Seagate, Seagate Technology, the Seagate logo and Sidewinder 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. 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 assumes no
responsibility for the accuracy, completeness, sufficiency, or usefulness of this manual, nor for any problem that
might arise from the use of the information in this manual.
10005136-001
, March 1998
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:
• Reorient the receiving antenna.
• Relocate the computer with respect to the receiver.
• 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:
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.
How to Identify
Caution
. 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.
Additional warnings:
•
To prevent fire or electrical shock hazard, do not expose the unit to rain or moisture.
•
To avoid electrical shock, do not open the cabinet. Refer servicing to qualified personnel.
Important Information 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 might arise from the use of the information in this manual.
Sensors and switches........................................................................................... 73
Drive media (Travan minicartridges)...................................................................... 74
STT20000A Product ManualPage vii
Table of Contents
Glossary75
Acronyms and measurements78
Acronyms and abbreviations................................................................................. 78
Units of measurement........................................................................................... 80
Page viiiSTT20000A Product Manual
IntroductionChapter 1
Introduction
1
Drive overview
The Seagate STT20000A extends the Seagate family of one-inch high, DC2000
drives that feature high performance, high reliability, and quiet operation. The drive
transfers data at up to 60 megabytes per minute (Mbytes/min) without compression.
With optimal system resources and compressible data structures, nominal transfer
rates of up to 120 Mbytes/min can be observed using software data compression
(assumes 2:1 compression ratio).
System optimizations include but are not limited to allocating the maximum amount
of the base 640 Kbytes of memory available
Data compression is available within the Seagate Backup software package for
DOS and Windows and typically provides for up to a 2:1 compression ratio. The
compression ratio is dependent on the specific system and the nature of the files
being compressed.
This drive optimizes throughput through the Seagate feature FastSense
feature enables the drive to automatically sense the fastest supportable data
transfer rate of the host system and choose a transfer speed of either 1,000, 733, or
489 kilobytes/second (Kbyte/sec). This process maximizes system throughput by
eliminating tape repositioning, which is typically required when the tape drive
operates faster than the host computer.
The product is available as an internal device in either a 3.5-inch or half-high 5.25inch configuration. The drive form factors are tailored for easy installation in today's
computers.
The drive supports the QIC-3220-MC format standard and will provide 10 gigabytes
uncompressed storage capacity, 20 gigabytes compressed, with a Travan TR-5
cartridge.
The drive will also read tapes conforming to the QIC-3095 standard.
A precision burst intelligent positioning system is used to achieve high track
densities.
TM
. This
STT20000A Product ManualPage 1
Chapter 1Introduction
The STT20000A conforms to the QIC-3220-MC development standard adopted by
Quarter-Inch Cartridge Drive Standards Inc. (QIC). The drive records in a serpentine
fashion utilizing a 1,7 RLL (Run Length Limited) data encoding method, and
provides for 108 data tracks and one (1) directory track on Travan TR-5 media.
The drive offers electronically erasable, programmable, read-only memory (flash
EEPROM), which enables qualified Seagate OEMs to download revised firmware to
the drive.
With the availability of greater capacity disk drives and the growth of small networks,
the need for cost-effective, high-capacity storage has grown. The STT20000A is
ideal for high-end standalone computers, workstations, and small networks.
Built using long-wearing materials and custom Large Scale Integration (LSI)
components, the ATAPI drive was engineered for heavy-duty computer applications.
Providing carefully controlled tape handling and rapid, smooth operation, the design
promotes long life for key components such as the motors, drive heads, and the
media itself. One major benefit of this new, computer grade engineering is low
power consumption.
Figure 1-1 illustrates the STT20000A ATAPI minicartridge internal drive. Figure 1-2
illustrates the internal drive equipped with mounting brackets.
Figure 1-1
STT20000A internal drive without mounting brackets
Page 2STT20000A Product Manual
IntroductionChapter 1
Figure 1-2
Internal STT20000A with mounting brackets
Features
The STT20000A embodies Seagate 's commitment to engineer reliable and durable
tape drive products. Key features of the drive are as follows:
• Internal form factor for installation in a 5.25-inch half-high or 3.5-inch by one-
inch space
• Capability to write and read Travan TR-5 (QIC-3220-MC) media, as well as read
TR-4 media conforming to the QIC-3095 standard
• QIC-3220-MC tape format compliance for compatibility and information
interchange
• Typical uncompressed capacities of 10 gigabytes on 740 foot TR-5 media
• Typical compressed capacities of 20 gigabytes on 740 foot TR-5 media
• Transfer rate optimized with
supportable data transfer rate (1,000, 733, or 489 Kbyte/sec)
• ATAPI interface that supports DMA and PIO modes 0, 1, or 2 with 512 Kbytes
on-drive data buffer to facilitate the most efficient use of the host computer and
tape drive.
• Uncorrectable error rate of less than 1 in 10
• Flash EEPROM to enable electrically upgradeable drive firmware
• Custom Seagate -designed LSI circuitry to reduce component count and boost
drive reliability
FastSense
—automatic selection of fastest
15
bits
• Low power consumption—less than 15.0 Watts (typical) for internal drives
STT20000A Product ManualPage 3
Chapter 1Introduction
Typical system configurations
The Enhanced IDE standard supports up to four ATAPI peripherals: two devices on
the primary port and two devices on the secondary port. Of the two devices, one
must be slave to the other, which is the master. Figure 1-3 shows sample
configurations for two ATAPI systems.
Figure 1-3
Sample ATAPI configurations
Computer
system
Computer
system
Enhanced
IDE
controller
Enhanced
IDE
controller
Acculogic
IDE
controller
Primary
IDE bus
Secondary
IDE bus
Primary
IDE bus
Secondary
IDE bus
Hard
disc
CD-ROM
(master)
STT20000A
(slave)
Hard
disc
STT20000A
Minicartridge technology overview
Having evolved from the original mass-storage medium—reel-to-reel, 1/2-inch tape
storage—the minicartridge technology of today offers fast, efficient, high-capacity
storage in a compact, easy-removable hard-shell package. In little more than a
decade, storage capacities have increased from some 60 megabytes (Mbytes) on 9
tracks (QIC-24, 1982) to the to the 20 Gbyte capacity achievable with the
STT20000A minicartridge drive on a single Travan TR-5 cartridge.
The streaming-tape intelligence in the STT20000A provides a continuous tape
motion with an uninterrupted, precisely coordinated flow of data to and from the
minicartridge. This "streaming" motion combined with the "serpentine" recording
method is one element that contributes to the increased storage capacities,
efficiency, and speed of today's minicartridge technology.
Use of the "serpentine" recording method exploits the bi-directional capabilities of
the cartridge. With this method, the tape is not rewound at the end of a track.
Page 4STT20000A Product Manual
IntroductionChapter 1
Instead, the write-read heads are logically or mechanically switched to a different
position on the tape and another track is written or read in the reverse direction.
That is, the drive first records track 1 in one direction and when the end of the tape
is reached, the head is moved and the direction of tape motion is reversed to record
track 2. This serpentine process continues until the entire tape is recorded. The
individual tracks are sequential to minimize the amount of head motion as the heads
change position for each track.
Flash EEPROM
The STT20000A incorporates leading-edge technology in the flash EEPROM, which
is useful should the drive's firmware need to be upgraded at some point. With the
permanently installed, electrically upgradeable, flash EEPROM memory, revised
firmware for the drive can be loaded via any one of two methods:
• Seagate OEM firmware cartridge (See chapter 4)
• Host IDE bus
This feature enables qualified OEMs needing to revise the drive firmware to do so
rapidly and at a reduced cost. Flash EEPROM should also prolong the life cycle of a
drive because many new techniques—such as increasing the capacity of the drive
through support for longer tapes—may require only a firmware upgrade.
Software
References
The STT20000A is a cost-effective means of backing up fixed disks. The drive is
compatible with DOS
Microsoft Windows 95, or Windows NT and will operate with many of the popular
backup software applications such as Seagate 's Backup for DOS and Windows,
Windows 95, NetWare, or Windows NT.
The following standards documents describe some of the technology incorporated in
the drives referenced in this manual.
•
QIC-170
•
QIC-157
•
QIC-3095-MC
•
QIC-3220-MC
For more information about a particular QIC standard, contact Quarter-Inch
Cartridge Standards, Inc., c/o Freeman Associates, 311 East Carrillo Street, Santa
Barbara, California 93101.
—Preformatted magnetic minicartridge
—ATAPI command set for streaming tape
TM
version 5.0 or later, Microsoft WindowsTM 3.1 or later,
—Serial recorded magnetic tape minicartridge (TR-4)
—Serial recorded magnetic tape minicartridge (TR-5)
STT20000A Product ManualPage 5
Chapter 1Introduction
About this manual
The remaining chapters and the appendices in this manual are briefly described in
the following table. A glossary of terms is also included.
information, and installation/connection steps
including cabling requirements and connector
pinouts.
Drive operation and
maintenance
ATAPI InterfaceLists general information about the interface.
Tape formatProvides an overview of the QIC-3220 tape
Theory of operationDetails the functional operation of various
GlossaryDefines key terms.
Acronyms and
measurements
Explains the simple operation of the drive.
format.
assemblies of the ATAPI drive.
Lists the acronyms and measurements used in the
manual.
Page 6STT20000A Product Manual
SpecificationsChapter 2
Specifications
2
Overview
The STT20000A provides exceptional reliability in storing large amounts of
computer data. This chapter includes the following specifications and requirements:
• Physical specifications
• Power requirements
• Drive performance specifications
• Environmental requirements
• Recommended tapes
• Tape capacities and formats
• Regulatory compliance
Physical specifications
The physical specifications of the STT20000A are listed in the following table.
Specification
Height
Width
Length
Weight
Figures 2-1 and 2-2 show the general dimensions of the STT20000A in 3.5-inch
configuration (without mounting brackets) and in the 5.25-inch configuration (with
mounting brackets).
Drive for 3.5-Inch
Mount
1.0 in/ 25 mm1.7 in/ 43 mm
4.0 in/102 mm5.87 in/149.1 mm
6.36 in/161.5 mm6.51 in/165.5 mm
1.0 lbs/0.5 kg1.5 lbs/0.7 kg
Drive for 5.25-
Inch Mount
STT20000A Product ManualPage 7
Chapter 2Specifications
Figure 2-1
STT20000A (3.5-Inch mount) general dimensions
4.00 in (101.6 mm)
6.36 in (161.5 mm)
0.157 in
(4 mm)
4.00 in (101.6 mm)
1.00 in
(25.4 mm)
Figure 2-2
STT20000A (5.25-Inch mount) general dimensions
0.86" (21.8mm)
5.76" (146.4mm)5.49" (139.4mm)
0.20" (5.0mm)
5.87"
(149.0mm)
DRIVE ACTIVE
(GREEN)
1.685"
(42.8mm)
Page 8STT20000A Product Manual
SpecificationsChapter 2
Power specifications
The following table lists the power specifications for the STT20000A. (Power
specifications are measured at the tape drive power connector and are nominal
values.)
SpecificationMeasurement
DC Voltage
Voltage Tolerance
Operational Current
Standby Current
Peak
Power Sequence
Ripple (peak to peak)
Power use
(nominal)
+12 VDC+5 VDC
± 10%± 5%
2.0 amps1.0 amp
0.2 amp0.6 amp
2.2 amps max.—
NoneNone
≤
100 mV
< 15 Watts
(excluding surge)
≤
100 mV
< 15 Watts
(excluding surge)
The following table lists pin assignments for the power connector for the drive.
PinAssignment
1
+12 VDC
2
3
4
STT20000A Product ManualPage 9
+12 return
+5 return
+5 VDC
Chapter 2Specifications
Performance specifications
The following table lists the performance specifications for the STT20000A.
up to 60 Mbytes/min native; up to 120 Mbytes
/min compressed
489 / 733 / 1,000 Kbytes per second
46, 70, or 94 ips
90 ips maximum
Serpentine
QIC-3220-MC
1,7 RLL
Reed Solomon ECC
15
Less than 1 in 10
data bits
FastSense
Head configuration
Recording media
Cartridge size
Data density
Tracks
Page 10STT20000A Product Manual
Wide write/narrow read
1650-Oe 740' Travan TR-5
3.2 in. x 2.4 in. x 0.4 in. (81 mm x 61 mm)
100,400 bits per inch
107 data tracks, one (1) directory track
SpecificationsChapter 2
Environmental requirements
The following table lists the environmental specifications for the STT20000A. The
drive may be mounted either vertically or horizontally.
SpecificationOperationalNon-operational
Temperature
Thermal gradient
Relative humidity
Maximum wet bulb temperature
Altitude
Vibration
Peak to Peak
Displacement
Peak Acceleration
Acoustic level operational
(A-wt sum)
1° t
o +113° F
+4
(+ 5° to + 45° C)
1° C per minute
1
–40° to +149
(–40° to + 65oC)
20° C per hour
oF2
(no condensation)
20% to 80%
non-condensing
1
5% to 95%
non-condensing
2
78.8° F (26° C)No condensation
–1000 to +15,000 feet–1000 to +50,000 feet
0.005 in. max.
(5 to 44.3 Hz)
0.50 g max.
(44.3 to 500 Hz)
55 dBA maximum
0.1 in. max.
(5 to 17 Hz)
1.5 g max.
(17 to 500 Hz)
—
(measured in suitable
enclosure at 3-ft distance
and operator height)
Shock (1/2 sine wave)
1
Specification applies to drive mechanism and media
2
Specification applies to drive mechanism only
2.5 g’s peak, 11 msec100 g's peak, 11 msec
STT20000A Product ManualPage 11
Chapter 2Specifications
Reliability
The STT20000A is designed for maximum reliability and data integrity. The following
table summarizes the reliability specifications.
FeatureSpecification
Non-recoverable error rate< 1 in 1015 bits
Error recovery and controlReed-Solomon Error Correction Code techniques
Error monitoring and reporting (Error Log)
Media pre-written
Retry on read
Data randomization
Mean-Time-Between-Failures
(MTBF)
Mean-Time-To-Repair (MTTR)Less than 0.33 hour
Mean-Time-Between Failures
The Mean-Time-Between Failures (MTBF) is greater than 200,000 hours. This
specification includes all power-on and operational time but excludes maintenance
periods. Operational time is assumed to be 20% of the power-on time. Operational
time is the time the tape is loaded.
Note:
Seagate does not warrant the stated MTBF as representative of any
particular unit installed for customer use. The failure rate quoted here is
derived from a large database of test samples. Actual rates may vary from
unit to unit.
Mean-Time-To-Repair
The Mean-Time-To-Repair (MTTR) is the average time required by as qualified
service technician to diagnose a defective drive and install a replacement drive. The
MTTR for the drive is less than 0.33 hour (20 minutes).
More than 250,000 hours
The STT20000A is a field replaceable unit. If a problem occurs with a subassembly
or component in the drive, the entire unit should be replaced. The faulty drive should
be returned to the factory in its original packaging. Contact your distributor, dealer,
your computer system company, or your Seagate sales representative to arrange
the return.
Page 12STT20000A Product Manual
SpecificationsChapter 2
Recommended tapes
The STT20000A uses pre-formatted minicartridges. The following cartridges are
recommended:
DescriptionSeagate3M/Imation
Travan—740 ft (QIC-3220-MC)
10.0 GB capacity
(20.0 GB capacity with data compression)
Note.The STT20000A reads and writes the QIC-3220-MC format.
The STT20000A reads (but does not write) the QIC-3095-MC format.
Regulatory compliance
The STT20000A complies with the regulations listed in the following table.
AgencyRegulation
CSA
TUV & IEC-RHEINLAND
UL
Canadian Dept. of Communications
EN55022 (CISPR-22)
with additional CE-Mark test requirements
20000TTTR-5
C22.2, No. 950-M89
EN 60 950/IEC 950
1950
Class B
Class B
FCC
Class B, Part 15
Use the STT20000A only in equipment where the combination has been determined
to be suitable by an appropriate certification organization (for example, Underwriters
Laboratories Inc. or the Canadian Standards Association in North America). You
should also consider the following safety points.
• Install the drive in an enclosure that limits the user's access to live parts, gives
adequate system stability, and provides the necessary grounding for the drive.
• Provide the correct voltages (+5 VDC and +12 VDC) based on the regulation
applied—Extra Low Voltage (SEC) for UL and CSA and Safety Extra Low
Voltage for BSI and VDE (if applicable).
STT20000A Product ManualPage 13
Chapter 2Specifications
Notes
Page 14STT20000A Product Manual
InstallationChapter 3
Installation
3
Introduction
This chapter explains how to install the STT20000A. The following paragraphs
briefly outline the organization of this chapter.
Before you begin
Handling guidelines
• The following section,
should read before you begin the installation.
•
Setting jumpers
•
Installing the drive
Because the drive unit can be damaged by electrostatic discharge, an electrostatic
grounding strap is recommended. This strap prevents an electrostatic discharge
from damaging the electronic components on or in the drive unit
If you do not have an electrostatic grounding strap, perform the installation at a
static-safe workstation. If one is not available, follow these guidelines as you install
the drive unit:
• Work in an uncarpeted area.
• To protect the
anti-static bag until you are ready to install it.
drive from static electricity, DO NOT remove the drive from its
Before you begin
shows the master/slave jumpers and describes their uses.
explains how to mount the internal drive unit.
contains general information that you
• Before you remove the drive from the anti-static bag, touch a metal or grounded
surface to discharge any static electricity buildup from your body.
Caution:
• Hold the drive by the edges only. Avoid direct contact with any printed circuit
• Lay the drive only on top of its anti-static bag or return the drive to its bag when
Caution:
STT20000A Product ManualPage 15
If you touch static-sensitive parts of the drive (such as the printed circuit
board) electronic components may be damaged.
board.
you need to lay the drive down.
If you substitute an ATAPI adapter card or longer cables, or if you chain the
tape drive to an existing ATAPI adapter or peripheral, the compatibility
and/or operation of the tape subsystem may be seriously affected.
Chapter 3Installation
Setting jumpers
Review the jumper settings to ensure that the jumpers are properly configured for
your system. Figure 3-1 shows the location of the jumper block. Figure 3-2 shows
the jumper block.
Note:
Record your jumper settings prior to installation. They are not visible after
the drive has been installed.
The default setting is Slave mode with a jumper over pin 3 and pin 4.
Your system setting may vary, so be sure to check your computer or ATAPI
controller manual to determine the proper configuration choice for your system.
Figure 3-1
Location of jumper block and connectors
NOTE:
Bottom of drive shown.
JUMPER
BLOCK
PIN 1
IDE
CONNECTOR
POWER
CONNECTOR
IDE PIN 1
Figure 3-2
Jumper block and jumper settings
(TOP OF TAPE DRIVE)
1
CABLE SELECT
6432
SLAVE
75
8
NOT USED
MASTER
JUMPER ON
JUMPER OFF
Page 16STT20000A Product Manual
InstallationChapter 3
Installing the drive
The internal drive can be installed in a one-half-inch high by 3.5-inch form factor
drive bay or in an inch-high by 5.25-inch form factor (with mounting brackets). The
drive can be installed in three different orientations: horizontally (LED to the left) and
vertically (on either side).
The following section provides directions for mounting the drive in either a 3.5-inch
enclosure or in a 5.25-inch enclosure.
1.Before you install the drive, write down the serial number and model number
shown on the drive and put this information in a safe place. You need this
information if you ever call for service.
2.With the computer cover removed, remove the face plate from the drive bay in
which you plan to install the drive. Refer to the manual that you received with
your computer for instructions about removing the face plate if necessary.
Note:
3.Attach any special mounting hardware to the drive that your system might
4.Locate the mounting screw holes in the drive brackets. Each side contains two
5.Slide the tape drive into the computer so that the drive bezel and the computer
If devices are installed in any drive bays adjacent to the one you are using
for the internal drive, partially removing those devices might give you more
working space.
require. Refer to the manual that you received with your computer for
requirements.
sets of holes. Use the set that aligns the drive properly within the drive bay.
face plate are flush. Then, align the mounting holes as shown in Figure 3-3.
Figure 3-3
Aligning the drive in the computer
STT20000A Product ManualPage 17
Chapter 3Installation
6. Secure the drive using the mounting screws. The threaded mounting brackets
are designed for M3.0 metric screws. If you are mounting the drive in a 3.5-inch
bay, use the screw supplied with the drive. Do not substitute other screws.
Using longer screws may damage the drive. If slide rails are needed, use the
plastic slide rails (supplied with the drive in some configurations).
7.Connect an available power cable to the power connector on the drive. Figure
3-1 shows the location of the power connector. The recommended power
mating connector requires an AMP 1-48024-0 housing with AMP 60617-1 pins
or equivalent.
Note:
8.Connect the interface cable with the connector on the rear of the unit. When
you make the connection, be sure pin 1 of the connector aligns with pin 1 on
the cable connector. See Figure 3-1 for the location of the connector and the
Pin 1 location.
Note:
9.Replace the computer cover. Be sure to reconnect any peripherals that you
disconnected during the installation.
10. Plug the computer and any peripherals into an AC power outlet.
11. Start the computer and install your tape backup software.
Mounting dimensions
Turn off all power before inserting connectors.
Pin 1 on the connector on the rear of the drive is to your right as you look at
the back of the drive (right side up). (See Figure 3-1.) Your cable should
have Pin 1 highlighted by a color or dark strip. Be sure to mate Pin 1 on the
cable to Pin 1 on the drive. Failure to do so could make the drive
inoperative. Also, the cable is keyed to prevent incorrect installation. Make
sure that the blocked pin in the cable connector coincides with the missing
pin on the connector on the rear of the drive. (See Figure 3-1.)
Figures 3-4 and 3-5, respectively, show the location of the mounting holes for the
internal drive without and with mounting brackets.
Page 18STT20000A Product Manual
InstallationChapter 3
Figure 3-4
Mounting holes on internal drive (without mounting brackets)
3.7 in (94 mm)
2.758 in
(70 mm)
6.36 in
(161.5 mm)
1.220 in
(31 mm)
1.0 in
4.0 in (102.6 mm)
0.157 in
(25.4 mm)
(4 mm)
Figure 3-5
Mounting holes on internal drive (with mounting brackets)
0.2 in (5 mm)
0.315 in
(8 mm)
3.543 in
(90 mm)
2.382 in
(60 mm)
0.984 in
(25 mm)
5.76 in (146.4mm)
5.87 in (149.0mm)
.075 in (1.9mm)
2 PLACES
3.12 in
(79,2mm)
1.81 in
(45.9mm)
0.197 in
(5mm)
1.7 in
(43mm)
2.36 in
(60mm)
0.4 in
(10.2mm)
0.62 in
(15.7mm)
0.86 in
(21.8mm)
3.12 in
(79mm)
2.08 in
(53mm)
0.51 in
(13.0mm)
5.49 in
(139mm)
STT20000A Product ManualPage 19
Chapter 3Installation
ATA-2 Interface pin assignments
The STT20000A provides a standard ATA-2 connector. The pin assignments for this
connector are listed in the following table for your reference.
PinAssignmentDescriptionSource
10
11
12
13
1
2
3
4
5
6
7
8
9
RESETResetHost
GndGroundN/A
DD7Data Bus bit 7Host/Device
DD8Data Bus bit 8Host/Device
DD6Data Bus bit 66Host/Device
DD9Data Bus bit 9Host/Device
DD5Data Bus bit 6Host/Device
DD10Data Bus bit 10Host/Device
DD4Data Bus bit 4Host/Device
DD11Data Bus bit 11Host/Device
DD3Data Bus bit 3Host/Device
DD12Data Bus bit 12Host/Device
DD2Data Bus bit 2Host/Device
14
15
16
17
18
19
20
21
22
23
Page 20STT20000A Product Manual
DD13Data Bus bit 13Host/Device
DD1Data Bus bit 1Host/Device
DD14Data Bus bit 14Baby sitting
DD0Data Bus bit 0Baby sitting
DD15Data Bus bit 15Host/Device
GNDGroundN/A
---Key pinN/A
DMARQDMA RequestDevice
GNDGroundN/A
DIOW-I/O WriteHost
InstallationChapter 3
PinAssignmentDescriptionSource
24
25
26
27
28
29
30
31
32
33
34
35
36
–REQGroundN/A
–I/OI/O ReadHost
GNDGroundN/A
IORDYI/O ReadyDevice
CSELCable SelectDevice
DMACKDMA AcknowledgeHost
GNDGroundN/A
INTRQInterrupt RequestDevice
10CS16-16-Bit I/ODevice
DA1Device Address Bit 1Host
PDIAGPassed DiagnosticsDevice
DA0Device Address Bit 0Host
DA2Device Address Bit 2Host
37
38
39
40
CS0-Chip Select 0Host
CD1-Chip Select 1Host
DASP-Device Active or Slave
Present
GroundGroundN/A
Device
STT20000A Product ManualPage 21
Chapter 3Installation
Notes
Page 22STT20000A Product Manual
Drive operation and maintenanceChapter 4
4
Drive operation and maintenance
Introduction
This chapter describes important operational procedures for the STT20000A. It
covers the following topics:
• Drive maintenance and troubleshooting instructions.
Front panel LED
The front panel of the Travan drive (see Figure 4-1) contains the cartridge opening
and one amber light-emitting diode (LED). This LED is lit any time that the tape is
NOT at the beginning of the tape. Thus, the LED indicates tape movement.
Figure 4-1
Front panel—internal drive
DRIVE ACTIVE
(AMBER)
STT20000A Product ManualPage 23
Chapter 4Drive operation and maintenance
Using Travan cartridges
The minicartridges recommended for use with the STT20000A are listed in chapter
2. This section describes some operations using the cartridges.
Loading and unloading cartridges
Your tape drive has a flip-up door that covers the cartridge opening when a tape
cartridge is not installed in the drive. Once a cartridge is inserted, it is held firmly in
place by the drive's positive locking mechanism.
Caution:DO NOT
any tape operations and wait until the amber LED is OFF before
removing the cartridge.
To load
door facing into the drive. Figure 4-2 illustrates the loading of a cartridge.
Figure 4-2
Loading a Travan cartridge
To unload
cartridge straight out. Figure 4-3 illustrates the unloading of a cartridge.
a cartridge, insert it with the metal base plate down and the tape access
a cartridge, wait until the drive activity LED is OFF and then pull the
remove a tape cartridge while the drive is active. Complete
Figure 4-3
Unloading a Tape cartridge
Page 24STT20000A Product Manual
Drive operation and maintenanceChapter 4
Setting the write–protect switch
Travan minicartridges feature a sliding write protect tab located in the upper left
corner of the cartridge. You can set the tab to keep data from being written on the
tape. Use this switch when you want to make sure that important data on the tape
will not be overwritten.
Figure 4-4 shows the cartridge with the switch in the non-protected (read/write) or
unlocked position.
Figure 4-4
Travan cartridge write-protect switch—unlocked position
Figure 4-5 shows the tab in the protected (read only) or locked position.
Figure 4-5
Travan cartridge write-protect switch—locked position
To return a cartridge to the "writeable" state, push the switch toward the end of the
cartridge or to the unlocked position.
STT20000A Product ManualPage 25
Chapter 4Drive operation and maintenance
Loading revised firmware via Seagate firmware cartridge
The STT20000A uses flash EEPROM. Flash EEPROM enables you to download
new firmware when revisions to firmware are released. Firmware revisions are
released on specially encoded cartridges that are automatically recognized by these
drives. These firmware revisions are available for qualified OEMs only from Seagate
Peripherals, Inc.
To load a firmware upgrade tape, follow these steps.
1.Power on the host system and the STT20000A drive. Allow the system boot up
process to reach the point where there is no ATAPI bus activity.
2.Place the firmware upgrade cartridge record switch to the non-record position.
Insert the firmware upgrade cartridge in the drive and observe the amber LED
light on the front of the drive.
3. Once the upgrade cartridge is inserted, tape motion begins. The drive LED
flashes on and off. Approximately 15 seconds later, tape motion stops, and the
LED continues to flash.
4. The LED flashes on and off at a steady rate as the firmware upgrade continues.
Approximately 45 seconds later, the drive resets internally, and the tape moves
back and forth, then stops.
5. The LED light will go off and remain off. Double check that the LED remains off .
Make sure that there is not further tape motion. Remove the upgrade cartridge.
6. The firmware is now upgraded to the new revision. The drive is operational and
the new firmware is active. Turning power off at this time does not affect the
firmware revision level.
Note:
If a problem occurs during the firmware loading process, the LED on the front panel
goes out. In that case, the firmware upgrade cartridge may be defective, or the drive
may not be operating correctly.
If after a repeat loading of the firmware cartridge, the same condition is observed,
contact your Seagate sales representative.
Firmware upgrade cartridges are available to qualified Seagate OEM customers.
Contact your Seagate sales representative for information.
Once the firmware upgrade cartridge is inserted in the drive, it is important
that no power interruption occurs while the firmware is loading. DO NOT
POWER OFF THE DRIVE AT THIS TIME. If a power interruption occurs,
the firmware may not be loaded correctly, and the drive may not operate
properly.
Page 26STT20000A Product Manual
Drive operation and maintenanceChapter 4
Drive maintenance
Minimal maintenance is needed to ensure that your STT20000 SCSI minicartridge
drive operates at peak condition. This section explains how to care for tape
cartridges and how to clean the drive head.
Caring for tape cartridges
Although minicartridge tape cartridges are ruggedly built, they must be handled with
care to preserve the data that they contain. The following points are guidelines for
storing and using minicartridges.
• Do not open the tape access door of the cartridge or touch the tape itself. One
fingerprint can prevent the drive from reading the tape.
• Keep the cartridge away from sources of electromagnetic fields, such as
telephones, dictation equipment, mechanical or printing calculators, motors, and
bulk erasers. Do not lay cartridges on the computer monitor or on the base unit
of the computer.
• Keep the cartridge away from direct sunlight and heat sources, such as
radiators or warm air ducts.
• Keep the cartridge free of moisture. Do not wet or submerge a cartridge in any
liquid.
• Do not expose the cartridge to temperature extremes. Allow the cartridge to
assume room temperature slowly.
• Retensioning the tape cartridge is always recommended for optimal
performance, particularly after exposure of the cartridge to temperature changes
or shock. Retensioning restores the proper tape tension to the media.
Cleaning the drive read/write head
Caution.
To properly maintain the tape drive, you should periodically clean the read/write
head. No other periodic maintenance is required.
Follow these guidelines to help ensure that your drive provides long, reliable service:
• Operate the drive in a clean, dust-free environment.
• Never apply a lubricant to the drive.
Never clean the read/write head of the drive with anything other than a
lint-free swab or an approved cleaning cartridge. Do not touch the head
with anything other than a lint-free swab.
• Generally Travan drives are highly reliable and require little user maintenance.
For normal operations cleaning once per month is quite adequate.
• For new cartridges, clean the head after two hours of tape movement.
Thereafter the drive can be cleaned as per normal operations.
STT20000A Product ManualPage 27
Chapter 4Drive operation and maintenance
You can clean the drive head by one of two methods: you can use the Seagate
approved 3M DC2000 cleaning cartridge DC051111 (12947), P/N CKDC2000, which
is available through Seagate Express 1-800-531-0968, or you can manually clean
the drive head. To manually clean the drive head, follow these steps.
1.Moisten a clean, lint-free swab in 90% isopropyl alcohol so that it is wet but not
dripping. (Never use a dry swab.)
2.Hold the drive access door open and wipe the head gently using a side-to-side
motion. The upright rectangle with the stripe in Figure 4-6 is the head.
Figure 4-6
Cleaning the drive head and capstan
CapstanTape Head
Troubleshooting
3.Use a new swab saturated with 90% isopropyl alcohol to wipe the capstan. The
capstan is the flat, roller to the left of the head as shown in Figure 4-6. Rotate
the capstan until its entire surface is clean.
4.Allow the drive to dry for 3 minutes before using.
If you experience problems after you install the drive, take the following actions to
try to solve the problems.
• Check that all connections are secure.
• Check the drive to be sure that the jumper settings are correct.
If a power interruption occurs during a backup or restore operation, start over when
the power is restored. If the drive appears to fail during a backup or restore
operation, try the following steps:
1.Remove and replace the cartridge and try again. Make sure you are using the
correct type of tape cartridge.
2.Turn off all power to the computer and drive. Wait for the computer to power
down and then start over.
Page 28STT20000A Product Manual
Drive operation and maintenanceChapter 4
3.Try a different tape—preferably one that has never been used.
4.Check all cable connections for proper contact.
5.Clean the tape drive head as previously instructed. Then try the operation
again.
If problems persist, contact your tape drive supplier or Seagate technical support at
US and Canada1-800-SEAGATE (1-800-732-4283)
Outside US and Canada1-405-936-1234
Seagate Web Sitehttp://www.seagate.com
Seagate BBS1-405-936-1630
Before you call technical support, be sure that you have the documentation for your
computer and for all installed peripheral devices.
STT20000A Product ManualPage 29
Chapter 4Drive operation and maintenance
Notes
Page 30STT20000A Product Manual
ATAPI InterfaceChapter 5
5
ATAPI interface
Introduction
The STT20000A provides an ATA Packet Interface (ATAPI) controller for
communications between the host computer and the drive. The drive supports the
QIC-157 standard interface.
The STT20000A provides a connection between the driver/card and the component
of the PC. Refer to chapter 3 for specific cabling and connector information.
ATA-2 Interface
ATA-2 Signals
DASP-
Note:
This chapter clarifies the use of several ATA-2 signals and ATAPI commands that
are either vague or optional in the QIC-157 specification.
The information about the ATA-2 interface is presented in the following topics: ATA2 Signals, ATA Registers, and ATA Commands.
Only the DASP and PDIAG- signals are described in the following paragraphs.
This signal is used during power-up handshake sequences for master/slave
identification per ATA-2 specifications.
Because the device has its own front-panel activity LED, this signal is not driven by
this device (to indicate activity) after power-up is complete.
Refer to the
interface.
QIC-157 Standard
for detailed information about the this
PDIAG-
This signal is used during power-up handshake sequences for master/slave
identification per ATA-2 specifications.
STT20000A Product ManualPage 31
Chapter 5ATAPI Interface
ATA registers
The following table lists the values for the registers during register initialization.
RegisterPORRESET–
(Hard Reset)
STATUS
00h00h00h10h41h
ATA Reset
(SRST Bit)
ATAPI Soft
Reset
Read/Identify
Device Cmds
(DRDY+ERR)
ERROR
01h
(No
01h01h01h04h
(ABRT)
Error)
Sector Count
(ATAPI Intr.
Reason)
Sector
Number
(ATAPI
Reserved)
Cylinder Low
(ATAPI Byte
Count High)
Cylinder High
(ATAPI Byte
Count High)
Drive/Head
01h01h01h01h—
01h01h01h01h—
14h14h14h14h14h
EBhEBhEBhEBhEBh
000000——
During an ATA soft reset or aborted ATA command, the host view of the DSC bit (Status
register) will be cleared, along with the DRDY bit. Any ATAPI command including ATAPI
Identify) can be used to set DRDY true and to re-enable host view of DSC bit.
Status Register
The following layout represents the Status Register. The CORR and IDX bits are not
used by the drive.
76543 2 1 0
BSYDRDY-
BitMnemonicDescription
7BSYBusy—set when only drive has access to ATA registers.
6DRDYDrive Ready—set when DSC is valid.
4DSCDrive Seek Complete—set when drive ready for command.
3DRQData Request—set when data ready to be transferred.
0CHECKCheck—set when an error has occurred.
(0)
DSCDRQCORR
(0)
IDX
(0)
CHECK
Page 32STT20000A Product Manual
ATAPI InterfaceChapter 5
Error Register
The following layout represents the Error Register.
76543 2 1 0
Sense Key [3..0]MCRABRTEOMILI
Bit(s)MnemonicDescription
7-4Sense KeySet to indicate the reason for the CHECK bit being set in
the Status Register.
3MCRMedia Change Request—Always 0.
2ABRTAborted Command—Set when an ATA or ATAPI
command is aborted.
1EOMEnd Of Media—The end of the current partition was
0ILIIllegal Length Indication—This bit is set when an illegal
Feature Register
The following layout represents the Feature Register.
7654 3 2 1 0
.... . . .
BitMnemonicDescription
0DMADMA Data Transfer—When this bit is a 1, the data transfer
detected. On a WRITE command, unrecoverable data
might be left in the buffer.
length block is read. Sense Status also indicates ILI.
DMA
is in DMA mode. If the bit is 0, PIO data transfer is used.
All ATAPI packet commands are transferred in PIO mode.
The value in this register must be set before
ATAPI command that transfers
every
data (including log/mode set/sense) to determine the transfer method. This register
is overwritten by the drive after every command completion to present Error
STT20000A Product ManualPage 33
Chapter 5ATAPI Interface
information. If you do not program this register correctly, the drive "hangs" in the
BSY state. To correct this problem, reset operations.
Supported ATA Commands
The ATA commands are briefly described in the following paragraphs.
Execute Drive Diags (90h)
This command is executed regardless of the state of the DRV bit. The command
causes an actual microprocessor reset (drive loses all logical position information).
Power-up diagnostics are performed, and the PDIAG/DASP handshake is
performed per ATA-2 specification. The master device will generate an interrupt.
Idle Immediate (E1h)
This command causes the device to set its Power Mode state to Idle and to
generate an interrupt. Although the drive has no actual power saving features, this
command is emulated for software compatibility.
Standby Immediate (E0h)
This command causes the device to set its Power Mode state to Standby and to
generate an interrupt. Although the drive has no actual power saving features, this
command is emulated for software compatibility.
Check Power Mode (E5h)
This command causes the device to return its Power Mode state in the Int Reason
register, and generate an interrupt. If the drive is in Standby mode, this command
returns 00h in the Int Reason register, otherwise this command returns FFh in the
Int Reason register (indicating IDLE mode).
Previous CmdInt Reason
Reset/Power-upFFh (Idle)
Standby Immed.00h (Standby)
Idle ImmediateFFh (Idle)
Any Other CmdFFh (Idle)
Sleep (E6h)
This command is treated as an Idle command and does NOT prevent the drive from
responding to further commands.
Page 34STT20000A Product Manual
ATAPI InterfaceChapter 5
Set Features (EFh)
If an unsupported feature is selected, the command is aborted. Otherwise, the
indicated parameter is set. The following list indicates the supported features:
Feature NumberSet Feature Commands
03hSet Transfer Mode from Sector Count register
66hDisable reverting to power-on defaults (no-op)
CChEnable reverting to power-on defaults (no-op)
Set Transfer Mode Feature
If the Set Transfer Mode feature (03h) is received, the Sector Count (ATAPI
Interrupt Reason) register is used to set the transfer mode based on the following
table. Any transfer modes not listed in the table cause the command to be aborted.
SectorTransfer Mode
00hPIO Transfer Mode 4 (default)
01hPIO Transfer Mode 2 (explicit IORDY disable)
08hPIO Transfer Mode 0
09hPIO Transfer Mode 1
0AhPIO Transfer Mode 2
0BhPIO Transfer Mode 3
0ChPIO Transfer Mode4
10hSingle Word DMA Mode 0
11hSingle Word DMA Mode 1
12hSingle Word DMA Mode 2
20hMulti-word DMA Mode 0
21hMulti-word DMA Mode 1
22hMulti-word DMA Mode 2
STT20000A Product ManualPage 35
Chapter 5ATAPI Interface
Issuing PIO and DMA transfer modes does not actually select these operations;
however, issuing these modes selects the rate of either type of transfer, as selected
by the DMA bit (bit 0) of the ATAPI Features register.
ATAPI Identify Device (A1h)
The protocol and timing of this command conforms to a standard ATA type
command as defined in ATA-2.
This command is similar to the ATA Identify Device command except it uses
Note:
a different op-code. The ATA Identify Device command is aborted.
This command is generally intended to be used by a low-level ATAPI driver to
determine the number and type of ATA/ATAPI devices attached to the interface.
This driver might be able to program transfer rates and other parameters in the host
ATA (IDE) interface.
The following table defines the values returned by the drive.
62Single Word DMA Mode0407hSelected DMA mode 2 (Upper Byte),
63Multi Word DMA Mode0407hSelected DMA mode 2 (Upper Byte)
64Enhanced PIO Mode0003hPIO Mode 3 and 4 Supported
65Minimum Multi Word DMA Cycle Time0078hMode 2 (120 nanoseconds)
66Recommended Multi Word DMA Cycle
Time
67Minimum PIO Cycle Time w/o IORDY0078hMode 4 (120 nanoseconds)
0078hMode 2 (120 nanoseconds)
valid
DMA modes 2,1,0 Supported.
DMA modes 2, 1, 0 supported.
68Minimum PIO Cycle Time with IORDY0078hMode 4 (120 nanoseconds)
69-255Reserved/Vendor Unique0000h—
ATAPI Packet Command (A0h)
Before issuing the ATAPI Packet command, the host writes to the Byte Count
register (high and low) the maximum/preferred number of bytes to be transferred in
a single PIO DRQ. For Data Transfer commands (READ and WRITE), this value is
assumed to be greater than or equal to 512 and is ignored.
ATAPI Soft Reset (08h)
The ATAPI Soft Reset command performs a complete microprocessor reset.
Current physical and logical position is lost, and if a tape is present, a LOAD
sequence is performed, resulting in a Ready at BOP0 condition (with Unit Attn).
The DSC is set to 1 before the BSY bit is cleared.
STT20000A Product ManualPage 37
Chapter 5ATAPI Interface
ATAPI interface
The following table lists the ATAPI interface commands for the drive. In this table,
DSC restrictive means that the host should wait for DSC to be set before issuing the
command for minimum IDE bus overhead. Note that all ATAPI commands are 12
bytes in length. The command descriptions show only the first 6 or 10 bytes of these
commands, even though the commands are actually 12 bytes long.
CodeDSC
Restrictive
00h
01h
03h
08h
0Ah
10h
11h
12h
15h
YTEST UNIT
YREWIND
NREQUEST
bufferREADDelay occurs if first READ is not READ 0 blocks.
bufferWRITEWrite 0 not required to initialize DSC.
YWRITE
YSPACESpace forward/reverse Filemarks and space to
NINQUIRYDSC not affected.
—MODE
CommandComments
Not DSC restrictive on some other drives.
READY
Null status if DSC not set.
SENSE
Flush always. WFM 0 to flush.
FILEMARK
EOD only.
Select speed, FDP, page 2B updates only.
SELECT
19h
1Ah
1Bh
2Bh
34h
3Bh
Page 38STT20000A Product Manual
YERASEConstitutes a logical erase; accepted at BOP0/1
or EOD only.
—MODE
SENSE
YLOAD/UNL
OAD
YLOCATELocates logically only; can also select partition.
YREAD
POSITION
—WRITE
BUFFER
UNLOAD to make not ready; LOAD to return to
Ready. LOAD w/Retension any time. (All LOADS
imply REWIND and select partition 0.)
Also used to wait for previous command done.
Use for download only. Drive must be "unloaded".
ATAPI InterfaceChapter 5
4Ch
4Dh
Reserved Fields
Unless otherwise stated, all reserved and unsupported fields are not verified when
the drive accepts a command. These fields are filled with 00s for future
compatibility.
—LOG
SELECT
—LOG
SENSE
Resets Error Counts.
Contains Error Counts (WRITE and READ) and
tape capacity.
STT20000A Product ManualPage 39
Chapter 5ATAPI Interface
Erase command
Bit=>
Byte
0Operation code (19h)
1Reserved1 (Long)
2Reserved
3Reserved
4Reserved
5Reserved
76543210
The Erase command is only accepted when the drive is ready and located at either
BOP 0/1 or EOD. Erase at BOP causes the drive to write a Control/Filler Frame at
the beginning of the current partition, followed by an EOD pattern. (The Use Count
field of the Control Frame is incremented from its previous value). This action results
in a logical erasure of the current partition. If partition 0 is erased, partition 1
becomes logically erased because of the use count field. Erase at EOD is accepted,
but no operation is performed except a write flush if following a WRITE command.
This result is because all data following EOD is already logically erased.
The DSC bit is reset (0) after this command is accepted and is set (1) when the
command is complete. REQUEST SENSE can then be used to verify successful
command completion.
Page 40STT20000A Product Manual
ATAPI InterfaceChapter 5
Inquiry command
Bit
Byte
0Operation code (12h)
1Reserved
2Reserved
3Reserved
4-7Allocation Length
8-15Vendor ID (8 ASCII characters) ASCII “Seagate “
16-31Product ID (16 ASCII characters ASCII “STT20000A “
76543210
The INQUIRY command is always accepted, regardless of the state of the DSC bit.
The command does not modify the status of DSC. The INQUIRY command returns
the lesser of 36 bytes or the Allocation Length parameter of information. The
following table defines the returned values.
Much of the information returned by this command is redundant with the
The INQUIRY command is not to be used by the low-level driver; rather, it is
intended to be used by applications, which usually have access to the drive only
through the ATAPI protocol.
STT20000A Product ManualPage 41
Chapter 5ATAPI Interface
Load/Unload command
Bit
Byte
0Operation code (1Bh)
1Reserved
2Reserved
3Reserved
4ReservedRe-TenLoad
5Reserved
76543210
LOAD (with or without Re-tension) is accepted any time a tape is present in the
drive, (even if status indicates it is already loaded). This command includes implicit
rewind and select partition 0 operations. The DSC bit is reset (0) after this command
is accepted and is set (1) when the drive has initialized and is ready. REQUEST
SENSE can then be used to verify successful command completion.
The UNLOAD option(s) re-tensions the tape (if selected) and moves the tape to the
logical BOT or EOT end (as selected), then causes the drive to report not ready to
any subsequent media access commands. Either a manual load operation or LOAD
command is required for the drive to return to ready.
Page 42STT20000A Product Manual
ATAPI InterfaceChapter 5
Locate command
Bit
Byte
0Operation code (2Bh)
1ReservedCPReserved
2Reserved
3(MSB)
4Logical Block Address
5
6(LSB)
7Reserved
8Partition
9Reserved
76543210
If the Change Partition (CP) bit is set, the drive first changes to the specified
partition, then attempts to locate before the specified logical block. (All addresses
are interpreted as logical.) A locate to Block 0 (in any partition) is treated like a
rewind (to BOP)and does not start a read-ahead. Depending on the exact sequence
of commands, LOCATE to Block 0 might or might not report a Blank Check error.
The DSC bit is reset (0) after this command is accepted and is set (1) when
completed. REQUEST SENSE can then be used to verify successful command
completion.
STT20000A Product ManualPage 43
Chapter 5ATAPI Interface
Log Select command
Bit
Byte
0Operation code (4Ch)
1ReservedPCRReserved
201(PC)Reserved
3Reserved
4Reserved
5Reserved
6Reserved
7(MSB) Parameter List Length
8(LSB)
9Reserved
76543210
The PC (Page Control) field is 01, for current values. The Parameter List Length
field specifies the number of data bytes to transfer. If the PCR bit is 1 and the
Parameter List Length is 0, the error counters are all reset (0).
All of the counters defined in the Log Sense command are reset by the Log Select
command and are otherwise only cleared by a power-on (hard) or ATAPI reset.
Page 44STT20000A Product Manual
ATAPI InterfaceChapter 5
Log Sense command
Bit
76543210
Byte
0Operation code (4Dh)
1Reserved
201(PC)Page Code
3Reserved
4Reserved
5(MSB)Parameter Pointer
6(LSB)
7(MSB)Allocation Length
8(LSB)
9Reserved
The PC (Page Control) field is 01, for current values. The Page Code field identifies
which page of data is being requested. The Parameter Pointer field allows
requested parameter data to begin from a specific parameter code. The Allocation
Length field specifies the number of data bytes to transfer.
The following table presents the supported log pages.
ByteDescriptionValueMeaning
0
1
2,3
4
5
6
7
Page Code00hSupported Log Pages Page
Reserved00h-
Page Length00,04h4 Supported Pages
First Supported Page00hSupported Log Pages Page Code
03hError Counter (Read) Page Code
31hTape Capacity Page Code
Last Supported Page00hFiller
STT20000A Product ManualPage 45
Chapter 5ATAPI Interface
Error Counter Page (Read)
The following table presents the Error Counter Page layout.
48-51Odd Tracks (Forward) Read RetriesN,N,N,NCounter Value
Tape Capacity Page Code
The following table presents the Tape Capacity Page layout.
ByteDescriptionValueMeaning
0
1
2,3
4,5
6
7
8-11
12-15
16-19
20-23
24-27
Page Code31hTape Capacity Page
Reserved00h-
Page Length00,20h32 Bytes Following
Parameter Code0001hRemaining Capacity, Part 0 Code
Parameter Bits40hDevice Controlled Counter
Parameter Length04h4-byte Counter
Remaining Capacity, Partition 0 ValueN,N,N,N
Parameter: Code, Bits, Length0002h,
40h,04h
Remaining Capacity, Partition 1 ValueN,N,N,N
Parameter: Code, Bits, Length0003h,
40h,04h
Maximum Capacity, Partition 0 ValueN,N,N,N
Remaining Capacity, Part 1 Code
Maximum Capacity, Part 0 Code
28-31
32-35
Parameter: Code, Bits, Length0004h,
40h,04h
Maximum Capacity, Partition 1 ValueN,N,N,N
Maximum Capacity, Part 1 Code
STT20000A Product ManualPage 47
Chapter 5ATAPI Interface
The Remaining Capacity for non-current partitions shall be the same as the
Maximum Capacity for that partition. Capacities are multiplied by 1024 to determine
the number of bytes. These values are conservative estimates.
The Parameter bit, TSD (not shown), is zero implying that the drive can save
parameters across resets, etc. Parameters are not saved but are re-computed
correctly from any logical position, regardless of the previous states of the tape
drive.
Page 48STT20000A Product Manual
ATAPI InterfaceChapter 5
Mode Select command
Bit
Byte
0Operation code (15h)
1Reserved1 (PF)Reserved
2Reserved
3(MSB) Parameter List Length
4(LSB)
5Reserved
76543210
The Mode Select command provides a means to change device parameters. The
PF (Page Format) bit is 1, since the Mode Pages are in SCSI-2 format. The only
changeable parameters are Speed Selection (in the Mode Parameter Header), and
certain fields in Mode Page 2Bh (MFM mode). The Parameter List Length field
specifies the length in bytes of the Mode Select parameter list that are transferred to
the device as data. A Parameter List Length of zero indicates that no data is
transferred.
Mode Sense should be issued prior to Mode Select to determine the supported
pages, page lengths, and other parameters.
The device terminates the Mode Select command with a Check Condition status,
sets the Sense Key to Illegal Request, and sets the Additional Sense Code to
Invalid Field in Parameter List for the following conditions:
•If an attempt is made to change an unchangeable value in the Mode Select
header, block descriptor, or any page.
•If an attempt is made to send a page with a length not equal to the parameter
length reported for that page by the Mode Sense command.
•If an attempt is made to send a value for a parameter that is outside the range
supported by the device.
STT20000A Product ManualPage 49
Chapter 5ATAPI Interface
Mode Sense command
Bit
Byte
0Operation code (1Ah)
1ReservedDBDReserved
200(PC)Page Code
3(MSB) Allocation Length
4(LSB)
5Reserved
76543210
The PC (Page Control) field is 00, since only current values are reported. If DBD
(Disable Block Descriptor) is set (1), then the Mode Block Descriptor is not included
in the data returned to the host. The Allocation Length field specifies the number of
data bytes to transfer
The following pages are supported for Mode Select and Mode Sense commands.
Page CodeDescription
11hMedium Partition Page
2AhCapabilities and Mechanical Status Page
2BhTape Parameters Page (MFM mode)
3FhReturn All Pages
Mode Parameter Header
The following table describes the Mode Parameter header.
The Block Descriptor is returned to the MODE SENSE command unless the DBD bit
in the command packet is set to one. If the Block Descriptor is not sent, the Block
Descriptor Length field (in the Mode Parameter Header) is 0.
ByteDescriptionValueMeaning
4
5-7
8
9-11
Density CodeNNCurrent Density
Number of Blocks000000hZero
Reserved00h—
Block Length000200hAlways 512 byte blocks
The Number of Blocks is 0, indicating that all blocks in the media match this
descriptor, (the blocks are fixed 512 byte blocks).
None of the Block Descriptor parameters may be changed (Block Length is fixed).
STT20000A Product ManualPage 51
Chapter 5ATAPI Interface
Mode Medium Partition Page
The following table describes the Mode Medium Partition Page layout.
ByteDescriptionValueMeaning
0Page Code11hMedium Partition Page
1Page Length06h6 Bytes of Information
2,3Maximum Additional Partitions,
Additional Partitions Defined
4FDP (bit 7), reserved80hFixed Data Partitions
5Medium Format Recognition03hFormat and Partition Recognition
6,7Reserved00h,00h—
00h,00hNot Supported
None of the Medium Partition Page (11h) parameters can be changed.
Mode Capabilities and Mechanical Status Page
The following table describes the Mode Capabilities and Mechanical Status Pages
ByteDescriptionValueMeaning
.
0
1
2,3
Page Code2AhCapabilities and Mechanical Status Page
Continuous Transfer Limit (blocks)0034h52 blocks per Read/Write command
Current Speed Selected (Kbytes
per second)
Buffer Size (in 512 bytes)02D8h14 frames of 52 blocks = 728
600.1,000 Kbytes/sec Maximum
0000h—
NNNNCurrent transfer rate
Protect status
Page 52STT20000A Product Manual
ATAPI InterfaceChapter 5
ByteDescriptionValueMeaning
.
18-19
Reserved00h—
None of the Mode Capabilities and Mechanical Status Page (2Ah) parameters can
be changed.
Mode Tape Parameters Page
ByteDescriptionValueMeaning
0
1
2
3
4
5
6,7
8,9
Page Code2BhTape Parameters Page
Page Length0Eh14 Bytes of Information
Density in Kilo bits per inchNNDensity can imply tape format
Reserved00h—
Reserved (Format Fill Byte)00hNot used, MFM mode is read only
BSEG20hNumber of Blocks per Segment (32)
SEGTRKNNNNNumber of Segments per Track
TRKSNNNumber of Tracks (per Tape)
10
11
12
13,14
15
MAXSECT80hMax MFM Sector Value (128)
MAXCYLNNMax MFM Cylinder Value
MAXHDNNMax MFM Head Value
Reserved0000h—
WDAM,RM,FW (bits 7-5)00hNot Used, MFM mode is read only
This page is used for MFM (Modified Frequency Modulation), or floppy interface
tape formats, such as 2080, 2120, TR1, TR2, TR3, etc. This feature is not available
in the STT20000A.
The following fields are changeable: SEGTRK, TRKS, MAXCYL, and MAXHD.
STT20000A Product ManualPage 53
Chapter 5ATAPI Interface
Read command
Bit
Byte
0Operation code (08h)
1Reserved1 (Fixed)
2(MSB)
3Transfer Length
4(LSB)
5Reserved
76543210
The Transfer Length specifies the number of fixed 512 byte blocks to be transferred.
A transfer length of 0 indicates that no data is to be transferred but will initiate a
read-ahead.
The DSC bit is reset (0) after this command is accepted and is set (1) when at least
52 blocks in the buffer are available for the next READ command. Issuing a READ
command when the DSC bit is reset (0) will keep the ATA bus busy (BSY = 1) while
the drive is reading the required data into the buffer. This delay could be more than
a minute if exhaustive retries are required to read the data.
Page 54STT20000A Product Manual
ATAPI InterfaceChapter 5
Read Position command
Bit
76543210
Byte
0Operation code (34h)
1Reserved
2Reserved
3Reserved
4Reserved
5Reserved
6Reserved
7Reserved
8Reserved
9Reserved
The following table describes the Read Position layout.
ByteDescriptionValueMeaning
0
1
2,3
4-8
8-11
12
13-15
BOP, EOP, BPUnn80h = Beginning of Partition
40h = End of Partition
04h = Block Position Unknown
Partition Number00/01hCurrent Partition (bit 0)
Reserved00h-
First Block Location
(Host Block Location)
Last Block Location
(Medium Block
Location)
Reserved00h—
Blocks in Buffer000000
NNNNNNNNLogical Number of next block to transfer
NNNNNNNN
*
between host and buffer
Not Supported
*
Not Supported
STT20000A Product ManualPage 55
Chapter 5ATAPI Interface
ByteDescriptionValueMeaning
16-19
These fields might appear to report the number of bytes/blocks in the buffer.
*
Bytes in Buffer00000000
*
Not Supported
However, this information is not guaranteed to be accurate. You should not rely on
this information.
The only position that is guaranteed is the host logical block position. The First and
Last Block Locations both return the same host location, and Blocks and Bytes in
Buffer are reported as 0.
Because Read Position is DSC restrictive on all ATAPI tape drives, it can be used to
“wait” for any previous command to complete. This can be useful for applications
with ATAPI only access to determine the actual completion of a command. Note,
this will keep the ATA bus busy during the “wait”. DSC polling (to wait for DSC set)
is preferred when possible.
Page 56STT20000A Product Manual
ATAPI InterfaceChapter 5
Request Sense command
Bit
Byte
0Operation code (03h)
1Reserved
2Reserved
3Reserved
4Allocation Length
5Reserved
76543210
An Allocation Length value of 20 will return all Request Sense data.
The Request Sense command is always accepted, regardless of the state of the
DSC bit, but the status is valid only when DSC or CHK (error) is set (1). If DSC and
CHK are both reset (0), a non-error “null” status is returned. Normally, if CHK is set,
DSC is set. The only time CHK is set and DSC is reset, is during writes at logical
end of media; DSC remains a buffer indicator, and CHK is set to indicate EOM,
which is a warning, not an error.
If a command completes with a check (error) condition, the next command issued, if
not Request Sense or Inquiry, will be aborted, and a deferred error will be reported.
If the command is Request Sense, a non-deferred error is reported. The Inquiry
command does not affect status reporting.
The following table describes the REQUEST SENSE layout.
ByteDescriptionValueMeaning
0
1
2
Valid, Error Code70h,71h80h = Information Field Valid
+ 70h = Current Errors
or 71h = Deferred Errors
Reserved (Segment Number)00—
Filemark, EOM, ILI, Sense KeyNN 80h = Filemark
+ 40h = EOM
+ 20h = ILI
+ Sense Key
STT20000A Product ManualPage 57
Chapter 5ATAPI Interface
3-6
7
8-11
12
13
14
15
16,17
18,19
InformationNNNNNNNNTransfer Residue or
Unwritten Blocks + Filemarks
Additional Sense Length0Ah10 bytes following
Command Specific Information00hNot Supported
Additional Sense Code (ASC)NN
Additional Sense Code
Qualifier (ASCQ)
Field Replaceable Unit Code00hNot Supported
SKSV + Sense Key Specific00hNot Supported
Sense Key Specific0000hNot Supported
Pad0000hPad to 4-byte boundary
NN
Page 58STT20000A Product Manual
ATAPI InterfaceChapter 5
Rewind command
Bit
Byte
0Operation code (01h)
1Reserved
2Reserved
3Reserved
4Reserved
5Reserved
76543210
The Rewind command first ensures that all buffered write data has been transferred
to the medium, then causes the device to position to BOP of the current partition.
The DSC bit is reset (0) after this command is accepted and is set (1) when the
drive is ready to write at BOP0 (or encountered a hardware error). REQUEST
SENSE can then be used to verify successful command completion.
STT20000A Product ManualPage 59
Chapter 5ATAPI Interface
Space command
Bit
Byte
0Operation code (11h)
1ReservedSpace Code
2(MSB)
3Count
4(LSB)
5Reserved
76543210
The only Space codes that are supported are 001b (Filemarks) and 011b (End of
Data on Current Partition). For Space Filemarks, negative count (2s compliment)
indicates Space Filemarks Reverse.
The DSC bit is reset (0) after this command is accepted and is set (1) when the
command is completed and the drive is ready. REQUEST SENSE can then be used
to verify successful command completion.
Page 60STT20000A Product Manual
ATAPI InterfaceChapter 5
Test Unit Ready command
Bit
Byte
0Operation code (00h)
1Reserved
2Reserved
3Reserved
4Reserved
5Reserved
76543210
This command can be used to determine the readiness of the device to accept a
media access command. It’s purpose is to indicate the cartridge state: no cartridge
(or drive fault), cartridge becoming ready, or cartridge/drive ready.
If the drive is busy with a previous command (DSC reset), the drive will wait for the
previous operation to complete before releasing the ATA bus. On some other ATAPI
tape drives, Test Unit Ready does not wait for DSC set before completing, and if an
application needs to “wait” for an command done via the ATAPI interface, Read
Position should be used instead.
STT20000A Product ManualPage 61
Chapter 5ATAPI Interface
Write command
Bit
Byte
0Operation code (0Ah)
1Reserved1 (Fixed)
1Reserved
2(MSB)
3Transfer Length
4(LSB)
5Reserved
76543210
The Transfer Length specifies the number of fixed 512 byte blocks to be transferred.
A transfer length of 0 indicates that no data is to be transferred but is used on some
drives to put DSC into write buffer mode.
The DSC bit is reset (0) after this command is accepted and all data has been
transferred. This bit is set (1) when there are at least 52 empty blocks in the buffer
available for the next WRITE command. Issuing a WRITE command when the DSC
bit is reset (0) will keep the ATA bus busy (BSY=1) until buffer
Page 62STT20000A Product Manual
ATAPI InterfaceChapter 5
Write Filemark command
Bit
Byte
0Operation code (10h)
1Reserved
2Reserved
3Reserved
4ReservedCount
5Reserved
76543210
After receiving this command, the device sets DSC (0) and returns completion
status. Any data remaining in the buffer is then written to tape (flush/ synchronize),
and if the count is 1, a Filemark is written. In any case, an EOD is then written.
The Immed bit in the command packet is ignored, and the DSC bit is reset (0) after
this command is accepted. The DSC bit is set (1) after the EOD has been
successfully written. REQUEST SENSE can then be used to verify successful
command completion.
STT20000A Product ManualPage 63
Chapter 5ATAPI Interface
Write Buffer (download microcode) command
Bit
Byte
0Operation code (3Bh)
1Reserved101 (Mode)
2Reserved
3Reserved
4Reserved
5Reserved
6(MSB)
7Transfer Length
8(LSB)
9Reserved
76543210
The Write Buffer command is intended only to provide a method for downloading
new drive microcode (firmware) into Flash EPROM, so the only valid MODE is 101
(download microcode and save). The drive must be Not Ready (unloaded) for this
command to be accepted, and the transfer length is set to the download file size,
which is currently 0x026800. All data is transferred in one command.
Page 64STT20000A Product Manual
Tape FormatChapter 6
6
Tape format
Introduction
The STT20000A conforms to the QIC-3220-MC recording format standard. This
format is for streaming magnetic tape in a minicartridge that is to be used for
information interchange among information processing systems, communication
systems, and associated equipment.
This chapter provides an overview of the tape format used by the STT20000A.
Tape partitioning
The drive uses factory pre-written Travan TR-5 media. The tape is always divided
into two partitions:
Track positions
• Partition 1 is the directory partition and is recorded on the Directory track only.
• Partition 0 contains the data (tracks 0 through 107) and is recorded on all tracks
except the Directory track.
Recording data at 100,400 bits per inch (BPI), the drive can store 10.0 GB on the
data partition of one 740-foot long, 0.315-inch (8.0 mm) wide Travan TR-5 tape.
Using software data compression, these capabilities are typically doubled.
The recording format and partitioning support Quick File Access (QFA).
The centermost track is called the Directory Track and has larger guard bands on
both sides of it to allow it to be written without interfering with its adjacent tracks.
Track zero is the track immediately below the Directory Track. The even numbered
tracks are positioned sequentially below track 0. Thus, track 2 is below track 0, and
track 4 is below track 2, and so on down to track 70, which is the closest to the
reference edge of the tape. (The reference edge is the edge of the tape that is
nearest to the baseplate of the cartridge.)
Track 1 is the track immediately below the Directory Track. The odd numbered
tracks are positioned sequentially up from track 1. Thus, track 3 is above track 1,
and track 5 is above track 3, and so up to track 71, which is the closest to the upper
edge of the tape.
STT20000A Product ManualPage 65
Chapter 6Tape Format
Track numbering
All even numbered tracks, and the Directory Track, are recorded in the forward
direction (the direction from the BOT marker to the EOT marker). All odd numbered
tracks are recorded in the reverse direction (the direction from the EOT marker to
the BOT marker). All even numbered tracks are located below the Directory Track;
all odd numbered tracks are above it.
Track format
Tracks are recorded sequentially beginning with track 0, then track 1, and so on.
Before recording, data are grouped into blocks, and blocks are grouped into frames
with 128 blocks per frame.
Two numbering methods are used for blocks: physical numbering and logical
numbering. Both numbers start from 0 at the beginning of each partition.
• Physical numbering is related directly to the recorded block on the tape. Each
new block is given a unique physical number, regardless of its contents.
• Logical numbering does not relate to the blocks physically recorded on the tape;
rather, this type of numbering is the block numbering system used by the host
computer. Often the host system operates with logical blocks that are a different
size from the 512-byte blocks that are physically recorded on the tape.
Frames
The host blocks can be larger or smaller than 512-bytes and can also be fixed
or variable. Fixed host blocks contain the same number of data bytes in each
block. Variable host blocks may contain a different number of data bytes in each
block.
The format provides both a physical block number for each block recorded on the
tape and a logical block number that can span more than one physical block. These
two numbers are recorded in the control field of every block.
Every track on the tape is recorded in blocks that contain 512 data bytes. The data
bytes are 8-bit bytes, which are numbered b0 to b7 with b7 being the most
significant bit.
A frame is made up of 128 blocks—108 data blocks plus 20 error-correction code
(ECC) blocks. Figure 6-1 illustrates the general track layout of sequentially recorded
frames.
Figure 6-1
General track layout
Frame NFrame N+1Frame N+2Frame N+3Frame N+4
Page 66STT20000A Product Manual
Tape FormatChapter 6
Frames are numbered indirectly using the 26 most significant bits of the Physical
Block Address. Frame operation is controlled by the drive and generally invisible to
the host. Frames are used primarily as a means to control the error correction
operations.
Frames can be overwritten with new data frames or an end-of-data (EOD) frame.
Append operations can only begin at EOD.
An underrun is not allowed in the middle of a frame, regardless of the frame type.
Filler blocks can be used to complete a frame as long as they are not used interior
to a logical block.
A frame that cannot be completed on one track is rewritten in its entirety at the
beginning of the following track. Frames are not split around corner turns.
The general frame layout—108 data blocks and 20 ECC blocks—is illustrated in
Figure 6-2.
Figure 6-2
General frame layout
Data
Block
0
Data
Block
1
Data
Block
2
...Data
Block
107
ECC
Block
0
ECC
Block
1
The four types of frames are as follows:
•
Data frames
• The
Media Header frame
contain data and information blocks in addition to ECC blocks.
contains only Media Header blocks and ECC blocks.
This frame is recorded as the first frame on the Directory Track.
•
Track ID frames
are recorded as part of the pre-formatting process of the
cartridge. These frames are easily distinguished from other frame types
because they reside entirely outside of the data region of the tape.
• An
frame is an absolute indicator of the end of the recorded data. It is
EOD
recorded after the last frame containing host data upon terminating a Write
process.
...ECC
Block
19
STT20000A Product ManualPage 67
Chapter 6Tape Format
Blocks
Information in the Block Control byte determines the type of block being recorded
except for ECC blocks which are recognized by their block numbers. Also,
information about the number of user data bytes available in each data block is
recorded in the Block Control byte of the block.
The Data Field of the blocks always contain 512 bytes. However, the number of
valid data bytes in the block may be less than 512.
The seven different types of blocks are as follows:
•
Data blocks
data block can contain from 1 through 511 valid data bytes depending on the
selected logical block size of the host.
•
Media Header blocks
well as the Volume Directory. The first frame on the Directory Track is the Media
Header Frame. This frame contains 108 Media Header blocks (plus the normal
20 ECC blocks).
•
Information blocks
blocks—contain specific types of information. Filemark blocks are physical
blocks written to tape in response to a host WRITE FILEMARKS command.
Setmark blocks are physical blocks written to tape in response to a host WRITE
SETMARKS command. Cancelmark blocks are physical blocks written to tape
under firmware control.
•
Filler blocks
used to fill incomplete frames.
•
EOD blocks
•
ECC blocks
integrity during read operations.
•
Track ID
cartridge.
contain user data. A full Data block contains 512 bytes; however,
contain specific host., drive, and vendor information as
—Filemark blocks, Setmark blocks, and Cancelmark
contain no valid information in the data area. These blocks are
are absolute indicators of the end of recorded data.
contain error correction parity bytes that are used to ensure data
blocks are recorded as part of the pre-formatting process of the
Tape reference servo pattern
To increase track density, a track servo reference pattern is prerecorded on the tape
at the factory. The pattern is recorded referenced to servo patterns in the region
between the beginning-of-tape (BOT) hole and the load point market (LP) hole. The
same pattern is recorded between the end-of-tape (EOT) hole and the early warning
(EW) hole. The servo pattern is written across the entire width of the tape.
Page 68STT20000A Product Manual
Tape FormatChapter 6
Write equalization
The drive uses the technique of write equalization. Write equalization inserts short
pulses in the write current to break up the long spacing intervals. These pulses are
too short to be detected in the read process but result in significant improvement in
read-back resolution.
On 1650-Oersted media, write equalization provides the benefit of compatibility with
Magneto-Resistive (MR) heads. MR heads are prone to saturation by low frequency
flux with high energy content. Equalization redistributes this energy to higher
frequencies and eliminates the problem.
Randomization
To reduce problems resulting from long strings of repetitive data with a bad peak
shift or amplitude characteristics, a data randomizer algorithm is used on all bytes in
the data and control area of each block. This randomizing takes place prior to the
encoding of the data.
STT20000A Product ManualPage 69
Chapter 6Tape Format
Notes
Page 70STT20000A Product Manual
Theory of operationsChapter 7
7
Theory of operations
Overview
The STT20000A is a low-cost, high-performance TR-5 minicartridge tape drive that
is ideal for stand-alone users or small network computer systems. With capacities of
10.0 Gbytes to 20.0 Gbytes dependent upon media and data compression, this
drive offers quick, efficient backup and restore operations. Its unique
FastSense
feature automatically selects the appropriate transfer rate—1,000, 733, or 489
Kbytes/sec—based on the speed of the operating system.
The STT20000A is based on proven Seagate designs, Seagate firmware, and the
latest technology. This drive uses second generation, custom LSIs for efficient
circuit layout and increased reliability with low power consumption. The drive also
uses flash EEPROM devices for easy firmware upgrades.
TM
Block diagram
This chapter describes the drive in more detail and explains implementation specific
information.
The electronics of the STT20000A are laid out on one main printed circuit board
(PCB). Figure 7-1 shows a simplified block diagram of the drive.
Figure 7-1 Simplified block diagram for STT20000A
256KB
EEPROM
(5 volt)
Control Logic Module
IDE
Interface
V20 uP
(10 MHz)
Digital ASIC
buffer mgr.
ECC
RWW
40 MHz
Crystal
Read Channel
Write Driver
Stepper
Motor
Motor
Control
Head,
Non RWW
Capstan
Motor
IDE ONLY
512KB
DRAM
STT20000A Product ManualPage 71
Sensors:
-cartridge present
-write protect
-tape hole
-top stop
Chapter 7Theory of operations
Drive mechanisms
This section generally describes the hardware design features of the STT20000A. You may want to refer to the block
diagrams referenced previously as you read this information.
Mechanics
The mechanical package for the STT20000A was designed to provide you with all
the advantages of easy cartridge loading and unloading while maintaining the
positioning accuracy necessary for high-density data recording. The orientation of
the cartridge is the same as the majority of QIC minicartridge drives in the field.
Cartridge-load mechanism
The cartridge is inserted in the drive by sliding it through the aperture in the bezel
and into a tray mechanism. When fully inserted the back portion of the cartridge
protrudes about 3/4-inch from the aperture. A switch is actuated at this point that
causes a microprocessor to complete the loading operation.
When the tape is in motion, the amber LED on the front panel flashes. The LED is
not lit when the tape is positioned at BOT.
Capstan/drive-motor assembly
Chassis
Control circuits
In the STT20000A, the cartridge is driven by the capstan/belt motor assembly,
which is on a linear slide. The cartridge is loaded against the cartridge drive roller
which exerts a net radial dynamic force of 18 to 26 ounces. The motor is a brushless
DC drive motor with integral capstan which is designed to provide maximum
reliability.
The motor operates from the 12V nominal supply and moves the tape at speeds
from 35 to 100 inches per second (IPS).
The drive mechanism is mounted in a molded frame that provides the mounting
holes for the industry standard 3.5-inch by one inch form factor. A 5.25-inch
mounting kit is an available option. The bezel is a simple snap-on design that is
available in several standard and custom colors. The front-panel LED is amber and
indicates tape activity.
The control logic module shown in Figure 7-1 includes a buffer manager to handle
data movement between the controller, the buffer, and the tape formatter. This
module also includes logic to perform ECC and CRC generation and testing,
WRITE/READ data formatting, head stepper control, and drive motor control.
Page 72STT20000A Product Manual
Theory of operationsChapter 7
The microprocessor directs all functions performed by the control logic. The
instructions are read from a flash EEPROM, which can be updated with new
firmware through a specially written tape cartridge.
The 512-Kbyte DRAM data buffer allows the drive to maintain streaming when the
host cannot provide data continuously at the tape streaming rate.
The write driver receives data from the write formatter and generates write current,
causing data to be written on tape by the tape head.
The read channel amplifies and conditions the signal from the tape head and passes
it back to the read formatter.
The head stepper and drive motor both receive current from the control logic to
control the stepping of the head from track to track and to move the tape forward
and back across the tape head.
Head design
The recording/playback head is a state-of-the art, thin-film design—a thin-film
inductive write head paired with an advanced magneto-resistive read head. This
head design provides the drive with exceptional performance and reliability. The
material composition of the head also results in exceptional wear characteristics,
resulting in stable performance throughout the life of the drive.
Flash EEPROM
Because the drive uses flash EEPROM (electronically erasable, programmable
read-only memory), the drive firmware can be easily upgraded when new revisions
of the firmware are released. The circuitry includes 128 Kbyte of flash EEPROM.
You can load new firmware by using a specially encoded firmware upgrade
cartridge. Refer to chapter 4 for information about loading new firmware using a
Seagate firmware upgrade cartridge.
Sensors and switches
A number of mechanical and optical sensors and switches are integrated in the drive
design. The Cartridge In switch detects when a cartridge is fully loaded and
positioned against the A-plane datum of the cartridge. The Unsafe switch senses
the position of the SAFE indicator on the cartridge and disables writing of writeprotected (SAFE) cartridges.
The Head-Position Sensor is an electro-optical assembly (LED and photo-transistor)
to determine the approximate head position.
The drive has an electro-optical sensor assembly comprised of a solid-state light
source (LED) and a photo-sensor (photo-transistor) that sense the beginning-of-tape
(BOT), end-of-tape (EOT), load point, and early warning holes of the cartridge.
STT20000A Product ManualPage 73
Chapter 7Theory of operations
Drive media (Travan minicartridges)
The drive is designed to use Travan TR-5 cartridges. These small (approximately 2
inches by 3 inches by 0.4 inch) cartridges house 1650-Oersted Gamma Ferric Oxide
magnetic tape. Figure 7-2 shows a Travan minicartridge.
Figure 7-2
Travan minicartridge
The cartridge also provides for write protection so that existing data on the cartridge
is not overwritten. A write-protected cartridge allows the existing data to be read but
does not allow new data to be written to the tape. The position of the sliding writeprotect tab on the cartridge determines whether or not data can be written to the
tape. See chapter 4 for illustrations of the write-protect position.
Page 74STT20000A Product Manual
GlossaryAppendix A
Glossary
A
ATA Packet Interface—
(standard QIC-157).
Azimuth—
reference edge.
Backup—
Beginning of Media (BOM)—
Beginning of Tape (BOT)—
Bezel—
Bit—
Bit Error Rate—
Block—
BOP—
BOT marker—
Byte—
The angular deviation, in minutes of arc, of the mean flux transition line from the line normal to the tape
Copy of a file or collection of files on fixed disk, diskette, or tape. Ensures against data loss.
Front panel of a drive.
A single digit in the binary numbering system.
The number of errors divided by the total number of bits written or read.
A group of 512 consecutive data bytes plus additional control bytes recorded as a unit.
Beginning of Partition. The position at the beginning of the permissible recording region of a partition.
The beginning of tape (BOT) marker is a set of two holes punched side by side in the tape.
A group of 8 binary bits operated on as a unit.
The interface providing for communications between the host computer and the drive
Equal to the physical beginning of the tape.
Equal to the logical beginning of the tape.
Cancelmark—
Filemark or Setmark, the drive when reading the tape will logically ignore the Cancelmark and the Filemark or Setmark
it cancels.
Cartridge—
Control field—
address, track address, and block type.
Cyclic Redundancy Check (CRC)—
error detection.
Data block—
Data Compression—
Compressed data requires less storage space than uncompressed data.
Data Density—
(bpi).
Decompression—
Dew—
Collection of moisture in a tape drive.
A "negative" Filemark or Setmark. When a Cancelmark follows as the first block in the next frame after a
An enclosure containing magnetic tape wound on two coplanar hubs.
A group of 8 bytes recorded before the data area in each block, containing information about clock
A group of 2 bytes recorded at the end of each block of data for the purpose of
A block containing user valid data in its data field
The process of removing redundant data from a data stream before recording the data to tape.
The number of single-byte characters stored per unit length of track. Usually expressed as bits-per-inch
The process of restoring compressed data to its original state.
STT20000A Product ManualPage 75
Appendix AGlossary
Directory track
Disc Drive—
by a program.
ECC
—(Error Correction Code) Special drive generated information that can be used to correct bad blocks.
ECC block—
Encoding—
End-of-Data (EOD)—
End-of-Media (EOM)—
End-of-Partition (EOP)
End of Tape (EOT)—
Error Correction Codes (ECC)-
reconstruct errors during the data reading operation.
Early Warning (EW)—
of the usable recording area in the forward direction.
File—
A logical unit of information.
—The track at the centerline of the tape, identified as track 254 by its Track ID frame.
A peripheral storage device that rotates the disk, writes data onto it, and reads data from it as instructed
A block containing drive-generated ECC data in its data field and part of control field.
A method whereby a group of data bits is translated into a group of recording bits.
Indicates the point where the host stopped writing data to the tape.
Equal to the physical end of tape.
—The position at the end of the permissible recording area of a partition.
Equal to the logical end of the tape.
Information written on tape during the recording operation that can later be used to
The early warning marker is a single hole punched in the tape to indicate the approaching end
Filler block—
Fixed Disk—
Frame—
Full-high (or full-height)—
Half-high (or half-height)—
Head Clog—
obstruct the reading or writing of data.
Interleaving—
are not recorded physically adjacent.
Magnetic Tape—
information processing.
Media Header block
Noise—
radiated sources.
Randomizing—
RF envelope level.
A block containing no valid information in its data field.
A non-removable hard disk. All data must be transferred to and from the disk via the computer.
A group of 128 blocks forming a complete logical group.
Usually refers to a tape drive fitting in a vertical space of 3-1/2 inches.
Refers to the size of tape drive occupying a vertical space of about 1-1/2 inches.
Particles from the tape or from outside the drive adhere to the head gap on a read or write head and
The process of shuffling the order of data blocks before writing them to tape so the consecutive bytes
A tape that accepts and retains magnetic signals intended for input, output, and storage of data for
—A unique block identifying the type of format being recorded.
A disturbance of the signal caused by the read channel, write channel, head/tape interaction, or conducted or
A re-coding of data symbols before they are written to tape in order to provide a consistently uniform
Page 76STT20000A Product Manual
GlossaryAppendix A
RLL (Run Length Limited)—
with regard to the maximum and minimum distances between flux transitions.
Serpentine—
a track. This recording method exploits the bi-directional capabilities of the cartridge.
Streaming
start and stop within an inter-block gap.
Tape Drive—
drive. (See also Disk Drive.)
Track
—A longitudinal area on the tape along which magnetic signals can be serially recorded.
Track ID block
Uncorrected Bit Error Rate—
Underrun
for streaming operation.
A recording method in which tracks are laid down sequentially, and the tape is not rewound at the end of
—A method of recording on magnetic tape that maintains continuous tape motion without the requirement to
A peripheral storage device that records data onto removable tape cartridges. Used to back up a disk
—A block recorded in the Load Point and Early Warning regions to designate the track number.
—A condition developed when the host transmits or receives data at a rate less than required by the device
A data encoding method where data bits are encoded so that certain constraints are met
The probability of a bit being in error, without using any error correction techniques.
QICQuarter Inch Cartridge Drive Standards, Incorporated
RAMRandom Access Memory
RLLRun Length Limited
SCSISmall Computer System Interface
ULUnderwriters' Laboratories, Inc.
VDCVolts Direct Current
VDEVerband Deutscher Electrotechniker
STT20000A Product ManualPage 79
Appendix BAcronyms and Measurements
Units of measurement
MeasureMeaning
AAmp
CCelsius or Centigrade
cmcentimeter
dBadecibels, A-weighted sound power reference one picowatt
FFahrenheit
ftfoot or feet
gacceleration of a free-falling body; equal to 32.17 feet per second
Gbytegigabyte
HzHertz
in.inch
kkilo