HP C737990900 User Manual
the SCSI
interface
hp ultrium drives
technical reference manual
generation 2 SCSI and FC drives
volume 3: the SCSI interface
Part Number: C7379–90900 Volume 3
Edition 4, February 2003
Notice
The information contained in this
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without notice.
Hewlett-Packard makes no
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© Copyright 2000–2003 by
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Revision History
Version Date Changes
Edition 1 Nov. 2000 All
Edition 2 Mar. 2001 Addition of Read and Write attribute commands and Drive Error Codes
Edition 3 May 2002 Inclusion of the Request Block Address command and the Control mode
page, together with numerous small changes
Edition 4 Feb 2003 Generation 2 SCSI and FC drive version
This document is frequently revised and updated. To find out if there is a
later version, please ask your HP OEM Representative.
2
The Purpose of this Manual
This is one of five volumes that document HP Ultrium drives. This volume
provides background information for driver and application developers. The
following products are covered. Capacities are when the drive is using data
compression with a compression ratio of 2:1, where applicable:
■ HP Ultrium Generation 2 Full-Height SCSI Internal Drive
■ HP Ultrium Generation 2 Full Height FC Internal Drive
Note Throughout this manual frequent reference is made to SCSI
commands. For more information on SCSI commands for
HP Ultrium drives see volume 3, the SCSI Interface, of the
HP Ultrium Technical Reference Manual. Ordering details are
given below.
Related Documents
The following documents provide additional information:
Document s S p ecific to HP Ultrium Drives
■ Hardware Integratio n G u id e, volume 1 of the HP Ultrium Technical
Reference Manual
■ The SCSI Interface, volume 3 of the HP Ultrium Technical Reference
Manual
■ Specifications, volume 4 of the HP Ultrium Technical Reference Manual
■ HP Ultrium Configuration Guide, volume 5 of the HPUltrium Technical
Reference Manual
■ Background to Ultrium Drives, volume 6 of the HP Ultrium Technical
Reference Manual
Please contact your HP supplier for copies.
■ The features and benefits of HP Ultrium drives are discussed in the
HP Ultrium Technology White Paper.
■ For a general backgrounder on LTO technology and licensing, go to
http://www.lto-tec hnolog y.com .
3
Documentation Map
The following will help you locate information in the 6-volume Technical
Reference Manual:
Drives—general
Connectors 1 HW Integration : ch. 7 1 HW Integration: ch. 4
Controller architecture
Front Panel LEDs 1 HW Integration : ch. 6 1 HW Integration: ch. 3
Mechanism and hardware 6 Background: ch. 3
Specifications
Installation and Configuration
Connectors 1 HW Integration: ch. 7 1 HW Integration: ch. 4
Determining the configuration
External drives (SCSI only) 1 HW Integration: ch. 5n/a
In Libraries 1 HW Integration: ch. 1
In Servers (SCSI only) 1 HW Integration: ch. 4n/a
In Tape Arrays (SCSI only)
Modes of Usage (SCSI only) 1 HW Integration: ch. 8n/a
Optimizing performance (SCSI only) 1 HW Integration: ch. 8n/a
UNIX configuration 5 UNIX Confi g
SCSI Drives FC Drives
6 Background: ch. 4
4 Specs
SCSI Drives FC Drives
2 SW Integration: ch. 2 2 SW Integration: ch. 2
1 HW Integration: ch. 3n/a
2 SW Integration: ch. 4
Operation
SCSI Drives FC Drives
External drives (SCSI only) 1 HW Integration: ch. 5n/a
In Libraries 1 HW Integration: ch. 1
In Servers (SCSI only) 1 HW Integration: ch. 4n/a
In Tape Arrays (SCSI only)
4
1 HW Integration: ch. 3n/a
Cartridges
SCSI Drives FC Drives
Cartridge Memory (LTO-CM) 2 SW Integration: ch. 5
6 HW Integration: ch. 5
Cartridges 1 HW Integration: ch. 9 1 HW Integrati on: ch. 5
Features
Managing the use of cartridges 2 SW Integration: ch. 1
Use of cartridges 2 SW Integration: ch. 3
6 HW Integration: ch. 5
Interface
SCSI Drives FC Drives
SCSI Guide 3 SCSI
Commands
Error codes 1 HW Integration: ch. 10 1 HW Integ r ation: ch. 6
Implementation 3 SCSI: ch. 1
Interpreting sense data
Messages 3 SCSI: ch. 2
Mode pages
—see the MODE SENSE comma nd
Pre-execution checks
Responding to Sense Keys and ASC/Q 2 SW Integration: ch. 6
Sense Keys and ASC/Q
—see REQUEST SENSE command
3 SCSI: ch. 4
2 SW Integration: ch. 3
3 SCSI: ch. 4
3 SCSI: ch. 3
3 SCSI: ch. 4
Maintenance and Troubleshooting
SCSI Drives FC Drives
Cleaning 2 SW Integration: ch. 5
2 SW Integration: ch. 7
External drives (SCSI only) 1 HW Integration: ch. 5n/a
In Libraries 1 HW Integration: ch. 1
In Servers (SCSI only)
In Tape Arrays (SCSI only) 1 HW Integration: ch. 3n/a
Monitoring drive and tape condition 2 SW Inte gration: ch. 7
Software troubleshooting techniques
1 HW Integration: ch. 4n/a
2 SW Integration: ch. 1
5
Dealing with Errors
SCSI Drives FC Drives
Error Codes 1 HW Integration: ch. 10 1 HW Integ r ation: ch. 6
Handling errors 2 SW Integration: ch. 5
How error correction works 6 Background: ch. 4
Logs—see the LOG SENSE command
Recovering from write and read errors 2 SW Integration: ch. 7
Software response to error correction 2 SW Integration: ch. 3
Software response to logs
TapeAle rt l og 2 SW Integration: ch. 7
3 SCSI: ch. 4
2 SW Integration: ch. 3
Ultrium Features
SCSI Drives FC Drives
Adaptive Tape Speed (ATS) 6 Background: ch. 1
Autoload 1 HW Integration: ch. 2
Automation Control Interface (ACI) 1 HW Integration: ch. 2
6 Background: ch. 1
Cartridge Memo ry (L TO -CM)s 1 HW Integration: ch. 2
2 SW Integration: ch. 5
6 HW Integration: ch. 5
Data Compression, how it works
Data Compression, managing 2 SW Integration: ch. 5
Design principles 6 Background: ch. 1
OBDR and CD-ROM emulation
Performance optimization 1 HW Integration: ch. 8n/a
Performance, factors affecting 2 SW Integration: ch. 4
Software design 2 SW Integration: ch. 1
Supporting Ultrium features
Ultrium Format 6 Background: ch. 2
6 Background: ch. 5
6 Background: ch. 1
2 SW Integration: ch. 7
2 SW Integration: ch. 1
2 SW Integration: ch. 5
6
General Documents and Standardization
■ Small Computer System Interface (SCSI-1), ANS I X3 .131-1986. This is the
ANSI authorized standard for SCSI implementation, available through
ANSI
■ Enhanced Small Computer System Interface (SCSI-2), ANSI X3T9.2-1993
Rev. 10L, available through ANSI
Copies of General Documents can be obtained from:
ANSI
11 West 42nd Street
New York, NY 10036-8002
USA
ISO
CP 56
CH-1211 Geneva 20
Switzerland
ECMA
Global Engineering Documents
114 Rue du Rhône
CH-1204 Geneva
Switzerland
2805 McGaw
Irvine, CA 92714
USA
Tel: +41 22 849 6000
Web URL:
http://www.ecma.c h
Tel: 800 854 7179 or 714 261 1455
7
8
The Purpose of this Manual 3
Related Documents 3
Documents Specific to HP Ultrium Drives 3
Documentation Map 4
General Documents and Standardization 7
1 Interface Implementation 13
The SCSI Interface 13
Supported Messages 14
Supported Commands 14
SCSI Features 15
Design Approach 15
Power-On 15
Reset Strategy 15
Abort Handling 16
Bus Parity Errors (Parallel SCSI only) 18
Disconnect Strategy (Parallel SCSI only) 19
Multi-Initiator Support 19
Fibre Channel Operation 20
Fibre Channel Addressing 20
Names 20
Addresses 21
HP’s Implementation of Names and Addresses 21
Implications for Libraries 22
Field Replaceable Units 23
Descriptions of Signals (Parallel SCSI only) 23
contents
Contents
Contents 9
2 Messages 25
Message Out Support (Parallel SCSI only) 25
Message In Support (Parallel SCSI only) 26
Extended Message Support 27
Status 29
3 Commands—Introduction 31
Summary 31
Command Details 32
Pre-Execution Checks 32
Bad LUN Check 32
Deferred Error Check 33
Diagnostic Status Check 33
Fixed Bit Check 34
Flag Link Check 34
Illegal Command Check 34
Illegal Field/Request Check 34
Media Access Check 35
Media Information Check 36
Media Write Check 37
Parameter List Check 37
Reservation Check 37
Unit Attention Check 38
Command Descriptor Block 38
10 Contents
4 Commands 41
ERASE 19h 42
INQUIRY 12h 44
INQUIRY Data Pages 45
Vital Product Data Pages 49
Supported Vital Product Data Pages Page 49
Unit Serial Number Page 50
Device Identification Page 51
Defined Identifiers 52
Drive Component Revision Levels Pages 53
LOAD/UNLOAD 1Bh 55
LOCATE 2Bh 58
LOG SELECT 4Ch 60
LOG SENSE 4Dh 62
Log Page Format 63
Supported Log Pages Page 64
Write Error Counters Log Page 65
Read Error Counters Log Page 66
Sequential Access Device Log Page 66
TapeAlert Log Page 67
Tape Usage Log Page 69
Tape Capacity Log Page 69
Data Compression Log Page 70
Performance Data Log Page 70
MODE SELECT 15h/55h 72
Mode Parameter Pages 74
Mode Page Representation 74
Mode Data Format 74
Mode Block Descriptor 77
Read-Write Error Recovery Mode Page 78
Disconnect-Reconnect Page 79
SCSI Drives 79
FC Drives 80
Control Mode Page 81
Data Compression Characteristics Page 82
Device Configuration Page 83
Medium Partitions Mode Page 85
Fibre Channel Logical Unit Control Mode Page 86
Fibre Channel Port Control Mode Page 87
Information Exceptions Mode Page 89
MODE SENSE 1Ah/5Ah 91
PREVENT/ALLOW MEDIUM REMOVAL 1Eh 94
READ 08h 95
READ ATTRIBUTE 8Ch 99
MAM Attribute Data 103
Attribute ID Values 104
Device Common Attributes 104
Medium Common Attributes 106
Contents
Contents 11
Host Common Attributes 107
READ BLOCK LIMITS 05h 110
READ BUFFER 3C h 111
READ POSITION 34h 115
RECEIVE DIAGNOSTICS RESULTS 1Ch 119
RELEASE UNIT 17h/57h 121
REPORT DENSITY SUPPORT 44h 123
REPORT LUNS A0h 126
REQUEST SENSE 03h 128
Request Sense Data 129
Sense Data Management 131
Current Sense 132
UNIT ATTENTION Sense 132
DEFERRED ERROR Sense 133
Sense Keys 135
Additional Sense Codes 136
Error Codes 140
RESERVE UNIT 16h/56h 141
REWIND 01h 144
SEND DIAGNOSTIC 1Dh 145
Standard Self-Test 147
SPACE 11h 148
TEST UNIT READY 00h 151
VERIFY 13h 152
WRITE 0Ah 154
WRITE ATTRIBUTE 8Dh 157
WRITE BUFFER 3Bh 160
WRITE FILEMARKS 10h 164
12 Contents
Glossary 165
Index 169
Interface Implementation
HP Ultrium drives use SCSI-3 as the interface to connect to the host system.
This chapter gives an overview of how the interface operates.
Full details of the messages are given in Chapter 2 and of commands in
Chapter 3 and Chapter 4.
The SCSI Interface
The Small Computer Sy stem Interf ace (SCS I) is an industry standard , a ppr o v ed
by the American National Standards Institute (ANSI). You are recommended
to read the ANSI standard document in conjunction with this manual. The
ANSI specification defines the interface in general while this document
describes the HP Ultrium implementation.
The SCSI implementation provides a drive with a standard set of features and
functions. These include the following:
■ Synchronous data transfers
1
■ Asynchronous data transfers
■ Implementation of all mandatory and most optional commands of the
Sequential Access command set
■ LVD (Low-Voltage differential) SCSI connection
■ Ultra3 wide SCSI
■ Conformance to the following SCSI standards:
— SAM-2 T10/1157-D rev.23
— SPI-3 ANSI NCITS.336:2000
— SPC-2 ANSI NCITS.351:2001
— SSC ANSI NCITS.335:2000
Interface Implem en ta tion 13
Supported Messages
The following messages are supported by the drives:
■ ABORT
■ BUS DEVICE RESET
■ COMMAND COMPLETE
■ DISCONNECT
■ IDENTIFY
■ IGNORE WIDE RESIDUE
■ INITIATOR DETECTED ERROR
■ MESSAGE PARITY ERROR
■ MESSAGE REJECT
■ NO-OP
■ RESTORE POINTERS
■ SAVE DATA POINTER
■ Extended Message: PARALLEL PRO TOCOL REQUEST
■
■
For implementation details on these messages, see Chapter 2, “Messages”
(no operation)
Extended Message: S YNCHRONOUS DATA TRANSFER REQUEST
Extended Message: WIDE DATA TRANSFER REQUEST
Supported Commands
The following commands are supported by the drives. They include all
Mandatory and Extended commands and most Optional commands.
19h
12h
1Bh
2Bh
4Ch
4Dh
15h/55h
1Ah/5Ah
1Eh
08h
05h
14 Interface Implementation
ERASE
INQUIRY
LOAD/UNLOAD
LOCATE
LOG SELECT
LOG SENSE
MODE SELECT
MODE SENSE
PREVENT/ALLOW MEDIUM REMOVAL
READ
READ BLOCK LIMITS
57h/17h
03h
44h
A0h
56h/16h
01h
1Dh
11h
00h
13h
0Ah
RELEASE UNIT
REQUEST SENS E
REPORT DENSITY SUPPORT
REPORT LUNS
RESERVE UNIT
REWIND
SEND DIAGNOSTIC
SPACE
TEST UNIT READY
VERIFY
WRITE
3Ch
34h
1Ch
READ BUFFER
READ POSITION
RECEIVE DIAGNOSTIC RESULTS
SCSI Features
Design Approach
Power-On
WRITE BUFFER
3Bh
WRITE FILEMARKS
10h
For implementation details on these commands, see Chapter 3, “Commands—
Introduction” and Chapter 4, “Commands”.
The features supported by the drive are based on standards, both official and
de facto. The dr iv e is fully compliant w ith the SC SI-3 specif ication and supports
all features required by that standard. However, since most tape drive support
software has been written using the SCSI-2 standard, this document is based
on SCSI- 2 and uses SCSI-2 terminology. Since SCSI-2 is virtually a compliant
subset of SCSI-3, this is not inconsistent. However, where SCSI-3 makes an
option in SCSI-2 a requirement, the SCSI-3 requirement is always used. Also,
all required SCSI-3 extensions are supported by the drive.
Interface Implementation
Reset Strategy
Soft Resets On receiv ing a r e set through the Host Interf ace (S CS I or FC), the Host Interfac e
The drive will respond to TEST UNIT READY, INQUIRY, REPORT LUNS and
REQUEST SENSE commands within 5 seconds of power on. The first command
other than Inquiry or Request Sense from any initiator will get a
CONDITION
this, any medium access command will be reported with a sense key of
READY
Medium access commands will be reported with additional sense of 0401h
(drive in process of becoming ready).
is returned to a known base state. If the reset command is received over the
Automation Controller Interface serial port, the SCSI and ACI interfaces are
returned to known bas e states . The baud r at e fo r the port will be r eturned to its
status with UNIT ATTENTION sense data for the power on. After
and additional sense of 3E00h (LUN has not self-configured yet).
Interface Implem en ta tion 15
CHECK
NOT
default setting. The know n base s tate is def ined in the S CS I-3 specifi cation and
includes the following:
■ The current I/O process is aborted.
■ Any queued I/O processes from other initiators are removed.
■ All reservations are cleared.
■ All mode values are reset to their defaults.
■ Synchronous/Wide negotiations are cleared (SCSI drives only).
■ A UNIT ATTENTION condition is set.
■ Any buffered writes are flushed to tape.
■ The logical position is undefined.
Hard Resets The Reset button on the front panel and the ACI_RESET_L line on the
Abort Handling
The drive will be able to respond to
SENSE
and REPORT LUNS within 250 ms of the reset line being released. The
first command other than these from any initiator will get a
CONDITION
status with UNIT ATTENTION sense data for the reset. However,
TEST UNIT RE ADY, INQUIRY, REQUEST
CHECK
other commands may not be processed until the internal state of the drive has
been reset. Any commands which cannot be processed will be accepted and
queued until the drive is ready to process them.
Automation Controller Interface are both connected to the Power-Up Reset
interrupt on the processor. The effect is equivalent to power-cycling the drive.
The contents of the tape and cartridge memory may not be consistent after the
action and any data in the drive buffer will be lost.
If an abort condition is detected before a command phase completes, the bus
is set to bus free and the command is not executed.
If an abort condition is detected between the end of the command phase and
the start of the status phase, then the bus is set to bus free and the processing
below is carried out.
If an abort condition is detected during status phase, the bus is set to bus free.
If a command, other than
TEST UNIT READY, INQUIRY and REQUEST SENSE, is
received after the abort but before the drive is ready to process the command,
the drive will disconnect and wait until the abort processing has completed
before executing the command. A
TEST UNIT READY command will report with
16 Interface Implementation
GOOD status immediately. A REQUEST SENSE command will give NO SENSE.
An
INQUIRY command will return the required data and give GOOD status.
Command Abort Processing
ERASE
INQUIRY
LOAD/UNLOAD
LOCATE
LOG SEL ECT
LOG SENSE
MODE SELECT
MODE SENSE
PREVENT/ALLOW
MEDIUM REMOVAL
READ
Long erase is aborted as quickly as possible without corrupting tape format.
Short erase completes.
None
Load completes and logically positions tape at BOT. Unload is aborted
leaving logical position at BOT unless operation is past the “point of no
return” in which case the tape is ejected.
The logical position is set back to that at the start of the operation unless the
operation is past its “point of no return”, in which case the operation
completes.
If data transfer is complete, command is completed, otherwise, no action is
taken
None
If data transfer is complete, command is completed, otherwise, no action is
taken.
None
The command completes.
The current position is set to the first record boundary at or after the start of
the current data burst.
Interface Implementation
READ BLOCK LIMITS
READ BUFFER
READ POSITION
RECEIVE DIAGNOSTICS
RESULTS
RELEASE UNIT
REQUEST SENSE
None
None
None
None
The command completes.
None
Interface Implem en ta tion 17
Command Abort Processing
RESERVE UNIT
REWIND
SEND DIAGNOST IC
SPACE
The command completes.
The command completes.
Vendor Unique
The logical position is set back to that at the start of the operation unless the
operation has passed its “point of no return”, in which case the operation
completes.
TEST UNIT READY
WRITE
None
The data up to first record boundary in the current burst is written to tape.
Any subsequent data is discarded. If there is no record boundary in the
current burst, the record is truncated to the amount of data transferred and
written to tape.
WRITE BUFFER
If data transfer is complete, command is completed, otherwise, no action is
taken.
WRITE FILEMARKS
VERIFY
The command completes.
The logical position is set to the next record boundary after the point where
the verify was aborted.
Bus Pari ty Errors (Parallel SCSI only)
On detecting a bus parity error during a Command or Data Out phase or
receiv ing an Initiator det ected er r or mess age during a Dat a In or S tatus phase ,
the drive attempts t o r e try the bus phase. A Restor e Poin t er s me ssage is sen t t o
the initiator and the transfer is repeated. Only one retry is attempted. If the
retry fails or the restore pointers message is rejected, then the drive goes to
status phase and attempts to report
an initiator detected error message, t he dri ve goes t o bus fr ee . Th e sense ke y is
set to
error) or 4B00h (data phase error).
If an Initiator Detected Error or Message Parity Error message is received
during Message In phase, the initiator has detected an error in the message.
The dri v e will go to Messag e In and r esen d the mess age tha t was in err o r . If the
subsequent message is rejected with an Initiator Detected Error, then the drive
goes to Status phase and sends
18 Interface Implementation
CHECK CONDI T ION st atu s. If this f ails with
ABORTE D C O MMA ND w ith additional sense of 4A00h (command phase
CHECK CONDITION status. The sense k ey is set
to ABORTED COMMAND with additional sense of 4800h (Initiator Detected
Error).
If the subsequent message is rejected with an Message Parity Error, then the
driv e goes to Status phase and sends
is set to
ABORTED COMMAND with additional sense of 4300h (message
error).
On detecting a bus parity error during a Message Out phase, the drive will
handshake in all message bytes until ATN is deasserted. It will then stay in
Message Out phase to indicate to the initiator that the whole Message Out
phase should be resent.
Disconnect Strategy (Parallel SCSI only)
The disconnect strategy used by the drive is based on the assumption of
maximizing bus utiliz atio n for large sequen tial data transf ers fr om a large data
buffer. The drive will disconnect whenever it believes that it will provide better
bus utilization. This may be between command and data phases, between
bursts of data or before sending status. However, the drive will guarantee that
it will send the configured maximum burst size or the remaining data in the
transfer in any single data phase burst if the max imum burst size has been set
to a value other than zero.
Multi-Ini t iator Support
CHECK CONDITION status. The sense key
Interface Implementation
All drives will support at least two initiators on the same bus. If more initiators
are supported, all features are supported for the supported number of
initiators.
The drive supports untagged queueing when operating with multiple initiators.
If a command from one initiator is being processed when a command, other
than
TEST UNIT READY, INQUIRY, REPORT LUNS and REQUEST SENSE, is
received from a second initiator, then the drive will disconnect and the new
command is queued. Commands other than
these from different initiators are
always executed in strict order of receipt. If the queue is full or disconnect
privilege is not granted in the new command, the drive will report
T
EST UNIT READY, INQUIRY, REPORT L UNS an d RE Q UE S T SENSE co mmand s ar e
BUSY status.
always processed immediately, irrespective of whether a command from
another initiator is being processed.
The drive will maintain sense data for the supported number of initiato r s. If an
additional initiator connects to the drive, the drive will erase all sense data for
Interface Implem en ta tion 19
the initiator that least recently connected before processing the command for
the new initiator. See “Sense Data Management” on page 131 for more
details.
Fibre Channel Operation
Note This applies only to Fibre Channel drives.
The following sections have information specific to Fibre Channel operation:
■ “Fibre Channel Logical Unit Control Mode Page” on page 86
■ “Fibre Channel Port Control Mode Page” on page 87
■ “Vital Product Data Pages” on page 49
Fibre Channel Addressing
Before describing HP’s implementation of Fibre Channel addressing, the
concepts of Names and Addresses need to be clarified.
Names
Names are 64-bit identifiers assigned permanently to the tape drive during
manufacture. They are commonly referred to as World Wide Names since they
must be guaranteed unique. The names are typically used for identifying the
device to operating systems, since addresses are assigned dynamically. There
at least eight different name formats distinguished by the Network Address
Authority (NAA). Only one is used on HP Ultrium drives. This is the IEEE
Registered Name (NNA=5) and has the following format:
This name is made up of three fields:
■ NAA Identifier (4 bits). “5” indicates a IEEE Registered Name.
■ IEEE Company ID (24 bits). Assigned by IEEE to the company.
■ Vendor Specified ID (36 bits). Assigned by the company.
20 Interface Implementation
Addresses
Each Fibre Channel port also has a Port Address which is assigned during
loop initialization and/or Fabric Login. This is a 24-bit value in the following
format:
The AL_PA is the Arbitrated Loop Physical Address. This is normally assigned
dynamically during loop initialization.
If the loop is not attached to a fabric (in other words, when it is private,) the top
two bytes will be zero. If the loop is attached to a fabric, the tape drive is
assigned the top two bytes when it logs into the fabric.
Together, the three bytes pr o vi de a unique addres s on the F ibr e Channel f abr ic
that is used for frame addressing. It forms the equivalent of the Target ID or
Initiator ID in SCSI.
HP’s Implementation of Names and Addresses
The HP implementation uses three adjacent IEEE Registered Names:
■ The first (last bits = 00) is used as the Port A World Wide Name.
■ The second (last bits = 01) is used as the Port B World Wide Name.
Interface Implementation
■ The third name (last bits = 10) is used for the Device World Wide Name.
(These are assigned during manufacture from HP’s pool of names, although
only the first will actually be stored in the drive NV-RAM).
The port addresses will be assigned using the ‘standard’ AL_PA initialization
mechanisms. The ‘Fibre Channel Port Control mode page’ controls this. The
drive has the ability to support hard addresses as part of this scheme.
Interface Implem en ta tion 21
The values of the names can be obtained using the Device Identification Vital
Product Information Page (part of the
INQUIRY command).
Implications for Libraries
■ Normally a standalone drive will operate using its own ‘hard’ names.
■ The drive kno ws it is in a library or other ‘managed’ environment since one
of the signal lines on the ACI (Automation Control Interface) will be tied
down.
In this case, the dr iv e wi ll not go on the FC loop until it is t old to . The libr ary
can optionally download a new, soft base name (Port A/Device Name)
into the drive at this point. The drive will then use this as the origin of its
names. The library manufacturer would be responsible for obtaining this
IEEE Registered Name. It would be a property of the library, not the drive.
■ If the library wants to ‘warm swap’ drives, it can. It just ‘turns off’ the drive
with the soft name using the ACI and then turns on the spare drive,
downloading the same name to it.
■ If a drive is r emo ved f rom th e library, it will not have the ACI signal tied low
and so will re v ert to its or iginal h ard name . It should f or get the s oft name in
this case.
■ If the library controller breaks, the drive will time out the ACI interface in
~10 seconds. The drive still knows it is in a library since the ACI signal is
22 Interface Implementation
still tied low, so in this case it will use the soft name last downloaded. This
will allow drive access without confusing the host.
Field Replaceable Units
An FRU code identifies which part of the hardware is considered to have
failed. These codes turn up in sense data byte 14 and as the sense code
qualifier for sense codes 4400h (internal target failure) and 40XX (diagnostic
failure).
Althoug h the r e are no actual Field Replaceable Units on HP Ultrium dri ves, the
following sub-assemblies can be replaced at Repair Centres:
■ Drive PCA ■ Head Assembly
■ Mechanism ■ Front Panel
Descriptions of Signals (Parallel SCSI only)
The SCSI interface consists of 2 7 signals—9 contr ol lines, 16 data lines and 2
parity lines. A description of these signals is given in the following table.
Interface Implementation
Signal Name Driven by Description
-BSY
-SEL
-C/D
-I/O
Busy — OR-tied signal used to indicate that the SCSI bus is in use.
Select Initiator
Target
Control/Data Target Indicates whether control or data information is on the data
Input/Output Target Controls the direction of data movement on the bus with
Used to select a target during the Selection phase.
Used to select an initiator during the Reselection phase.
bus.
True (low) Control information
False (high) Data information
respect to the Initiator. This signal is also used to distinguish
between Selection and Reselection phases.
Interface Implementation 23
Signal Name Driven by Description
True (low) Input to the initiator
False (high) Output from the initiator
-MSG
Message Target Indicates a Message phase on the bus.
True (low) Message phase
False (high) Command, Data or Status phases
-REQ
-ACK
Request Target Indicates a request for a REQ/ACK data transfer handshake.
Acknowledge Initiator Indicates an acknowledgment for a REQ/ACK data transfer
handshake.
-ATN
Attention Initiator Indicates that the initiator has a message to send to the
target.
-RST
Reset — OR-tied signal that is used to indicate a Reset condition.
DB(15-0) Data Bus — 16 data-bit signals that, with the parity-bit signal, form the
data bus. DB15 is the most significant bit , and has the highest
priority during the Arbitration phase.
DB(P1-P0) Data Bus — Data parity bits that ar e s et t o odd, but are jumper-selectable
options. There are two discrete parity bits, one for the lower 8
data bits, the other for the upper 8 bits. Parity is not valid
during the Arbitration phase.
24 Interface Implementation
Messages
2
This chapter includes all SCSI messages, both supported and unsupported.
Parts of this chapter come from Section 5, Logical Characteristics, of the SCSI
standards (see page 13).
The message system provides an initiator and a target on the SCSI bus with a
means of managing communication. The available messages are listed in this
chapter.
Message Out Support (Parallel SCSI only)
Name Code Support
Abort 06h An abort condition is generated (see “Abort Handling” on page 16).
Bus Device Reset 0Ch A reset condition is generated (see “Reset Strategy” on page 15).
Extended Message 01h See “Extended Message Support” below.
Identify 80h+ The Identify Out message is sent by the initiator to identify the Logical Unit
to be accessed and to set Disconnect Privilege.
Initiator Detected
Error
05h The initiator has detected an error in the data being sent in a Command,
Data or Status phase. The drive will send a restore data pointers message
to retry the data transfer. (See “Message In Support (Parallel SCSI only)”
below for details).
If the message is received immediately after an Identify message or after
the Command Complete message has been sent, the drive will go Bus
Free.
Messages 25
Name Code Support
Message Parity
Error
Message Reject 07h This message is sent when the initiator does not support a message sent b y
No Operation 08h This message has no effect and is ignored.
09h The initiator has detected a parity error in a message. The drive will retry
the message. (See ““Message In Support (Parallel SCSI only)” below for
details).
If the message is received immediately after an Identify message or after
the Command Complete message has been sent, the drive will go Bus
Free.
the drive or that the message is inappropriate. If the message being
rejected is Disconnect, Synchronous Data Transfer Request or Wide Data
Transfer Request, the operation continues without those features. For all
other messages, the message is treated as an Abort message.
If the message is received during a Command, Data or Status phase,
immediately after an Identify message or after the Command Complete
message has been sent, the drive will go Bus Free.
Message In Support (Parallel SCSI only)
Name Code Support
Command Complete 00h This message is sent by the drive at the end of the status phase to
indicate that a command is complete. Once the message is sent, the
drive releases the bus and goes to Bus Free.
Disconnect 04h This message is sent by the driv e to indicate that it is about to disconnect
from the bus and go to Bus Free. During a Data phase, it is always preceded by a Save Data P o inter s message. If a Message Rej ect message is
received in response to this message, then the disconnect is prevented.
Extended Message 01h See “Extended Message Support” below.
Identify 8Xh The Identify In message is sent to the initiator during reconnect to
indicate which Logical Unit is reconnecting.
26 Messages
Name Code Support
Ignore Wide
Residue
23h This message is sent by the drive to the host to indicate that a byte on a
wide bus is not valid.
This is supported whenever a wide transfer is acti ve. It should be sent at
the end of the data phase. The standard action of the drive is to send
this message between the data phase and the status phase with no
disconnect.
Message Reject 07h This message is sent to the initiator when the message received by the
drive is unsupported or inappropriate.
Restore Pointers 03h This message causes the initiator to reset its data transfer pointers to the
values they held when the last save data pointers message was sent. It
will be sent when a parity error is detected on the bus or when an
Initiator Detected Error message is received in order to retry the data
phase.
Save Data Pointers 02h This message instructs the initiator to save its current data transfer
pointers for use with a subsequent Restore pointers message. This
message will always be sent before a Disconnect message during data
phases.
Extended Message Support
Name Code Support
Messages
Synchronous Data
Transfer Request
01h The drive will never initiate a Synchronous data transfer negotiation, but
will expect the initiator to do so.
If the message is received after selection and befor e the command phase,
it will then go to message-in phase and respond with a valid r esponse to
complete the negotiation.
Wide Data Transfer 03h The drive will never initiate a Wide data transfer negotiation but will
expect the initiator to do so.
If the message is received after selection and befor e the command phase,
it will then go to message-in phase and respond with a valid r esponse to
complete the negotiation.
Note that SDTR negotiated parameter s will become asynchr onou s after a
WDTR.
Messages 27
Name Code Support
Parallel Protocol
Request
04h The drive will never initiate a Parallel Protocol Request transfer
negotiation but will expect the initiator to do so.
If the message is received after selection and befor e the command phase,
it will then go to message-in phase and respond with a valid r esponse to
complete the negotiation.
Synchronous Data Transfer Request
7 6 5 4 3 2 1 0
0
1
2
3
4
Extended Message (01h)
Extended Message Length (03h)
SDTR (01h)
Transfer Period Factor
Req/Ack Offset
Wide Data Transfer Request
7 6 5 4 3 2 1 0
0
1
2
3
Extended Message (01h)
Extended Message Length (02h)
WDTR (01h)
Transfer Width Exponent
28 Messages
Parallel Protocol Request
7 6 5 4 3 2 1 0
0
1
2
3
4
Extended Message (01h)
Extended Message Length (06h)
Parallel Protocol Request (04h)
Transfer Period Factor
Reserved (0)
7 6 5 4 3 2 1 0
5
6
7
Reserved (0) QAS_Req DT_Req IU_Req
Req/Ack Offset
Transfer Width Exponent
Fields:
Transfer Period
Factor
09h Transfer period of 12.5s (FAST-80). Only valid when DT transfers have been
requested
0Ch Transfer period of 50s (FAST-20) — LVD/SE drives only
19h Transfer period of 100s (FAST-10)
32h Transfer period of 200s (FAST-5)
Req/Ack Offset This has a maximum value of 255.
Transfer Width
Exponent
For ST transfers, this can be either 0 (Narrow) or 1 (Wide).
For DT transfers, it must be set to 1.
QAS_Req 0 This bit will be ignored and the drive will always return zero.
DT_Req This bit determines whether DT mode has been requested, in other words, packetized
data transfers.
IU-Req 0 This bit will be ignored and the drive will always return zero.
Status
A Status byte is sent from the drive to the host during the Status phase at the
end of each command as specified in the SCSI specification, unless the
command has been cleared by an
message, or by a hard reset.
ABORT message, by a BUS DEVICE RESET
Messages
The Status bytes that the drive returns are as follows:
00h GOOD: This status indicates that the drive has successfully completed the command.
02h CHECK CONDITION: Any er r o r, exception, or abnor mal condition that causes sense data
to be set returns
CHECK CONDITION. The REQUEST SENSE command should be sent
following this status to determine the nature of the error.
04h CONDITION MET: This status will never be returned by an HP Ultrium tape drive.
Messages 29
08h BUSY: The drive is unable to execute the command at this time. Try again later. The drive
tries to avoid using this status code during normal operation. It can sometimes be used
after commands have been aborted, during power-on and if there are multiple selecting
initiators.
10h INTERMEDIATE: This status will never be returned by an HP Ultrium tape drive.
14h INTERMEDIATE CND: This status will never be returned by an HP Ultrium tape drive.
18h RESERVATION CONFLICT: Returned if the drive is reserved by another party. See the
Reservation check.
22h COMAND TERMINATED: This status will never be returned by an HP Ultrium tape drive.
28h QUEUE FULL: This status can be returned by an HP Ultrium FC drive but will never be
returned by a SCSI tape drive.
30 Messages
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