Seagate STD124000N User manual

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Scorpion 24 DDS-3 Tape Drive
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STD124000N
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STD224000N
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STD624000N
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Product Manual
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Scorpion 24 DDS-3 Tape Drive
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STD124000N
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STD224000N
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STD624000N
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Product Manual
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© 1997 Seagate Technology, Inc. All rights reserved
Publication Number: 10004436-002, Rev. B, May, 1998
Seagate, Seagate Technology, the Seagate logo, Scorpion and the Scorpion logo
are trademarks or registered trademarks of Seagate Technology, Inc. Other product
names are trademarks or registered trademarks of their owners.
Seagate reserves the right to change, without notice, product offerings or
specifications. No part of this publication may be reproduced in any form without
written permission from Seagate Technology, Inc.

Product Manual Page iii
FCC Notice
This equipment generates and uses radio frequency energy and, if not installed and
used properly—that is, in strict accordance with the manufacturer’s instructions—
may cause interference to radio communications or radio and television reception. It
has been tested and found to comply with the limits for a Class B computing device
in accordance with the specifications in Part 15 of FCC Rules, which are designed to
provide reasonable protection against such interference in a residential installation.
However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause interference to radio or television
reception, which can be determined by turning the equipment on and off, you are
encouraged to try to correct the interference by one or more of the following
measures:
z
Reorient the receiving antenna.
z
Relocate the computer with respect to the receiver.
z
Move the computer into a different outlet so that the computer and receiver are
on different branch circuits.
If necessary, you should consult the dealer or an experienced radio/television
technician for additional suggestions. You may find the following booklet prepared
by the Federal Communications Commission helpful:
How to Identify and Resolve Radio-TV Interference Problems
This booklet (Stock No. 004-000-00345-4) is available from the U.S. Government
Printing Office, Washington, DC 20402.
Warning. Changes or modifications made to this equipment which have not been
expressly approved by Seagate Technology may cause radio and
television interference problems that could void the user’s authority to
operate the equipment.
Further, this equipment complies with the limits for a Class B digital apparatus in
accordance with Canadian Radio Interference Regulations.
Cet appareil numérique de la classe B est conforme au Règlement sur brouillage
radioélectrique, C. R. C., ch. 1374.
The external device drive described in this manual requires shielded interface cables
to comply with FCC emission limits.
Additional Warnings:
z
To prevent fire or electrical shock hazard, do not expose the unit to rain or
moisture.
z
To avoid electrical shock, do not open the cabinet.
z
Refer servicing to qualified personnel.

Page iv DAT Drives
About This Manual
All information contained in or disclosed by this document is considered proprietary
by Seagate Technology. By accepting this material, the recipient agrees that this
material and the information contained therein are held in confidence and in trust
and will not be used, reproduced in whole or in part, nor its contents revealed to
others, except to meet the purpose for which it was delivered. It is understood that
no right is conveyed to reproduce or translate any item herein disclosed without
express written permission from Seagate Technology.
Seagate Technology provides this manual “as is,” without warranty of any kind,
either expressed or implied, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Seagate Technology reserves
the right to change, without notification, the specifications contained in this manual.
Seagate Technology assumes no responsibility for the accuracy, completeness,
sufficiency, or usefulness of this manual, nor for any problem that may arise from
the use of the information in this manual.
Following are brief descriptions of the sections in this manual.
Chapter 1, “Introduction” on page 1 provides general specifications, features and
an overview on DAT technology.
Chapter 2, “Specifications” on page 9 contains physical, performance,
environmental, power, drive tape handling and DAT cartridge specification tables.
Chapter 3, “Installation” on page 15 provides cautions, unpacking tips, inspection
information and installation/connection steps, including cabling requirements and
connector pinouts.
Chapter 4, “Drive Operations” on page 33 explains the simple operation of drives.
Chapter 5, “SCSI Interface” on page 43 lists general information about the SCSI-2
interface.
Chapter 6, “DDS-3 Tape Format” on page 47 explains the DDS, DDS-DC, DDS-2
and DDS-3 tape formats.
Chapter 7, “Data Compression” on page 61 describes the data compression
algorithm and explains pertinent information for effective use of data compression.
Chapter 8, “Theory of Operations” on page 71 details the functional operation of
various assemblies of the drives.
Chapter 9, “Maintenance and Reliability” on page 83 presents maintenance
procedures and reliability information.
Appendix A, “Acronyms and Measurements” on page 87 lists the acronyms and
measurements used in the manual.
Appendix B, “Vendor-Unique SCSI Information” on page 91 provides specific
SCSI information for programming and retrieving configuration data.
The glossary on page 95 defines key terms.

Product Manual Page v
Contents
1 Introduction.......................................................................1
Overview..............................................................................................1
DDS Format Standard Compatibility 1
Scorpion 24 Capacity and Transfer Rates 2
Features ..............................................................................................3
Models.................................................................................................4
DAT Technology Overview...................................................................6
Helical Scan Recording..................................................................6
Recording Formats ........................................................................7
DDS-3 Recording Format ........................................................7
DDS-2 Recording Format ........................................................7
DDS Recording Format ...........................................................7
DDS-DC Recording Format.....................................................8
2 Specifications....................................................................9
Overview..............................................................................................9
Physical Specifications.........................................................................9
Power Specifications..........................................................................11
Drive Performance Specifications.......................................................12
Environmental Requirements .............................................................13
DDS Cartridge Specifications.............................................................13
Regulatory Compliance......................................................................14
3 Installation.......................................................................15
Introduction........................................................................................15
Guidelines and Cautions (Internal Models) .........................................15
Unpacking and Inspection..................................................................16
Cabling and Connectors.....................................................................16
Cabling Considerations................................................................16
Electrical Characteristics..............................................................16
SCSI Connector—Internal Models ...............................................18
SCSI Connector—External Models ..............................................19
Installing Internal Drives.....................................................................20
Configuring Options.....................................................................20
Setting the Switchbank Parameters .............................................20
SCSI Device Address (S1, S2, S3) .......................................22
Media Recognition System (MRS) (S4) .................................22

Contents
Page vi DAT Drives
Parity Check Enable/Disable (S5)..........................................23
DDS Pass-Through Mode Enable/Disable (S6)......................23
Inquiry String (S7)..................................................................23
Power-on Self-Test Mode Enable/Disable (S8) ......................23
Switches 9 and 10.................................................................23
Setting the Jumpers...............................................................24
SCSI Device Address Jumpers..............................................25
Hardware Data Compression.................................................26
Active Terminator..................................................................26
Terminator Power..................................................................26
Mounting the Drive.......................................................................27
Completing the Power and Interface Connections........................29
Installing External Drives....................................................................29
Selecting the SCSI Address.........................................................30
Completing the Interface Connection ...........................................30
Connecting the Power Cord.........................................................31
4 Drive Operations .............................................................33
Introduction........................................................................................33
Data Compression Operation.............................................................33
Front Panel LED Operation................................................................34
Loading/Unloading the Cartridge........................................................37
Loading/Unloading a Cartridge (Normal Operation)......................37
Unloading a Cartridge (Manual Operation)...................................38
Using a Blank Cartridge .....................................................................39
Using a Cartridge Containing Data .....................................................40
Loading Revised Firmware Using Seagate Firmware Cartridges.........40
Flash Memory....................................................................................40
Firmware Download Process..............................................................41
5 SCSI Interface..................................................................43
Introduction........................................................................................43
SCSI-2 Interface................................................................................43
ANSI X3.131, 199x Conformance Statement (SCSI-2).......................45
General Features...............................................................................45
Typical System Configurations...........................................................46
6 DDS-3 Tape Format.........................................................47
Introduction to DDS Recording Format Standards..............................47
DDS-3 Tape Format...........................................................................47
Basic Groups...............................................................................48
Entities ........................................................................................49
Subgroups...................................................................................49
Basic Group Transformation Summary ........................................49
Subcode Information....................................................................49

Contents
Product Manual Page vii
Subcode Location........................................................................49
DDS-3 Track Geometry ...............................................................50
Recorded Patterns.......................................................................51
Format of a Track........................................................................51
Positioning Accuracy....................................................................52
Timing Tracking...........................................................................52
Tape Layouts in the DDS-3 Standard.................................................53
Layout of a Single Data Space Tape (Single Partition)........................53
Device Area.................................................................................54
Reference Area............................................................................54
System Area................................................................................55
Data Area....................................................................................55
Appending to Tape.......................................................................55
EOD Area....................................................................................57
Early Warning Point (EWP)..........................................................57
Initialization..................................................................................57
Layout of a Partitioned Tape ..............................................................58
Partition 1....................................................................................59
Partition 0....................................................................................59
Initialization of Partitioned Tapes..................................................59
Housekeeping Frames.......................................................................60
DDS-3 Recording Format Standard—Further Reference....................60
7 Data Compression ..........................................................61
Introduction........................................................................................61
Data Compression—General..............................................................61
Data Compression Considerations...............................................62
Hardware Compression ...............................................................63
Data Integrity...............................................................................63
DCLZ Algorithm .................................................................................64
DCLZ Algorithm...........................................................................64
Simplified Compression Operation...............................................64
Dictionary ....................................................................................65
Simplified Decompression Operation............................................66
SCSI/Data-Compression Chip............................................................68
Overview .....................................................................................68
Features......................................................................................68
8 Theory of Operations...................................................... 71
Overview............................................................................................71
The STD124000N Drive...............................................................72
Motors and Control Circuits..........................................................73
SCSI Controller............................................................................74
Helical Scan Recording—Four-Head Design................................75
Motors and Control Circuits................................................................76
Read and Write LSI .....................................................................77
Timing Tracking Circuitry .............................................................77
SCSI Controller............................................................................77

Contents
Page viii DAT Drives
Flash Memory....................................................................................77
Sensors .............................................................................................78
Read-After-Write................................................................................78
Media Recognition System (MRS)......................................................79
DDS Data Cartridge...........................................................................79
9 Maintenance and Reliability...........................................83
Maintenance......................................................................................83
Head Cleaning.............................................................................83
Automatic Drive Spin-Down and Write .........................................84
Guidelines for High Temperature or Humidity Conditions
(Outside the Specified Operating Environment)...................84
Reliability ...........................................................................................85
Mean Time Between Failures.......................................................85
Mean Time To Repair..................................................................85
A Acronyms and Measurements .......................................87
Acronyms and Abbreviations..............................................................87
Measurements...................................................................................89
B Vendor-Unique SCSI Information ..................................91
Overview............................................................................................91
MODE SELECT Flash Memory Configuration Page (30H)...................92
MODE SENSE Flash Memory Configuration Page (30H).....................93
Glossary......................................................................................95

Product Manual Page ix
Figures
Figure 1. 3.5-inch Internal DDS Drive...................................................5
Figure 2. 5.25-Inch Internal DDS Drive.................................................5
Figure 3. External DDS Drive...............................................................6
Figure 4. Internal DDS Drive—General Dimensions ...........................10
Figure 5. Internal DDS Drive with Rails—General Dimensions............10
Figure 6. External Subsystem—General Dimensions .........................11
Figure 7. Switchbank Access—3.5-Inch Internal Model ......................20
Figure 8. Switchbank Access—5.25-Inch Internal Model ....................21
Figure 9. Dip Switch Default Settings .................................................22
Figure 10. Location of Jumpers for Internal Model..............................24
Figure 11. Location of Jumpers for Internal Model with Rails..............24
Figure 12. Jumper Configurations.......................................................25
Figure 13. Mounting Hole Locations (Internal Drive without Rails).......27
Figure 14. Mounting Hole Locations (Internal Drive with Rails) ...........28
Figure 15. Rear Panel (External Model)..............................................30
Figure 16. Daisy Chain Diagram.........................................................31
Figure 17. Front Panel—Internal Model..............................................35
Figure 18. Front Panel—Internal Model with Rails..............................36
Figure 19. Front Panel—External Subsytem.......................................36
Figure 20. Cartridge Loading (Internal DAT Drive)..............................37
Figure 21. Locations on Drive.............................................................38
Figure 22. SCSI System Sample Configurations.................................46
Figure 23. Structure of a Basic Group................................................48
Figure 24. Track Configuration...........................................................50
Figure 25. Timing Tracking.................................................................53
Figure 26. Layout of a Single Data Space Tape..................................54
Figure 27. Appending Rules...............................................................55
Figure 28. Tolerance on Seamless Appending ...................................56
Figure 29. Layout of a Partitioned Tape..............................................58
Figure 30. Layout of SCSI/Data Compression Device.........................69
Figure 31. Simplified Block Diagram—Scorpion 24 DDS-3 Drive ........73
Figure 32. Block Diagram—SCSI Controller DAT Models...................74
Figure 33. Four-Head Design.............................................................75
Figure 34. Alternate Azimuth Angles ..................................................76
Figure 35. DDS Cartridge...................................................................80
Figure 36. Cartridge Design Features.................................................81
Figure 37. Write-Protect Tab on the DDS Cartridge............................81

Figures
Page DAT Drives
x

Product Manual Page 1
Introduction
Overview
The Seagate®Scorpion®24 digital data storage (DDS) drive is designed for
computer environments that require high-performance, high-capacity data storage.
Based on a 3.5-inch mechanism, the internal and external Scorpion 24 models
provide 12 Gbytes of data-storage capacity, 24 Gbytes compressed, with a native
transfer rate of 1.1 Mbytes per second, 2.2 Mbytes per second compressed.
The Scorpion 24 drive combines established DAT technology, high-density
recording and hardware data-compression capability along with Seagate’s proven
computer grade design to provide unmatched reliability and performance
characteristics among DDS products. The Scorpion 24 is ideal for workstation,
server and network/enterprise applications such as:
z
Backup of high-capacity fixed discs
z
Data interchange between systems
z
Network server
z
Loader products
z
Online data collection
z
Near-line secondary storage for text, graphics or multimedia information of all
types
z
Archival storage
DDS Format Standard Compatibility
The Scorpion 24 drive supports the DDS-3, DDS-2 and DDS recording formats.
Compatibility with each of these standards ensures complete write and read
interchange of recorded digital data between all compliant drive and media vendors.
Additionally, the Scorpion 24 drive supports DDS-DC, the DDS data compression
standard, effectively doubling storage capacity and transfer rates.
1

Chapter 1 Introduction
Page 2 DAT Drives
The Scorpion 24 drive complies with:
z
The DDS recording format standard, ANSI/ECMA-139, 3,81mm Wide Magnetic
Tape Cartridge for Information Interchange - Helical Scan Recording - DDS
Format.
z
The DDS-DC recording format standard, ANSI/ECMA-150, 3,81mm Wide
Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording -
DDS-DC Format using 60 m and 90 m Length Tapes.
z
The DDS-2 recording format standard, ANSI/ECMA-198, 3,81mm Wide
Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording -
DDS-2 Format using 120 m Length Tapes.
z
The DDS-3 recording format standard, ANSI/ECMA-236, 3,81mm Wide
Magnetic Tape Cartridge for Information Interchange - Helical Scan Recording -
DDS-3 Format using 125 m Length Tapes.
Scorpion 24 Capacity and Transfer Rates
The Scorpion 24 provides the following capacities and transfer rates, depending on
recording mode and tape length:
Recording Mode
DDS DDS-DC DDS-2 DDS-3
Tape length 60 meter 90 meter 120 meter 125 meter
Capacity (native) 1.3 Gbytes 2.0 Gbytes 4.0 Gbytes 12.0 Gbytes
Capacity (compressed) N/A 4.0 Gbytes 8.0 Gbytes 24.0 Gbytes
Transfer rate (native) 780
Kbytes/sec 780 Kbytes/sec 780 Kbytes/sec 1.1 Mbytes/sec
In data-compression mode, the Seagate Scorpion 24 drive typically doubles the
storage capacity and transfer rate of the native uncompressed operation. Tape
capacity and sustained data-transfer rate are also dependent upon the
characteristics of the files being compressed, along with other system parameters,
including the speed of the host, the operating system and the application software
used.
The Scorpion 24 drive also offers synchronous or asynchronous SCSI transfers with
a high-speed burst data-transfer rate of 10 Mbytes per second.
The Scorpion 24 provides unmatched reliability through three levels of error-
correction code (ECC) and the four-head design, which provides for read-after-write
(RAW) error detection and correction. The Scorpion 24 also contains an onboard
serial port that provides the capability for extensive testing of the drives.

Introduction Chapter 1
Product Manual Page 3
Features
The Scorpion 24 DDS drive represents Seagate’s commitment to engineering
reliable and durable tape drive products that implement leading-edge technology.
Key features of the drive include:
z
Platform based on 3.5-inch DDS drive components
z
3.5-inch internal form-factor for installation in a 3.5-inch half-height space
(model STD124000N)
z
3.5-inch drive with factory-installed 5.25-inch mounting rails and bezel for
installation in a 5.25-inch half-height space (model STD224000N)
z
External subsystem with built-in, auto-sensing, worldwide power supply (model
STD624000N)
z
Capability to write and read DDS-3, DDS-2, DDS-DC and DDS cartridges
z
Advanced onboard DDS-DC hardware using Data Compression Lempel-Ziv
(DCLZ) data-compression algorithm
z
ANSI/ECMA DDS-3, DDS-2, DDS-DC and DDS tape format compliance for
compatibility and interchange
z
High-speed random access of 20 seconds (average) to any file on a 60 m tape;
30 seconds for a 90 m tape; 40 seconds on a 120 m tape; and 40 seconds on a
125 m tape
z
High-speed transfer rates for fast backups:
– 1.1 Mbytes per second (66 Mbytes per min) typical—uncompressed data
– 2.2 Kbytes per second (132 Mbytes per min) typical—compressed data
z
High-performance SCSI burst transfer rate of 7 Mbytes per second
asynchronous and 10 Mbytes per second synchronous
z
Flash memory to store setup parameters
z
Four-head design with RAW error detection and rewrites
z
Three levels of ECC to ensure data integrity
z
Uncorrectable error rate of less than 1 in 1015 bits
z
Flash memory to enable field firmware upgrades
z
Custom Seagate-designed LSI circuitry to reduce component count and boost
drive reliability
z
Advanced, single-chip, DDS formatter LSI
z
Low power consumption—less than 5.5 watts (typical) for internal drives

Chapter 1 Introduction
Page 4 DAT Drives
z
Single-ended SCSI connection with these features:
– Embedded full LSI, high-speed SCSI-2 controller
– Software selectable synchronous or asynchronous SCSI data transfer
– Onboard output jack on internal models for configuring the SCSI
address if repackaged in an external box
z
Automatic power-on self-tests available
z
Manual emergency cartridge ejection procedure
z
Support for TapeAlert™ Certified Solutions
Models
The Scorpion 24 3.5-inch and 5.25-inch internal drive form-factors are tailored for
easy installation in today’s computers, and the full-featured embedded SCSI
controller facilitates easy integration into a variety of systems.
Scorpion 24 Model Names
Capacity 24.0 Gbytes*
3.5-in internal STD124000N
5.25-in internal STD224000N
External STD624000N
*Typical with data compression
Scorpion 24 models include:
z
A 3.5-inch, half-height DDS-3 drive that mounts internally (model
STD124000N).
z
A 5.25-inch, half-height DDS-3 drive that consists of a 3.5-inch drive with 5.25-
inch mounting rails and bezel that mounts internally in a 5.25-inch, half-height
space (model STD224000N).
z
A complete external subsystem that contains the 3.5-inch DDS-3 drive and
built-in worldwide power supply (model STD624000N).

Introduction Chapter 1
Product Manual Page 5
Figures 1, 2 and 3 illustrate the internal, internal with rails and external drives,
respectively.
Figure 1. 3.5-Inch Internal DDS Drive
Figure 2. 5.25-Inch Internal DDS Drive

Chapter 1 Introduction
Page 6 DAT Drives
Figure 3. External DDS Drive
DAT Technology Overview
Developed for the audio electronics market, DAT technology was first applied in
computer peripherals in the late 1980s. Unlike traditional magnetic tape audio
cartridge products, DAT technology proves inherently reliable through the
helical
scan recording method,
which provides a high recording density with a very low
error rate. All DAT products, including computer implementations, use the helical
scan recording method. This recording method has been used in professional video
tape recorders (VTRs) since 1956 and in home video cartridge recorders (VCRs)
since 1974. In 1986, DAT products that used helical scan technology were first
developed for audio applications. DAT consumer products are specifically designed
for digital audio recording and playback.
Helical Scan Recording
Helical scan recording was originally developed as a method of efficiently recording
high-quality television signals on a relatively slow moving tape. It requires that both
the tape and the recording head move simultaneously. This recording method
results in an extremely high recording density, far higher than can be achieved with
stationary-head devices such as 1/2-inch open-reel or 1/4-inch cartridge tapes. (See
chapter 8, “Helical Scan Recording—Four-Head Design” for additional information.)
In helical scan recording, both the read and write heads are located on a rapidly
rotating cylinder or drum. The cylinder is tilted at an angle in relation to the vertical
axis of the tape. As the tape moves horizontally, it wraps around the part of the
circumference of the cylinder (102°) so that the head enters at one edge of the tape
and exits at the other edge before the tape unwraps.

Introduction Chapter 1
Product Manual Page 7
The horizontal movement of the tape in combination with the angular movement of
the cylinder causes the track to be recorded diagonally across the tape rather than
straight down its length. The resulting recorded track, nearly one inch, is
approximately eight times longer than the width of the tape.
Recording Formats
The Seagate Scorpion 24 DDS drive is designed to comply with the industry-
standard DDS-3, DDS-2, DDS-DC and DDS recording formats. These formats are
summarized in the following text.
DDS-3 Recording Format
The DDS-3 recording format provides for writing data in helical tracks that are the
same width as DDS-2. The significant capacity increase associated with DDS-3 is
achieved by: 1) doubling linear recording density from 61 Kbpi (DDS-2) to 122 Kbpi
along with the use of PRML encoding; 2) increasing tape length to 125 meters and
3) using the timing tracking system, which eliminates the need for dedicated top and
bottom servo burst information associated with the previous ATF system.
DDS-2 Recording Format
The DDS-2 or narrow track recording format provides for writing data in helical
tracks that are narrower than the previous DDS track width. This format doubles
capacity by increasing track density one and a half times, along with a 33% increase
in tape length; the higher output MP+ media associated with the 120-m DDS-2
cartridges ensures reliable data integrity given the decrease in track widths from
13.6 µm with DDS and DDS-DC to 9 µm with DDS-2.
DDS Recording Format
This standard format was codeveloped by DDS manufacturers to support DAT
devices as computer peripherals. The objectives of DDS are to maximize storage
capacity and performance, facilitate data interchange, provide compatibility with
existing tape storage command sets and provide extremely fast random access.
The DDS format also takes advantage of the helical scan recording method and the
inherent error correction capability of the DAT technology to augment error detection
and correction.
The format consists of a finite sequence of data groups where each data group is a
fixed-length recording area. A data group is made up of 22 data frames and 1 ECC
frame; each frame is made up of two helical scan tracks. The advantages of the
fixed-length data group is that ECC is easily generated, and buffering requirements
are simplified. (See Chapter 6, “Tape Formats,” for additional information.)
Although data groups are fixed-length and always contain 22 data frames, the DDS
format is designed such that variable-length computer records can be stored in the
fixed-length data groups.

Chapter 1 Introduction
Page 8 DAT Drives
DDS-DC Recording Format
A superset of the basic DDS format, DDS-DC drives can write compressed and
uncompressed data to the same cartridge. Because DDS-DC is based on the DDS
format, backward-compatibility is maintained.
Introduced by the DDS Manufacturers Group and approved by ANSI and ECMA,
DDS-DC is a
record compression
industry-standard format that provides support for
lossless
compression algorithms based on substitution—such as those of the
Lempel-Ziv family.
This format supports compressed and uncompressed records. A recorded DDS
cartridge may contain compressed records, uncompressed records, filemarks and
setmarks. Compressed records exist within recorded objects called
entities . Entities
and uncompressed records are collected into groups.
Many aspects of the DDS-DC format are identical to those of the DDS format:
z
The series of transformations (randomizing, interleaving, generation and
inclusion of two Reed-Solomon error-correction codes) applied to a group
before recording
z
The tape layout
z
The third group-based level of Reed-Solomon error-correction codes (C3)
The only differences between the DDS and DDS-DC formats are in the contents of
the groups.