Quantum 816022001A02SCSI User Manual

ATL SuperLoader™ DLT and ATL

SuperLoader™ LTO

Software Interface

Guide

81-60220-01 A02

Quantum ATL SuperLoader DLT and ATL SuperLoader LTO Software Interface Guide, 81-60220-01 A02,
March 2003. Made in USA.

Quantum Corporation provides this publication “as is” without warranty of any kind, either express or
implied, including but not limited to the implied warranties of merchantability or fitness for a particular
purpose. Quantum Corporation may revise this publication from time to time without notice.

COPYRIGHT STATEMENT

© 2003 Quantum Corporation. All rights reserved.

Your right to copy this manual is limited by copyright law. Making copies or adaptations without prior
written authorization of Quantum Corporation is prohibited by law and constitutes a punishable violation of
the law.

TRADEMARK STATEMENT

DLTtape, Super DLTtape, the Super DLTtape logo, and SuperLoader are trademarks, and Quantum and the
Quantum logo are registered trademarks, of Quantum Corporation.

Other trademarks are the property of their respective owners.

6207947-00cN 98

Contents

Intended Audience...............................................................................xv

Purpose .................................................................................................xvi

Organization.........................................................................................xvi

Document Conventions.................................................................... xvii

Chapter 1 Theory of Operation 1

SuperLoader DLT...................................................................................2

SuperLoader LTO...................................................................................2

Medium Changer Elements .................................................................. 2

Medium Transport Element ...........................................................3

Data Transfer Element..................................................................... 3

Storage Elements.............................................................................. 3

Events .......................................................................................................3

Power Cycle ......................................................................................4

SuperLoader Offline ........................................................................4

Magazine Insertion/Removal........................................................4

Maximum Temperature Exceeded................................................ 5

Automatic Drive Cleaning .................................................................... 5

Element Status Information............................................................6

Automatic Cleaning Operation......................................................6

Quantum ATL SuperLoader Software Interface Guide iii

Chapter 2 Messages 9

Message Format......................................................................................9

Supported SCSI Messages...................................................................13

Abort (06h) ......................................................................................13

Bus Device Reset (0Ch)..................................................................13

Command Complete (00h) ...........................................................14

Disconnect (04h)............................................................................14

Identify (80h-FFh) ..........................................................................15

Ignore Wide Residue (23h) ........................................................... 16

Initiator Detected Error (05h) .......................................................17

Linked Command Complete (0Ah).............................................18

Linked Command Complete, Flag (0Bh)...................................19

Message Parity Error (09h) ........................................................... 19

Message Reject (07h).....................................................................19

No Operation (08h)........................................................................20

Restore Pointers (03h)....................................................................20

Save Data Pointer (02h).................................................................20

Synchronous Data Transfer Request (01h).................................21

Wide Data Transfer Request Extended Message (03h) ............23

Chapter 3 Media Changer Commands 27

Overview of Command and Status Processing................................27

Media Changer Command Descriptions ..........................................29

Initialize Element Status Command (07h) ........................................31

Inquiry Command (12h)......................................................................32

Standard Inquiry Data Page .........................................................33

Vital Product Data Page................................................................38

Command Support Data...............................................................42

Load Unload Command (1Bh) ........................................................... 45

Log Sense Command (4Dh) ................................................................46

Supported Pages Log Page (Page 00h)........................................49

Last n Error Events Page (07h).....................................................50

TapeAlert Page (2Eh).....................................................................52

Move Statistics Page (30h) ............................................................54

Hard/Soft Error Statistics Page (31h) .........................................56

Device Wellness Page (33h)..........................................................59

Device Status Page (3Eh)...............................................................62

iv Quantum ATL SuperLoader Software Interface Guide

Mode Select (6) / (10) Command (15h / 55h).................................. 66

Mode Parameter List ..................................................................... 68

Mode Sense (6) / (10) Command (1Ah/ 5Ah) ................................. 74

Mode Sense Data Headers............................................................76

Mode Sense Mode Pages............................................................... 78

TapeAlert Page (1Ch) .................................................................... 79

Element Address Assignment Page............................................82

Transport Geometry Parameters Page........................................85

Device Capabilities Page...............................................................86

Move Medium Command (A5h)........................................................89

Persistent Reserve In Command (5Eh)..............................................91

Persistent Reserve Out Command (5Fh)......................................... 101

Position to Element Command (2Bh) .............................................. 116

Prevent/Allow Medium Removal (1Eh) ........................................ 118

Read Buffer Command (3Ch) ...........................................................120

Combined Header and Data Mode (000b) ...............................122

Data Mode (0010b)....................................................................... 123

Descriptor Mode (0011b)............................................................. 123

Read Data from Echo Buffer (1010b).........................................123

Echo Buffer Descriptor Mode (1011b).......................................124

Read Element Status Command (B8h) ............................................126

Element Status Data..................................................................... 128

Element Status Page ....................................................................130

Medium Transport Element Descriptor ................................... 131

Storage Element Descriptor........................................................ 134

Import/Export Element Descriptor ..........................................135

Data Transfer Element Descriptor.............................................137

Release Element (10) Command (57h).............................................140

Release Unit (6) Command (17h) .....................................................143

Report Device Identifier Command (A3h) ..................................... 145

Report LUNS Command (A0h)........................................................148

Request Sense Command (03h)........................................................151

Reserve Element (10) Command (56h)............................................160

Reserve Element (6) Command (16h)..............................................163

Send Diagnostic Command (1Dh) ...................................................166

Set Device Identifier Command (A4h)............................................ 168

Test Unit Ready Command (00h).....................................................170

Quantum ATL SuperLoader Software Interface Guide v

Write Buffer Command (3Bh)...........................................................171

Write Combined Header and Data Mode (0000b) .................. 172

Write Data Mode (0010b)............................................................172

Download Microcode Mode (0100b).........................................173

Download Microcode and Save Mode (0101b)........................173

Write Data to Echo Buffer (1010b).............................................173

vi Quantum ATL SuperLoader Software Interface Guide

Figures

Figure 1 Extended Message ............................................................ 12

Figure 2 Identify Message...............................................................15

Figure 3 Ignore Wide Residue Message........................................17

Figure 4 Synchronous Data Transfer Request Message .............21

Figure 5 Wide Data Transfer Request Message ...........................24

Figure 6 Initialize Element Status Command ..............................31

Figure 7 Inquiry Command ............................................................ 32

Figure 8 Inquiry Command ............................................................ 33

Figure 9 Standard Inquiry Data (LTO)..........................................34

Figure 10 Standard Inquiry Data (DLT)..........................................35

Figure 11 Supported Vital Product Data.........................................39

Figure 12 Unit Serial Number Page (80h).......................................39

Figure 13 Device Identification Page (83h).....................................40

Figure 14 Identifier Descriptor .........................................................41

Figure 15 Command Support Data Page ........................................ 43

Figure 16 Load Unload Command Descriptor Block....................45

Quantum ATL SuperLoader Software Interface Guide vii

Figure 17 LOG SENSE Command Descriptor Block ..................... 46

Figure 18 Supported Pages Page......................................................49

Figure 19 Last n Error Events Log Sense Header ..........................50

Figure 20 Format for Last n Error Events Log Sense.....................51

Figure 21 TapeAlert Log Sense Header Format.............................52

Figure 22 TapeAlert Page Log Parameters Format .......................53

Figure 23 Move Statistics Format.....................................................54

Figure 24 Hard/Soft Move Error Statistics Format.......................57

Figure 25 Device Wellness Log Sense Header ...............................59

Figure 26 Device Wellness Log Sense (0000h-000Fh)....................60

Figure 27 Log Parameters for Device Wellness Log Sense...........61

Figure 28 Device Status Log Sense Header ....................................62

Figure 29 Parameters for Device Status Log Sense Page.............. 63

Figure 30 Device Status Log Sense Page (0001h) ........................... 64

Figure 31 Mode Select (6) Command Descriptor...........................67

Figure 32 Mode Select (10) Command Descriptor.........................67

Figure 33 Mode Select (6) Mode Parameter List............................68

Figure 34 Mode Select (10) Mode Parameter List.......................... 69

Figure 35 Mode Select (6) Parameter Header.................................70

Figure 36 Mode Select (10) Parameter Header...............................70

Figure 37 Mode Select Parameter.....................................................71

Figure 38 Mode Select Page Descriptor...........................................72

Figure 39 Mode Sense (6) Command Descriptor Block ................74

Figure 40 Mode Sense (10) Command Descriptor Block ..............75

Figure 41 Mode Sense (6) Data Header...........................................77

Figure 42 Mode Sense (10) Data Header.........................................77

Figure 43 Mode Sense Page Descriptor...........................................78

viii Quantum ATL SuperLoader Software Interface Guide

Figure 44 TapeAlert Page Format Descriptor ................................ 79

Figure 45 Element Address Assignment Page...............................83

Figure 46 Transport Geometry Parameters Page...........................85

Figure 47 Transport Geometry Descriptor ..................................... 86

Figure 48 Device Capabilities Page..................................................87

Figure 49 Move Medium Descriptor Block .................................... 89

Figure 50 Persistent Reserve In Descriptor Block..........................91

Figure 51 Read Keys Parameters......................................................93

Figure 52 Read Reservations Parameters........................................95

Figure 53 Persistent Reserve In Read Reservations.......................97

Figure 54 Persistent Reserve Out Descriptor ...............................102

Figure 55 Persistent Reserve Out Command ............................... 102

Figure 56 Persistent Reserve Out Parameter List ........................ 112

Figure 57 Position to Element Descriptor..................................... 116

Figure 58 Prevent/Allow Medium Removal ...............................118

Figure 59 Read Buffer Command Descriptor Block.................... 120

Figure 60 Read Buffer Header ........................................................ 122

Figure 61 Read Buffer Descriptor...................................................123

Figure 62 Echo Buffer Descriptor...................................................124

Figure 63 Read Element Status Descriptor ................................... 126

Figure 64 Element Status Data Header .........................................128

Figure 65 Element Status Page .......................................................130

Figure 66 Data................................................................................... 131

Figure 67 Medium Transport Element Descriptor ......................132

Figure 68 Storage Element Descriptor...........................................134

Figure 69 Import/Export Element Descriptor .............................136

Figure 70 Data Transfer Element Descriptor................................138

Quantum ATL SuperLoader Software Interface Guide ix

Figure 71 Release (10) Descriptor Block........................................140

Figure 72 Release (10) ID Only Parameter List ............................142

Figure 73 Release Unit (6) Descriptor Block (LTO) .....................143

Figure 74 Release Unit (6) Descriptor Block (DLT) .....................144

Figure 75 Report Device Identifier Descriptor .............................145

Figure 76 Report Device Identifier.................................................146

Figure 77 Report LUNS Descriptor................................................148

Figure 78 LUN Reporting Parameter List.....................................149

Figure 79 Request Sense Command Descriptor Block................151

Figure 80 Request Sense Command Data .....................................151

Figure 81 Request Sense ..................................................................152

Figure 82 Reserve Element (10) Descriptor ..................................160

Figure 83 Reserve (10) ID Only Parameter List............................162

Figure 84 Reserve Element (6) Descriptor (LTO).........................163

Figure 85 Reserve Element (6) Descriptor (DLT).........................164

Figure 86 Send Diagnostic Descriptor...........................................166

Figure 87 Set Device Identifier Descriptor....................................168

Figure 88 Set Device Identifier Parameter List.............................169

Figure 89 Test Unit Ready Descriptor ........................................... 170

Figure 90 Write Buffer Descriptor..................................................171

x Quantum ATL SuperLoader Software Interface Guide

Tables

Table 1 Message Format ................................................................ 10

Table 2 Supported Messages.........................................................10

Table 3 Extended Message ............................................................ 12

Table 4 Response to Disconnect Message ...................................15

Table 5 Identify Message...............................................................16

Table 6 Ignore Wide Residue........................................................17

Table 7 Response to Initiator Detected Error..............................18

Table 8 Transfer Rates.................................................................... 23

Table 9 Supported Media Changer Commands ........................28

Table 10 Standard Inquiry Data (LTO and DLT)......................... 36

Table 11 Unit Serial Number Page Field Descriptions................ 40

Table 12 Identifier Descriptor Field Descriptions ........................ 41

Table 13 Supported Identifiers ....................................................... 42

Table 14 Command Support Data Page ........................................43

Table 15 Unload Command Descriptor Block..............................45

Table 16 Log Sense Command Descriptor Block ......................... 47

Quantum ATL SuperLoader Software Interface Guide xi

Table 17 Last n Error Events Log Sense Header ..........................50

Table 18 Parameters Last n Error Events Log Sense....................51

Table 19 TapeAlert Log Sense Header Field Descriptions .........53

Table 20 TapeAlert Page Log Parameters.....................................54

Table 21 Move Statistics................................................................... 56

Table 22 Hard/Soft Error ................................................................58

Table 23 Device Wellness Log Sense Header ...............................59

Table 24 Device Status Log Sense Header ....................................63

Table 25 Parameters for Device Status Log Sense Page ..............63

Table 26 Device Status Log Sense (0001h)..................................... 65

Table 27 Mode Select (6)/(10) Command Descriptor.................. 68

Table 28 Mode Select Parameter List .............................................69

Table 29 Mode Select Parameter Header ......................................71

Table 30 Mode Select Parameter Block..........................................72

Table 31 Mode Select Page Descriptor...........................................73

Table 32 Mode Sense Command Descriptor Block......................75

Table 33 Mode Sense Data Heade ..................................................78

Table 34 Mode Sense Page Descriptor...........................................79

Table 35 TapeAlert Page Format Descriptor ................................80

Table 36 Element Address Assignment Page ...............................84

Table 37 Transport Geometry Parameters Page...........................86

Table 38 Device Capabilities Page.................................................. 88

Table 39 Move Medium Command ...............................................90

Table 40 Persistent Reserve In Command..................................... 92

Table 41 Read Keys Parameters...................................................... 94

Table 42 Read Reservations Parameters........................................96

Table 43 Persistent Reserve In Read Reservations Descriptor ...97

xii Quantum ATL SuperLoader Software Interface Guide

Table 44 Persistent Reservation Type Codes................................ 99

Table 45 Persistent Reserve Out Command Service Action.....105

Table 46 Persistent Reservation Type Codes.............................. 110

Table 47 Persistent Reserve Out Parameter List ........................113

Table 48 Device Server Interpretation of Service and Scope

Value.................................................................................115

Table 49 Position to Element Command ..................................... 117

Table 50 Prevent/Allow Medium Removal Command

Descriptor Block..............................................................119

Table 51 Read Buffer Command Descriptor Block.................... 121

Table 52 Read Buffer Header........................................................122

Table 53 Echo Buffer Descriptor...................................................125

Table 54 Read Element Status Command Descriptor Block.....127

Table 55 Element Status Data .......................................................129

Table 56 Medium Transport Element Descriptor ......................133

Table 57 Storage Element Descriptor...........................................135

Table 58 Import/Export Element Descriptor ............................. 137

Table 59 Data Transfer Element Descriptor................................139

Table 60 Release (10) Command...................................................141

Table 61 Report Device Identifier Command Descriptor

Block.................................................................................. 146

Table 62 Report Device Identifier Parameter Data....................147

Table 63 Report LUNS Command Descriptor Block................. 149

Table 64 Request Sense Data.........................................................153

Table 65 Supported Sense Keys for Request Sense....................155

Table 66 Supported ASC / ASCQ (Hex) for Request Sense..... 156

Table 67 Reserve Element (10) Command.................................. 161

Table 68 Send Diagnostic Command Data .................................166

Quantum ATL SuperLoader Software Interface Guide xiii

Table 69 Set Device Identifier Command Descriptor Block.....169

Table 70 Set Device Identifier Parameter List.............................169

Table 71 Write Buffer Command Data........................................172

xiv Quantum ATL SuperLoader Software Interface Guide

Preface

This section outlines the scope and contents of the Quantum ATL
SuperLoader™ Software Interface Guide. It contains information
about the intended audience, purpose, organization, and
document conventions.

Intended Audience 0

This interface guide is a written for the following audiences:

• Original Equipment Manufacturers (OEMs) that integrate the

Quantum ATL SuperLoader into a system or subsystem

• System integrators that are responsible for the SCSI interface

• End users that operate and troubleshoot the SuperLoader

Quantum ATL SuperLoader Software Interface Guide xv

Preface
Purpose

Purpose 0

This interface guide describes the procedures and issues involved
in the development of software applications and utilities to
communicate with the Quantum ATL SuperLoader.

• SCSI interfaces

• SCSI Messages

• Media Changer Commands

Organization 0

This reference manual is organized as follows:

• Chapter 1, Theory of Operation
the SuperLoader models, media changer elements, events, and
automatic drive cleaning.

• Chapter 2, Messages
the SuperLoader.

• Chapter 3, Media Changer Commands
protocol features implemented in the media changer.

describes the SCSI messages supported by

describes differences between

describes the SCSI

xvi Quantum ATL SuperLoader Software Interface Guide

Preface

Document Conventions

Document Conventions 0

This manual uses the following conventions to designate specific
elements:

Element Convention Example

Abbreviations Lowercase, except where standard usage

requires uppercase

Acronyms Uppercase SCSI

Binary Notation Number followed by lowercase b 101b

Commands Uppercase (unless case-sensitive) FORMAT UNIT

Decimal Notation Number followed without suffix 101

Field Initial Caps (unless case-sensitive) Application Data

Hexadecimal Notation Number followed by h 101h

Sense Key Uppercase (unless case-sensitive) ILLEGAL REQUEST

Mb (megabits)
MB (megabytes)

Quantum ATL SuperLoader Software Interface Guide xvii

Preface
Document Conventions

xviii Quantum ATL SuperLoader Software Interface Guide

Chapter 1

1Theory of Operation

The SuperLoader products are an integration of two separate
devices, a tape drive and a media changer. The media changer
consists of all the mechanics and electronics required to store and
move tape cartridges while the tape drive provides the read/write
functionality.

Each device has a separate interface for communication to the host.
The SCSI command set supported by the tape drive is documented
separately. The SCSI command set supported by the media
changer device is detailed in xxx.

The SuperLoader is fully compliant with the ANSI SCSI-2 standard
for tape drive and media changer devices and implements many
optional features.

The SuperLoader does not act as an initiator on the SCSI bus.
Therefore, it does not generate unsolicited interrupts to the bus,
initiate its own SCSI commands, or assert bus reset.

Quantum ATL SuperLoader Software Interface Guide 1

Chapter 1 Theory of Operation
SuperLoader DLT

SuperLoader DLT 1

The SuperLoader DLT family of products utilize a single SCSI ID
and two logical units. The tape drive always resides at logical unit
0 and the media changer resides at logical unit 1. The SuperLoader
supports narrow and wide, synchronous and asynchronous data
transfers. Both LVD and single-ended versions are available.

SuperLoader LTO 1

The SuperLoader LTO family of products utilize two separate SCSI
IDs. The tape drive and media changer each reside on a unique ID.
The media changer device supports narrow and wide,
asynchronous data transfers only. The tape drive device supports
narrow and wide, synchronous and asynchronous data transfers.

Medium Changer Elements 1

The medium changer command set accesses the address space for
the set of physical locations and mechanisms with the
SuperLoader. This guide uses the SCSI-2 term element to refer to
one member of the SuperLoader address space. Each element is a
discrete physical entity that can hold a single tape cartridge. Each
element within a SuperLoader is represented by a unique 16-bit
element address. The SuperLoader consists of the following
medium changer elements.

• Medium transport element

• Storage elements

• Data transfer elements

2 Quantum ATL SuperLoader Software Interface Guide

Chapter 1 Theory of Operation

Events

You can issue the Mode Sense command to determine the
SuperLoader configuration. You can also use this command to
determine the first address and the number of elements of each
type.

Although the SuperLoader does have a mailslot, it is not reported
as an Import/Export element for use by the host system. It is
strictly to allow users to access tape cartridges using the front
panel or On-board Remote Management tool.

Medium Transport
Element

Data Transfer
Element

Storage Elements1

This mechanism can hold a single cartridge and is considered a

1

single medium transport element. It is used to move media
between elements within the SuperLoader.

The SuperLoader is configured with a single tape drive.

1

All of the storage elements within the SuperLoader are contained
within removable magazines. There are two magazines which hold
eight tape cartridges each, for a total of 16 storage elements. Since
the magazines are removable, a user may insert or remove a
magazine at any time. Because of this, the SuperLoader always
reports 16 storage elements, regardless of how many magazines
are currently installed. When a magazine is removed, the
corresponding storage elements are reported as inaccessible. This
is done via the Read Element Status–Storage Element Descriptor
on page 134–byte 2, bit 3.

Events 1

Events are system conditions created y operator actions or system
failures. These events are recorded in sense data for the SCSI host
to retrieve via the Request Sense command.

Quantum ATL SuperLoader Software Interface Guide 3

Chapter 1 Theory of Operation
Events

Power Cycle 1

SuperLoader
Offline

When the SuperLoader is powered-on, it goes through an
initialization sequence, during which it:

• Resets and initializes all hardware

• Responds to SCSI commands which do not require movement

• Responds to Test Unit Read and all movement type comands
with a not ready, initialization in progress check condition
(SK=02 ASC=29 ASCQ=02).

When the power on initialization is complete, it:

• Generates a Power On/Reset Occurred event (SK=6 ASC=29
ASCQ=02)

• If initialization is sucessful, it generates a note ready to ready
transition (SK=6 ASC=28 ASCQ=00), otherwise, failure sense
data is set accordingly.

When a user accesses the SuperLoader via the front panel or On-

1

board Remote Management in such a way that would cause
conflict with a SCSI command, the SuperLoader is put into an
offline state. If a SCSI command is received while in this offline
state, a not ready check condition is reported (SK=01 ASC=04
ASCQ=07).

Magazine
Insertion/
Removal

The SuperLoader must be powered-on with at least one magazine,
otherwise a check condition is reported (SK=-2 ASC=04

1

ASCQ=03).

While the system is online, the user may remove a magazine blank
and replace it with a magazine. The SuperLoader will calibrate the
newly installed magazine and check the presence of tape
cartridges in each of the storage elements. While this inventory is
in progress, the SuperLoader LTO will report a not ready check
condition (SK=02 ASC=04 ASCQ=01). The SuperLoader DLT does
not provide any indication that the operation is in progress. Once
the inventory is complete, all SuperLoaders report a unit attention
(SK=06 ASC=3B ASCQ=13).

4 Quantum ATL SuperLoader Software Interface Guide

Chapter 1 Theory of Operation

Automatic Drive Cleaning

Similarly, while a magazine is in the process of being removed, a
not ready check condition is reported (SK=02 ASC=04 ASCQ=07).
Once the operation is complete, by replacing the magazine with a
blank, a unit attention is reported (SK=06 ASC=3B ASCQ=12).

While one or both of the magazine bays are open, a not ready
check condition is reported (SK=02 ASC=04 ASCQ=03).

Maximum
Temperature
Exceeded

The SuperLoader monitors the ambient temperature within the
system. If the temperature exceeds the maximum safe temperature

1

for the media, the SuperLoader will disable all movement until the
temperature decreases below a safe threshold. While the
temperature remains excessive, SCSI commands that require
movement will fail (SK=04 ASC=0B ASCQ=01).

Automatic Drive Cleaning 1

There are two modes of automatic drive cleaning support
available:

• Host-initiated cleaning

• SuperLoader managed cleaning

Both modes provide automatic cleaning of the drive, but the first is
managed by the host and the second is managed by the
SuperLoader. These two modes are configured separately, and
only one should be enabled at any given time.

When automatic drive cleaning of the drive is enabled, either the
host of the SuperLoader is responsible for all cleaning functions
such as:

• Detecting when a drive requires cleaning

• Tracking and selecting cleaning cartridges

• Moving a cleaning cartridge to the drive

Quantum ATL SuperLoader Software Interface Guide 5

Chapter 1 Theory of Operation
Automatic Drive Cleaning

• Determining when a cleaning cartridge has used all of its

By default, the SuperLoader is configured to allow for host­initiated cleaning. If automatic cleaning is disabled from the host,
the SuperLoader can be configured to manage the automatic
cleaning of the drive. This is done by enabling the “Auto Clean”
function. Please refer to the Quantum ATL SuperLoader Automated
Tape Library User Manual for information on how this is done.

Note: There is no way for the host and SuperLoader to know

In host-initiated cleaning mode, the host tracks all cleaning
cartridges and their use. When the SuperLoader Auto Clean
feature is enabled, a “cleaning slot” is allocated and the cleaning
cartridge is stored in this storage element. The SuperLoader
assumes that any cartridge stored in this location is a cleaning
cartridge and will attempt to use it as such.

available cleaning cycles

how the other is configured with respect to automatic
drive cleaning. It is up to the user to make sure only one
is enabled.

The SuperLoader does not keep track of the number of times a
cleaning tape is used. Instead, it relies on the tape drive to report
when the tape has expired. When this happens, the superLoader
will notify the user via the front panel. The Auto Clean function is
automatically disabled until the user inserts a new cleaning tape
and re-enables the feature.

Element Status
Information

When the SuperLoader Auto Clean feature is enabled, the

1

allocated storage element is reported as inaccessible to the host.
This is done by setting the access bit to 0 in the Read Element
Status Storage Element Descriptor page.

Automatic
Cleaning
Operation

when the SuperLoader Auto Clean feature is enabled, the
SuperLoader checks if the drive needs cleaning after each

1

successful move from the drive. Therefore, each time the drive is
unloaded, it is checked.

6 Quantum ATL SuperLoader Software Interface Guide

Chapter 1 Theory of Operation

Automatic Drive Cleaning

The movement of the cleaning tape is handled differently
depending on the SuperLoader model.

SuperLoader DLT 1

If the move command, that unloaded the drive, was initiated from
SCSI, the cleaning tape is moved from its storage slot, to the drive,
the cleaning is performed and the cleaning tpae is returned to its
storage slot, before command complete status is returned to the
SCSI host. If an unrecoverable error occrus when moving a
cleaning cartridge that prevents a subsequent host initiated
command from completing, a check condition will be set in the
returned status byte and sense data is set appropriately.

SuperLoader LTO 1

If the move command that unloaded the drive was initiated from
SCSI, command complete is returned to the host when the move
completes. The cleaning tape is then moved from its storage slot to
the drive. The cleaning is performed and once complete, the
cleaning tape is returned to its stoage location. If a SCSI command
is received during this cleaning process, a not ready check
condition is reported (SK=-2 ASC=30 ASCQ=03).

Quantum ATL SuperLoader Software Interface Guide 7

Chapter 1 Theory of Operation
Automatic Drive Cleaning

8 Quantum ATL SuperLoader Software Interface Guide

Chapter 2

2Messages

The SCSI message system allows communication between an
initiator and the SuperLoader for interface management and
command qualification. Messages can be originated by either the
initiator or the SuperLoader. This section contains a detailed
description of the messages supported by the SuperLoader.

Message Format 2

A message can be one or more bytes in length. One or more
messages can be sent during a single MESSAGE phase, but a
message cannot be split over MESSAGE phases. The initiator is
required to end the MESSAGE OUT phase (by negating ATN)
when it sends certain messages that are identified in table 1

When a connection to the SuperLoader is established, for example
the SuperLoader is selected with ATN asserted, the first message
byte passed by the initiator must be either an IDENTIFY, ABORT,
or BUS DEVICE RESET message. If not, the SuperLoader discards
the message, saves no status information, and goes to the BUS
FREE phase.

Quantum ATL SuperLoader Software Interface Guide 9

.

Chapter 2 Messages
Message Format

If an initiator supplies an unsupported message, for example,
COMMAND COMPLETE or a reserved or undefined message
code, the SuperLoader returns a MESSAGE REJECT message and
continues where it left off, possibly returning to MESSAGE OUT if
ATN is raised.

Table 1 Message
Format

The first byte of the message, as defined in table 1

, determines the

format of the message.

Message Code Message

00h One-byte message (COMMAND COMPLETE)

01h Extended message

02h – 1Fh One-byte message

20h – 2Fh Two-byte message

40h – 7Fh Reserved

80h – FFh One-byte message (IDENTIFY)

The SuperLoader supports the messages listed in table 2. The
message code and the direction of the message flow is also
included in the table (In = target to initiator, Out = initiator to
target).

Table 2 Supported
Messages

10 Quantum ATL SuperLoader Software Interface Guide

Message Message Code Direction

ABORT 06h Out

BUS DEVICE RESET 0Ch Out

COMMAND COMPLETE 00h In

DISCONNECT 04h In Out

Chapter 2 Messages

Message Format

Message Message Code Direction

EXTENDED MESSAGE
(Synchronous Data and Wide
Data Transfer Requests)

IDENTIFY 80h – FFh In Out

IGNORE WIDE RESIDUE 23h In

INITIATOR DETECTED
ERROR

LINKED COMMAND
COMPLETE

LINKED COMMAND
COMPLETE (with flag)

MESSAGE PARITY ERROR 09h Out

MESSAGE REJECT 07h In Out

NO OPERATION 08h Out

RESTORE POINTERS 03h In

SAVE DATA POINTER 02h In

*

01h In Out

05h Out

0Ah In

0Bh In

*

Extended message (figure 1).

Two-byte messages consist of two consecutive bytes. The value of
the first byte, as defined in table 1

, determines which message is to
be transmitted. The second byte is a parameter byte that is used as
defined in the message description.

A value of 1 in the first byte indicates the beginning of a multiple­byte extended message. The minimum number of bytes sent for an
extended message is three. The extended message format is shown
in figure 1

Quantum ATL SuperLoader Software Interface Guide 11

and the data fields are described in table 3.

Chapter 2 Messages
Message Format

Figure 1 Extended
Message

Bit
Byte76543210

0

1

2

3 to
n-1

Table 3 Extended
Message

Field Description

Extended Message
Length

This field specifies the length, in bytes, of the Extended Message
Code plus the Extended Message Arguments that follow.
Therefore, the total length of the message is equal to the Extended
Message Length plus 2.

A value of 0 for the Extended Message Length indicates that 256
bytes follow.

Extended Message (01h)

Extended Message Length

Extended Message Code

Extended Message Arguments

Extended Message Code The SuperLoader supports the following Extended Messages:

01h SYNCHRONOUS DATA TRANSFER REQUEST
03h WIDE DATA TRANSFER REQUEST

12 Quantum ATL SuperLoader Software Interface Guide