handle only to lift the magazine out of the receiver.

5.6.4 Installing the Magazine into the Receiver
To install the magazine into the receiver:
1. Slide the magazine down into the receiver (Figure 5–5) while holding the
magazine by the handle. Since the magazine is slotted, you can restore it in
the correct orientation only.
2. Push the receiver closed.
3. Observe that the receiver is fully closed in the THZ27 subsystem before
proceeding.

5–10 Media Loader Operation

Media Loader Operation
5.6 Magazine
Figure 5–5 Receiver Opened

FRONT
BEZEL

Ejec

Loa

Slot

Pow

Wri

d/U

nloa

Sele

er O

te P

Tap

Driv

Loa

rote

e In

Use
Cle
anin

Use

g Ta

e Fa

d Fa

ult

SHR-X0046-90

Media Loader Operation 5–11

6
SCSI Interface
6.1 Overview
This chapter covers the details of the SCSI Protocol features that the product
implements.
The following sections do not fully reiterate the ANSI SCSI specification but
rather describes which commands, messages, and options are supported, and
what the error recovery procedures are.

6.2 General SCSI Bus Operation
6.2.1 Data Transfer
The THZ02 supports asynchronous and synchronous data transfers. There are
differential and single ended versions of the product. Odd parity is generated
during all information transfer phases where the device writes data to the SCSI
bus, and checked during all information transfer phases where data is read from
the bus. However, parity will not be checked if the corresponding controller or
remote panel switch is set to Disable Parity Checking.
The THZ02 supports a maximum block size of 256K bytes.
Disconnects from the SCSI bus will be done at regular intervals during a data
transfer. This is to allow other devices access to the bus. This disconnecting is
configurable by use of the disconnect-reconnect mode parameters page.

6.2.2 Initiator/Target Operation
The THZ02 does not act as an initiator on the SCSI bus.
Therefore, the device will not do any of the following:
•

Generate unsolicited interrupts to the host.

•

Initiate its own SCSI commands.

•

Assert bus reset.

SCSI Interface 6–1

SCSI Interface
6.2 General SCSI Bus Operation
6.2.3 SCSI IDs And Logical Unit Numbers
The SCSI ID is a value ranging from 0-7 which determines the address of the
device controller on the SCSI bus. The THZ02 has a switch-selectable SCSI ID,
so that this value may be changed easily. The default setting will be factory
shipped at SCSI address 0. The THZ02 with optional medium changer has two
logical units, that will always appear as LUN 0 (the tape drive), and LUN 1 (the
medium changer).
Unsupported LUN numbers shall be treated as follows: If the logical unit number
(LUN) specified in the IDENTIFY message is invalid, the THZ02 shall accept the
command descriptor block (CDB). There are three cases of what happens next:
1. If the command is INQUIRY, the target shall return the inquiry data with the
peripheral qualifier set to 011, indicating that the target will never support
the LUN in question.
2. If the command is REQUEST SENSE, the target shall return sense data.
The sense key shall be ILLEGAL REQUEST, with an additional sense code of
INVALID logical unit number.
3. For any other command, the target shall terminate the command with
CHECK CONDITION status, and generate the above sense data.

6.2.4 Unit Attention Condition
Queued unit attentions are implemented on this device, and are maintained
separately for each valid LUN for each initiator. Unit attentions will be created
in the following circumstances:
Power on
BUS reset
Bus device reset message
When the media may have changed asynchronously
Another initiator changed the mode parameters
A firmware (microcode) update has completed
Two queued unit attentions are not unusual. For example, if a unit is powered
up and a cartridge is loaded, Power up and not-ready to ready transition unit
attentions are created. Due to a limited number of unit attention buffers, if an
initiator does not clear unit attentions queued for it, at some point the tape device
will stop generating new unit attentions for that I-L combination (but existing
ones will be left queued).
A LOAD command will not generate a unit attention for the initiator that issued
the command, since the transition to ready is synchronous.

6–2 SCSI Interface

SCSI Interface
6.2 General SCSI Bus Operation
6.2.5 Behavior Around Power-On and SCSI Bus Reset
•

All device SCSI lines shall go to high impedance when the THZ02 is powered
off.

•

The THZ02 will not generate any spurious signals on the SCSI bus at
power-on.

•

Within 5 seconds of power on, and within 250 milliseconds (typically under
4 ms) after a bus reset, the THZ02 will respond to SCSI bus selections
and return appropriate, normal, responses. Tape motion commands will be
returned with CHECK CONDITION status, Sense Key Not Ready, until the
media has been made ready.

•

The hard bus reset option is implemented.

•

The media is rewound to BOP.

The THZ02 will be able to recognize multiple bus resets in succession and bus
resets of arbitrarily long duration. It will recover within the time limits specified
above, following the last bus reset.

6.2.6 Data Cache and Tape Write Interaction
The THZ02 contains a data cache that is used to buffer blocks (records) until
they are written. This section defines specific times that blocks shall be written
to tape. A mode select parameter is present that allows the data cache to
be disabled (unbuffered mode). In this mode, every WRITE command will
cause the data to be written to the media before the STATUS byte and the
COMMAND COMPLETE message is returned to the host. Unbuffered mode is
not recommended due to the poor performance that will result.
The write data cache shall be written (flushed) to the media under the following
circumstances:
•

When two or more WRITE FILEMARKS commands are issued without
intervening tape motion commands.

•

When a WRITE 0 FILEMARKS command is issued.

•

Data which has been in the cache for a period of more than specified by the
value of the Mode Parameter "Write Delay Time", shall be automatically
written to media.

•

When a nonwrite type media access command is received (for example,
SPACE, READ, UNLOAD, etc.).

SCSI Interface 6–3

SCSI Interface
6.2 General SCSI Bus Operation
6.2.7 Other SCSI Functionality
1. Linked commands are supported.
2. Untagged queuing is supported.
3. The THZ02 does not use the wide-SCSI data path.

6.2.8 Bus Phases
The THZ02 conforms to the bus state transition table shown in the SCSI-2
standard, "Phase Sequences". In addition, the information in the following
sections applies.

6.2.9 ATTENTION Signal Response
The THZ02 will respond to an ATN condition at least at every phase transition, as
long as the initiator sets the ATN bit before the target deasserts the REQ for the
last byte of the previous phase. Generally ATN will be recognized immediately by
the THZ02, and it will change the bus phase to Message Out.

6.2.10 STATUS Phase
The THZ02 will enter the status phase just once per command, unless a retry
is requested by the initiator. The only exception is during error cases when the
device goes immediately to bus free, as defined in the SCSI-2 standard (Section
6.3 of rev 10c).
The status bytes that the tape drive returns are as follows:
•

GOOD (00): This status indicates that the drive has successfully completed
the command.

•

CHECK CONDITION (02): A contingent allegiance condition has occurred.
The REQUEST SENSE command should be sent following this status to
determine the nature of the event.

•

BUSY (08): The target is busy. This status is returned whenever the device
is unable to accept a command from an otherwise acceptable initiator. The
initiator should reissue the command at a later time.

•

INTERMEDIATE GOOD (10h): This status is returned instead of GOOD
status for commands issued with the Link bit set. Following the return of
this status, the drive will proceed to the command phase for the transfer of
the next linked command.

•

RESERVATION CONFLICT (18h): This status is returned by the drive
whenever an SCSI device attempts to access the drive when it has been
reserved for another initiator with a RESERVE UNIT command.

•

COMMAND TERMINATED (22h): This is the status returned for a command
that was terminated by a TERMINATE I/O PROCESS message. This status
also indicates that a contingent allegiance condition has occurred.

6–4 SCSI Interface

SCSI Interface
6.2 General SCSI Bus Operation
•

QUEUE FULL (28h): This status is returned when a QUEUE TAG type
message is received and the command queue is full. The command received is
discarded.
Note
In contrast to the BUSY status condition, the DRIVE NOT READY sense
key is returned as part of the Sense data following a REQUEST SENSE
command and indicates that a media access command has been issued
and the media is not ready to be accessed (for example, the media is not
installed, the media has been unloaded, the drive is currently initializing
the media to prepare it for access, etc.).

In the not ready state, the initiator cannot perform any operation which would
cause tape motion (for example, write, read, verify, space, etc.). These commands
will return a CHECK CONDITION status with a DRIVE NOT READY sense key.
The initiator may, however, execute commands that don’t require access to the
media and a GOOD status may be returned. These commands are as follows:
— INQUIRY
— LOAD UNLOAD
— LOG SENSE/SELECT
— MODE SELECT
— MODE SENSE
— PREVENT/ALLOW MEDIUM REMOVAL
— READ BLOCK LIMITS
— READ BUFFER
— READ ELEMENT STATUS
— RECEIVE DIAGNOSTIC RESULTS
— REQUEST SENSE
— RESERVE/RELEASE UNIT
— SEND DIAGNOSTIC (nonmedia access diagnostics)
— WRITE BUFFER
The TEST UNIT READY command is used to determine whether the tape drive
would accept a media access command without returning CHECK CONDITION
status.

SCSI Interface 6–5

SCSI Interface
6.3 SCSI Message System

6.3 SCSI Message System
The message system allows communication between an initiator and a target for
the purpose of physical path management.
To support certain SCSI-1 initiators, an Identify message is not required by
the THZ02. If a message is sent by the initiator after the SELECTION phase,
it should be an IDENTIFY, ABORT, or BUS DEVICE RESET message. If the
THZ02 receives any other message in this case, it will go directly to BUS FREE
phase.
The following messages are supported:
Table 6–1 Supported SCSI Messages
Code

In/Out

Description

Section

06
0D
0C

Out
Out
Out

ABORT
ABORT TAG
BUS DEVICE RESET

0E
00

Out
In

CLEAR QUEUE
COMMAND COMPLETE

04
01

In
Both

DISCONNECT
EXTENDED MESSAGE (SDTR only)

80->FF
05

Both
Out

IDENTIFY
INITIATOR DETECTED ERROR

LINKED COMMAND COMPLETE

LINKED COMMAND COMPLETE w/flag

Out

MESSAGE PARITY ERROR

Both

MESSAGE REJECT

Out

NO-OP

RESTORE POINTERS

SAVE DATA POINTER

ABORT (06h)
ABORT TAG (0Dh)
BUS DEVICE RESET
(0Ch)
CLEAR QUEUE (0Eh)
COMMAND
COMPLETE (00h)
DISCONNECT (04h)
EXTENDED
MESSAGE (01h)
IDENTIFY (80h-FFh)
INITIATOR
DETECTED ERROR
(05h)
LINKED COMMAND
COMPLETE (0Ah)
LINKED COMMAND
COMPLETE, with
Flag (0Bh)
MESSAGE PARITY
ERROR (09h)
MESSAGE REJECT
(07h)
NO-OP (No Operation)
(08h)
RESTORE
POINTERS (03h)
SAVE DATA
POINTER (02h)

ABORT (06h)
This message is sent from the initiator to the target to clear, on the selected unit,
the current I/O process. Buffered (cached) write operations will be completed if
possible. The target goes directly to the BUS FREE phase after successful receipt
of this message. Current settings of mode select parameters and reservations are
not affected. Commands, data and status for other initiators is not affected.
This message can be sent to a logical unit that is not currently performing an
operation for the initiator. If no unit has been selected, the target goes to BUS
FREE, and no commands, data or status on the target is affected.

6–6 SCSI Interface

SCSI Interface
6.3 SCSI Message System
ABORT TAG (0Dh)
This message is sent from the initiator to the target to clear, on the selected
unit, the current I/O operation only. The target goes directly to the BUS FREE
phase after successful receipt of this message. Current settings of mode select
parameters and reservations are not affected.
BUS DEVICE RESET (0Ch)
This message from an initiator clears all commands, data and status in the
tape controller. When it recognizes this message, the drive aborts the command
currently being executed and proceeds to the BUS FREE state. The drive then
executes a hard reset which leaves it as if a bus reset had occurred. All data in
the write buffer is lost.
CLEAR QUEUE (0Eh)
This message clears all I/O processes for all initiators. A Unit Attention condition
will be generated for all other initiators that had outstanding I/O processes,
with Additional Sense Code (ASC) of Command Cleared by Another Initiator.
The target goes directly to the BUS FREE phase after successful receipt of this
message. Current settings of mode select parameters and reservations are not
affected.
COMMAND COMPLETE (00h)
This message is sent from a target to an initiator to indicate that the execution of
a command (or a series of linked commands) has completed and valid status has
been sent to the initiator. After it has sent the message successfully, the target
goes to the BUS FREE phase by releasing BSY. If received by the tape unit, it is
handled as an illegal message; the drive returns MESSAGE REJECT and enters
the STATUS phase reporting CHECK CONDITION with the sense key set to
COMMAND ABORTED.
DISCONNECT (04h)
A target sends DISCONNECT to tell an initiator that the present physical path
is going to be broken (the target intends to disconnect by releasing BSY). Later,
reselection is required in order to complete the current operation. This message
does not cause the initiator to save the Data pointer.
When received from an initiator, the tape drive may respond in one of two ways.
First, it may take the message as a request by the initiator to disconnect and
comply by entering message in phase and sending the DISCONNECT message
back to the initiator (possibly preceded by the SAVE DATA POINTERS message).
In this case, it will delay a minimum of 200 s before arbitrating for the bus
again. Alternately, it may enter the message in phase and return MESSAGE
REJECT.
EXTENDED MESSAGE (01h)
This is sent as the first byte of a multiple-byte message (> 2 bytes) by either
initiator or target. EXTENDED MESSAGE has the following format:

SCSI Interface 6–7

SCSI Interface
6.3 SCSI Message System
Figure 6–1 Extended Message Format
Byte 0
Byte 1
Byte 2
Byte 3

Extended Message Identifier − 01h
Extended Message Length
Extended Message Code
Extended Message additional parameters

The extended message length specifies the length of the extended message plus
the number of additional parameter bytes that are to follow. The length does not
include bytes 0 and 1. A value of 0 for the extended message length indicates 256
bytes to follow.
Possible extended message codes are as follows:
00h — MODIFY DATA POINTER (not supported)
01h — SYNCHRONOUS DATA TRANSFER REQUEST
02h — Reserved
03h — WIDE DATA TRANSFER REQUEST (not supported)
04h-7Fh — Reserved
80-FFh — Vendor Unique
If the tape drive receives an extended message which it does not support, it
switches to message in phase and returns MESSAGE REJECT after all the bytes
of the message have been transferred.
IDENTIFY (80h-FFh)
These messages are sent either by the initiator or by the target to establish (or
reestablish) the physical connection path between an initiator and target for a
particular logical unit. The message byte consists of the following bits:
Bit 7: Always set to 1.
Bit 6: Set by initiator if target is allowed to disconnect/reconnect.
Bit 5: Must be set to 0 ("Target Routines" not supported)
Bit 4: Reserved. Must be set to 0.
Bit 3: Reserved. Must be set to 0.
Bits 2-0: Logical Unit Number (LUN).
When the identify message is sent from a target to an initiator during
reconnection, a RESTORE POINTERS message is implied.
INITIATOR DETECTED ERROR (05h)
This message is sent from an initiator to inform a target that an error (for
example, a bus parity error) has occurred that does not prevent the target from
trying the operation again. When received, the THZ02 attempts to retransfer the
last command, data or status bytes by using the RESTORE POINTERS message
mechanism.
LINKED COMMAND COMPLETE (0Ah)
This message is sent from a target to an initiator to indicate that the execution of
a linked command (with the Flag bit 0) is complete and that status has been sent.
The initiator then sets the pointers to the initial state for the next command.
When received as a target, it is handled as an illegal message; the drive enters
the MESSAGE IN phase and returns MESSAGE REJECT.
LINKED COMMAND COMPLETE, with Flag (0Bh)
This message is sent from a target to an initiator to indicate that the execution
of a linked command (with the Flag bit set to 1) is complete and that status has
been sent.
6–8 SCSI Interface

SCSI Interface
6.3 SCSI Message System
MESSAGE PARITY ERROR (09h)
This message is sent from the initiator to the target to indicate that one or more
bytes in the last message it received had a parity error.
To indicate that it intends to send the message, the initiator sets the ATN signal
before it releases ACK for the REQ/ACK handshake of the message that has the
parity error. This provides an interlock so that the target can determine which
message has the parity error. If the target receives this message under any other
conditions, it proceeds directly to the BUS FREE state by releasing the BSY
signal, signifying a catastrophic error.
The target’s response to this message shall be to switch to the MESSAGE
IN phase and resend from the beginning all the bytes of the message which
generated the original MESSAGE PARITY ERROR message.
MESSAGE REJECT (07h)
This message is sent from the initiator or target to indicate that the last message
received was inappropriate or has not been implemented.
In order to indicate its intentions of sending this message, the initiator asserts
the ATN signal before it releases ACK for the REQ/ACK handshake of the
message that is to be rejected.
MESSAGE REJECT is issued in response to any messages which the drive
considers to be illegal or not supported. When sending to the initiator, the tape
device will do so before requesting any additional message bytes.
NO-OP (No Operation) (08h)
If a target requests a message, the initiator sends NO-OP if it does not currently
have any other valid message to send. The message is accepted when the drive is
acting as a target, and may be sent when it is an initiator. If NO-OP is received
during a selection, the drive proceeds to the command phase (provided that ATN
does not continue to be asserted). The NO-OP message is ignored by the tape
drive.
RESTORE POINTERS (03h)
This message is sent from a target to direct the initiator to restore the most
recently saved pointers (for the currently attached logical unit). Pointers to the
command, data and status locations for the logical unit are restored to the active
pointers. command and status pointers are restored to the beginning of the
present command and status areas. The data pointer is restored to the value
at the beginning of the data area in the absence of a SAVE DATA POINTER
message, or to the value at the last SAVE DATA POINTER message occurred for
that logical unit.
When the RESTORE POINTERS message is received as a target, the target
switches to the message in phase and returns MESSAGE REJECT.
SAVE DATA POINTER (02h)
This message, sent from a target to the initiator, saves a copy of the present
active data pointer for the logical unit which is currently attached.
The tape drive accepts this message if in the initiator mode (while performing
a COPY command). As a target, the tape drive sends this message before a
disconnect during a data transfer. It does not send a SAVE DATA POINTER
message if it intends to move directly to STATUS phase. When received as a
target, it switches to message in phase and returns MESSAGE REJECT.

SCSI Interface 6–9

SCSI Interface
6.3 SCSI Message System
Synchronous Data Transfer Request (SDTR)
This extended message allows the target and initiator to agree on the values of
the parameters relevant to synchronous transfers. THZ02 will not initiate the
Synchronous Data Transfer Request message, but relies on the Initiator to do so.
The SDTR message has the following format:
Figure 6–2 SDTR Extended Message Format

Byte 0
Byte 1
Byte 2
Byte 3
Byte 4

Extended Message Identifier − 01h
Length = 3
Message Code = 1 (SDTR msg)
Transfer Period (min=50. = 32h)
Transfer Req/Ack Offset (max=15)

6.4 Tape Drive SCSI Commands
6.4.1 Control Byte — Flag and Link Bits
The control byte of the command descriptor block contains the Flag and Link bits.
Use of these bits is entirely initiator dependent. Setting the Link bit provides
an automatic link to the next command, bypassing the usual ARBITRATION,
SELECTION, and MESSAGE OUT phases which would normally occur between
commands.
All other bits in the control byte are considered to be reserved.

6–10 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2 Summary of Supported Sequential-Access Device Commands
The following table shows what SCSI commands are supported by the THZ02
tape drive.
Table 6–2 THZ02 Supported SCSI Commands
Opcode

Command

Section

19
12
1B
2B
4C
4D
15
1A
1E

ERASE
INQUIRY
LOAD-UNLOAD
LOCATE
LOG SELECT
LOG SENSE
MODE SELECT
MODE SENSE
PREVENT/ALLOW MEDIUM
REMOVAL
READ
READ BLOCK LIMITS
READ BUFFER
READ POSITION
RECEIVE DIAG RESULTS
RELEASE UNIT
REQUEST SENSE
RESERVE UNIT
REWIND
SEND DIAGNOSTIC
SPACE
TEST UNIT READY
VERIFY
WRITE
WRITE BUFFER
WRITE FILEMARK

Section 6.4.2.1
Section 6.4.2.2
Section 6.4.2.3
Section 6.4.2.4
Section 6.4.2.5
Section 6.4.2.6
Section 6.4.2.7
Section 6.4.2.8
Section 6.4.2.9

08
05
3C
34
1C
17
03
16
01
1D
11
00
13
0A
3B
10

Section 6.4.2.10
Section 6.4.2.11
Section 6.4.2.12
Section 6.4.2.13
Section 6.4.2.14
Section 6.4.2.15
Section 6.4.2.16
Section 6.4.2.17
Section 6.4.2.18
Section 6.4.2.19
Section 6.4.2.20
Section 6.4.2.21
Section 6.4.2.22
Section 6.4.2.23
Section 6.4.2.24
Section 6.4.2.25

SCSI Interface 6–11

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.1 ERASE (19h)
Figure 6–3 ERASE CDB
Bit
7

0
1

Byte

Immed

Long

Flag

Link

Operation Code (19h)
Logical Unit Number

Reserved

Unused

Reserved

ERASE causes data on the tape to be erased. Any write data that is currently
held in buffer memory and has not been written to tape yet, is flushed to tape
before the ERASE is executed.
Immed
If the Immediate bit is set to 0, the target will not return status until the selected
operation has completed. If the bit is set to 1, status will be returned as soon as
the operation has been initiated.
Long
The Long bit controls the distance to be erased. If the bit is set, filler and EOD
blocks will be written if needed, and then the entire rest of the tape will be
erased.
Note
This command is a NOP on the THZ02 unless the Long bit is set.

6.4.2.2 INQUIRY (12h)
The INQUIRY command implementation is dependent upon the type of firmware
that is loaded in the THZ02 controller. Refer to Table 6–3 for the appropriate
section for your type of code.
Table 6–3 INQUIRY Command Sections
Code Type

Description

Section

Type 1
Type 2
Type 3

SCSI II
8mm emulation
AS400
attachment

Section 6.4.2.2.1
Section 6.4.2.2.2
Section 6.4.2.2.3

6–12 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.1 INQUIRY — SCSI II INQUIRY tells the drive to send information
regarding the device’s parameters to the initiator.
Figure 6–4 INQUIRY CDB
Bit
7

0
1

Logical Unit Number

Reserved

EVPD

Page Code

Reserved

Allocation Length

Operation Code (12h)

2
Byte

Unused

Reserved

Flag

Link

The INQUIRY command executes normally even if the specified LUN is not
attached. INQUIRY returns a CHECK CONDITION status only when the target
cannot return the requested inquiry data. If INQUIRY is received from an
initiator with a pending UNIT ATTENTION condition (before the drive reports
CHECK CONDITION status), the target will perform the INQUIRY and will not
clear the UNIT ATTENTION condition.
EVPD
The THZ02 implements the Vital Product Data pages option on LUNs 0 and 1.
Page Code
There are three Vital Product Data pages implemented:
00h — Supported Vital Product Data pages
80h — Unit Serial Number page
C0h — Code Build Information page
If the page code field contains a different value, the drive generates a CHECK
CONDITION with ILLEGAL REQUEST sense key.
Allocation Length
This specifies the maximum number of bytes that the initiator has allocated for
returned inquiry data. An allocation length of 0 indicates that no inquiry data is
transferred. This condition is not considered an error. The drive will terminate
the DATA IN phase when allocation length bytes have been transferred, or when
all available inquiry data has been transferred to the initiator, whichever is less.

SCSI Interface 6–13

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.1.1 Drive Inquiry Response
The THZ02 passes back the following information in response to an INQUIRY
command on the drive LUN:
Figure 6–5 Inquiry Response Data
Bit
7
0

Peripheral Qualifier

RMB

ISO Version

AENC

Device Type Modifier
ECMA Version

ANSI−Approved Version

Reserved

Response Data Format

TrmIOP

Additional Length (33h)

Reserved

Reserved
RelAdr

WBus32 WBus16

Sync

Linked

08−15

Vendor ID = "DEC

16−31

Product ID = "THZ02

32−35
36−55

Peripheral Device Type

Rsrved

CmdQue

SftRe

"
(C) DEC"

Product Revision Level = "hhss"
Vendor Unique bytes

Peripheral Qualifier
The tape drive returns one of the following values in this field:
•

000b — The indicated peripheral device type is connected to the logical unit.

•

001b — The indicated peripheral device type is not connected to the logical
unit, however, the tape drive is capable of supporting the indicated peripheral
device type at the specified logical unit.

•

011b — The target is not capable of supporting a physical device on this
logical unit. For this case, the peripheral device type will be set to 1Fh.

6–14 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
ANSI Approved Version
The ANSI approved version is set to 2, indicating compliance with SCSI-2.
AENC
AENC — Set to 0 (asynchronous event notification not supported).
TrmIOP
TrmIOP — Set to 1 (Terminate I/O process message supported).
Response Data Format
Response data format — set to 2 (inquiry data in SCSI-2 format).
Additional Length
Additional length — The tape drive sets this field to indicate the number of
additional bytes of inquiry response data available. This value is not adjusted to
reflect the actual number of bytes which will be transferred (possibly determined
by the allocation length specified by the initiator).
Sync
Sync — Set to 1 (synchronous data transfers supported).
Linked
Linked — Set to 1 (linked commands supported).
Vendor Identification
Vendor identification — see figure.
Product Identification
Product identification — see figure. Note: if a media loader is attached to the
tape drive , the Product ID will indicate "THZ27" instead of "THZ02".
Product Revision Level
Product revision level — This field contains four bytes of ASCII data, which
define the product’s software revision levels. The first two bytes are the read
/write board’s firmware version number, the second two bytes are the controller’s
(SCSI target’s) firmware version number. When a firmware update is performed
on the THZ02, this part of the revision level field will change appropriately.

SCSI Interface 6–15

SCSI Interface
6.4 Tape Drive SCSI Commands
Vendor Specific
Vendor specific — (see below)
Figure 6–6 Inquiry Vendor Unique Bytes Definition
36

Released SCSI (controller) Firmware

Firmware Major Version #

Firmware Minor Version #

EEPROM Format Major Version #

EEPROM Format Minor Version #

Firmware Personality

Firmware Sub−personality

Tape Directory Format Version #

Controller Hardware Version #

Drive EEPROM Version #

Drive Hardware Version #

Media Loader Firmware Version #

Media Loader Hardware Version #

Media Loader Mechanical Version #

50
51
|
55

Media Loader Present flag
VU−reserved

Vendor Specific Inquiry Bytes
To more precisely identify the product and the installed firmware, additional
information is available:
Released flag — differentiates between released and test versions of firmware.
Various version numbers (see figure) in binary (not ASCII)
Firmware personality — coded value identifying OEM versions of product
Sub-personality — further differentiates product versions
Loader present — nonzero if a media loader is present

6–16 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.1.2 Vital Product Data Pages
The following figures show the information in the supported vital product data
pages.
Figure 6–7 Supported Vital Product Data Pages page

Bit
7
0

Peripheral Qualifier

Peripheral Device Type

Page Code (00h)

reserved

Page Length (3 more bytes)

00h − (this page)

80h − Unit Serial Number page

C0h − Firmware Build Info page (VU)

Figure 6–8 Unit Serial Number Page
Bit
7
0

Peripheral Qualifier

Peripheral Device Type

Page Code (80h)

reserved

Page Length (14h)

4−13

Controller Serial Number

14−23

Drive Serial Number

Controller Serial Number
The controller serial number is the serial number of the controller card mounted
on the top of the THZ02. It can be found on the bar code label. The controller
serial number is returned in ASCII.
Drive Serial Number
The drive serial number is the serial number of the electronics module mounted
on the bottom of the THZ02. It can be found on the bar code label. The controller
serial number is returned in ASCII.

SCSI Interface 6–17

SCSI Interface
6.4 Tape Drive SCSI Commands
Figure 6–9 Firmware Build Information Page — VU
Bit
7
0

Peripheral Qualifier

Peripheral Device Type

Page Code (C0h)

reserved

Page Length (20h)

4−5

Drive Firmware Checksum

6−7

Drive EEPROM Checksum

8−11

Controller Firmware Checksum

12−35

Controller Firmware Build Date

The checksums are binary, and are for positive firmware and EEPROM
identification.
Firmware build date is an ASCII string in the DD-Mmm-YYYY HH:MM::SS
format.
6.4.2.2.1.3 Media Loader Inquiry Response
The THZ02 controller generates inquiry data on the medium changer LUN that
is very similar to that for the tape drive LUN. The key differences are:
•

Peripheral device type is set to "8" for SCSI-2 medium changer.

•

Product ID bytes are set to "TZ media changer".

6–18 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.2 INQUIRY — 8mm Emulation INQUIRY tells the drive to send
information regarding the device’s parameters to the initiator.
Figure 6–10 INQUIRY CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (12h)
Logical Unit Number

Reserved

4
5

Allocation Length
Unused

Reserved

SCSI Interface 6–19

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.2.1 Drive Inquiry Response
The THZ02 passes back the following information in response to an INQUIRY
command on the drive LUN:
Figure 6–11 Inquiry Response Data

Bit
7

Peripheral Qualifier

RMB

ISO Version

Peripheral Device Type
Device Type Modifier

ECMA Version

ANSI−Approved Version

Reserved

Additional Length − 2Fh

Peripheral Qualifier
The tape drive returns one of the following values in this field:
•

000b — The indicated peripheral device type is connected to the logical unit.

•

011b — The target is not capable of supporting a physical device on this
logical unit. For this case, the peripheral device type will be set to 1Fh.

Peripheral Device Type
On the tape drive LUN, this field is set to 01h, indicating a sequential access
device. On the medium changer LUN, this field is set to 08h. All other LUNs will
return 1Fh.
RMB
The Removable Medium bit is 1.
Device-Type Modifier
The device-type modifier is set to 0.
ISO Version
The ISO version is set to 0.
ECMA Version
The ECMA version is set to 0.
ANSI Approved Version
The ANSI approved version is set to 1, indicating compliance with SCSI-1.
Additional Length
Additional length — The tape drive sets this field to 2Fh, indicating the number
of additional bytes of inquiry response data available.

6–20 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Vendor Specific
Vendor specific — (see below)
Figure 6–12 Inquiry Vendor Unique Bytes Definition
Bit
7

Reserved

08
|
|
|
15

(MSB)

16
|
|
|
31

(MSB)

32
|
|
|
35

(MSB)

36
|
|
|
55

(MSB)

Vendor Identification
(LSB)

Product Identitification
(LSB)

Firmware Revision Level
(LSB)

Vendor Unique
(LSB)

Vendor Specific Inquiry Bytes
Vendor Identification
Vendor identification — see figure.
Product Identification
Product identification — see figure. Note: if a media loader is attached to the
tape drive, the product ID will indicate "THZ27" instead of "THZ02".
Product Revision Level
Product revision level — This field contains four bytes of ASCII data, which
define the product’s software revision levels. The first two bytes are the read
/write board’s firmware version number, the second two bytes are the controller’s
(SCSI target’s) firmware version number. When a firmware update is performed
on the THZ02, this part of the revision level field will change appropriately.

SCSI Interface 6–21

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.3 INQUIRY — AS400 Attachment INQUIRY tells the drive to send
information regarding the device’s parameters to the initiator.
Figure 6–13 INQUIRY CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (12h)
Logical Unit Number

Reserved

4
5

Allocation Length
Unused

Reserved

6–22 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.2.3.1 Drive Inquiry Response
The THZ02 passes back the following information in response to an INQUIRY
command on the drive LUN:
Figure 6–14 Inquiry Response Data

Bit
7

Peripheral Qualifier

RMB

ISO Version

3
4

Peripheral Device Type
Device Type Modifier

ECMA Version
Reserved

ANSI−Approved Version
Response Data Format

Additional Length − 33h

Peripheral Qualifier
The tape drive returns one of the following values in this field:
•

000b — The indicated peripheral device type is connected to the logical unit.

•

011b — The target is not capable of supporting a physical device on this
logical unit. For this case, the peripheral device type will be set to 1Fh.

Peripheral Device Type
On the tape drive LUN, this field is set to 01h, indicating a sequential access
device. On the medium changer LUN, this field is set to 08h. All other LUNs will
return 1Fh.
RMB
The Removable Medium bit is 1.
Device-Type Modifier
The device-type modifier is set to 0.
ISO Version
The ISO version is set to 0.
ECMA Version
The ECMA version is set to 0.
ANSI Approved Version
The ANSI approved version is set to 1, indicating compliance with SCSI-1.
Response Data Format
The response data format is set to a 1 to indicate vendor unique response data is
being returned.
Additional Length
Additional length — The tape drive sets this field to 33h, indicating the number
of additional bytes of inquiry response data available.

SCSI Interface 6–23

SCSI Interface
6.4 Tape Drive SCSI Commands
Vendor Specific
Vendor specific — (see below).
Figure 6–15 Inquiry Vendor Unique Bytes Definition
Bit
7

Reserved

08
|
|
|
15

(MSB)

16
|
|
|
31

(MSB)

32
|
|
|
35

(MSB)

36
|
|
|
55

(MSB)

Vendor Identification
(LSB)

Product Identitification
(LSB)

Firmware Revision Level
(LSB)

Vendor Unique
(LSB)

6–24 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.3 LOAD-UNLOAD (1Bh)
Figure 6–16 LOAD-UNLOAD CDB
Bit
7

0
1

Byte

Operation Code(1Bh)
Logical Unit Number

Reserved

4
5

Reserved
Unused

EOT
Reserved

Immed

Re−Ten

Load

Flag

Link

LOAD-UNLOAD tells the target to load or unload the media in the tape cartridge.
If no cartridge is in the drive, both LOAD and UNLOAD will return a CHECK
CONDITION status with a NOT READY sense key set. If the drive has received
an UNLOAD command with the Immed bit set and then receives another
command which would involve tape motion or TEST UNIT READY, the drive
will return a CHECK CONDITION status with a NOT READY sense key set.
Operation of the UNLOAD version of this command will be different if a media
loader is present. See the chapter on Media Loader Operation. If a loader is
present, and an UNLOAD command is received by the subsystem, the current
cartridge will be unloaded and automatically moved to the magazine slot it
originated from. Then the cartridge from the next slot in the magazine, if not
empty, is automatically moved from the magazine into the drive, loaded, and
made ready. If the next magazine slot is empty, no CHECK CONDITION status
is created.
If the cartridge is unloaded into magazine slot 6 (the last one), the subsystem does
not cycle back to slot 0. This is to prevent accidental overwriting of data when
using the subsystem in sequential auto-loading mode. The next cartridge must be
selected and loaded manually, or with an SCSI MOVE MEDIUM command.
A media loader does not affect the device’s processing of the LOAD flavor of the
LOAD-UNLOAD command.
The command specific bits are used as follows:
•

Immed — If this bit is set, status is returned as soon as the operation is
started. Otherwise, the status is returned after the operation has completed.

•

Re-Ten — Retension operations are not needed on the THZ02, so this bit is
ignored.

•

Load — When a cartridge is inserted, the media is automatically loaded and
positioned by the drive at BOM. Logically, the drive will be positioned at the
beginning of partition 0.
If the Load bit is set, and the media is already loaded, no action is taken.
If the media was unloaded but the cartridge was not removed, a LOAD will
cause it to be loaded to BOP again and made ready.

SCSI Interface 6–25

SCSI Interface
6.4 Tape Drive SCSI Commands
If the Load bit is 0 and media is loaded, the drive writes any buffered
data and filemarks to the tape and rewinds the tape to BOM and unloads
the media into the THZ02 cartridge. The "Operate Handle" green LED is
luminated and the cartridge can be removed from the drive. If the media is
already unloaded, no action is taken.
•

EOT — This bit is ignored by the THZ02, unless both the EOT and Load
bits are both set, then the drive returns CHECK CONDITION, ILLEGAL
REQUEST.

6.4.2.4 LOCATE (2Bh)
Figure 6–17 LOCATE CDB
Bit
7
0
1
Byte

Imm

Operation Code (2Bh)
Logical Unit Number

2
3

Reserved
Reserved

(MSB)

4
Block Address
5
6

(LSB)

Reserved

Partition

Unused

Reserved

Flag

Link

The LOCATE command is used to do high speed positioning to the specified block
address. Average positioning time is about 90 seconds, maximum time is under 3
minutes.
The READ POSITION command can be used to obtain the block address, when
writing, where particular blocks of data (for example, a data file) are about to be
written. Then the LOCATE command can be used to position back to the same
logical position for high performance restore operations of particular blocks of
data.
•

BT — The Block Type bit indicates how the block address field is interpreted.
For the THZ02 products, SCSI logical block addresses are always returned,
for example, the setting of the BT bit does not affect the values returned. The
first recorded object (block or filemark) is at address 0, and block addresses
count both data blocks and filemarks.

•

CP — Since multiple partitions are not supported this bit must be 0.

•

Imm — If set, STATUS is returned when the command has been started.

6–26 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Block Address
The SCSI logical block address to which the media will be positioned. These
addresses start at 0, and include data blocks and filemarks, so they could also be
considered an object address.
6.4.2.5 LOG SELECT (4Ch)
Figure 6–18 LOG SELECT CDB
Bit
7

Byte

PCR

Operation Code (4Ch)

1 Logical Unit Number (0)

Reserved

(MSB)
Parameter List Length
(LSB)

8
9

Unused

Reserved

Flag

Link

LOG SELECT allows the host to manage statistical information maintained
by the device about its own hardware or the installed media. The description
should be read in conjunction with the description of the LOG SENSE command
which follows it, to provide the reader with information about log page format,
parameters and supported pages. The command specific bits are used as follows:
•

PCR — If Parameter Code Reset bit is set to 1 and parameter list length is
0, all accumulated values of page code 2 and 3 are set to 0 and all threshold
values are set to default. If PCR is set 1 and the parameter list length field is
not 0, the command will be terminated with a CHECK CONDITION status,
with sense key of ILLEGAL REQUEST, and ASC of INVALID FIELD IN
CDB.

•

SP — The Save Page bit is not supported and must be set to 0. If the SP bit
is set, the command will be terminated with CHECK CONDITION status,
with sense key of ILLEGAL REQUEST, and ASC of INVALID FIELD IN
CDB.

SCSI Interface 6–27

SCSI Interface
6.4 Tape Drive SCSI Commands
•

PC — The page control field defines the type of parameter values to be
selected:

Figure 6–19 LOG Page Control Definitions

Type of Parameter Values

00b
01b
10b
11b

Threshold Values
Cumulative Values
Default Threshold Values
Default Cumulative Values

All types of parameter values all changeable through LOG SELECT.
Parameter List Length
This field specifies the length in bytes of the LOG SELECT parameter list to
be transferred from the initiator to the target during the DATA OUT phase.
A parameter list length of 0 indicates that no data is to be transferred. This
condition is not considered as an error (see also the description of parameter code
reset and page control fields above).
Error Detection Summary in LOG SELECT CDB
Following conditions constitute errors that will be detected by the drive in
relation to the CDB. The request sense data is set to ILLEGAL REQUEST,
INVALID FIELD IN CDB.
•

If PCR bit is set to 1 and parameter list length is not 0.

•

If SP bit is set 1.

•

A parameter list length that would cause a parameter with in a valid page to
be truncated or otherwise incompletely initialized.

6.4.2.5.1 Operation of LOG SELECT The purpose of the LOG SELECT
command is to allow the initiator to modify and initialize parameters within
the logs supported by the device.
To achieve this, during the DATA OUT phase the initiator must send the log page
header of the page to be cleared, with the page length field set to 0. The following
pages can be cleared in this manner:
_________________________________________
| Page Code | Page Description
|
|-----------------------------------------|
|
02h
| Write Error Counter Page
|
|
03h
| Read Error Counter Page
|
|_________________________________________|
If multiple pages are sent during this DATA OUT phase, they must be sent
in ascending order according to page code. Otherwise the command will
terminate with a CHECK CONDITION status with the sense key set to ILLEGAL
REQUEST and an additional sense code of INVALID FIELD IN PARAMETER
LIST. The same status will be returned if an unsupported page code appears in
any header, or if the specified page cannot be cleared.

6–28 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
LOG SELECT Page Format
Each Log page will begin with 4 byte header followed by n number of log
parameter blocks (one block for each parameter code). Each block, except for
parameter code 05h, will be of size 8 bytes. The parameter block for code 05h will
be of size 12 bytes.
Figure 6–20 Read/Write Error Log Select Page Format
7
0

Reserved

Page Code

1
2

Reserved
(MSB)
Page Length

(LSB)

Log Parameter(s)
7
0

(MSB)
Parameter Code

−−−
(LSB)

1
2

TSD

ETC

TMC

Parameter Length

4 (MSB)
|
|
|
11

Parameter Value

Rsvd

(LSB)

Note
Parameter value for code 05h will be of 8 bytes, hence the parameter
length shall be set to 8.

SCSI Interface 6–29

SCSI Interface
6.4 Tape Drive SCSI Commands
Byte 2 of log parameter block in Figure 6–20 is referred to as parameter control
byte.
•

DU — Disable update: DU bit is not defined for LOG SELECT and target
shall ignore any value.

•

DS and TSD — Saving parameters is not supported hence they both should be
set to 1. If the DS and/or TSD are set to 0, the command is terminated with
CHECK CONDITION status with the sense key set to ILLEGAL REQUEST
with the additional sense code set to INVALID FIELD IN PARAMETER LIST.

•

ETC — Enable threshold comparison: When set 1, drive shall perform a
comparison with threshold values once the cumulative value is updated.
Comparison criteria is defined in TMC. If the comparison is met and
RLEC bit of MODE SELECT/SENSE control page is set 1 then a UNIT
ATTENTION is generated for all initiators. The additional sense code
set to LOG EXCEPTION and the additional sense code qualifier set to
THRESHOLD CONDITION MET. If RLEC bit is 0 and comparison is met
then UNIT ATTENTION is not generated.

•

TMC — Threshold met criteria: See Figure 6–27 for the list of criteria. Once
the specified criteria in this field met and ETC bit is 1 and RLEC bit in
MODE SENSE/SELECT control page is set 1 then UNIT ATTENTION is
generated for all initiators.

•

LP — List parameter: This bit should always be set to 0 to indicate that
parameter codes are treated as data counters.

Error Detection Summary in Log Select Pages
The host should issue a LOG SENSE command to initialize host software which
allows:
•

Correct determination of the pages the drive uses.

•

Determination of the parameter codes and length of each parameter.

The following conditions constitute errors in the parameter block that will cause
drive to return CHECK CONDITION with the sense data set to ILLEGAL
REQUEST and additional sense code INVALID FIELD IN PARAMETER LIST:
•

If a page header is received with unsupported page codes.

•

Incorrect log page length is specified in the page header.

•

An illegal parameter code within a valid page code.

•

Parameter codes for a supported page are not sent in ascending order.

•

LP bit is set to 1 in the parameter control byte.

•

DS bit is set 0 in the parameter control byte.

•

TSD bit is set 0 in the parameter control byte.

6–30 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.6 LOG SENSE (4Dh)
Figure 6–21 LOG SENSE CDB
Bit
7

Byte

Reserved

PPC

SP(0)

Page Code

Reserved

Operation Code (4Dh)

1 Logical Unit Number (0)
2

(MSB)
Parameter Pointer
(LSB)

6
7

(MSB)
Allocation Length
(LSB)

8
9

Unused

Reserved

Flag

Link

LOG SENSE allows the host to retrieve statistical information maintained by
the device about its own hardware or the installed media. It is a complementary
command to LOG SELECT.
PPC
A Parameter Pointer Control bit of 0 indicates that the parameter data requested
from the device will start with the parameter code specified in the parameter
pointer field and return the number of bytes specified in the allocation length
field in ascending order of parameter codes from the specified log page. A PPC bit
of 0 and a parameter point field of 0 causes all available parameter data for that
page code to be returned to the initiator.
If PPC bit is set, then target shall return with parameter code values which
have changed since last LOG SENSE or LOG SELECT command. Target shall
return the parameter codes following the parameter pointer field. If parameter
pointer field is 0 then target shall return all the parameter code values which
have changed since last LOG SENSE or LOG SELECT.
If the target does not support a parameter code within this page then it will not
return any data associated with this parameter.
SP
Saving log parameters is not supported and shall be always 0.
If the SP bit is set, the command is terminated with CHECK CONDITION status
with the sense key set to ILLEGAL REQUEST, and an additional sense code of
INVALID FIELD IN CDB.

SCSI Interface 6–31

SCSI Interface
6.4 Tape Drive SCSI Commands
PC
The page control field defines the type of parameter values to be returned:
Figure 6–22 LOG Page Control Definitions

Type of Parameter Values

00b
01b
10b
11b

Threshold Values
Cumulative Values
Default Threshold Values
Default Cumulative Values

The default threshold values are the maximum values that each parameter can
attain.
The current cumulative values are the values computed since the last reset of the
device (either by power-cycling, BUS DEVICE RESET or SCSI RESET).
The default cumulative values are the values to which each parameter gets
initialized on a reset condition as described above. Default values are 0.
By default current threshold values = default threshold values.
Note
All types of parameter values are changeable through LOG SELECT.

Page Code
The page code field identifies which log page is being requested by the initiator.
If the page is not supported then the command terminates with a CHECK
CONDITION status with the sense key set to ILLEGAL REQUEST and an
additional sense code of INVALID FIELD IN CDB. Supported pages are as
follows:
Figure 6–23 LOG SENSE Pages Supported

Page Code
00h
02h
03h
07h
32h

Page Description
List of Supported Pages Page
Write Error Counter Page
Read Error Counter Page
History Page
Compression ratio page

Parameter Pointer
The parameter pointer field allows the host to specify at which parameter within
a log page the requested data should begin. For example if a page supports
parameters 0 through 5, and the parameter pointer field contains 3, then only
parameters 3, 4 and 5 are returned to the initiator. Similarly, if a page supports
parameters 1, 3 and 6, and the parameter pointer field contains 2, then only
parameters 3 and 6 are returned to the initiator.

6–32 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
If parameter pointer is larger than the highest numbered parameter on the page,
then the target will terminate the command with CHECK CONDITION status.
The sense key is set to ILLEGAL REQUEST and the additional sense code is set
to INVALID FIELD IN CDB.
Note
Parameters within a page are always returned in ascending order
according to parameter code.

The following parameter codes are supported for the error counter pages.
Figure 6–24 Parameter Codes Supported

Parameter
Code

Description

00h
01h
02h
03h
04h
05h
06h
8000h

Errors corrected with substantial delays
Errors corrected with possible delays
Total rewrites or rereads
Total errors corrected
Total times correction algorithm processed
Total bytes processed
Total uncorrected errors
Vendor Unique

Parameter codes 00h, 01h, and 04h will always return value of 0.
Allocation Length
The allocation length field is used to inform the target how much space the
initiator has allocated for data. There must be sufficient space allocated for
all the requested data, otherwise the command will terminate with a CHECK
CONDITION status with sense key of ILLEGAL REQUEST, and ASC of INVALID
FIELD IN CDB.
Error Detection Summary in LOG SENSE CDB
Following conditions constitute errors that will be detected by the drive in
relation to the CDB. The request sense data is set to ILLEGAL REQUEST,
INVALID FIELD IN CDB.
•

If a page is not supported.

•

If parameter pointer is larger than highest numbered parameter on the page.

•

If SP bit is set 1.

•

If the allocation length is smaller than the data being returned by target.

Supported Pages Page Format (Page 0)
When page 0 is requested, the 4 byte page header is returned followed by the
pages supported in ascending order, one byte for each.

SCSI Interface 6–33

SCSI Interface
6.4 Tape Drive SCSI Commands
Figure 6–25 Supported Pages Page Format

7
0

Reserved

Page Code (00h)

1
2

Reserved
(MSB)
Page Length (05h)

(LSB)

00h

02h

03h

07h

32h

Read/Write Error Log SENSE Page Format (Page 2 and 3)
Each log page will begin with 4 byte header followed by n number of log
parameter blocks, each block of 8 bytes except for parameter code 5h.
The log parameter block for the parameter total bytes processed (5h) will be of
size 12 bytes since the parameter value is 8 bytes long.
Figure 6–26 Read/Write Error Log SENSE Page Format
7
0

Reserved

Page Code

1
2

Reserved
(MSB)
Page Length

(LSB)

Log Parameter(s)
7
0

(MSB)
Parameter Code

−−−
(LSB)

1
2

TSD

ETC

TMC

Parameter Length

4 (MSB)
|
|
|
11

Parameter Value

6–34 SCSI Interface

Rsvd

(LSB)

SCSI Interface
6.4 Tape Drive SCSI Commands
For example, if PPC bit is 0 and parameter pointer is 0 then target will return
4 bytes of page header with page length of 44h followed by 8 bytes of parameter
value data for each parameter code except for parameter code 5h. For 5h it will
return 12 bytes.
So for parameter code 0h, 1h, 2h, 3h, 4h, 6h, 8000h each page will be of 8 bytes.
For parameter code 5h page will be of 12 bytes.
DU, DS, TSD, ETC, TMC and LP are collectively referred to as parameter control
byte.
•

DU — Disable update: A 0 value indicates that target shall update all log
parameter values. A value of 1 indicates that target will not update the log
parameter values except in response to LOG SELECT. This bit is set by the
drive when accumulated values reaches its maximum. This is also returned
set if the host set the bit in last LOG SELECT command. The default is 0.
Note
For parameter types other than threshold and cumulative values, this bit
is always 0.

•

DS — Disable save: Saving parameters is not supported, therefore this bit
will always be set to 1.

•

TSD — Target save disable: Saving parameter is not supported, therefore
this bit will always be set to 1.

•

ETC — Enable threshold comparison: ETC of 1 indicates that comparison
to threshold is performed. ETC of 0 indicates that this comparison is not
performed. This bit is set 1 by MODE SELECT. Default is 0.

•

TMC — Threshold met criteria: This field is valid only if host sets ETC to
1. It determines the basis for comparison and is specified by host by LOG
SELECT. If the result of comparison is true (cumulative = threshold) and
MODE SELECT/SENSE control mode page RLEC bit is set 1, then a unit
attention is generated for all initiators. The sense key will be set to UNIT
ATTENTION, ASC will be set to LOG EXCEPTION and ASCQ will be set to
THRESHOLD CONDITION MET. If the RLEC bit in control mode page is 0
then, UNIT ATTENTION will not be generated.
Note
It must be noted that this comparison is performed in real time. Therefore
user doesn’t need to issue a LOG SENSE command to get the CHECK
CONDITION. Once ETC is selected, RLEC bit in control mode page, the
CHECK CONDITION will be issued based upon the criteria defined in
the TMC bits if the criteria is met in real time.
CHECK CONDITION will not identify for which parameter code the
criteria is met. User will need to issue LOG SENSE to read the counters
to see for which parameter code criteria is met.

SCSI Interface 6–35

SCSI Interface
6.4 Tape Drive SCSI Commands
Figure 6–27 Threshold Met Criteria

Code
00b
01b
10b
11b

•

Basis of Comparison
Every update of the cumulative value
Cumulative value
equal to threshold value
Cumulative value not equal to threshold value
Cumulative value greater than threshold value

LP — List parameter: This bit will always be set to 0 as we treat the
parameter codes as data counter. When data counter reaches its defined
maximum value then it shall not increment and DU bit shall be set to 1. If
the data counter is at or reaches its maximum value during the execution
of a command, the drive will complete the command. If the RLEC bit
of CONTROL MODE PAGE is 1, drive then will issue status of CHECK
CONDITION and set the sense key to RECOVERED ERROR with additional
sense code set to LOG COUNTER AT MAXIMUM.

6.4.2.7 MODE SELECT (15h)
The MODE SELECT command implementation is dependent upon the type of
firmware that is loaded in the THZ02 controller. Refer to Table 6–4 for the
appropriate section for your type of code.
Table 6–4 MODE SELECT Command Sections
Code Type

Description

Section

Type 1
Type 2
Type 3

SCSI II
8mm emulation
AS400 attachment

Section 6.4.2.7.1
Section 6.4.2.7.2
Section 6.4.2.7.3

6–36 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1 MODE SELECT — SCSI II MODE SELECT enables the host to
configure the device. Implementing MODE SELECT and MODE SENSE
requires a certain amount of handshaking between the host and the drive.
Before configuring the drive, the host should issue a MODE SENSE to get the
current configuration and determine what parameters are configurable. The host
interprets this information and may then issue MODE SELECT to set the drive
to the host’s preferred configuration.
The drive always powers-up with its default configurations set. This is also true
if the drive receives a BUS DEVICE RESET message or a hard reset through the
RST line on the SCSI bus.
Figure 6–28 MODE SELECT CDB
Bit
7

0
1

Byte

Operation Code (15h)
Logical Unit Number

Reserved

Parameter List Length

Unused (00)

Reserved

SP(0)

Flag

Link

PF
The Page Format bit indicates that the data sent by the host after the MODE
SELECT header and block descriptors complies with the definition of pages in the
SCSI-2 specification. The SCSI-1 format will not be implemented, so this bit is
required to be set.
SP
The Save Parameters bit instructs the drive to save all saveable pages. This is
not supported.
PARAMETER LIST LENGTH
This specifies the length in bytes of the mode select parameter list that is
transferred during the DATA OUT phase. A zero parameter list length indicates
that no data is transferred.

SCSI Interface 6–37

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1.1 Mode Select Parameter List
The mode select parameter list shown below, contains a 4-byte header, followed
by one 8-byte block descriptor.
Figure 6–29 Mode Select Parameter List
Bit
7

Reserved

1
Byte

Reserved
ignored

Buffered Mode

Speed

Block Descriptor Length (08h)
Block Descriptor:

0
1

Density Code
(MSB)

Number of Blocks (000000h)

(LSB)

4
5

Reserved
(MSB)

Block Length

(LSB)
Page Descriptors

0
1
2

Page Code
Additional Page Length

Page Defined or Vendor−Unique Parameter Bytes

Buffered Mode
The drive will implement immediate reporting on WRITE commands through
buffered mode.
If the field is 0, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the buffered
mode field is 1, then the drive reports GOOD status on WRITE commands as
soon as the data block has been transferred to the buffer. This is the default
configuration for the drive. If buffered mode is not used, the tape drive will suffer
a significant degradation in performance, but not capacity.
If this field is greater than 1, the command will be rejected with a CHECK
CONDITION, with a sense key of ILLEGAL REQUEST.
Speed
The tape drive supports only one speed, the default speed.

6–38 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Block Descriptor Length
This specifies the length in bytes of all the block descriptors. Since the drive only
allows one block descriptor, this value must be 8 or 0. Any other value causes
a CHECK CONDITION status with an ILLEGAL REQUEST sense key to be
returned.
Density Code
This field should match the current density of the media, or will be set to 0 if the
density is unknown.
00h — use default density
0Ah — 6667 bpi MFM serial cartridge tape X3B5/86-199 (read only)
16h — 10000 bpi MFM serial cartridge tape X3.193-1990 (read only)
17h — 42500 bpi MFM serial cartridge tape X3B5/91-174
18h — 42500 bpi MFM serial cartridge tape
Number of Blocks
This MODE SENSE field will be sent as 0, indicating that all of the remaining
logical blocks on the tape will have the medium characteristics specified by the
block descriptor.
Block Length
This specifies the length in bytes of each logical block transferred over the SCSI
bus. A block length of 0 indicates that the length is variable (for example, is
specified in the I/O command). Any other value indicates the number of bytes per
block to use for read, write and verify type commands that specify a "Fixed" bit
of 1 (for example, fixed block mode) which also causes the transfer length in the
CDB to be defined as a block count.
6.4.2.7.1.2 Mode Select Pages
Following the block descriptor are the mode select pages, which set the device
parameters. Each page has a 2-byte header which identifies the page code and
indicates the number of bytes in that page.
The page codes that are supported as follows:
Figure 6–30 MODE SENSE/SELECT Pages Supported

Page
Code
00h
10h
02h
01h
11h
3Eh
3Fh

Description
No requested page
Device Configuration
Disconnect/Reconnect
Error Recovery Page
Medium partition Parameters
EEPROM Parameter Select
All pages

Sense/
Select
Sense
both
both
both
both
Select
Sense

SCSI Interface 6–39

SCSI Interface
6.4 Tape Drive SCSI Commands
Additional Page Length
This indicates the number of bytes in that page. However, the value does not
include bytes 0 and 1. The length is returned on MODE SENSE and must
subsequently be set to the same value when performing mode select. If the page
length does not match that expected by the drive a CHECK CONDITION status
is returned with the sense key set to ILLEGAL REQUEST. The drive also returns
a CHECK CONDITION status with an ILLEGAL REQUEST sense key if the
host sends an unsupported page code, or a page field with values that are not
supported or are not changeable. In this case, no parameters will be changed by
the command.
6.4.2.7.1.3 Device Configuration Page (10h)
The drive supports the device configuration page which has the following format:
Figure 6–31 Device Configuration Page Format
Bit

Byte

Page Code(10h)

Res

CAP

Active Format

CAF

Active Partition

Write Buffer Full Ratio

Read Buffer Empty Ratio

Additional Page Length (0Eh)

1
2

(MSB)
Write Delay Time

7
8

(LSB
DBR

BIS

9
10
11
12

RSmk

AVC

SOCF

RBO

Gap Size
EOD Defined

EEG

SEW

Reserv ed

(MSB)
Buffer Size at Early Warning (optional)

(LSB)

Select Data Compression Algorithm

Reserved

In this page, only the write delay parameter is changeable.

6–40 SCSI Interface

REW

SCSI Interface
6.4 Tape Drive SCSI Commands
PS
Set if the parameters are saveable.
CAP, CAF, Active Format
These fields are not supported and must be 0 on MODE SELECT.
Active Partition
Only partition 0 is supported. Setting this field to any other value will be rejected
by the drive with a CHECK CONDITION status and the ILLEGAL REQUEST
sense key set.
Write Buffer Full Ratio and Read Buffer Empty Ratio
These indicate how full/empty the buffer memory should be before restarting the
writing/reading of the media. THZ02 will set these fields to 0 (unused) because
it uses an automatic, adaptive mechanism to dynamically adjust its full/empty
ratios according to the average data rates over the SCSI bus.
Write Delay Time
This indicates the maximum time that the drive will wait with a partially full
buffer before forcing the data to tape (100 ms increments). Note that the buffer
full/empty ratio, which is dynamic, can cause data to be written sooner than the
write delay time would indicate. The write delay time defaults to 50 (32h). This
causes the buffer to be flushed in 5 seconds. Maximum value is 6500 (1964h) and
the minimum is 10 (0Ah). This represents delays from almost 11 minutes down
to 1 second.
Byte 8:
DBR — set to 0 (data buffer recovery not supported)
BIS — set to 1 (block identifiers supported in media format)
RSmk — set to 0 (setmarks not supported)
AVC — set to 0
SOCF — set to 0
RBO — set to 0
REW — set to 0 (don’t report early warning EOM on reads)
Gap Size
This field is not used and is set to 0.
EOD Defined
This field is set to 00h; any other value will be rejected by the drive.
EEG
The Enable EOD Generation bit is set to indicate that the drive will generate an
EOD. The drive generates an EOD mark before any change of direction following
a write-type operation. This bit is ignored on MODE SELECT.
SEW and Buffer Size At Early Warning
The Synchronize at Early Warning bit and buffer size at EW fields are not
supported and must be 0.
Select Data Compression Algorithm
This field is not used and must be 0.

SCSI Interface 6–41

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1.4 Disconnect/Reconnect Page (02h)
The drive shall support the disconnect/reconnect page which has the following
format:
Figure 6–32 Disconnect/Reconnect Page Format
Bit

Byte

Page Code(02h)

Additional Page Length (0Eh)

Buffer Full Ratio

Buffer empty Ratio

(MSB)
Bus Inactivity Limit
(LSB)

5
6

(MSB)
Disconnect time Limit

7
8

(LSB)
(MSB)
Connect Time Limit

(LSB)

10 (MSB)
Maximum Burst Size
11
12

(LSB)
Reserved

Reserved

DTDC

In this page, only the maximum burst size parameter is changeable.
The following parameters in this page are supported:
Maximum Burst Size
This value specifies the maximum amount of data that will be transferred without
disconnecting. A value of 0 sets no limit. This value is in units of 512 bytes. For
example, a value of 8 means 4k bytes. Values that are not multiples of 8 are
rounded up to the closest multiple of 8.
Data Transfer Disconnect Control (DTDC)
This option is not supported, so this field should be 0.

6–42 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1.5 Medium Partition Page (11h)
The drive supports the medium partitions parameter page, which has the
following format:
Figure 6–33 Medium Partition Page Format
Bit

Byte

Additional Page Length (06)

Maximum Additional Partitions

Additional Partitions Defined
FDP

SDP

PageCode(11h)

IDP

PSUM

Reserved

Medium Format Recognition (01)

Reserved

In this page, no parameters are changeable.
Maximum Additional Partitions
No additional partitions are supported, this field must be 0.
Additional Partitions Defined
The field specifies the number of additional partitions to be defined for the
tape based on the settings of the SDP and IDP bits. The maximum allowed is
the value returned in the maximum additional partitions field. Since only one
partition is supported, this field must be 0.
Option Flags
FDP — The Fixed Data Partitions bit must be 0.
SDP — The Select Data Partitions bit must be 0.
IDP — The Initiator Defined Partitions bit must be 0.
PSUM — The Partition Size Unit of Measure field must be 0.
Medium Format Recognition
This field is only valid on a MODE SENSE and is set to 01h indicating that
automatic format recognition is supported.

SCSI Interface 6–43

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1.6 Read/Write Error Recovery Page (01h)
The drive shall support the error recovery page which has the following format:
Figure 6–34 Error Recovery Page Format
Bit

1
2
Byte

DTE

DCR

Page Code(01h)
Additional Page Length (0Ah)

rsvd

EER

Read Retry Count

Reserved

Write Retry Count

Reserved

PER

In this page, only the post error (PER) flag parameter is changeable. If PER
is set, CHECK CONDITIONs will be created, with sense key of RECOVERED
ERROR, and VU sense data detailing the cause. Normally, these events should
be rare, and only occur if the recovered write or read retry rates reach excessive
levels.
Option Flags
•

TB — The Transfer Block (when not fully recovered) function is not supported.

•

EER — The Enable Early Recovery function is always enabled.

•

PER — The Post Error bit turns on reporting of CHECK CONDITION to
report recovered read/write errors. The default setting of this bit depends on
the personality of the firmware installed.

•

DTE — The Disable Transfer on Error feature is not supported so this bit
must be 0.

•

DCR — The Disable ECC Correction bit feature is not supported so this bit
must be 0.

Read Retry Count
This field reports the maximum number of rereads that are done before declaring
an unrecoverable error.
Write Retry Count
This field reports the maximum number of overwrite retries that will be
performed before declaring an unrecoverable error.

6–44 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1.7 EEROM Vendor Unique Page (3Eh)
The drive shall support a vendor unique page in which one may use to modify
saveable parameters. This page is only supported with the MODE SELECT
command. Only one saveable parameter may be changed per MODE SELECT
command. It has the following format:
Figure 6–35 EEROM Vendor Unique Page Format

1
2

Page Code
Additional Page Length

ASCII String of parameter name and value

The ASCII string has a parameter name, followed by one or more space
characters, a parameter value and an ASCII line feed or null character. When
the string is parsed, the parameter value will be interpreted as indicated in the
following table. The parameter name may be in upper or lower case.
Table 6–5 EEROM Vendor Unique Page Parameters
Name

Value
Representation

VENDORID
PRODUCTID
PRODUCTPID

ASCII
ASCII
ASCII

FORCEDENSITY
DEFFIXEDBLKLEN
ENBINQMEDCHGR

ASCII decimal
ASCII decimal
ASCII decimal

Usage
Vendor identification field in inquiry data
Product identification field in inquiry data
Product identification field in inquiry data of
THZ02 drive
0=automatic, 1=THZ01, 2=THZ02
Default fixed block size
0=Disable Media Changer bit, 1=enable

SCSI Interface 6–45

SCSI Interface
6.4 Tape Drive SCSI Commands
Here is an example of an EEROM vendor unique page which will modify the
VENDORID parameter to "XXXYY ".
Figure 6–36 EEROM Vendor Unique Page Example 1
0
1

Page Code (3EH)
Page Length (0FH)

"v"

(76H)

"e"

(65H)

"n"

(6EH)

"d"

(64H)

"o"

(6FH)

"r"

(72H)

"i"

(69H)

"d"

(64H)

(20H)

"X"

(58H)

"X"

(58H)

"X"

(58H)

"Y"

(59H)

"Y"

(59H)

<LF>

(0AH) or (00H)

6–46 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Here is an example of an EEROM vendor unique page which will modify the
FORCEDENSITY parameter to 1.
Figure 6–37 EEROM Vendor Unique Page Example 2
0
1

Page Code (3EH)
Page Length (0FH)

"F"

(46H)

"O"

(4FH)

"R"

(52H)

"C"

(43H)

"E"

(45H)

"D"

(44H)

"E"

(45H)

"N"

(4EH)

"S"

(53H)

"I"

(49H)

"T"

(54H)

"Y"

(59H)

(20H)

"1"

(31H)

<LF>

(0AH) or (00H)

SCSI Interface 6–47

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.1.8 Mode Select Changeable Parameters
The following table lists the changeable mode parameters and their minimum
and maximum values allowed. See the previous definitions for the units that
are used. Parameter rounding is supported for all parameters except the block
descriptor length.
Table 6–6 Changeable Mode Parameters
Page: Parameter

Default

Minimum

Maximum

Header: buffered mode, device specific byte
Block descriptor length
Block descriptor: block length
Read-write error recovery: PER bit
Disconnect-reconnect: maximum burst size
Device configuration: write delay time

1
08h
00000h
1
0080h
0032h

0
00h
00000h
0
0000h
0000h

1
08h
40000h
1
FFFFh
0064h

6.4.2.7.2 MODE SELECT — 8mm Emulation MODE SELECT enables the
host to configure the device. Implementing MODE SELECT and MODE SENSE
requires a certain amount of handshaking between the host and the drive.
Before configuring the drive, the host should issue a MODE SENSE to get the
current configuration and determine what parameters are configurable. The host
interprets this information and may then issue MODE SELECT to set the drive
to the host’s preferred configuration.
The drive always powers-up with its default configurations set. This is also true
if the drive receives a BUS DEVICE RESET message or a hard reset through the
RST line on the SCSI bus.
Figure 6–38 MODE SELECT CDB
Bit
7

0
1

Byte

Operation Code (15h)
Logical Unit Number

Reserved

Parameter List Length

Unused (00)

Reserved

SP(0)

Flag

Link

Parameter List Length
This specifies the length in bytes of the mode select parameter list that is
transferred during the DATA OUT phase. A 0 parameter list length indicates
that no data is transferred.

6–48 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.2.1 Mode Select Parameter List
The mode select parameter list shown below, contains a 4-byte header, followed
by one 8-byte block descriptor.
Figure 6–39 MODE SELECT Data Header
Bit
7

Reserved

Byte

RSVD

Buffered Mode

Speed

Block Descriptor Length (08h)

Figure 6–40 MODE SELECT Block Descriptor
Bit
7

Density Code

1 (MSB)
2

Number of Blocks (000000h)

(LSB)

Reserved

5 (MSB)
6

Block Length

(LSB)

Figure 6–41 MODE SELECT Page Descriptor

Bit

RSVD

NBE C

EBD

NAL

Reserved

Motion Threshold

Reconnect Threshold

Gap Threshold

SCSI Interface 6–49

SCSI Interface
6.4 Tape Drive SCSI Commands
Buffered Mode
The drive implements immediate reporting on WRITE commands through
buffered mode.
If the field is 0, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the buffered
mode field is 1, then the drive reports GOOD status on WRITE commands as
soon as the data block has been transferred to the buffer. This is the default
configuration for the drive. If buffered mode is not used, the tape drive will suffer
a significant degradation in performance, but not capacity.
Speed
The tape drive supports only one speed, the default speed. This field must be 0.
Block Descriptor Length
This specifies the length in bytes of all the block descriptors. Since the drive only
allows one block descriptor, this value must be 0 or 8.
Density Code
This field is returned as 0.
Number of Blocks
This field must be sent as 0, indicating that all of the remaining logical blocks on
the tape will have the medium characteristics specified by the block descriptor.
Block Length
This specifies the length in bytes of each logical block transferred over the SCSI
bus. A block length of 0 indicates that the length is variable (for example, is
specified in the I/O command). Any other value indicates the number of bytes per
block that will be used for read, write and verify type commands that specify a
"Fixed" bit of 1 (for example, fixed block mode).

6–50 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.2.2 EEROM Vendor Unique Page (3Eh)
The drive shall support a vendor unique page in which one may use to modify
saveable parameters. This page is only supported with the MODE SELECT
command. Only one saveable parameter may be changed per MODE SELECT
command. It has the following format:
Figure 6–42 EEROM Vendor Unique Page Format

1
2

Page Code
Additional Page Length

ASCII String of parameter name and value

The ASCII string has a parameter name, followed by one or more space
characters, a parameter value and an ASCII line feed or null character. When
the string is parsed the parameter value will be interpreted as indicated in the
following table. The parameter name may be in upper or lower case.
Table 6–7 EEROM Vendor Unique Page Parameters
Name

Value
Representation

VENDORID
PRODUCTID
PRODUCTPID

ASCII
ASCII
ASCII

FORCEDENSITY
ASCII decimal
DEFFIXEDBLKLEN ASCII decimal
ENBINQMEDCHGR ASCII decimal

SCSI Interface 6–51

SCSI Interface
6.4 Tape Drive SCSI Commands
Here is an example of an EEROM vendor unique page which will modify the
VENDORID parameter to "XXXYY ".
Figure 6–43 EEROM Vendor Unique Page Example 1
0
1

Page Code (3EH)
Page Length (0FH)

"v"

(76H)

"e"

(65H)

"n"

(6EH)

"d"

(64H)

"o"

(6FH)

"r"

(72H)

"i"

(69H)

"d"

(64H)

(20H)

"X"

(58H)

"X"

(58H)

"X"

(58H)

"Y"

(59H)

"Y"

(59H)

<LF>

(0AH) or (00H)

6–52 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Here is an example of an EEROM vendor unique page which will modify the
FORCEDENSITY parameter to 1.
Figure 6–44 EEROM Vendor Unique Page Example 2
0
1

Page Code (3EH)
Page Length (0FH)

"F"

(46H)

"O"

(4FH)

"R"

(52H)

"C"

(43H)

"E"

(45H)

"D"

(44H)

"E"

(45H)

"N"

(4EH)

"S"

(53H)

"I"

(49H)

"T"

(54H)

"Y"

(59H)

(20H)

"1"

(31H)

<LF>

(0AH) or (00H)

SCSI Interface 6–53

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.2.3 Mode Select Changeable Parameters
The following table lists the changeable mode parameters and their minimum
and maximum values allowed. See the previous definitions for the units that
are used. Parameter rounding is supported for all parameters except the block
descriptor length.
Table 6–8 Changeable Mode Parameters
Page: Parameter

Default

Minimum

Maximum

1
08h
00000h
1
0080h
0032h

0
00h
00000h
0
0000h
0000h

1
08h
40000h
1
FFFFh
0064h

6.4.2.7.3 MODE SELECT — AS400 Attachment MODE SELECT enables the
host to configure the device. Implementing MODE SELECT and MODE SENSE
requires a certain amount of handshaking between the host and the drive.
Before configuring the drive, the host should issue a MODE SENSE to get the
current configuration and determine what parameters are configurable. The host
interprets this information and may then issue MODE SELECT to set the drive
to the host’s preferred configuration.
The drive always powers-up with its default configurations set. This is also true
if the drive receives a BUS DEVICE RESET message or a hard reset through the
RST line on the SCSI bus.
Figure 6–45 MODE SELECT CDB
Bit
7

0
1

Byte

Operation Code (15h)
Logical Unit Number

Reserved

Parameter List Length

Unused (00)

Reserved

SP(0)

Flag

Link

6–54 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
SP
The Save Parameters bit instructs the drive to save all saveable pages. This is
not supported.
PARAMETER LIST LENGTH
This specifies the length in bytes of the mode select parameter list that is
transferred during the DATA OUT phase. A 0 parameter list length indicates
that no data is transferred.
6.4.2.7.3.1 Mode Select Parameter List
The mode select parameter list shown below, contains a 4-byte header, followed
by one 8-byte block descriptor.
Figure 6–46 Mode Select Parameter List
Bit
7

Reserved
Reserved

1
Byte

ignored

Buffered Mode

Speed

Block Descriptor Length (08h)

Block Descriptor:
0
1

Density Code
(MSB)

Number of Blocks (000000h)

(LSB)

4
5

Reserved
(MSB)

Block Length
(LSB)

7
Page Descriptors
0
1
2

Page Code
Additional Page Length

Page Defined or Vendor−Unique Parameter Bytes

SCSI Interface 6–55

SCSI Interface
6.4 Tape Drive SCSI Commands
Buffered Mode
The drive will implement immediate reporting on WRITE commands through
buffered mode.
If the field is 0, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the buffered
mode field is 1, then the drive reports GOOD status on WRITE commands as
soon as the data block has been transferred to the buffer. This is the default
configuration for the drive. If buffered mode is not used, the tape drive will suffer
a significant degradation in performance, but not capacity.
If this field is greater than 1, the command will be rejected with a CHECK
CONDITION, with a sense key of ILLEGAL REQUEST.
Speed
The tape drive supports only one speed, the default speed.
Block Descriptor Length
This specifies the length in bytes of all the block descriptors. Since the drive only
allows one block descriptor, this value must be 8 or 0. Any other value causes
a CHECK CONDITION status with an ILLEGAL REQUEST sense key to be
returned.
Density Code
This field should match the current density of the media, or will be set to 0 if the
density is unknown.
00h — use default density
0Ah — 6667 bpi MFM serial cartridge tape X3B5/86-199 (read only)
16h — 10000 bpi MFM serial cartridge tape X3.193-1990 (read only)
17h — 42500 bpi MFM serial cartridge tape X3B5/91-174
18h — 42500 bpi MFM serial cartridge tape
Number of Blocks
This MODE SENSE field will be sent as 0, indicating that all of the remaining
logical blocks on the tape will have the medium characteristics specified by the
block descriptor.
Block Length
This specifies the length in bytes of each logical block transferred over the SCSI
bus. A block length of 0 indicates that the length is variable (for example, is
specified in the I/O command). Any other value indicates the number of bytes per
block to use for read, write and verify type commands that specify a "Fixed" bit
of 1 (for example, fixed block mode) which also causes the transfer length in the
CDB to be defined as a block count.

6–56 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.2 MODE SELECT Pages
Following the block descriptor are the MODE SELECT pages, which set the
device parameters. Each page has a 2-byte header which identifies the page code
and indicates the number of bytes in that page.
The page codes that are supported as follows:
Figure 6–47 MODE SENSE/SELECT Pages Supported

Page
Code
00h
10h
02h
01h
11h
3Eh
3Fh

Description
No requested page
Device Configuration
Disconnect/Reconnect
Error Recovery Page
Medium partition Parameters
EEPROM Parameter Select
All pages

Sense/
Select
Sense
both
both
both
both
Select
Sense

PS Bit
For the MODE SELECT command this bit is reserved. For the MODE SENSE
command, a Parameters Saveable (PS) bit of 1 indicates that the page can be
saved in nonvolatile memory by the drive. If the PS bit is 0, the supported
parameters cannot be saved. (Saveable pages are not supported.)
Additional Page Length
This indicates the number of bytes in that page. However, the value does not
include bytes 0 and 1. The length is returned on MODE SENSE and must
subsequently be set to the same value when performing MODE SELECT. If the
page length does not match that expected by the drive a CHECK CONDITION
status is returned with the sense key set to ILLEGAL REQUEST. The drive also
returns a CHECK CONDITION status with a ILLEGAL REQUEST sense key if
the host sends an unsupported page code, or a page field with values that are not
supported or are not changeable. In this case, no parameters will be changed by
the command.

SCSI Interface 6–57

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.3 Device Configuration Page (10h)
The drive shall support the device configuration page which has the following
format:
Figure 6–48 Device Configuration Page Format
Bit

1
2
Byte

Page Code(10h)
Additional Page Length (0Eh)

Res

CAP

CAF

Active Format

Active Partition

Write Buffer Full Ratio

Read Buffer Empty Ratio

(MSB)
Write Delay Time

7
8

(LSB
DBR

BIS

RSmk

AVC

9
10
11
12

SOCF

RBO

REW

Gap Size
EOD Defined

EEG

SEW

Reserv ed

(MSB)
Buffer Size at Early Warning (optional)

(LSB)

Select Data Compression Algorithm

Reserved

PS
In this page, only the write delay parameter is changeable.
Set if the parameters are saveable.
CAP, CAF, Active Format
These fields are not supported and must be 0 on MODE SELECT.

6–58 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Active Partition
Only partition 0 is supported. Setting this field to any other value will be rejected
by the drive with a CHECK CONDITION status and the ILLEGAL REQUEST
sense key set.
Write Buffer Full Ratio and Read Buffer Empty Ratio
These indicate how full/empty the buffer memory should be before restarting the
writing/reading of the media. THZ02 will set these fields to 0 (unused) because
it uses an automatic, adaptive mechanism to dynamically adjust its full/empty
ratios according to the average data rates over the SCSI bus.
Write Delay Time
This indicates the maximum time that the drive will wait with a partially full
buffer before forcing the data to tape (100 ms increments). Note that the buffer
full/empty ratio, which is dynamic, can cause data to be written sooner than the
write delay time would indicate. The write delay time defaults to 50 (32h). This
causes the buffer to be flushed in 5 seconds. Maximum value is 6500 (1964h) and
the minimum is 10 (0Ah). This represents delays from almost 11 minutes down
to 1 second.
Byte 8:
DBR — set to 0 (data buffer recovery not supported)
BIS — set to 1 (block identifiers supported in media format)
RSmk — set to 0 (setmarks not supported)
AVC — set to 0
SOCF — set to 0
RBO — set to 0
REW — set to 0 (don’t report early warning EOM on reads)
Gap Size
This field is not used and is set to 0.
EOD Defined
This field is set to 00h; any other value will be rejected by the drive.
EEG
The Enable EOD Generation bit is set to indicate that the drive will generate an
EOD. The drive generates an EOD mark before any change of direction following
a write-type operation. This bit is ignored on MODE SELECT.
SEW and Buffer Size At Early Warning
The Synchronize at Early Warning bit and buffer size at EW fields are not
supported and must be 0.
Select Data Compression Algorithm
This field is not used and must be 0.

SCSI Interface 6–59

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.4 Disconnect/Reconnect Page (02h)
The drive shall support the disconnect/reconnect page which has the following
format:
Figure 6–49 Disconnect/Reconnect Page Format
Bit

Byte

Page Code(02h)

Additional Page Length (0Eh)

Buffer Full Ratio

Buffer empty Ratio

(MSB)
Bus Inactivity Limit
(LSB)

5
6

(MSB)
Disconnect time Limit

7
8

(LSB)
(MSB)
Connect Time Limit

(LSB)

10 (MSB)
Maximum Burst Size
11
12

(LSB)
Reserved

Reserved

DTDC

In this page, only the maximum burst size parameter is changeable.
The following parameters in this page are supported:
Maximum Burst Size
This value specifies the maximum amount a data that will be transferred without
disconnecting. A value of 0 sets no limit. This value is in units of 512 bytes. For
example, a value of 8 means 4k bytes. Values that are not multiples of 8 are
rounded up to the closest multiple of 8.
Data Transfer Disconnect Control (DTDC)
This option is not supported, so this field should be 0.

6–60 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.5 Medium Partition Page (11h)
The drive supports the medium partitions parameter page, which has the
following format:
Figure 6–50 Medium Partition Page Format
Bit

Byte

Additional Page Length (06)

Maximum Additional Partitions

Additional Partitions Defined
FDP

SDP

PageCode(11h)

IDP

PSUM

Reserved

Medium Format Recognition (01)

Reserved

SCSI Interface 6–61

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.6 Read/Write Error Recovery Page (01h)
The drive shall support the error recovery page which has the following format:
Figure 6–51 Error Recovery Page Format
Bit

1
2
Byte

DTE

DCR

Page Code(01h)
Additional Page Length (0Ah)

rsvd

EER

Read Retry Count

Reserved

Write Retry Count

Reserved

PER

TB — The transfer block (when not fully recovered) function is not supported.

•

EER — The enable early recovery function is always enabled.

•

PER — The post error bit turns on reporting of CHECK CONDITION to
report recovered read/write errors. The default setting of this bit is depends
on the personality of the firmware installed.

•

DTE — The disable transfer on error feature is not supported so this bit must
be 0.

•

DCR — The disable ECC correction bit feature is not supported so this bit
must be 0.

6–62 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.7 EEROM Vendor Unique Page (3Eh)
The drive shall support a vendor unique page in which one may use to modify
saveable parameters. This page is only supported with the MODE SELECT
command. Only one saveable parameter may be changed per MODE SELECT
command. It has the following format:
Figure 6–52 EEROM Vendor Unique Page Format

1
2

Page Code
Additional Page Length

ASCII String of parameter name and value

Value
Representation

VENDORID
PRODUCTID
PRODUCTPID

ASCII
ASCII
ASCII

FORCEDENSITY
ASCII decimal
DEFFIXEDBLKLEN ASCII decimal
ENBINQMEDCHGR ASCII decimal

SCSI Interface 6–63

SCSI Interface
6.4 Tape Drive SCSI Commands
Here is an example of an EEROM vendor unique page which will modify the
VENDORID parameter to "XXXYY ".
Figure 6–53 EEROM Vendor Unique Page Example 1
0
1

Page Code (3EH)
Page Length (0FH)

"v"

(76H)

"e"

(65H)

"n"

(6EH)

"d"

(64H)

"o"

(6FH)

"r"

(72H)

"i"

(69H)

"d"

(64H)

(20H)

"X"

(58H)

"X"

(58H)

"X"

(58H)

"Y"

(59H)

"Y"

(59H)

<LF>

(0AH) or (00H)

6–64 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Here is an example of an EEROM vendor unique page which will modify the
FORCEDENSITY parameter to 1.
Figure 6–54 EEROM Vendor Unique Page Example 2
0
1

Page Code (3EH)
Page Length (0FH)

"F"

(46H)

"O"

(4FH)

"R"

(52H)

"C"

(43H)

"E"

(45H)

"D"

(44H)

"E"

(45H)

"N"

(4EH)

"S"

(53H)

"I"

(49H)

"T"

(54H)

"Y"

(59H)

(20H)

"1"

(31H)

<LF>

(0AH) or (00H)

SCSI Interface 6–65

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.7.3.8 Mode Select Changeable Parameters
The following table lists the changeable mode parameters and their minimum
and maximum values allowed. See the previous definitions for the units that
are used. Parameter rounding is supported for all parameters except the block
descriptor length.
Table 6–10 Changeable Mode Parameters
Page: Parameter

Default

Minimum

Maximum

1
08h
00000h
1
0080h
0032h

0
00h
00000h
0
0000h
0000h

1
08h
40000h
1
FFFFh
0064h

6.4.2.8 MODE SENSE (1Ah)
The MODE SENSE command implementation is dependent upon the type of
firmware that is loaded in the THZ02 controller. Refer to Table 6–11 for the
appropriate section for your type of code.
Table 6–11 Mode Sense Command Sections
Code
Type

Description

Section

Type 1
Type 2
Type 3

SCSI II
8mm emulation
AS400 attachment

Section 6.4.2.8.1
Section 6.4.2.8.2
Section 6.4.2.8.3

6.4.2.8.1 MODE SENSE — SCSI II MODE SENSE allows the drive to report
its media, current or changeable configuration parameters to the host. It is a
complementary command to MODE SELECT.
Figure 6–55 MODE SENSE CDB
Bit
7

0
1
Byte

Operation Code (1Ah)
Logical Unit Number
PC

Reser.

DBD

Reserved

Allocation Length
Unused

Reserved

Page Code

6–66 SCSI Interface

Reserved

Flag

Link

SCSI Interface
6.4 Tape Drive SCSI Commands
DBD
If the Disable Block Descriptors bit is 0, the device returns the block descriptor
data. If set, then the block descriptor information is not returned.
PC
The page control field indicates the type of page parameter values to be returned
to the host as shown in the following table:
Figure 6–56 MODE SENSE Page Control Definition

PC
0
0
1
1

0
1
0
1

Description
Report Current Values
Report Changeable Values
Report Default Values
Report Saved Values

The additional page length field of each page returned by the drive indicates the
number of bytes supported for that page.
Page Code
This allows the host to select any specific page, or all the pages supported by the
drive.
Allocation Length
The allocation length field specifies the number of bytes that the host has
allocated for returned MODE SENSE data. An allocation length of 0 means
that the drive will return no MODE SENSE data. This is not considered an error
and GOOD status is returned.

SCSI Interface 6–67

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.1.1 MODE SENSE Parameter List
The MODE SENSE data contains a 4-byte header followed by one 8-byte block
descriptor, followed by zero or more variable length pages, depending on the page
code and the allocation length:
Figure 6–57 MODE SENSE Data Header
Bit
7

Byte

Sense Data Length

Reserved

Buffered Mode

Speed (0h)

Block Descriptor Length (08h)

Figure 6–58 MODE SENSE Block Descriptor
Bit
7

Density Code

1 (MSB)
2

Number of Blocks (000000h)

(LSB)

Reserved

5 (MSB)
6

Block Length

(LSB)

Figure 6–59 MODE SENSE Page Descriptor

Bit

Page Code

Additional Page Length

Page Defined or Vendor−Unique Parameter Bytes

6–68 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Data Length
The sense data length specifies the length in bytes of the following MODE SENSE
data that is available to be transferred during DATA IN phase. The sense data
length does not include itself.
WP
A Write-Protected bit of 0 indicates that the tape is write-enabled. A WriteProtected bit of 1 indicates that the tape is write-protected.
Buffered Mode
The drive implements immediate reporting on WRITE commands through
buffered mode.
If the field is 0, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the buffered
mode field is 1, then the drive reports GOOD status on WRITE commands as
soon as the data block has been transferred to the buffer. This is the default
configuration for the drive. If buffered mode is not used, the tape drive will suffer
a significant degradation in performance, but not capacity.
Speed
The tape drive supports only one speed, the default speed.
Block Descriptor Length
This specifies the length in bytes of all the block descriptors. Since the drive only
allows one block descriptor, this value will be 8.
Density Code
This field matches the current density of the media, or 0 if the density is
unknown.
00h — use default density
0Ah — 6667 bpi MFM serial cartridge tape X3B5/86-199 (read only)
16h — 10000 bpi MFM serial cartridge tape X3.193-1990 (read only)
17h — 42500 bpi MFM serial cartridge tape X3B5/91-174
18h — 42500 bpi MFM serial cartridge tape
Number of Blocks
This field will be sent as 0, indicating that all of the remaining logical blocks on
the tape will have the medium characteristics specified by the block descriptor.
Block Length
This specifies the length in bytes of each logical block transferred over the SCSI
bus. A block length of zero indicates that the length is variable (for example, is
specified in the I/O command). Any other value indicates the number of bytes per
block that will be used for read, write and verify type commands that specify a
"Fixed" bit of 1 (for example, fixed block mode).

SCSI Interface 6–69

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.1.2 MODE SENSE Pages
Following the block descriptor are the MODE SELECT pages, which set the
device parameters. Each page has a 2-byte header which identifies the page code
and indicates the number of bytes in that page.
The page codes that are supported as follows:
Figure 6–60 MODE SENSE Pages Supported

Page
Code
00h
10h
02h
01h
11h
3Eh
3Fh

Description
No requested page
Device Configuration
Disconnect/Reconnect
Error Recovery Page
Medium partition Parameters
EEPROM Parameter Select
All pages

Sense/
Select
Sense
both
both
both
both
Select
Sense

PS Bit
A Parameters Saveable (PS) bit of 1 indicates that the page can be saved in
nonvolatile memory by the drive. If the PS bit is 0, the supported parameters
cannot be saved. (Saveable pages are not supported.)
Additional Page Length
This indicates the number of bytes in that page. However, the value does not
include bytes 0 and 1. The length is returned on MODE SENSE and must
subsequently be set to the same value when performing MODE SELECT.

6–70 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.1.3 Device Configuration Page (10h)
The drive shall support the device configuration page which has the following
format:
Figure 6–61 Device Configuration Page Format
Bit

1
2
Byte

Page Code(10h)
Additional Page Length (0Eh)

Res

CAP

CAF

Active Format

Active Partition

Write Buffer Full Ratio

Read Buffer Empty Ratio

(MSB)
Write Delay Time

7
8

(LSB
DBR

BIS

RSmk

AVC

9
10
11
12

SOCF

RBO

REW

Gap Size
EOD Defined

EEG

SEW

Reserv ed

(MSB)
Buffer Size at Early Warning (optional)

(LSB)

Select Data Compression Algorithm

Reserved

PS
In this page, only the write delay parameter is changeable.
Set if the parameters are saveable.
CAP, CAF, Active Format
These fields are not supported and will be 0.

SCSI Interface 6–71

SCSI Interface
6.4 Tape Drive SCSI Commands
Active Partition
Only partition 0 is supported.
Write Buffer Full Ratio and Read Buffer Empty Ratio
These indicate how full/empty the buffer memory should be before restarting the
writing/reading of the media. THZ02 will set these fields to 0 (unused) because
it uses an automatic, adaptive mechanism to dynamically adjust its full/empty
ratios according to the average data rates over the SCSI bus.
Write Delay Time
This indicates the maximum time that the drive will wait with a partially full
buffer before forcing the data to tape (100 ms increments). Note that the buffer
full/empty ratio, which is dynamic, can cause data to be written sooner than the
write delay time would indicate. The write delay time defaults to 50 (32h). This
causes the buffer to be flushed in 5 seconds. Maximum value is 6500 (1964h) and
the minimum is 10 (0Ah). This represents delays from almost 11 minutes down
to 1 second.
Byte 8:
DBR — set to 0 (data buffer recovery not supported)
BIS — set to 1 (block identifiers supported in media format)
RSmk — set to 0 (setmarks not supported)
AVC — set to 0
SOCF — set to 0
RBO — set to 0
REW — set to 0 (don’t report early warning EOM on reads)
Gap Size
This field is not used and is set to 0.
EOD Defined
This field is set to 00h.
EEG
The Enable EOD Generation bit is set to indicate that the drive will generate an
EOD. The drive generates an EOD mark before any change of direction following
a write-type operation.
SEW and Buffer Size At Early Warning
The Synchronize at Early Warning bit and buffer size at EW fields are not
supported and will be 0.
Select Data Compression Algorithm
This field is not used and will be 0.

6–72 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.1.4 Disconnect/Reconnect Page (02h)
The drive shall support the disconnect/reconnect page which has the following
format:
Figure 6–62 Disconnect/Reconnect Page Format
Bit

Byte

Page Code(02h)

Additional Page Length (0Eh)

Buffer Full Ratio

Buffer empty Ratio

(MSB)
Bus Inactivity Limit
(LSB)

5
6

(MSB)
Disconnect time Limit

7
8

(LSB)
(MSB)
Connect Time Limit

(LSB)

10 (MSB)
Maximum Burst Size
11
12

(LSB)
Reserved

Reserved

DTDC

The following parameters in this page are supported:
Maximum Burst Size
This value specifies the maximum amount a data that will be transferred without
disconnecting. A value of 0 sets no limit. This value is in units of 512 bytes. For
example, a value of 8 means 4k bytes. Values that are not multiples of 8 are
rounded up to the closest multiple of 8.
Data Transfer Disconnect Control (DTDC)
This option is not supported, so this field will be 0.

SCSI Interface 6–73

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.1.5 Medium Partition Page (11h)
The drive supports the medium partitions parameter page, which has the
following format:
Figure 6–63 Medium Partition Page Format
Bit

Byte

Additional Page Length (06)

Maximum Additional Partitions

Additional Partitions Defined
FDP

SDP

PageCode(11h)

IDP

PSUM

Reserved

Medium Format Recognition (01)

Reserved

Maximum Additional Partitions
No additional partitions are supported, this field will be 0.
Additional Partitions Defined
The field specifies the number of additional partitions to be defined for the
tape based on the settings of the SDP and IDP bits. The maximum allowed is
the value returned in the maximum additional partitions field. Since only one
partition is supported, this field will be 0.
Option Flags
FDP — The Fixed Data Partitions bit will be 0.
SDP — The Select Data Partitions bit will be 0.
IDP — The Initiator Defined Partitions bit will be 0.
PSUM — The Partition Size Unit of Measure field will be 0.
Medium Format Recognition
This field is set to 01h indicating that automatic format recognition is supported.

6–74 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.1.6 Read/Write Error Recovery Page (01h)
The drive shall support the error recovery page which has the following format:
Figure 6–64 Error Recovery Page Format
Bit

1
2
Byte

DTE

DCR

Page Code(01h)
Additional Page Length (0Ah)

rsvd

EER

Read Retry Count

Reserved

Write Retry Count

Reserved

PER

Option Flags
•

TB — The transfer block (when not fully recovered) function is not supported.

•

EER — The enable early recovery function is always enabled.

•

PER — The post error bit turns on reporting of CHECK CONDITION to
report recovered read/write errors. The default setting of this bit is off.

•

DTE — The disable transfer on error feature is not supported so this bit will
be 0.

•

DCR — The disable ECC correction bit feature is not supported so this bit
will be 0.

SCSI Interface 6–75

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.2 MODE SENSE — 8mm Emulation MODE SENSE allows the drive to
report its media, current or changeable configuration parameters to the host. It
is a complementary command to MODE SELECT.
Figure 6–65 MODE SENSE CDB
Bit
7

0
1
Byte

Operation Code (1Ah)
Logical Unit Number
PC

Reser.

DBD

Reserved

Allocation Length
Unused

Reserved

Page Code

Reserved

Flag

Link

Allocation Length
The allocation length field specifies the number of bytes that the host has
allocated for returned MODE SENSE data. An allocation length of 0 means
that the drive will return no MODE SENSE data. This is not considered an error
and GOOD status is returned.

6–76 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.2.1 MODE SENSE Parameter List
The MODE SENSE data contains a 4-byte header followed by one 8-byte block
descriptor, followed by zero or more variable length pages, depending on the page
code and the allocation length:
Figure 6–66 MODE SENSE Data Header
Bit
7

Byte

Sense Data Length

Medium Type

Buffered Mode

Speed

Block Descriptor Length (08h)

Figure 6–67 MODE SENSE Block Descriptor
Bit
7

Density Code

1 (MSB)
2

Number of Blocks (000000h)

(LSB)

Reserved

5 (MSB)
6

Block Length

(LSB)

Figure 6–68 MODE SENSE Page Descriptor

Bit

RSVD

NBE C

EBD

NAL

Reserved

Motion Threshold

Reconnect Threshold

Gap Threshold

SCSI Interface 6–77

SCSI Interface
6.4 Tape Drive SCSI Commands
Data Length
The sense data length specifies the length in bytes of the following MODE SENSE
data that is available to be transferred during DATA IN phase. The sense data
length does not include itself.
WP
A write-protected bit of 0 indicates that the tape is write-enabled. A writeprotected bit of 1 indicates that the tape is write-protected.
Buffered Mode
The drive implements immediate reporting on WRITE commands through
buffered mode.
If the field is 0, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the buffered
mode field is 1, then the drive reports GOOD status on WRITE commands as
soon as the data block has been transferred to the buffer. This is the default
configuration for the drive. If buffered mode is not used, the tape drive will suffer
a significant degradation in performance, but not capacity.
Speed
The tape drive supports only one speed, the default speed.
Block Descriptor Length
This specifies the length in bytes of all the block descriptors. Since the drive only
allows one block descriptor, this value will be 8.
Density Code
This field is returned as 0.
Number of Blocks
This field will be sent as 0, indicating that all of the remaining logical blocks on
the tape will have the medium characteristics specified by the block descriptor.
Block Length
This specifies the length in bytes of each logical block transferred over the SCSI
bus. A block length of 0 indicates that the length is variable (for example, is
specified in the I/O command). Any other value indicates the number of bytes per
block that will be used for read, write and verify type commands that specify a
"Fixed" bit of 1 (for example, fixed block mode).

6–78 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3 MODE SENSE — AS400 Attachment MODE SENSE allows the drive
to report its media, current or changeable configuration parameters to the host.
It is a complementary command to MODE SELECT.
Figure 6–69 MODE SENSE CDB
Bit
7

0
1
2

Byte

Operation Code (1Ah)
Logical Unit Number
PC

DBD

Reserved

Allocation Length
Unused

Reserved

Page Code

Reserved

Flag

Link

PF
The Page Format bit when set indicates that the mode sense parameters after
the block descriptors, are structured. The Page Format bit when cleared indicates
that the mode sense parameters after the block descriptors, are vendor specific.
DBD
If the Disable Block Descriptors bit is 0, the device returns the block descriptor
data. If set, then the block descriptor information is not returned.
PC
The page control field indicates the type of page parameter values to be returned
to the host as shown in the following table:
Figure 6–70 MODE SENSE Page Control Definition

PC
0
0
1
1

0
1
0
1

Description
Report Current Values
Report Changeable Values
Report Default Values
Report Saved Values

SCSI Interface 6–79

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3.1 MODE SENSE Parameter List
The MODE SENSE data contains a 4-byte header followed by one 8-byte block
descriptor, followed by zero or more variable length pages, depending on the page
code and the allocation length:
Figure 6–71 MODE SENSE Data Header
Bit
7

Byte

Sense Data Length

Medium Type

Buffered Mode

Speed

Block Descriptor Length (08h)

Figure 6–72 MODE SENSE Block Descriptor
Bit
7

Density Code

1 (MSB)
2

Number of Blocks (000000h)

(LSB)

Reserved

5 (MSB)
6

Block Length

(LSB)

Figure 6–73 MODE SENSE Page Descriptor

Bit

RSVD

NBE C

EBD

NAL

Reserved

Motion Threshold

Reconnect Threshold

Gap Threshold

6–80 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Data Length
The sense data length specifies the length in bytes of the following MODE SENSE
data that is available to be transferred during DATA IN phase. The sense data
length does not include itself.
WP
A write-protected bit of 0 indicates that the tape is write-enabled. A writeprotected bit of 1 indicates that the tape is write-protected.
Buffered Mode
The drive implements immediate reporting on WRITE commands through
buffered mode.
If the field is 0, then the drive does not report a GOOD status on WRITE
commands until the data blocks are actually written to tape. If the buffered
mode field is 1, then the drive reports GOOD status on WRITE commands as
soon as the data block has been transferred to the buffer. This is the default
configuration for the drive. If buffered mode is not used, the tape drive will suffer
a significant degradation in performance, but not capacity.
Speed
The tape drive supports only one speed, the default speed.
Block Descriptor Length
This specifies the length in bytes of all the block descriptors. Since the drive only
allows one block descriptor, this value will be 8.
Density Code
This field matches the current density of the media, or 0 if the density is
unknown.
00h — use default density
0Ah — 6667 bpi MFM serial cartridge tape X3B5/86-199 (read only)
16h — 10000 bpi MFM serial cartridge tape X3.193-1990 (read only)
17h — 42500 bpi MFM serial cartridge tape X3B5/91-174
18h — 42500 bpi MFM serial cartridge tape
Number of Blocks
This field will be sent as 0, indicating that all of the remaining logical blocks on
the tape will have the medium characteristics specified by the block descriptor.
Block Length
This specifies the length in bytes of each logical block transferred over the SCSI
bus. A block length of 0 indicates that the length is variable (for example, is
specified in the I/O command). Any other value indicates the number of bytes per
block that will be used for read, write and verify type commands that specify a
"Fixed" bit of 1 (for example, fixed block mode).

SCSI Interface 6–81

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3.2 MODE SENSE Pages
Following the block descriptor are the MODE SELECT pages, which set the
device parameters. Each page has a 2-byte header which identifies the page code
and indicates the number of bytes in that page.
The page codes that are supported as follows:
Figure 6–74 MODE SENSE Pages Supported

Page
Code
00h
10h
02h
01h
11h
3Eh
3Fh

Description
No requested page
Device Configuration
Disconnect/Reconnect
Error Recovery Page
Medium partition Parameters
EEPROM Parameter Select
All pages

Sense/
Select
Sense
both
both
both
both
Select
Sense

6–82 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3.3 Device Configuration Page (10h)
The drive shall support the device configuration page which has the following
format:
Figure 6–75 Device Configuration Page Format
Bit

1
2
Byte

Page Code(10h)
Additional Page Length (0Eh)

Res

CAP

CAF

Active Format

Active Partition

Write Buffer Full Ratio

Read Buffer Empty Ratio

(MSB)
Write Delay Time

7
8

(LSB
DBR

BIS

RSmk

AVC

9
10
11
12

SOCF

RBO

REW

Gap Size
EOD Defined

EEG

SEW

Reserv ed

(MSB)
Buffer Size at Early Warning (optional)

(LSB)

Select Data Compression Algorithm

Reserved

PS
In this page, only the write delay parameter is changeable.
Set if the parameters are saveable.
CAP, CAF, Active Format
These fields are not supported and will be 0.

SCSI Interface 6–83

6–84 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3.4 Disconnect/Reconnect Page (02h)
The drive shall support the disconnect/reconnect page which has the following
format:
Figure 6–76 Disconnect/Reconnect Page Format
Bit

Byte

Page Code(02h)

Additional Page Length (0Eh)

Buffer Full Ratio

Buffer empty Ratio

(MSB)
Bus Inactivity Limit
(LSB)

5
6

(MSB)
Disconnect time Limit

7
8

(LSB)
(MSB)
Connect Time Limit

(LSB)

10 (MSB)
Maximum Burst Size
11
12

(LSB)
Reserved

Reserved

DTDC

SCSI Interface 6–85

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3.5 Medium Partition Page (11h)
The drive supports the medium partitions parameter page, which has the
following format:
Figure 6–77 Medium Partition Page Format
Bit

Byte

Additional Page Length (06)

Maximum Additional Partitions

Additional Partitions Defined
FDP

SDP

PageCode(11h)

IDP

PSUM

Reserved

Medium Format Recognition (01)

Reserved

6–86 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.8.3.6 Read/Write Error Recovery Page (01h)
The drive shall support the error recovery page which has the following format:
Figure 6–78 Error Recovery Page Format
Bit

1
2
Byte

DTE

DCR

Page Code(01h)
Additional Page Length (0Ah)

rsvd

EER

Read Retry Count

Reserved

Write Retry Count

Reserved

PER

Option Flags
•

TB — The transfer block (when not fully recovered) function is not supported.

•

EER — The enable early recovery function is always enabled.

•

PER — The post error bit turns on reporting of CHECK CONDITION to
report recovered read/write errors. The default setting of this bit is off.

•

DTE — The disable transfer on error feature is not supported so this bit will
be 0.

•

DCR — The disable ECC correction bit feature is not supported so this bit
will be 0.

SCSI Interface 6–87

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.9 PREVENT/ALLOW MEDIUM REMOVAL (1Eh)
Figure 6–79 PREVENT/ALLOW MEDIUM REMOVAL CDB
Bit
7

0
1

Byte

Operation Code (1Eh)
Logical Unit Number

Reserved

4
5

Reserved
Unused

Reserved

Prevent
Flag

Link

This command enables or disables the unloading of the tape cartridge.
Prevent
If this bit is set, the Unload button on the drive front panel is effectively disabled,
and the UNLOAD command will not unload the media or the cartridge. Any
buffered data is written to tape, along with EOD blocks.
When the Prevent bit is set to 0, the Unload button and UNLOAD commands
are reenabled. By default after power up, hard reset, or BUS DEVICE RESET
message, the prevent medium removal function is cleared.
If a media loader is present, the MOVE MEDIUM command will not be allowed
to remove a cartridge if Prevent has been selected.

6–88 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.10 READ (08h)
Figure 6–80 READ CDB
Bit
7

Byte

SILI

Fixed

Operation Code (08h)

Logical Unit Number

(MSB)

Reserved

Transfer Length

(LSB)

4
5

Unused

Reserved

Flag

Link

READ transfers one or more data blocks to the initiator starting with the next
block on the drive.
Fixed
This bit specifies the meaning of the transfer length field and whether fixedlength or variable-length blocks are to be transferred.
If the Fixed bit is set to 0, a variable block mode is requested. A single block is
transferred with the transfer length specifying the maximum number of bytes the
initiator has allocated for the returned data.
If the Fixed bit is set to 1, the transfer length specifies the number of blocks to
be transferred to the initiator. This is valid only if the logical unit is currently
operating in fixed block mode.
When the transfer length is 0, no data is transferred and the current position on
the logical unit is not changed.
A successful READ with the Fixed bit set to 1 transfers (current block
length) (transfer length) bytes of data to the host. Upon termination of READ,
the media is logically positioned after the last block transferred (EOM side).

SCSI Interface 6–89

SCSI Interface
6.4 Tape Drive SCSI Commands
SILI
If the Suppress Incorrect Length Indicator bit is set the target will not return
CHECK CONDITION status if the only error is that the transfer length is not
equal to the actual block length recorded on the media. All other error conditions
are still reported.
If the SILI bit is not set and the actual block length is different from the specified
transfer length, a CHECK CONDITION status is returned. Within the sense
data, the Incorrect Length Indicator (ILI) bit and Valid bit will be set to 1. The
sense key field will be set to NO SENSE. The information bytes will be set to the
difference (residue) between the requested transfer length and the actual block
length, or in fixed blocked mode, the difference (residue) between the requested
number of blocks and the actual number of blocks read. No more than transfer
length bytes are transferred to the initiator and the tape is logically positioned
after the block (EOM side).
If the drive reads a filemark, it will return a CHECK CONDITION status. Within
the sense data, the filemark and valid bits are set and the sense key field is set
to NO SENSE. The information fields contain the residue count. The additional
sense code and additional sense code qualifier fields are set to filemark detected.
Upon termination, the media will be logically positioned after the filemark (EOM
side).
If the drive detects EOD during the READ, the drive will return a CHECK
CONDITION status. Within the sense data, the Valid bit is set and the sense key
field is set to BLANK CHECK. The EOM bit may be set if the drive determines
that the tape is positioned past the PSEN marker. The information fields contain
the residue count. The additional sense code and additional sense code qualifier
fields are set. Upon termination, the media will be physically positioned before
EOD and after the last block on tape.
The meaning of EOM is different for a read than for a write type of command.
EOM is only reported when the physical EOM/P is encountered. The drive
returns a CHECK CONDITION status. The EOM and Valid bits are set and the
sense key is set to MEDIUM ERROR. The information fields contain the residue
count and the additional sense code and additional sense code qualifier fields are
set to EOM/P detected. The tape is physically positioned at EOM/P.
If any READ command cannot be completed successfully the drive returns a
CHECK CONDITION status. Further commands should attempt to move past
the error and complete successfully.

6–90 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.11 READ BLOCK LIMITS (05h)
Figure 6–81 READ BLOCK LIMITS CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (05h)
Logical Unit Number

Reserved

Unused

Reserved

READ BLOCK LIMITS tells the drive to return its limits for block length. The
READ BLOCK LIMITS data shown below is sent during the DATA IN phase of
the command. The command does not reflect the currently selected block size,
only the available limits. MODE SENSE returns the current block size.
Figure 6–82 READ BLOCK LIMITS Data
Bit
7
0

Reserved

1 (MSB)
2
Byte

Maximum block length
(LSB)

3
4 (MSB)
5

Minimum block length (0001h)
(LSB)

Maximum Block Length
This field indicates the maximum block size. The device supports a maximum
block length of 256k bytes.
Minimum Block Size
This field indicates the minimum block size. The device supports a minimum
block length of 1 byte.

SCSI Interface 6–91

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.12 READ BUFFER (3Ch)
Figure 6–83 READ BUFFER CDB
Bit
7

0
1

Byte

Operation Code (3Ch)
Logical Unit Number

2
3

Reserved

Mode

Buffer ID
(MSB)

Buffer Offset

5
6

(LSB)
(MSB)

Allocation Length

8
9

(LSB)
Unused

Reserved

Flag

Link

READ BUFFER is used in conjunction with WRITE BUFFER as a diagnostic
function for testing the drive’s data buffer and the SCSI bus integrity.
Mode
The drive supports the following values within the field. If any nonsupported
value is set, the drive terminates the command with a CHECK CONDITION
status and an ILLEGAL REQUEST sense key set.
Figure 6–84 READ BUFFER Modes Supported

Mode

Description

000b
010b
011b

Combined Header and Data
Data
Descriptor

Buffer ID and Offset
The drive only supports a single buffer ID field of 0, and offsetting of data is not
supported. If these fields are non-0, the drive returns a CHECK CONDITION
status with an ILLEGAL REQUEST sense key set.
Allocation Length
The allocation length specifies the maximum number of bytes that the initiator
has allocated for returned data.

6–92 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.12.1 Combined Header and Data Mode In this mode, the drive returns
a 4-byte header followed by the data bytes. The drive terminates the DATA IN
phase when allocation length bytes of header and data have been transferred, or
when all available data has been transferred to the initiator, whichever is less.
The 4-byte READ BUFFER header is followed by data bytes from the targets
data buffer. The header has the following format:
Figure 6–85 READ BUFFER Data Header
Bit
7

Reserved

Byte 1 (MSB)
2

Available Length

(LSB)

Available Length
The available length field specifies the total number of data bytes available in
the target’s buffer. This number is not reduced to reflect the allocation length,
nor is it reduced to reflect the actual number of bytes written using the WRITE
BUFFER command. Following the READ BUFFER header, the target will
transfer data from its data buffer.
6.4.2.12.2 Data Mode
data.

In this mode, the DATA IN phase only contains buffer

6.4.2.12.3 Descriptor Mode In this mode, a maximum of four bytes of READ
BUFFER descriptor information are returned. The drive returns the descriptor
information for the buffer specified by the buffer ID. In this mode, the drive does
not reject the valid buffer IDs with a CHECK CONDITION status, but returns
all 0s in the READ BUFFER descriptor.
The offset boundary is 12 (0Ch), indicating buffer offsets should be integral
multiples of 4k.
Figure 6–86 READ BUFFER Descriptor
Bit
7
0

Offset Boundary(0h)

Byte 1 (MSB)
2
3

Buffer Capacity
(LSB)

SCSI Interface 6–93

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.13 READ POSITION (34h)
Figure 6–87 READ POSITION CDB
Bit
7
0
1

Byte

Operation Code (34h)
Logical Unit Number

Reserved

Unused

Reserved

Flag

Link

The READ POSITION command is used to read a position identifier, or SCSI
logical block address. The LOCATE command uses this identifier to position back
to this same logical position, in a high performance fashion.
BT
The Block Type bit indicates how the position is interpreted. Since this device
uses the same logical block address whether this bit is set or not, the setting
of BT is ignored. The logical block address values include all recorded objects:
blocks and filemarks.

6–94 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.13.1 READ POSITION Data Format The BOP and EOP bits will be set as
appropriate. The Block Position Unknown (BPU) bit is never set since the setting
of the BT bit in the read position CDB does not affect the block address values
returned.
Figure 6–88 READ POSITION Data Format

Bit

Byte

BOP

EOP

Reserved

Partition Number

2
3

Reserved

2
BPU

Reserved

(MSB)
First Block Location

5
6

(LSB)

7
8

(MSB)

Last Block Location

10
(LSB)

11
12

Reserved

13 (MSB)
14

Number of Blocks in Buffer
(LSB)

15
16 (MSB)
17

Number of Bytes in Buffer

18
19

(LSB)

First Block Location
The block address associated with the current logical position; the next block to
be transferred between the target and initiator if a READ or WRITE command is
issued.
Last Block Location
The block address associated with the current physical position; the next block to
be transferred to the media and from the target’s buffer. If the buffer is empty, or
has only a partial block, the same value as first block location will be reported.
The first block or filemark written onto the media is at address 0.
Number of Blocks in Buffer
The number of data blocks and filemarks in the target’s buffer.

SCSI Interface 6–95

SCSI Interface
6.4 Tape Drive SCSI Commands
Number of Bytes in Buffer The number of data bytes and filemarks in the
buffer that have not been written to the medium.
6.4.2.14 RECEIVE DIAGNOSTICS RESULTS (1Ch)
Figure 6–89 RECEIVE DIAGNOSTICS RESULTS CDB
Bit
7

0
1

Operation Code (1Ch)
Logical Unit Number

Reserved

2
Byte

Reserved
(MSB)

Allocation Length

(LSB)

Unused

Reserved

Flag

Link

RECEIVE DIAGNOSTIC RESULTS tells the drive to send analysis data to the
initiator after completion of a SEND DIAGNOSTIC command. The following data
will be returned by this command. A REQUEST SENSE command should be
issued to obtain more detailed information following a CHECK CONDITION on a
SEND DIAGNOSTIC command.
Figure 6–90 Receive Diagnostic Result Data Format
Bit
7

Byte

Controller Present flag

Controller Error flag

Drive Present flag

Drive Error flag

Media Loader Present flag

Media Loader Error flag

This information simply indicates which of the main components of the subsystem
has failed testing.

6–96 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.15 RELEASE UNIT (17h)
Figure 6–91 RELEASE UNIT CDB
Bit
7

0
1

Byte

Operation Code (17h)
Logical Unit Number

3rdPty

Third Party Device ID

Reserved

Unused

Reserved

Flag

Rsvd

Link

RELEASE UNIT releases the drive if it is currently reserved by the requesting
initiator.
It is not an error to attempt to release the drive if it is not currently reserved by
the requesting initiator. However, if it reserved by other initiator, the drive is not
released.
3rdPty
The third-party release option for RELEASE UNIT allows an initiator to release
a logical unit that was previously reserved using the third-party reservation
option. If the third-party (3rdPty) bit is 0, then the third-party release option
is not requested. If the 3rdPty bit is 1, the drive is released if it was originally
reserved by the same initiator using the third-party reservation option, and if the
device is the same SCSI device that was specified in the third-party device ID
field.
6.4.2.15.1 Medium Changer Considerations The optional element reservation
feature defined for medium changer devices in SCSI-2 is not supported, so the
RELEASE command is defined the same as for the tape drive: Only the whole
loader unit can be released. Reserve/release of the loader and drive LUNs are
handled independently.

SCSI Interface 6–97

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.16 REQUEST SENSE (03h)
The REQUEST SENSE command implementation is dependent upon the type
of firmware that is loaded in the THZ02 controller. Refer to Table 6–12 for the
appropriate section for your type of code.
Table 6–12 Request Sense Command Sections
Code Type

Description

Section

Type 1
Type 2
Type 3

SCSI II
8mm emulation
AS400 attachment

Section 6.4.2.16.1
Section 6.4.2.16.2
Section 6.4.2.16.3

REQUEST SENSE tells the target to

6.4.2.16.1 REQUEST SENSE — SCSI II
transfer sense data to the initiator.
Figure 6–92 REQUEST SENSE CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (03h)
Logical Unit Number

Reserved

Allocation Length

Unused

Reserved

The sense data is valid for a CHECK CONDITION or RESERVATION CONFLICT
status returned on the previous command. The sense data bytes are preserved by
the target until retrieved by the REQUEST SENSE command, or until the receipt
of any other command from the same initiator.
If the drive receives an unsolicited REQUEST SENSE, then it returns sense
data with the appropriate values in the EOM, sense key, additional sense code,
and additional sense code qualifier. The positional information provided reflects
the logical position of the drive. The drive returns information based on the
(nondiagnostic) data still in its buffer as well as the data on tape.
REQUEST SENSE does not cause the drive to flush its buffered data to tape.
Therefore, if the host requires the exact physical positioning of the media, it
should precede the REQUEST SENSE with a WRITE FILEMARKS with length
0 (Immed = 0) command, which forces the drive to flush any currently buffered
data to tape. A subsequent REQUEST SENSE will return the actual physical
(and logical) position of the drive to the initiator.
Allocation Length
The allocation length specifies the maximum number of sense bytes to be
returned. The drive terminates the transfer when allocation length bytes have
been transferred or when all available sense data has been transferred to the
host, whichever is less.

6–98 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.16.1.1 Sense Information Format
Figure 6–93 REQUEST SENSE Data
Bit
7
0

Valid

Error Code
Segment Number

1
2

Filemrk

(MSB)

EOM

ILI

Reservd

Sense Key

4
Information Bytes
Byte

5
(LSB)

6
7
8

Additional Sense Length
(MSB)

9
Command Specific Information Bytes
10
11

(LSB)

Additional Sense Code

Additional Sense Code Qualifier

Sub−Assembly Code

SKSV

(MSB)

C/D

Reserved

BPV

Bit Pointer

Field Pointer
17
18

(LSB)
Internal Status Code (VU)

Valid
A Valid bit of 1 indicates that the information bytes contain valid information as
defined in the SCSI specification.
Error-Code
A value of 70h indicates a current error — the report is associated with the most
recently received command.
A value of 71h indicates a deferred error — the report is associated with a
previous command and not as a result of the current command.
No other values will be returned.
Segment Number
This byte is always 0.
Filemark
This bit indicates that the current command has read a filemark.

SCSI Interface 6–99

SCSI Interface
6.4 Tape Drive SCSI Commands
EOM
This bit indicates that an end-of-medium condition (end of partition or beginning
of partition) exists. The warning is also given by setting the sense key to NO
SENSE and the additional sense code qualifier to end of partition or beginning of
partition.
For write-type operations, the drive returns a CHECK CONDITION on any
operation which occurs after detection of the early warning EOP marker. The
EOM and additional sense code fields will be set. For read-type operations, the
drive does not return a CHECK CONDITION until the drive encounters the
physical EOP.
ILI
The Incorrect Length Indicator bit indicates that the requested logical block
length did not match the logical block length of the data on the tape. Only READ
or VERIFY may cause this bit to be set.
Sense Key
In most cases, additional sense code and/or qualifier information is available. See
the tables later in this section.
Information Bytes
These bytes contain the differences (residue) of the requested length minus
the actual length in either bytes, blocks, or filemarks, as determined by the
command. Negative values are indicated by two’s complement notation. The
bytes are valid for all read, write, space and verify tape commands for which a
CHECK CONDITION status has been generated. The information bytes are 0
for MODE SELECT/SENSE, INQUIRY, READ BLOCK LIMITS and TEST UNIT
READY.
Additional Sense Length
This specifies the number of additional sense bytes to follow. If the allocation
length of the command descriptor block is too small to transfer all of the
additional sense bytes, the additional sense length is not adjusted to reflect
the truncation.
Command Specific Information Bytes
Command Specific bytes are handled as device specific and can be logged by the
operating system on error conditions. On media errors, this usually contains the
current SCSI logical block address.
Additional Sense Code (ASC) and ASC Qualifier
These two bytes provide additional information about the sense key and cause of
the CHECK CONDITION status. See the tables later in this section.
Sub-Assembly Code
Unused at present, returned as 0.
Field Pointer Bytes
C/D — When set, indicates that the illegal parameter is in the CDB. A C/D of 0
indicates that the illegal parameter is in the parameter list from the initiator.
BPV — When the Bit Pointer Valid bit is set, it indicates that the bit pointer field
is valid and designates which bit of the byte designated by the field pointer is in
error. For a multi-bit field, it points to the most significant bit of the field.

6–100 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Field Pointer — Indicates which byte of the CDB or parameter list was in error.
For a multi-byte field, the most significant byte is indicated.
Table 6–13 Sense Keys Used
Sense
Key

Description

No Sense. Check the filemark/EOM/ILI bits and the ASC/Q bytes.

Recovered Error. This can be caused by rounding of mode parameters on a
MODE SELECT, or to report that R/W error rates are reaching subsystem
specification limits for optimal operation, however, the device may still be able
to continue to function without any unrecovered errors for a long period of time.

Not Ready. The media is not ready for tape operation commands. Media might
not be present in the drive, or may be in the process of loading or calibrating.

Medium Error. An unrecoverable write, read or positioning error has occurred.
Detailed device specific information may be available.

Hardware Error. The additional sense code/qualifier fields may provide more
specific information.

Illegal Request. The CDB or supplied parameter data had an unsupported or
illegal operation specified. Check bytes 15, 16 and 17.

Unit Attention. Unit attentions are created after a device reset, if the media
asynchronously become ready to this initiator, if another initiator changes mode
parameters, and if the firmware is updated.

Data Protected. The current media is write protected. This can be due to the
Write Protect switch on the cartridge, or if the media is not CompacTape III
type.

Blank Check. An EOD or LongGap has been encountered.

Command Aborted. Generated when a command has been aborted by the tape
device for some reason. Check the ASC/Q bytes.

Volume Overflow. Physical end of media has been reached during writing. The
initiator ignored the EOM condition and continued writing.

Miscompare. A compare error occurred during reading by the self-tests invoked
during execution of a send diagnostic.

SCSI Interface 6–101

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–14 Additional Sense Codes/Qualifiers Used
ASC
00h

03h

04h

05h
07h
08h
0Ah
0Ch
11h

14h

15h
17h
18h
1Ah
1Dh
20h
21h
24h

ASCQ
00h
01h
02h
03h
04h
05h
06h
00h
01h
02h
00h
01h
02h
03h
00h
00h
00h
01h
02h
00h
00h
00h
01h
02h
03h
08h
09h
0Ah
00h
01h
02h
03h
04h
00h
01h
02h
00h
01h
00h
00h
00h
00h
01h
00h
81h
82h
83h
84h
85h

Description
No additional sense code
No additional sense qualifier
Unexpected FM encountered
End of medium encountered
Setmark encountered
Beginning of medium encountered
EOD encountered
I/O process terminated
Peripheral device write error
Peripheral device write fault
No write current
Excessive write errors
Unit not ready
Cause nonreportable
Calibration in process
LOAD command needed
Manual intervention needed
LUN doesn’t respond to selection
Multiple LUNs selected
LUN communications failure
LUN communications timeout
LUN communications parity error
Error log overflow
Write error
Unrecovered read error
Read retries exhausted
Error too long to correct
Multiple read errors
Incomplete block read
No gap found
Miscorrected error
Recorded entity not found
Filemark not found
FM or setmark not found
EOD blocks not found
Block sequence error
Random positioning error
Mech position error
Detected by read of media
Recovered data without ECC
With retries
Recovered ECC error
Parameter list length error
Miscompare during verify operation
Illegal opcode
Invalid element address
Invalid CDB field
Invalid mode on write buffer
Media in drive
Command queue not empty
Insufficient resources
Invalid buffer ID
(continued on next page)

6–102 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–14 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

25h
26h

27h

28h
29h
2Ah
2Bh
2Ch
2Fh
30h
37h
39h
3Ah
3Bh

3Dh
3Fh
40h

43h
44h
45h
47h
48h

ASCQ

Description

86h
87h
88h
89h
8Ah
8Bh
8Ch
00h

Invalid offset
Invalid size
Out of sequence
Image data over limit
Update in progress
Image/personality is bad
Not immediate command
Illegal LUN
Parameter list error
Invalid field
Parameter not supported
Parameter value invalid
Write protected
Hardware write protect
Software write protect
Data safety write protect
Not ready to ready
Reset occurred
Parameters changed
Mode parameters changed
Log parameters changed
Copy command without disconnect privilege
Command sequence error
Commands cleared by another initiator
Can’t read medium
Unknown format
Rounded parameter
Saving parameters not supported
Media not present
VU cartridge missing
Sequential positioning error
Tape position error at BOM
Tape position error at EOM
Reposition error
Media destination element full
Media source element empty
Invalid bits in ID message
Target operating conditions changed
Microcode has been changed
Inquiry data has changed
Diagnostic/POST failed
ROM EDC failure
RAM failure
Bad drive status
Loader diags failed
Message error
Internal target failure
Unexpected select interrupt
EDC error detected by port
Select/reselect failure
SCSI parity error
IDE message received

00h
01h
02h
00h
80h
81h
82h
00h
00h
00h
01h
02h
00h
00h
00h
00h
01h
00h
00h
00h
80h
00h
01h
02h
08h
0Dh
0Eh
00h
00h
01h
03h
00h
80h
81h
82h
83h
00h
00h
80h
81h
00h
00h
00h

(continued on next page)

SCSI Interface 6–103

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–14 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

49h
4Ah
4Bh
4Eh
50h

00h
00h
00h
00h
00h
01h
02h
00h
00h
00h
01h
02h
00h
01h
02h
03h
00h
01h
02h
03h
00h
00h

Invalid message error
Command phase error
Data phase error
Overlapped commands attempted
Write append error
Write append position error
Position error related to timing
Erase failure
Cartridge fault
Media load/eject failure
Unload tape failure
Media removal prevented
Operator request/state change input
Operator media removal request
Operator selected write protect
Operator selected write permit
Log exception
Threshold condition met
Log counter at maximum
Log list codes exhausted
Calibration error
Directory read error

51h
52h
53h
5Ah

5Bh

80h
81h

6–104 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.16.2 REQUEST SENSE — 8mm Emulation
target to transfer sense data to the initiator.

REQUEST SENSE tells the

Figure 6–94 REQUEST SENSE CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (03h)
Logical Unit Number

Reserved

Allocation Length

Unused

Reserved

The sense data is valid for a CHECK CONDITION or RESERVATION CONFLICT
status returned on the previous command. The sense data bytes are preserved by
the target until retrieved by the REQUEST SENSE command, or until the receipt
of any other command from the same initiator.
If the drive receives an unsolicited REQUEST SENSE, then it returns sense
data with the appropriate values in the EOM, sense key, additional sense code,
and additional sense code qualifier. The positional information provided reflects
the logical position of the drive. The drive returns information based on the
(nondiagnostic) data still in its buffer as well as the data on tape.
REQUEST SENSE does not cause the drive to flush its buffered data to tape.
Therefore, if the host requires the exact physical positioning of the media, it
should precede the REQUEST SENSE with a WRITE FILEMARKS with length 0
(Immed =0) command, which forces the drive to flush any currently buffered data
to tape. A subsequent REQUEST SENSE will return the actual physical (and
logical) position of the drive to the initiator.
Allocation Length
The allocation length specifies the maximum number of sense bytes to be
returned. The drive terminates the transfer when allocation length bytes have
been transferred or when all available sense data has been transferred to the
host, whichever is less.

SCSI Interface 6–105

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.16.2.1 Sense Information Format
Figure 6–95 REQUEST SENSE Data
Bit
7
0

Valid

Error Code
Reserved

1
2

Filemrk

(MSB)

EOM

ILI

Reservd

Sense Key

4
Information Bytes
Byte

5
6

(LSB)

7
8

Additional Sense Length
(MSB)

9
Reserved
10
11

(LSB)

Additional Sense Code

Additional Sense Code Qualifier

Reserved

(MSB)

Read/Write Error Counter

(LSB)

BPE

FPE

ECO

TME

TNP

BOT

XFR

TMD

FMKE

URE

WE1

SSE

PEOT

WSEB

WSEO

Reserved

22
23
24
25

Reserved
(MSB)
Tape Remaining
(LSB)

Valid
A Valid bit of 1 indicates that the information bytes contain valid information as
defined in the SCSI specification.

6–106 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Error-Code
A value of 70h indicates a current error — the report is associated with the most
recently received command.
A value of 71h indicates a deferred error — the report is associated with a
previous command and not as a result of the current command.
No other values will be returned.
Filemark
This bit indicates that the current command has read a filemark.
EOM
This bit indicates that an end-of-medium condition (end of partition or beginning
of partition) exists. The warning is also given by setting the sense key to NO
SENSE and the additional sense code qualifier to end of partition or beginning of
partition.
For write-type operations, the drive returns a CHECK CONDITION on any
operation which occurs after detection of the early warning EOP marker.The
EOM and additional sense code fields will be set. For read-type operations, the
drive does not return a CHECK CONDITION until the drive encounters the
physical EOP.
ILI
The Incorrect Length Indicator bit indicates that the requested logical block
length did not match the logical block length of the data on the tape. Only READ
or VERIFY may cause this bit to be set.
Sense Key
In most cases, additional sense code and/or qualifier information is available. See
the tables later in this section.
Information Bytes
These bytes contain the differences (residue) of the requested length minus
the actual length in either bytes, blocks, or filemarks, as determined by the
command. Negative values are indicated by two’s complement notation. The
bytes are valid for all read, write, space and verify tape commands for which a
CHECK CONDITION status has been generated. The information bytes are 0
for MODE SELECT/SENSE, INQUIRY, READ BLOCK LIMITS and TEST UNIT
READY.
Additional Sense Length
This specifies the number of additional sense bytes to follow. If the allocation
length of the command descriptor block is too small to transfer all of the
additional sense bytes, the additional sense length is not adjusted to reflect
the truncation.
Additional Sense Code (ASC) and ASC Qualifier
These two bytes provide additional information about the sense key and cause of
the CHECK CONDITION status. See the tables later in this section.

SCSI Interface 6–107

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–15 Sense Keys Used
Sense
Key

Description

No Sense. Check the filemark/EOM/ILI bits and the ASC/Q bytes.

Not Ready. The media is not ready for tape operation commands. Media might
not be present in the drive, or may be in the process of loading or calibrating.

Medium Error. An unrecoverable write, read or positioning error has occurred.
Detailed device specific information may be available.

Hardware Error. The additional sense code/qualifier fields may provide more
specific information.

Illegal Request. The CDB or supplied parameter data had an unsupported or
illegal operation specified. Check bytes 15, 16 and 17.

Data Protected. The current media is write protected. This can be due to the
Write Protect switch on the cartridge, or if the media is not CompacTape III
type.

Blank Check. An EOD or longgap has been encountered.

Command Aborted. Generated when a command has been aborted by the tape
device for some reason. Check the ASC/Q bytes.

Volume Overflow. Physical end of media has been reached during writing. The
initiator ignored the EOM condition and continued writing.

Miscompare. A compare error occurred during reading by the self-tests invoked
during execution of a send diagnostic.

Table 6–16 Additional Sense Codes/Qualifiers Used
ASC
00h

03h

04h

ASCQ
00h
01h
02h
03h
04h
05h
06h
00h
01h
02h
00h
01h
02h
03h

6–108 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–16 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

05h
07h
08h

00h
00h
00h
01h
02h
00h
00h
00h
01h
02h
03h
08h
09h
0Ah
00h
01h
02h
03h
04h
00h
01h
02h
00h
01h
00h
00h
00h
00h
01h
00h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
00h

LUN doesn’t respond to selection
Multiple LUNs selected
LUN communications failure
LUN communications timeout
LUN communications parity Error
Error log overflow
Write error
Unrecovered read error
Read retries exhausted
Error too long to correct
Multiple read errors
Incomplete block read
No gap found
Miscorrected error
Recorded entity not found
Filemark not found
FM or setmark not found
EOD blocks not found
Block sequence error
Random positioning error
Mech position error
Detected by read of media
Recovered data without ECC
With retries
Recovered ECC error
Parameter list length error
Miscompare during verify operation
Illegal opcode
Invalid element address
Invalid CDB field
Invalid mode on write buffer
Media in drive
Command queue not empty
Insufficient resources
Invalid buffer ID
Invalid offset
Invalid size
Out of sequence
Image data over limit
Update in progress
Image/personality is bad
Not immediate command
Illegal LUN
Parameter list error
Invalid field
Parameter not supported
Parameter value invalid
Write protected
Hardware write protect
Software write protect
Data safety write protect
Not ready to ready

0Ah
0Ch
11h

14h

15h
17h
18h
1Ah
1Dh
20h
21h
24h

25h
26h

27h

28h

00h
01h
02h
00h
80h
81h
82h
00h

(continued on next page)

SCSI Interface 6–109

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–16 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

29h
2Ah

00h
00h
01h
02h
00h
00h
00h
00h
01h
00h
00h
00h
80h
00h
01h
02h
08h
0Dh
0Eh
00h
00h
01h
03h
00h
80h
81h
82h
83h
00h
00h
80h
81h
00h
00h
00h
00h
00h
00h
00h
00h
01h
02h
00h
00h
00h
01h
02h
00h
01h
02h
03h
00h

Reset occurred
Parameters changed
Mode parameters changed
Log parameters changed
Copy command without disconnect privilege
Command sequence error
Commands cleared by another initiator
Can’t read medium
Unknown format
Rounded parameter
Saving parameters not supported
Media not present
VU cartridge missing
Sequential positioning error
Tape position error at BOM
Tape position error at EOM
Reposition error
Media destination element full
Media source element empty
Invalid bits in ID message
Target operating conditions changed
Microcode has been changed
Inquiry data has changed
Diagnostic/POST failed
ROM EDC failure
RAM failure
Bad drive status
Loader diags failed
Message error
Internal target failure
Unexpected select interrupt
EDC error detected by port
Select/reselect failure
SCSI parity error
IDE message received
Invalid message error
Command phase error
Data phase error
Overlapped commands attempted
Write append error
Write append position error
Position error related to timing
Erase failure
Cartridge fault
Media load/eject failure
Unload tape failure
Media removal prevented
Operator request/state change input
Operator media removal request
Operator selected write protect
Operator selected write permit
Log exception

2Bh
2Ch
2Fh
30h
37h
39h
3Ah
3Bh

3Dh
3Fh
40h

43h
44h
45h
47h
48h
49h
4Ah
4Bh
4Eh
50h
51h
52h
53h
5Ah

5Bh

(continued on next page)

6–110 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–16 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

80h
81h

01h
02h
03h
00h
00h

Threshold condition met
Log counter at maximum
Log list codes exhausted
Calibration error
Directory read error

6.4.2.16.3 REQUEST SENSE — AS400 Attachment
the target to transfer sense data to the initiator.

REQUEST SENSE tells

Figure 6–96 REQUEST SENSE CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (03h)
Logical Unit Number

Reserved

Allocation Length

Unused

Reserved

The sense data is valid for a CHECK CONDITION or RESERVATION CONFLICT
status returned on the previous command. The sense data bytes are preserved by
the target until retrieved by the REQUEST SENSE command, or until the receipt
of any other command from the same initiator.
If the drive receives an unsolicited REQUEST SENSE, then it returns sense
data with the appropriate values in the EOM, sense key, additional sense code,
and additional sense code qualifier. The positional information provided reflects
the logical position of the drive. The drive returns information based on the
(nondiagnostic) data still in its buffer as well as the data on tape.
REQUEST SENSE does not cause the drive to flush its buffered data to tape.
Therefore, if the host requires the exact physical positioning of the media, it
should precede the REQUEST SENSE with a WRITE FILEMARKS with length 0
(Immed=0) command, which forces the drive to flush any currently buffered data
to tape. A subsequent REQUEST SENSE will return the actual physical (and
logical) position of the drive to the initiator.
Allocation Length
The allocation length specifies the maximum number of sense bytes to be
returned. The drive terminates the transfer when allocation length bytes have
been transferred or when all available sense data has been transferred to the
host, whichever is less.

SCSI Interface 6–111

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.16.3.1 Sense Information Format
Figure 6–97 REQUEST SENSE Data
Bit
7
0

Valid

Error Code
Reserved

1
2

Filemrk

(MSB)

EOM

ILI

Reservd

Sense Key

4
Information Bytes
Byte

5
6

(LSB)

7
8

Additional Sense Length
(MSB)

9
Reserved
10
11

(LSB)

Additional Sense Code

Additional Sense Code Qualifier

Reserved

(MSB)

Read/Write Error Counter

(LSB)

BPE

FPE

ECO

TME

TNP

BOT

XFR

TMD

FMKE

URE

WE1

SSE

PEOT

WSEB

WSEO

Reserved

22
23
24
25

Reserved
(MSB)
Tape Remaining
(LSB)

Valid
A Valid bit of 1 indicates that the information bytes contain valid information as
defined in the SCSI specification.

6–112 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Error-Code
A value of 70h indicates a current error — the report is associated with the most
recently received command.
A value of 71h indicates a deferred error — the report is associated with a
previous command and not as a result of the current command.
No other values will be returned.
Filemark
This bit indicates that the current command has read a filemark.
EOM
This bit indicates that an end-of-medium condition (end of partition or beginning
of partition) exists. The warning is also given by setting the sense key to NO
SENSE and the additional sense code qualifier to end of partition or beginning of
partition.
For write-type operations, the drive returns a CHECK CONDITION on any
operation which occurs after detection of the early warning EOP marker. The
EOM and additional sense code fields will be set. For read-type operations, the
drive does not return a CHECK CONDITION until the drive encounters the
physical EOP.
ILI
The Incorrect Length Indicator bit indicates that the requested logical block
length did not match the logical block length of the data on the tape. Only READ
or VERIFY may cause this bit to be set.
Sense Key
In most cases, additional sense code and/or qualifier information is available. See
the tables later in this section.
Information Bytes
These bytes contain the differences (residue) of the requested length minus
the actual length in either bytes, blocks, or filemarks, as determined by the
command. Negative values are indicated by two’s complement notation. The
bytes are valid for all read, write, space and verify tape commands for which a
CHECK CONDITION status has been generated. The information bytes are 0
for MODE SELECT/SENSE, INQUIRY, READ BLOCK LIMITS and TEST UNIT
READY.
Additional Sense Length
This specifies the number of additional sense bytes to follow. If the allocation
length of the command descriptor block is too small to transfer all of the
additional sense bytes, the additional sense length is not adjusted to reflect
the truncation.
Additional Sense Code (ASC) and ASC Qualifier
These two bytes provide additional information about the sense key and cause of
the CHECK CONDITION status. See the tables later in this section.

SCSI Interface 6–113

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–17 Sense Keys Used
Sense
Key

Description

No Sense. Check the filemark/EOM/ILI bits and the ASC/Q bytes.

Not Ready. The media is not ready for tape operation commands. Media might
not be present in the drive, or may be in the process of loading or calibrating.

Medium Error. An unrecoverable write, read or positioning error has occurred.
Detailed device specific information may be available.

Hardware Error. The additional sense code/qualifier fields may provide more
specific information.

Illegal Request. The CDB or supplied parameter data had an unsupported or
illegal operation specified. Check bytes 15, 16 and 17.

Data Protected. The current media is write protected. This can be due to the
Write Protect switch on the cartridge, or if the media is not CompacTape III
type.

Blank Check. An EOD or longgap has been encountered.

Command Aborted. Generated when a command has been aborted by the tape
device for some reason. Check the ASC/Q bytes.

Volume Overflow. Physical end of media has been reached during writing. The
initiator ignored the EOM condition and continued writing.

Miscompare. A compare error occurred during reading by the self-tests invoked
during execution of a send diagnostic.

Table 6–18 Additional Sense Codes/Qualifiers Used
ASC
00h

03h

04h

ASCQ
00h
01h
02h
03h
04h
05h
06h
00h
01h
02h
00h
01h
02h
03h

6–114 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–18 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

05h
07h
08h

00h
00h
00h
01h
02h
00h
00h
00h
01h
02h
03h
08h
09h
0Ah
00h
01h
02h
03h
04h
00h
01h
02h
00h
01h
00h
00h
00h
00h
01h
00h
81h
82h
83h
84h
85h
86h
87h
88h
89h
8Ah
8Bh
8Ch
00h

LUN doesn’t respond to selection
Multiple LUNs selected
LUN communications failure
LUN communications timeout
LUN communications parity error
Error log overflow
Write error
Unrecovered read error
Read retries exhausted
Error too long to correct
Multiple read errors
Incomplete block read
No gap found
Miscorrected error
Recorded entity not found
Filemark not found
FM or setmark not found
EOD blocks not found
Block sequence error
Random positioning error
Mech position error
Detected by read of media
Recovered data without ECC
With retries
Recovered ECC error
Parameter list length error
Miscompare during verify operation
Illegal opcode
Invalid element address
Invalid CDB field
Invalid mode on write buffer
Media in drive
Command queue not empty
Insufficient resources
Invalid buffer ID
Invalid offset
Invalid size
Out of sequence
Image data over limit
Update in progress
Image/personality is bad
Not immediate command
Illegal LUN
Parameter list error
Invalid field
Parameter not supported
Parameter value invalid
Write protected
Hardware write protect
Software write protect
Data safety write protect
Not ready to ready

0Ah
0Ch
11h

14h

15h
17h
18h
1Ah
1Dh
20h
21h
24h

25h
26h

27h

28h

00h
01h
02h
00h
80h
81h
82h
00h

(continued on next page)

SCSI Interface 6–115

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–18 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

29h
2Ah

2Bh
2Ch
2Fh
30h
37h
39h
3Ah
3Bh

3Dh
3Fh
40h

43h
44h
45h
47h
48h
49h
4Ah
4Bh
4Eh
50h
51h
52h
53h
5Ah

5Bh

(continued on next page)

6–116 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–18 (Cont.) Additional Sense Codes/Qualifiers Used
ASC

ASCQ

Description

80h
81h

01h
02h
03h
00h
00h

Threshold condition met
Log counter at maximum
Log list codes exhausted
Calibration error
Directory read error

6.4.2.17 RESERVE UNIT (16h)
Figure 6–98 RESERVE UNIT CDB
Bit
7

0
1

Byte

Operation Code (16h)
Logical Unit Number

3rdPty

Third−Party DeviceID

Reserved

Unused

Reserved

Flag

Rsrd

Link

RESERVE UNIT reserves the specified drive for exclusive use by the requesting
initiator or for another specified SCSI device. The reservation remains in effect
until one of the following conditions is met:
•

The initiator that made the reservation sends another RESERVE UNIT
command.

•

The drive is released by RELEASE UNIT from the same initiator.

•

A BUS DEVICE RESET message is received from any initiator.

•

A hard reset occurs.

The occurrence of the last two conditions is indicated by the drive returning a
CHECK CONDITION status with a sense key of UNIT ATTENTION on the next
command following the condition. It is not an error to issue RESERVE UNIT to a
drive that is currently reserved to the requesting initiator.
If the logical unit has previously been reserved by another initiator, the target
returns a RESERVATION CONFLICT status.
If, after honoring the reservation, any other initiator attempts to perform
any command except INQUIRY, REQUEST SENSE, or RELEASE UNIT, the
command is rejected with a RESERVATION CONFLICT status. A RELEASE
UNIT command issued by another initiator is ignored by that reserved logical
unit.

SCSI Interface 6–117

SCSI Interface
6.4 Tape Drive SCSI Commands
3rdPty
The third-party reservation option for RESERVE UNIT allows an initiator to
reserve a logical unit for another SCSI device. This option is intended for systems
that use COPY, and is implemented by the drive.
If the third-party (3rdPty) bit is 0, then the third-party reservation option is not
requested. If the 3rdPty bit is 1, RESERVE UNIT reserves the logical unit for
the SCSI device specified in the third-party device ID field. The drive preserves
the reservation until any one of the four conditions mentioned above occurs. The
drive ignores any attempt made by any other initiator to release the reservation
and returns a GOOD status.
An initiator that holds a current reservation may modify that reservation (for
example, to switch third-parties) by issuing another RESERVE UNIT to the
drive.
6.4.2.17.1 Medium Changer Considerations The optional element reservation
feature defined for medium changer devices in SCSI-2 is not supported, so the
RESERVE command is defined the same as for the tape drive: Only the whole
loader unit can be reserved. This is separate from a reservation of the tape drive.
The RESERVE/RELEASE commands operate on a LUN basis; so the medium
changer and tape drive are generally handled as different devices. But in the
case of a reserved drive LUN, a MOVE MEDIUM command issued to the loader
LUN can not insert/remove a cartridge on the drive, unless the drive is reserved
by the same initiator.
6.4.2.18 REWIND (01h)
Figure 6–99 REWIND CDB
Bit
7

0
1

Byte

Operation Code (01h)
Logical Unit Number

Reserved

Unused

Reserved

Immed

Flag

Link

REWIND tells the drive to position the tape at the beginning of the currently
active partition. Before rewinding, the drive writes any write data that is
buffered to the tape, and appends an EOD marker.
Immed
If the Immed (immediate) bit is set, the drive first writes any remaining buffered
data to tape followed by an EOD marker. It then returns status to the host before
beginning the actual rewind operation. If the Immed bit is not set, status will be
returned after the rewind has completed.

6–118 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.19 SEND DIAGNOSTIC (1Dh)
Figure 6–100 SEND DIAGNOSTIC CDB
Bit
7

0
1

Operation Code (1Dh)
Logical Unit Number

Rsv’d

Selftst

Dev OfL UnitOfL

Reserved

2
Byte

(MSB)
Parameter List Length

4
5

(LSB)
Unused

Reserved

Flag

Link

SEND DIAGNOSTIC tells the drive to perform diagnostic tests on itself.
The page format field is not supported and must be 0.
Two separate types of unit resident tests can be accessed:
•

Electronics Self-Test — (level 1 test) In order for for the diagnostic to be
invoked, a good portion of the controller hardware and software must be
functioning properly. This is the premise this test is based on: that full
power-up testing is not necessary. Therefore, this test does an extension of
the power-up self-tests. The code ROM EDC is verified, two queues used by
much of the controller software is checked by dequeuing and enqueuing items.
If there is a loader attached, a software reset is done on it. This test does not
attempt to write or read data to or from media. When complete, any errors
are posted in the extended sense data bytes. This test has an execution time
of approximately 5 seconds.
This test is specified by setting just the Selftest bit (Dev OfL, and UnitOfL
both 0).

•

Write/Read Functionality Test — (level 2 test) The level 2 test for the THZ02
is a NOP. GOOD status will be returned if this is requested, but no test will
be performed.

If the specified test passes, a GOOD status is returned. Otherwise, a CHECK
CONDITION is generated, and the sense data will contain information about the
failure.
Table 6–19 Sense Keys Used
Sense Key

Description

Medium Error. A positioning error has occurred where the returned
position does not match the expected.

Hardware Error. The additional sense code/qualifier fields will provide
more specific information.

Illegal Request. Illegal bit settings in the SEND DIAGNOSTIC
command.

Miscompare. A compare error occurred during a read.

SCSI Interface 6–119

SCSI Interface
6.4 Tape Drive SCSI Commands
Table 6–20 Additional Sense Codes
Additional
Sense
Code

Additional
Sense
Qualifier

15h

40h
40h
40h
40h

80h
81h
82h
83h

Description
A positioning error has occurred where the returned position
does not match the expected.
Level 1 ROM test failed.
Level 1 RAM test failed.
Level 1 test failed. Bad drive status.
Level 1 test failed. Loader reset failed.

6.4.2.20 SPACE (11h)
Figure 6–101 SPACE CDB
Bit
7

Byte

Operation Code (11h)

Logical Unit Number

(MSB)

Reserved

Code

Count

4
5

(LSB)
Unused

Reserved

Flag

Link

SPACE provides a variety of positioning functions that are determined by code
and count fields in the command descriptor block. Both forward (towards EOM/P)
and reverse (towards BOM/P) positioning are provided.
Code
The code is defined as follows:
Figure 6–102 SPACE Code Definition

Space Code
0
1
2
3

Space by:
Blocks
Filemarks
Sequential Filemarks
End−of−Data

Spacing by sequential filemarks is supported for count values of 0, 1 and 2 only.

6–120 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Count
When spacing over blocks or marks, the count field is interpreted as follows:
•

A positive value n causes forward movement over n blocks or marks. The
tape is logically positioned after the nth block or mark on the EOM/P side.

•

A 0 value causes no change in the logical position.

•

A negative value -n (two’s complement notation) causes reverse movement
over n blocks or marks. The tape is logically positioned on the BOM/P side of
the nth block or mark.

•

When spacing to EOD, the count field is ignored. Forward movement occurs
until the drive encounters EOD. The position is such that a subsequent
WRITE command would append data after the last object that has been
written to tape before EOD.

When executing SPACE, the drive implements the following hierarchy:
Blocks — lowest
Filemarks
EOD
BOM/P or EOM/P — highest
Therefore, SPACE n blocks will halt with GOOD status after the nth block, or
with CHECK CONDITION status on any occurrence of filemark, EOD, BOM/P, or
EOM/P. A space n filemarks will halt on the nth filemark or on any occurrence of
EOD, BOM/P or EOM/P, and so on.
Depending on the size of blocks, read ahead data in the buffer allows some
spacing requests to be satisfied without tape movement.

SCSI Interface 6–121

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.21 TEST UNIT READY (00h)
Figure 6–103 TEST UNIT READY CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (00h)
Logical Unit Number

Reserved

Unused

Reserved

TEST UNIT READY checks if the drive unit is ready for commands involving
tape movement. If the drive has a tape loaded, the command returns a GOOD
status. Otherwise, CHECK CONDITION is reported.
6.4.2.21.1 Medium Changer Considerations When directed at the media loader
LUN, this command will return CHECK CONDITION sense key of not ready if:
•

The keyswitch is in the Service position, and there is no 24 volts signal
(usually means that the loader assembly has been moved out of its sleeve
enough to trip the 24 V interlock.

6–122 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.22 VERIFY (13h)
Figure 6–104 VERIFY CDB
Bit
7

0
1
2
Byte

Immed

Fixed

Operation Code (13h)
Logical Unit Number

Reserved

(MSB)
Verification Length

(LSB)

4
5

Unused

Reserved

Flag

Link

VERIFY verifies one or more blocks beginning with the next block on the tape.
Both CRC and EDCs are validated.
Immed
If this bit is set, the VERIFY command will complete before any media movement
is done (for example, when processing has been initiated).
BC
This bit selects an CRC/ECC verification or a byte-by-byte compare. If the BC bit
is cleared, device is instructed to perform an internal CRC/ECC check of the data.
If this bit is set the command will be rejected.
Fixed
This bit operates in the same fashion as with the READ command.

SCSI Interface 6–123

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.23 WRITE (0Ah)
Figure 6–105 WRITE CDB
Bit
7

0
1

Operation Code (0Ah)
Logical Unit Number

Reserved

Fixed

2 (MSB)

Byte

Transfer Length

4
5

(LSB)
Unused

Reserved

Flag

Link

WRITE transfers one or more blocks from the host to the current logical position.
When in buffered mode (see MODE SELECT), the tape drive reports a GOOD
status on WRITE commands as soon as this data block has been transferred to
the data buffer.
The drive flushes the write buffer to tape under the following conditions:
•

The write hold-off time limit is exceeded. (See MODE SELECT command.)

•

Receipt of the following nonwrite commands:
LOAD-UNLOAD
REWIND
ERASE
LOCATE

•

A WRITE FILEMARKS command with the Immediate bit cleared.

If buffered mode is not selected, the buffer will flush after every write-type
command. Buffered mode can be configured through MODE SELECT, and if it
is not used, the tape drive suffers a significant degradation in performance with
respect to transfer rate and therefore loss of streaming.
FIXED
The Fixed bit specifies both the meaning of the transfer length field and whether
fixed-length or variable-length blocks are to be transferred. If the Fixed bit is
set to 0, variable block mode is selected. A single block is transferred form the
initiator and is written to the logical unit beginning at the current logical tape
position. Upon successful termination, the tape is logically positioned after this
block (EOM/P side). The transfer length specifies the number of bytes that the
drive handshakes out from the initiator.
If the Fixed bit is set to 1, the transfer length field specifies the number of blocks
to be transferred to the host beginning at the current tape position. This form
of WRITE is valid only if the logical unit is currently operating in fixed block
mode, in other words, when it has been instructed to use fixed-length blocks
with MODE SELECT. The current block length is the block length defined in the
MODE SELECT command. Upon termination, the tape is logically positioned
after these blocks.

6–124 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
Transfer Length
This field contains the length of the data transfer in bytes or blocks, depending
on whether fixed or variable block mode is selected.
If the transfer length is 0, no data is transferred and the current position on the
logical unit is not changed.
Exception Conditions
If EOT is detected while writing, the drive will finish writing any buffered
data. The command terminates with CHECK CONDITION status. Within the
sense data, the EOM bit is set, the sense key field is set to NO SENSE, and the
additional sense code and additional sense code qualifier fields are set to EOM/P
detected. The drive attempts to complete any subsequent writes, returning a
CHECK CONDITION status in each case.
If the drive encounters the physical EOM when attempting write, CHECK
CONDITION status is returned. Within the sense data, the EOM and Valid bits
are set, and the sense key field is set to MEDIUM ERROR. The information fields
contain the residue count and the additional sense code and additional sense code
qualifier fields are set to EOM/P detected. The tape is physically positioned at
EOM/P.

SCSI Interface 6–125

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.24 WRITE BUFFER (3Bh)
Figure 6–106 WRITE BUFFER CDB
Bit
7

0
1

Operation Code (3Bh)
Logical Unit Number

2
Byte

Reserved

Mode

Buffer ID (00h)

3 (MSB)
4

Buffer Offset (000000h)

5
6

(LSB)
(MSB)

Parameter List/Data Length

8
9

(LSB)
Unused

Reserved

Flag

Link

WRITE BUFFER is used in conjunction with READ BUFFER as a diagnostic
function for testing the device data buffer, DMA engine, SCSI bus interface
hardware, and the SCSI bus integrity. It is also used for downloading and
updating controller microcode (firmware).
Mode
The drive supports the following values within the field. If any other value is set,
the drive terminates the command with a CHECK CONDITION status and an
ILLEGAL REQUEST sense key set.
Figure 6–107 WRITE BUFFER Modes Supported

Mode

Description

000b
010b
100b
101b

Write combined header and data
Write data
Download Microcode
Download Microcode and Save

For all modes, only a buffer ID of 0 is supported. If the buffer ID field is non-0,
the command will be rejected. The target detects and rejects commands that
would overrun the buffer.

6–126 SCSI Interface

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.24.1 Header and Data Mode The data to be transferred is preceded by a
4-byte header consisting entirely of reserved bytes. This header is discarded (not
stored into the buffer). The buffer offset field must be 0 for this mode.
6.4.2.24.2 Write Data Similar to mode 000b, except there is no header in the
data passed to the target. The buffer offset must be 0. Potential buffer overruns
are detected and the command rejected.
6.4.2.24.3 Download Microcode Using buffer offsets, the host can download the
firmware image into the target’s buffer in pieces. These commands do not cause
the new image to become active — a download and save mode WRITE BUFFER
command must be issued.
The tape drive must be empty to allow downloading of an image. This is to
safeguard against accidentally starting a firmware update. If a cartridge is loaded
when all or part of a firmware image has been downloaded, another WRITE
BUFFER with download mode will be rejected. Overlapping or nonconsecutive
downloading of the image data is not supported. The firmware image must be
downloaded in integral multiples of 4k bytes.
Any error on a WRITE BUFFER command causes any downloaded image data to
be discarded, and the download must be restarted from the beginning.
6.4.2.24.4 Download Microcode and Save This mode can be used to download
and save the entire image at once, or to download the image data and save it,
or to cause a save operation after all the image data has been downloaded using
the download only mode. This mode of the command causes the image data to
be verified and the flash EEPROM firmware area to be updated. During the
reprogramming, the Write Protect and Drive Activity LEDs on the drive’s front
panel will blink.
Note
During the actual reprogramming of the FLASH memory chips, if any
type of powerfail occurs, or if the reprogramming fails part way through,
the subsystem will be unusable, and the controller board will need to be
replaced.

When the save operation is successfully completed, the firmware restarts itself,
causing POST to be rerun, and two unit attention conditions are generated:
power-up reset, and operating code has changed.

SCSI Interface 6–127

SCSI Interface
6.4 Tape Drive SCSI Commands
6.4.2.25 WRITE FILEMARKS (10h)
Figure 6–108 WRITE FILEMARKS CDB
Bit
7

0
1
Byte

WSmk

Immed

Operation Code (10h)
Logical Unit Number

Reserved

(MSB)

Number of Filemarks

4
5

(LSB)
Unused

Reserved

Flag

Link

WRITE FILEMARKS causes the specified number of filemarks to be written
beginning at the current logical position on tape. If the Immed bit is not set, any
data or filemarks in the write cache buffer are written to tape.
WSmk
If this bit is set, the tape drive writes a save-set mark to tape instead of a
filemark. Since setmarks are not supported by the THZ02, this field must be 0.
Immed
If this bit is set, the drive returns status as soon as the command descriptor block
has been validated, unless the filemark count is 0, or greater than 1 (since both
cause the write buffer to be flushed to media — see below).
An Immed bit of 0 indicates that the status will not be returned until the
operation is complete.
Number of Filemarks
This is the number of consecutive marks to be written to tape. A value of 0 is not
considered an error and GOOD status is returned.
This command may be used to force the drive to write any buffered write data to
the tape. If the drive is in buffered mode, and WRITE FILEMARKS is received
the requested filemarks are appended to the data, and the write buffer is flushed
to tape. A 0 value in the number of filemarks field indicates that no filemarks are
to be written to the tape, but still flushes any write data to tape.
If EOT is detected while writing filemarks, the drive finishes writing any buffered
data and terminates with CHECK CONDITION status. Within the sense data,
the EOM bit is set, the sense key field is set to NO SENSE and the additional
sense code and additional sense code qualifier fields are set to EOM/P detected.
The drive will attempt to complete any subsequent WRITE FILEMARKS,
returning a CHECK CONDITION status in each case. If the drive encounters the
physical EOM when attempting a WRITE FILEMARKS, CHECK CONDITION
status is returned.

6–128 SCSI Interface

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands

6.5 Supported SCSI-2 Medium Changer Device Commands
On the medium changer LUN, only commands defined for this device type are
allowed. The following commands are implemented:
Table 6–21 SCSI-2 Medium Changer Commands
Opcode
1

07
12
152
1A2
A51
3C
B81
1C
17
03
16
1D
00
3B

Command
INITIALIZE ELEMENT STATUS
INQUIRY
MODE SELECT
MODE SENSE
MOVE MEDIUM
READ BUFFER
READ ELEMENT STATUS
RECEIVE DIAG RESULTS
RELEASE
REQUEST SENSE
RESERVE
SEND DIAGNOSTIC
TEST UNIT READY
WRITE BUFFER

1 Medium changer specific commands
2 Commands with significant medium changer specific content

The rest of this chapter covers medium changer unique commands.
Medium changer element address assignment is as follows:
Table 6–22 Medium Changer Element Addresses
Address

Comments

0
1
2-0Fh
10h
11h-0FFh
100h
101h
102h
103h
104h
105h
106h
107h-0FFFFh

Default medium transport element
Medium transport element
Reserved
Data transfer element (tape drive)
reserved
Medium storage element (Magazine slot 0)
Medium storage element (Magazine slot 1)
Medium storage element (Magazine slot 2)
Medium storage element (Magazine slot 3)
Medium storage element (Magazine slot 4)
Medium storage element (Magazine slot 5)
Medium storage element (Magazine slot 6)
Reserved

SCSI Interface 6–129

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.1 INITIALIZE ELEMENT STATUS (07h)
Figure 6–109 INITIALIZE ELEMENT STATUS CDB
Bit
7

0
1

Byte

Flag

Link

Operation Code (07h)
Logical Unit Number

Reserved

Unused

Reserved

This command is a NOP on the THZ02, since it always maintains a table of the
current state of loader elements.

6–130 SCSI Interface

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.2 READ ELEMENT STATUS (B8h)
Figure 6–110 READ ELEMENT STATUS CDB
Bit
7

0
1
2

Operation Code (B8h)
Logical Unit Number

VolTag

Element Type Code

(MSB)
Starting Element Address

3
4

(LSB)
(MSB)
Number of Elements

(LSB)

6
7

Reserved
(MSB)

Allocation Length

(LSB)

10
11

Reserved
Reserved

Unused

Flag

Link

Figure 6–111 Element Type Code Definitions
Code
0h
1h
2h
3h
4h
5h−Fh

Description
All element types reported (valid in CDB only)
Medium Transport Element
Storage Element (magazine slot)
Import Export Element (not supported)
Data Transfer Element (tape drive)
reserved

The format of element status data is defined in the SCSI-2 specification. The
following sections show the information returned for the THZ02. The element
status data is made up of a header, and one or more status pages (for each
element type). The status pages are made up of a header and one or more
element descriptors (one for each element address). The data shown assumes the
CDB was specified in such a way that all descriptors for a given element type
would be returned.
The primary and alternate volume tag functions are not supported, so the flags
indicating these functions in the element status pages (below) are always set to 0.

SCSI Interface 6–131

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.2.1 Element Status Data Header
Figure 6–112 Element Status Data Header
Bit
7
0

(MSB)
First Element Address Reported
(LSB)

1
2

(MSB)
Number of Elements Reported

(LSB)

4
5

Reserved
(MSB)

6
7

6–132 SCSI Interface

Byte Count of Report Available
(LSB)

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.2.2 Medium Transport Element Status Page
Figure 6–113 Medium Transport Element Status Page
Bit
7
0

Element Type Code (1 = Medium Transport)

PVolTag AVolTag

(MSB)

Reserved
Transport Element Descriptor Length (06h)

(LSB)

4
5

Reserved
(MSB)
Byte Count of Descriptor Data Available (06h)

6
7

(LSB)

Descriptor:
8

(MSB)
Transport Element Address ( 1h)

(LSB)

Reserved

Except

Reserved

Additional Sense Code

Additional Sense Code Qualifier

Reserved

SValid

(MSB)

Invert

rsvd

Full

Reserved
Source Element Address

(LSB)

Reserved

Density code of Media (= 0 if empty) (VU)

unused

(VU)

There is only one medium transport element, which can be addressed explicitly
as element address 1, or implicitly as address 0.
PvolTag and AVolTag are always 0.

SCSI Interface 6–133

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.2.3 Storage Element Status Page
Figure 6–114 Storage Element Status Page
Bit
7
0

Element Type Code (2h = Storage Element)

PVolTag AVolTag

(MSB)

Reserved
Storage Element Descriptor Length (12h)

(LSB)

4
5

Reserved
(MSB)

Byte Count of Descriptor Data Available

(LSB)

Descriptor(s):
8

(MSB)
First Storage Element Address Reported

(LSB)

Reserved

Access

Except

Reserved

Additional Sense Code

Additional Sense Code Qualifier

Reserved

SValid

(MSB)

Invert

rsvd

Full

Reserved
Source Element Address

19
20

Reserved

24
25
25 to n

6–134 SCSI Interface

(LSB)

Density code of Media (= 0 if empty) (VU)
unused

(VU)

− descriptors for other Storage Elements reported

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
There are seven storage elements, corresponding to the seven slots in a magazine.
PvolTag and AVolTag are always 0.
Access is always 1, and full is set to 1 if a media cartridge is in the corresponding
magazine slot. Exception will be set to 1 if the magazine slot indicates a cartridge
has been removed, but is not in the medium transport or data transfer elements.
The source element address will always be set to this element’s address.

SCSI Interface 6–135

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.2.4 Data Transfer Element Status Page
Figure 6–115 Data Transfer Element Status Page
Bit
7

Element Type Code (4h = Data Transfer Element)

PVolTag AVolTag

(MSB)

Reserved

Data Transfer Element Descriptor Length (11h)
3

(LSB)

4
5

Reserved
(MSB)

Byte Count of Descriptor Data Available (11h)
(LSB)

7
Descriptor:
8

(MSB)
Data Transfer Element Address (10h)

(LSB)

Reserved

Access

Except

Reserved

Additional Sense Code

Additional Sense Code Qualifier

NotBus

rsvd

IDValid

LUValid

rsvd

Full

Logical Unit Number

SCSI Bus Address (same as tape drive’s)

15
16

Reserved

SValid

(MSB)

Invert

Reserved
Source Element Address

19
20

Reserved

24
25

6–136 SCSI Interface

(LSB)

Density code of Media (= 0 if empty) (VU)
unused

(VU)

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
PvolTag and AVolTag are always 0.
Access is always set, full is set if there is a cartridge in the tape drive.
IDValid and LUValid are always set; drive LUN is 0. The SCSI bus address field
is the same as the tape drive’s controller.
SValid is set if there is a cartridge in the drive, and source element address will
indicate which magazine slot it came from.

SCSI Interface 6–137

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.3 MODE SENSE/SELECT
All three pages that are specific to medium changers are supported.
6.5.3.1 Device Capabilities Page
The drive shall support the device capabilities page which has the following
format:
Figure 6–116 Device Capabilities Page Format
Bit

StorI/E

StorST

StorMT

Page Code (1Fh)

Additional Page Length (0Eh)

Reserved

StorDT
Reserved

Reserved

I/E

Reserved

I/E

Reserved

I/E

Reserved

I/E

Reserved

MT<>DT

MT<>I/E

MT<>ST

MT<>MT

Reserved

ST<>DT

ST<>I/E

ST<>ST

ST<>MT

Reserved

IE<>DT

IE<>I/E

IE<>ST

IE<>MT

Reserved

DT<>DT

DT<>I/E

DT<>ST

DT<>MT

Bit Field Values
•

Elements that can store media: StorDT, StorSt

•

Valid Source->Destination pairs: ST->DT, DT->ST

All the "MT->XX" and the "XX->MT" entries are 0, since the THZ27 loader will
not accept a medium transport element address as a source or destination.
All the "IE->XX" and the "XX->IE" entries are 0 since there is no import/export
element.
Bytes 12 through 15 are all 0 as the THZ27 does not support the exchange
medium command.
The THZ27 does not support "ST->ST" or "DT->DT".

6–138 SCSI Interface

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.3.2 Element Address Assignment Page
The drive shall support the element address assignment page which has the
following format:
Figure 6–117 Element Address Assignment Page Format
Bit

1
2

Page Code(1Dh)
Length (12h)

(MSB)
1st Medium Transport Element Address (01h)
(LSB)

3
4

(MSB)
Number of Medium Transport Elements (1)

5
6

(LSB)
(MSB)
1st Storage Element Address (100h)

7
8

(LSB)
(MSB)
Number of Storage Elements (07)

(LSB)

10 (MSB)
1st Import/Export Element Address (00h)
11

(LSB)

12 (MSB)
Number of Import/Export Elements (0)
13

(LSB)

14 (MSB)
1st Data Transfer Element Address (10h)
15

(LSB)

16 (MSB)
Number of Data Transfer Elements (01)
17

(LSB)

Reserved

SCSI Interface 6–139

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.3.3 Transport Geometry Parameters Page
The drive shall support the transport geometry page which has the following
format:
Figure 6–118 Transport Geometry Page Format
Bit

Page Code(1Eh)

Additional Page Length (02h)

Reserved

Rotate

Member Number in Transport Element Set (0)

Rotation of media is not appropriate for this type of loader, so the Rotate bit is 0.
There is only one medium transport element, so there is only one set, with one
member.

6–140 SCSI Interface

SCSI Interface
6.5 Supported SCSI-2 Medium Changer Device Commands
6.5.4 MOVE MEDIUM (A5h)
Figure 6–119 MOVE MEDIUM CDB
Bit
7

Operation Code (A5h)

Logical Unit Number

(MSB)

Reserved
Transport Element Address

3
4

(LSB)
(MSB)
Source Address
(LSB)

5
6

(MSB)
Destination Address

(LSB)

Reserved

10
11

Reserved
Unused

Reserved

Invert
Flag

Link

The MOVE MEDIUM command is used to move cartridges from the tape drive to
the magazine slot it came from, or from any magazine slot to the tape drive.
The transport element address field must be 0 or 1.

SCSI Interface 6–141

7
Firmware Update Procedure (From Tape)
This section describes the procedure for updating the firmware (code) of the
controller module of the THZ02 streaming cartridge tape subsystems, from a
cartridge that has the firmware image stored on it. Firmware update from the
host is also supported; see the section on the SCSI WRITE BUFFER command
for details.

7.1 THZ02 Firmware Updates
On the THZ02 cartridge tape product family, updates of the controller board’s
firmware can be done automatically by the subsystem, directly from a tape with
the appropriate information on it. The user uses the front panel to put the
subsystem into firmware update mode, and then simply loads a tape with the
THZ02 firmware image file stored on it. The subsystem will then automatically
read and verify the information on the tape as a valid THZ02 firmware image.
If the image data passes all the verifications, it is installed into the controller’s
nonvolatile code memory.
This chapter describes all the details of the firmware update procedure, so that
users with little or no prior experience with the product can do the update.
Before walking through the procedure, here are a few things to keep in mind:
Caution
During the firmware update, when the new image is actually being
programmed into the FLASH EEPROMs, a powerfail (but not bus reset)
will cause the controller module to be unusable. When doing a firmware
update, take reasonable precautions that a powerfail will not occur.

•

The subsystem can be updated even when not attached to an SCSI bus (for
example, stand-alone). However, since the power-on self-test (POST) needs to
pass for an update to be possible, and POST needs a properly terminated bus
to pass, if the user wants to do a firmware update on a standalone unit they
should do the following:
Ensure that the termination packs on the controller board are in the
"TERM" position, and the Term Power jumper in the "PWR" position. These
positions are labeled on the PCB etch (as are the "NO TERM" and "NO PWR"
positions).

Firmware Update Procedure (From Tape) 7–1

Firmware Update Procedure (From Tape)
7.2 Creating a "Firmware Update Tape"

7.2 Creating a "Firmware Update Tape"
To do the firmware update, a piece of CompacTape media with a copy of the
firmware image properly written to it must be available. This "FW Update Tape"
can easily be created, if it is not already available.

7.2.1 On UNIX Systems
The FTP utility can be used to transfer the binary firmware image file onto the
UNIX system; be sure to specify "type image" before doing the "get" or "put",
otherwise extra characters may be added to the file, causing the image file to be
invalid. The image file should be exactly 1024*256 bytes in size.
Use the ltf command with the -cfB options to copy the image file to the
CompacTape media using 4k byte blocks.
For example:
#ltf -cfB /dev/rmt0h 4096 thz_v10.image

7.3 Firmware Update Procedure
Firmware updates are supported on the THZ02 with and without the media
loader. The steps for performing the update are similar for each, and are given
separately below.

7.3.1 Updating the Firmware on THZ02 (Drive Only Configuration)
1. Get or make a CompacTape with the firmware image of the desired revision
level copied to it.
2. Put the THZ02 subsystem into firmware update mode.
This is done as follows:
a. Remove any cartridge that is in the target THZ02 unit and close the
handle (down position).
b. Press the Unload button on the unit’s front panel and hold it until the
Write Protect LED begins blinking (about 6 seconds). This indicates
that the THZ02 unit has recognized that the user is requesting firmware
update mode, and is waiting for completion of the sequence.
If the Write Protect LED never starts blinking, the user should check that
the device is in the proper state (no POST failures, no cartridge in drive,
drive handle in proper position).
c.

The Unload button should then be released, and then pressed again
within 4 seconds. Duration of the second press should be less than 1
second.

d. The "Tape in Use" LED on the unit’s front panel will begin flashing, as
well as the Write Protect LED, indicating that the tape unit recognizes
that firmware update mode has been selected.
e.

If not successful (for example, due to not pushing the button the second
time properly) the Write Protect LED should stop blinking within
several seconds. The procedure can then be tried again. If the drive and
controller are not properly communicating, the user will be unable to
select firmware update.

7–2 Firmware Update Procedure (From Tape)

Firmware Update Procedure (From Tape)
7.3 Firmware Update Procedure
3. Once firmware update mode is selected, the next cartridge that is
inserted into the drive (which will temporarily clear the two LEDs) will
be automatically read and the data examined and verified to be a valid
THZ02 firmware image. (A few minutes of tape movement will result from
calibration and directory processing before data is actually read.) Firmware
update mode is automatically cleared at this point.
4. If everything is okay, the controller’s flash EEPROM memory will be
automatically updated with the new firmware image.
7.3.1.1 Interpreting the Results
There are two possible results:
•

The firmware update cartridge is unloaded: this indicates a successful update.
On the THZ02, the media is placed into the cartridge, the door unlocked, and
the green "Operate Handle" LED is turned on.

•

The firmware update cartridge is not unloaded: this indicates an unsuccessful
update.
The subsystem should still be usable, but this depends on why the update
failed (power failure, bad image on the tape, no +12 V supplied to the
controller PCB, broken Flash EEPROMs, etc.)

Additional details are covered below.
1. If the image is valid, the flash EEPROM containing the current firmware will
be erased and the new image programmed in. The subsystem will complete
the update in about 2 minutes.
When the update is complete, the tape unit will reset itself, going through
power-on and self-test and automatically unload the tape containing the
firmware image so that it can be removed. This indicates a successful
firmware update.
2. If the tape is not a valid firmware update tape, or does not contain a valid
image, no update will be attempted. The Write Protect and Tape In Use LEDs
will not blink.
Caution
Be sure to wait a few minutes before doing this to ensure that an
unusually long update is not in progress, since a dead controller could
result if power is cycled prematurely!
If there is not a valid firmware image, the unit resets itself, and the tape will
be left loaded.
3. If the tape contains a valid image, but for some reason the reprogramming of
the flash memory fails, the controller will probably be unusable and will need
to be replaced. The tape unit will reset itself and rerun POST, which will fail
if the flash memory does not contain a valid image.

Firmware Update Procedure (From Tape) 7–3

Firmware Update Procedure (From Tape)
7.3 Firmware Update Procedure
7.3.2 Updating the Firmware on THZ27 Loader Configuration
1. Get or make a CompacTape with the firmware image of the desired revision
level copied to it.
2. Put the THZ27 subsystem into firmware update mode.
This is done as follows:
a. Remove any magazine that is in the THZ27’s loader receiver, and close
the receiver.
b. Put the keyswitch in the Service position (wrench icon).
c.

Press the Load-Unload button on the front panel and hold it until the
Write Protect LED begins blinking (about 6 seconds). This indicates
that the THZ27 unit has recognized that the user is requesting firmware
update mode, and is waiting for completion of the sequence.
If the Write Protect LED never starts blinking, the user should check that
the device is in the proper state (no POST failures, no cartridge in drive,
no magazine in loader, receiver door closed, keyswitch in proper position,
etc.).

d. The Unload button should then be released, and then pressed again
within 4 seconds. Duration of the second press should be less than 1
second.
e.

The "Tape in Use" LED on the front panel will begin flashing, as well
as the Write Protect LED, indicating that the subsystem recognizes that
firmware update mode has been selected.

If not successful (for example, due to not pushing the button the second
time properly) the Write Protect LED should stop blinking within several
seconds. The procedure can then be tried again.

3. Once firmware update mode is selected, the EJECT button should be pressed
twice, which will cause the receiver door to open. The Write Protect and Tape
In Use LEDs will stop blinking also (but the subsystem is still in update
mode).
4. A magazine with the firmware update tape in the first nonempty slot should
then be put into the loader receiver and the receiver closed. (The remainder
of the update procedure will go faster if the magazine has only the firmware
update cartridge in it, but it will work if other cartridges are also present.)
5. The Load-Unload button should then be pressed to cause the firmware update
tape to be loaded into the drive.
6. The drive will automatically read the tape and the data examined and verified
to be a valid THZ27 firmware image. (A few minutes of tape movement will
result from calibration and directory processing before data is actually read.)
Firmware update mode is automatically cleared at this point.
7. If everything is okay, the controller’s flash EEPROM memory will be
automatically updated with the new firmware image.
8. When done (okay or not) the subsystem resets itself. A full extended scan of
the loader will take place. If the firmware update cartridge was the only one
in the magazine this will go quickly. If there are six other cartridges present,
the extended scan will take a minute or so extra.

7–4 Firmware Update Procedure (From Tape)

Firmware Update Procedure (From Tape)
7.3 Firmware Update Procedure
7.3.2.1 Interpreting the Results
There are two possible results:
•

The firmware update cartridge is unloaded: this indicates a successful update.
On the THZ27, the cartridge is unloaded from the drive into the magazine
slot it came from — and the next one loaded if there is one.

•

Additional details are covered below.
1. If the image is valid, the flash EEPROM containing the current firmware will
be erased and the new image programmed in. The subsystem will complete
the update in about 2 minutes.
When the update is complete, the tape unit will reset itself, going through
power-on self-test and automatically unload the tape containing the firmware
image so that it can be removed. This indicates a successful firmware update.
2. If the tape is not a valid firmware update tape, or does not contain a valid
image, no update will be attempted. The Write Protect and Tape In Use LEDs
will not blink.
Caution
Be sure to wait a few minutes before doing this to ensure that an
unusually long update is not in progress, since a dead controller could
result if power is cycled prematurely.
If there is not a valid firmware image, the unit resets itself, and the tape will
be left loaded.
3. If the tape contains a valid image, but for some reason the reprogramming of
the flash memory fails, the controller will probably be unusable and will need
to be replaced. The tape unit will reset itself and rerun POST, which will fail
if the flash memory does not contain a valid image.

Firmware Update Procedure (From Tape) 7–5

8
Diagnostics
This chapter is intended to provide a general description of the diagnostic
strategy for the THZ02 subsystem. The main purpose here is to address the
global diagnostic issues.
The diagnostics consist of:
•

Power-on self-tests (POST) in the controller and drive

•

Microdiagnostics, invoked from the host via the SEND DIAGNOSTIC SCSI
command.

The benefits of utilizing the embedded diagnostic approach is that because the
diagnostics reside within the subsystem, as long as the capability to send flavors
of the SEND DIAGNOSTIC command exist on any given host system, these tests
will be able to run. For example, the boot ROMs on some host systems support
this type of testing.

8.1 Test Goals
Coverage by testing is:
•

75% POST only

•

25% via resident microdiagnostics only

•

Fault isolation to the FRU level only

With some overlap between POST and functional microdiagnostics and in
combination with host-based testing, total diagnostic test coverage will be 98%
detection of single stuck at faults, with 95% fault isolation to a single FRU.

Diagnostics 8–1

Diagnostics
8.2 Resident Power-On Self-Test (POST) Diagnostics

8.2 Resident Power-On Self-Test (POST) Diagnostics
The purpose of the resident POST microdiagnostics is to perform a comprehensive
self-test of the personality card logic, conforming to hardware size and cost goals.
The POST microdiagnostics will execute at power-up, or in response to a bus
device reset message from the host.
The POST package consists primarily of go/no-go tests. Controller POST is not
intended to perform any testing on the drive transport or medium changer, nor
will they be able to test much of the SCSI interface logic.
The POST tests cover:
Diagnostic LED test (needs human to verify results)
68020 microprocessor register and instruction tests
Local RAM tests
NCR 53C96 chip tests
EZ gate array tests
GPSP4 gate array test
Cache (EZ) RAM tests
Flash code ROM tests
Timer and other miscellaneous tests
POST testing will be completed, and the subsystem will respond normally to
all commands within 5 seconds. However, it can take somewhat longer for the
media (if loaded) to be made ready. After a bus reset the subsystem will be able
to respond to selections after 1 second or less.

8.2.1 Failure Action
The controller includes one green and one amber on-board status LED for fault
indication. On power-up, both lights will be lit. As the POST microdiagnostic
goes through each test these LEDs will blink. If all tests pass then only the green
light will be left lit.
If any test fails the green LED will be turned off. Communication over the SCSI
bus may or may not be possible. Cycling the power will probably be required to
get the subsystem to rerun the POST tests again.

8–2 Diagnostics

Diagnostics
8.3 Microdiagnostic Tests

8.3 Microdiagnostic Tests
These can be run using default parameter setting using vanilla versions of
the SEND DIAGNOSTIC command. With an appropriate parameter list, the
tests can be run with various parameter values (test pattern, pass count, block
size, block count). See the SEND DIAGNOSTIC command description in this
document.

8.3.1 Microdiagnostic Test Descriptions
The THZ02 controller microdiagnostic package consists of the following tests and
utilities:
8.3.1.1 Level 1 Test
This test is similar to the POST tests (only electronics tested) and is relatively
fast. Unlike POST, the drive and medium changer interfaces are tested if the
devices are present.
8.3.1.2 Level 2 Test
This test is a NOP for the THZ02.

Diagnostics 8–3

9
Technical Specifications
This chapter contains specifications of the THZ02 tape drive.

9.1 Physical Description
This section contains figures showing the front panel, top, side, and isometric
views of the tape drive.

9.1.1 Front Panel
The following figure shows the front panel of the THZ02 tape drive.
Figure 9–1 THZ02 Front View

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CARTRIDGE INSERT/RELEASE HANDLE
SHR-X0056G-91

Technical Specifications 9–1

Technical Specifications
9.1 Physical Description
9.1.2 Top View
The following figure shows the THZ02 tape drive as seen from the top.
Figure 9–2 Top View

9–2 Technical Specifications

Technical Specifications
9.1 Physical Description
9.1.3 Side View
The following figure shows the THZ02 tape drive as seen from the side.
Figure 9–3 Side View

Technical Specifications 9–3

Technical Specifications
9.1 Physical Description
9.1.4 Isometric View
The following is an isometric view of the THZ02 tape drive.
Figure 9–4 Isometric View

9–4 Technical Specifications

Technical Specifications
9.2 Physical Dimensions

9.2 Physical Dimensions
The tape drive width and height are standard 5-1/4 inch disk drive form factor
measurements. Both dimensions hold tolerances of ± 0.020 inches. The depth
dimensions have tolerances of +00, -0.040 in.
The following table lists basic size, depth, mounting holes, and weight.
Table 9–1 Size, Depth, Mounting Holes, Weight
Basic size

3.95 in high
(10.03 cm

5.70 in wide
14.47 cm

9.00 in deep (from rear of bezel)

22.86 cm)

Bezel depth

0.60 inch (1.52 cm)

Mounting holes

Standard for 5¼-in tape drives

Unpacking weight

6.5 lb (2.95 kg)

Packed weight

9 lb (4.08 kg)

9.3 Performance Specifications
The following sections describe performance specifications.

9.3.1 Nominal Tape Tension
Nominal tape tension is as follows:
•

3.0 ± 1 oz when stationary

•

4.7 ± 1 oz at operating speed

9.3.2 THZ02 Timing Characteristics
The following table lists timing characteristics of the THZ02 tape drive:
Table 9–2 THZ02 Timing Characteristics
Tape speed

100 in/sec

Nominal rewind time

2 min

Maximum access time

3 min

Load to BOT — blank tape

75 sec

Load to BOT — used tape

60 sec

Unload from BOT

15 sec

Technical Specifications 9–5

Technical Specifications
9.3 Performance Specifications
9.3.3 THZ27 Media Loader Timing Characteristics
The following table lists timing characteristics of the THZ27 media loader.
Table 9–3 THZ27 Media Loader Timing Characteristics
Nominal magazine scan

12 sec

Move cartridge slot to drive

27 sec

Move cartridge drive to slot

25 sec

Error recovery

30 sec

9.4 Power Requirements
The THZ02 tape drive operates on +5 and +12 dc power. The tape drive may also
be mounted in a tabletop enclosure or media loader that operate from ac power.
Refer to the following tables for power requirements.

9.4.1 THZ02 Power Requirements
The following tables list the power requirements of the drive itself.
Table 9–4 THZ02 Power Requirements (±5%)
Steady State

Maximum

5 volts

3.50 A

4.50 A

12 volts

1.22 A

2.60 A

Wattage

35 W

40 W

9.4.2 THZ02 Tabletop Power Requirements
The power requirement of the drive when mounted in the tabletop enclosure is:
100-240 Vac
50/60 Hz
50 W

9.4.3 THZ27 Power Requirements
The power requirement of the drive when mounted in the media loader is:
100-120, 220-240 Vac (selectable)
50/60 Hz
100 W

9–6 Technical Specifications

Technical Specifications
9.5 Environmental Specifications

9.5 Environmental Specifications
The tape drive conforms to modified Class B environment that includes general
offices and workspaces with:
•

Conditioned and marginally-conditioned areas with central or remote
air-conditioning

•

Complete temperature and humidity controls

•

Moderate control tolerances

•

Systems capable of maintaining comfort levels (for example, typical offices,
general work areas, and so forth)

•

Marginal heating or cooling apparatus

•

No humidity conditioning

•

Uncontrolled tolerances

•

Systems inadequate to always maintain comfort levels (for example, marginal
offices and work spaces, and so forth)

9.5.1 Temperature and Humidity
Refer to the following table for operating temperature and humidity ranges.
Table 9–5 Operating Ranges
Dry bulb temperature

10 to 40°C

Wet bulb temperature

25°C

Temperature gradient

11°C/h (across the range)

Temperature shock

10°C (over two min)

Relative humidity

20 to 80% noncondensing

Humidity gradient

10%/h

Refer to the following table for power-on ranges.
Table 9–6 Power-On Ranges — No Tape Loaded (Unpacked — 72 Hours)
Dry bulb temperature

10 to 40°C

Wet bulb temperature

25°C

Temperature gradient

15°C/h (across the range)

Temperature shock

15°C (over two min)

Relative humidity

10 to 90%

Humidity gradient

10%/h

Technical Specifications 9–7

Technical Specifications
9.5 Environmental Specifications
Refer to the following table for storage ranges.
Table 9–7 Storage Ranges (Unpacked or Packed)
Dry bulb temperature

-40 to 66°C

Wet bulb temperature

46°C

Temperature gradient

20°C/h with 5° margin (across the range)

Temperature shock

15°C with 5° margin (over two min)

Relative humidity

10 to 95% noncondensing

Humidity gradient

10%/h

Refer to the following table for shipment ranges.
Table 9–8 Shipment Ranges
Dry bulb temperature

-40 to 66°C

Wet bulb temperature

46°C

Temperature gradient

25°C/h with 5° margin (across the range)

Temperature shock

15°C with 5° margin (over two min)

Relative humidity

10 to 95% noncondensing

Humidity gradient

10%/h

9.5.2 Altitude
The tape drive operates in normal pressures from 60 to 8,000 feet.

9–8 Technical Specifications

Technical Specifications
9.6 Vibration and Shock Requirements

9.6 Vibration and Shock Requirements
Refer to the following tables for operating and nonoperating vibration
requirements:
Table 9–9 Operating Vibration Requirements (Within Specification — No
Damage)
Frequency range

5-500-5 Hz

Peak acceleration

0.25 g

Waveshape

0.010 in double amplitude

Application

X, Y, Z axes — 2 sweeps/axis

Table 9–10 Nonoperating Vibration Requirements (Unpacked — No damage)
Frequency range

10-50-300 Hz

Peak acceleration
(Vertical)

0.029

/Hz

Peak acceleration
(horizontal)

0.007

/Hz

Waveshape

Random

Application

X, Y, Z axes — 2 sweeps/axis

Refer to the following tables for operating and nonoperating shock requirements:
Table 9–11 Operating Shock Requirements (Within Specification — No Damage)
Peak acceleration

10 Gs

Duration

10 ms

Waveshape

1/2 Sine pulses

Application

X, Y, Z axes — repeat 3 times

Table 9–12 Nonoperating Shock Requirements (Unpacked — No Damage)
Bench test

Four in freefall onto a wooden surface

Technical Specifications 9–9

Technical Specifications
9.7 Electromagnetic Interference Susceptibility

9.7 Electromagnetic Interference Susceptibility
Electromagnetic interference (EMI) susceptibility includes:
•

Electromagnetic emissions

•

Conducted emissions

•

Radiated emissions

•

Magnetic radiated susceptibility

•

Radiated susceptibility

•

Conducted susceptibility

9.7.1 Electromagnetic Emissions
Electromagnetic emissions include:
CSA 108.8
EEC Directive 89/336
EN55022 and National standards are based on:
BS6527

NEN55022

Netherlands

VDE 0871 Class
B

Germany

F-Mark
Cispr22 Class B
•

FCC Rules
Part 15B

•

Class B
Certified

•

VCCI level
II

9.7.2 Conducted Emissions
Limits for Class B equipment are in the frequency range from 0.15 to 30 MHz.
Note that the limit decreases linearly with the logarithm of the frequency in the
range from 0.15 to 0.50 MHz.
Frequency Range (MHz)

Limits dB
Quasi-peak

Average

0.15 to 0.050

66 to 56*

56 to 46

0.50 to 5

5 to 30

*The limit decreases with the logarithm of the frequency.

9–10 Technical Specifications

Technical Specifications
9.7 Electromagnetic Interference Susceptibility
9.7.3 Radiated Emissions
Limits of radiated interference field strength, in the frequency range from 30
MHz to 30 GHz at a test distance of 3 and 10 meters, for Class B equipment are:
Frequency range (MHz)

Quasi-peak limit dB (µV/m)
@ 10 m

@3m

30 to 230

230 to 1000

Above 1000

9.7.4 Magnetic Radiated Susceptibility
Refer to the following table for magnetic radiated susceptibility limits:
Table 9–13 Low Frequency, Magnetic Fields, 10 to 3000 kHz
100 dB (pt) @ 10 kHz
declining to 80 dB (pt) @
1 MHz

No errors, no screen distortion

9.7.5 Radiated Susceptibility
Refer to the following table for radiated susceptibility limits:
Table 9–14 High Frequency, Electric Fields, 1 to 1000 MHz
3 V/m (rms) 80%
modulated 1 kHz

No errors, no screen distortion
SW recoverable errors
No hardware failure

Technical Specifications 9–11

Technical Specifications
9.7 Electromagnetic Interference Susceptibility
9.7.6 Conducted Susceptibility
The transient voltage is the actual peak voltage that is above the normal ac
voltage from the power source.
Refer to the following table for power and data cable voltage limits:
Table 9–15 Fast Transient (Bursts) for Power and Data Cables
2 kV

SW recoverable errors
No hardware failures

Refer to the following table for power cable voltage limits:
Table 9–16 High Energy Transient Voltage for Power Cables
1.2 kV

No errors

2.5 kV

SW recoverable errors
No hardware failure

Note
The maximum energy in a single pulse from the transient generator must
be limited to 2.5 W.

Refer to the following table for low-level conducted interference voltage limits:
Table 9–17 Low-Level Conducted Interference
3 V(rms) 80% modulated
1 kHz

No errors
SW recoverable errors
No hardware failure

9.7.7 ESD Failure Level Limits
The following table lists the ESD failure level limits for normal operator access
areas:
Table 9–18 ESD Failure Level Limits
Failure Type

Equipment

Failure Level

Allowable Errors

Hard

Office

1 to 12 kV

No operator intervention (soft
recoverable allowed)

Hardware

Office

Up to 15 kV

No component damage (soft
/hard errors allowed)

9–12 Technical Specifications

Technical Specifications
9.7 Electromagnetic Interference Susceptibility
9.7.8 Acoustic Noise Emissions
The acoustic noise emission levels are:
5.9 bels (idle mode)
6.0 bels (streaming mode)

9.8 Regulatory Requirements
Regulatory requirements include:
•

Safety

•

Electromagnetic emissions

•

Shipping
Shock
Vibration
Physical drop test

9.8.1 Safety Requirements
Safety requirements include:
UL1950 — Information Technology Including Electrical Business Equipment
CSA C22.2 #220 — Information Technology Including Electrical Business
Equipment
TUV EN50950 — Information Technology Including Electrical Business
Equipment

9.8.2 Electromagnetic Emission Requirements
Electromagnetic emission requirements include:
FCC, Part 15 Subpart J, Class B
VDE 0871 and 875, Class B

Technical Specifications 9–13

Technical Specifications
9.8 Regulatory Requirements
9.8.3 Shipping Requirements
Shipping requirements include:
Table 9–19 Shipping Requirements (Repetitive Synchronous Motion)
Impacts

14,200 total

Duration

35 min

Displacement

1/16 in

Application

Stimulate package in normal shipping position

Table 9–20 Vibration Requirements
Frequency range

5 to 300 Hz

Peak acceleration

1.19 Grms

Waveshape

Random vibration

Power spectral density

.003

Power spectral density

.02

2
2

/Hz @ 5 Hz

/Hz @ 10 Hz

Table 9–21 Physical Drop Test Requirements
Drop test distance

30 in

9.9 Drive Reliability Factors
The following tables list reliability factors:
Table 9–22 Reliability Factors
Design life

Seven years

The design life statistics provide
the point at which the statistical
failure rate begins to rise.

Head life

6000 tape motion hours
(average)

The head life may be less than
listed if alternate sources for tape
cartridges are used.

MTBF

60,000 hours

Digital Equipment Corporation
does not warrant that the predicted
MTBF is representative of any
particular unit installed for
customer use. The actual figures
will vary from unit to unit.

9–14 Technical Specifications

Index
A
Acoustic noise emissions, 9–13
Altitude
environmental specifications, 9–8
Automatic mode, 5–2

B
BACKUP command
Automatic mode, 5–2

C
Cartridge
inserting into magazine, 5–7
loading, 5–6
unloading, 5–6
write-protect switch, 5–7
Cartridge insert/release handle, 4–6
CompacTape III, 4–7
Conducted emissions, 9–10
Conducted susceptibility, 9–12
Configuration, 3–1

D
Description
figures of THZ02 tape drive, 9–1
Design life, 9–14
Drive reliability, 9–14
Drive reliability factors, 9–14
Drive timing characteristics
Drive performance specifications, 9–5

E
Eject button, 5–5
cartridge in drive, 5–6
no cartridge in drive, 5–6
unload function, 5–4
Electromagnetic emission requirements, 9–13
Electromagnetic emissions, 9–10
Electromagnetic interference (EMI), 9–10
EMI
electromagnetic interference, 9–10

Environmental specifications, 9–7
ESD failure level limits, 9–12

F
Failure level limits
ESD, 9–12
Fast transient voltage
data cables, 9–12
power cables, 9–12
Front panel controls, 4–2
Front panel figure, 9–1
Front panel indicators, 4–2
Front panel view, 9–1

H
High energy transient voltage
power cables, 9–12
Humidity
Environmental specifications, 9–7

I
Installation, 3–1
Isometric view, 9–4

L
Loader timing characteristics
Loader performance specifications, 9–6
Loading tape, 4–8
Load/Unload button, 5–5
reset function, 5–4
Low-level conducted interference, 9–12

M
Magazine, 5–7
removing from receiver, 5–10
restoration into receiver, 5–10
Magnetic radiated susceptibility, 9–11
Manual mode, 5–2
Mode Select key
Automatic mode, 5–2
description, 5–2
Manual mode, 5–2
mode definitions, 5–2

Index–1

Mode Select key (cont’d)
OCP Disabled mode, 5–2
Service mode, 5–4

N
Nominal tape tension
performance specifications, 9–5

O
OCP Disabled mode, 5–2
Operating modes, 5–2
Operating procedure
THZ02 tape drive, 4–1
THZ27 tape drive, 5–1

Side view, 9–3
Slot Select button, 5–5
operation, 5–5
Steps for loading tape, 4–8
Steps for unloading the tape, 4–9
Storage ranges
environmental specifications, 9–8

T
Technical specifications
THZ02 tape drive, 9–1
Temperature
Environmental specifications, 9–7
THZ02
installing, 3–1
Top view, 9–2

P
Performance specification
THZ02 tape drive, 9–5
Physical dimensions
THZ02 tape drive, 9–5
Physical drop test
shipping requirements, 9–14
POST, 4–1, 5–1
Power requirements
THZ02, 9–6
Power-on, 5–1
Power-on range
environmental specifications, 9–7
Power-on self-test, 4–1
status of OCP indicators, 5–1

R
Radiated emissions, 9–11
Radiated susceptibility, 9–11
Receiver, 5–10
Regulatory requirements, 9–13
Reset
Load/Unload button, 5–4

S
Safety requirements, 9–13
SCSI ID, 3–1
SCSI switch settings, 3–1
Service mode
unlocking the THZ27 subsystem, 5–4
Shipment ranges
environmental specifications, 9–8
Shipping requirements, 9–14
Shock
shipping requirements, 9–14
Shock requirements
environmental requirements, 9–9

Index–2

U
Unload button, 4–5
Unloading the tape, 4–9

V
Vibration
shipping requirements, 9–14
Vibration and shock requirements
environmental specifications, 9–9

W
Write-protect switch, 4–7, 5–7