Seagate ST12450W User manual

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Barracuda 2, 2HP Disc Drive
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ST12450W/WD
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Product Manual, Volume 1
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Barracuda 2, 2HP Disc Drive
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ST12450W/WD
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Product Manual, Volume 1
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© 1994 Seagate Technology, Inc. All rights reserved
Publication number: 83328900, Rev. A
March 1994
Seagate®, Seagate Technology®, and the Seagate logo are registered
trademarks of Seagate Technology, Inc. Barracuda™ is a trademark of
Seagate Technology, Inc. Other product names are registered trademarks
or 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.

Revision status summary sheet
Sheets
Revision Date Writer/Engineer Affected
A (preliminary-01) 1/25/94 L. Newman/J. Olson All
A (preliminary-02) 2/15/94 L. Newman/J. Olson All
A3/29/94 L. Newman/J. Olson All
Note. Product Manual 83328900 is Volume 1 of a two-volume
documentwiththeSCSIinterfaceinformationinthe Volume2
SCSI-2 Interface Product Manual, Part Number 77738479.

ST12450W/WD Product Manual, Rev. A v
Contents
1.0 Scope ................................................................................................................................. 1
2.0 Applicable standard and reference documentation ....................................................... 3
2.1 Standards ..................................................................................................................... 3
2.2 Applicable reference documents................................................................................... 3
3.0 General description........................................................................................................... 5
4.0 Standard features.............................................................................................................. 7
4.1 Performance ................................................................................................................. 7
4.1.1 Reliability............................................................................................................. 7
4.2 Unformatted and formatted capacities .......................................................................... 8
4.3 Options (factory installed) ............................................................................................. 8
4.4 Optional accessories..................................................................................................... 8
4.5 Installation..................................................................................................................... 9
5.0 Performancecharacteristics ............................................................................................ 11
5.1 Internal drive characteristics ......................................................................................... 11
5.2 SCSI seek performance characteristics ........................................................................ 11
5.2.1 Seek time ............................................................................................................ 13
5.2.2 Format drive command execution time................................................................ 13
5.3 General performance characteristics ............................................................................ 14
5.4 Start/stop time............................................................................................................... 15
5.5 Prefetch/multi-segmented cache control ....................................................................... 15
5.5.1 Adaptive read lookahead..................................................................................... 16
5.6 Caching write data ........................................................................................................ 17
5.7 Synchronized spindle operation .................................................................................... 17
6.0 Reliabilityspecifications................................................................................................... 21
6.1 Error rates..................................................................................................................... 21
6.1.1 Environmentalinterference.................................................................................. 21
6.1.2 Write errors ......................................................................................................... 21
6.1.3 Seek errors ......................................................................................................... 22
6.2 Reliability and service ................................................................................................... 22
6.2.1 Mean time between failures (MTBF).................................................................... 22
6.2.2 Air flow ................................................................................................................ 22
6.2.3 Preventivemaintenance...................................................................................... 26
6.2.4 Service life........................................................................................................... 26
6.2.5 Service philosophy.............................................................................................. 26
6.2.6 Installation ........................................................................................................... 26
6.2.7 Service tools........................................................................................................ 26
6.2.8 Hot plugging Barracuda 2, 2HP disc drives ......................................................... 26

vi ST12450W/WD Product Manual, Rev. A
7.0 Physical/electricalspecifications ................................................................................... 27
7.1 AC power requirements ............................................................................................ 27
7.2 DC power requirements ............................................................................................ 27
7.2.1 Conducted noise immunity ............................................................................ 28
7.2.2 Power sequencing......................................................................................... 28
7.2.3 12V current profile ......................................................................................... 29
7.3 Heat/powerdissipation.............................................................................................. 30
7.4 Environmentallimits.................................................................................................. 30
7.4.1 Temperature.................................................................................................. 30
7.4.2 Relative humidity ........................................................................................... 30
7.4.3 Effective altitude (sea level)........................................................................... 30
7.4.4 Shock and vibration ....................................................................................... 31
7.4.5 Air cleanliness ............................................................................................... 32
7.4.6 Acoustics....................................................................................................... 32
7.5 Electromagneticcompatibility.................................................................................... 32
7.6 Mechanical specifications ......................................................................................... 33
7.6.1 Drive orientation ............................................................................................ 34
7.6.2 Cooling .......................................................................................................... 34
8.0 Mediacharacteristics ...................................................................................................... 35
8.1 Media description...................................................................................................... 35
9.0 Defect and error management ........................................................................................ 37
9.1 Defects and errors .................................................................................................... 37
10.0 Option/configuration headers......................................................................................... 39
10.1 Drive ID/option select headers .................................................................................. 39
10.2 Synchronized spindles interface ............................................................................... 42
10.2.1 Electrical description...................................................................................... 42
10.3 Grounding................................................................................................................. 43
11.0 Interface requirements .................................................................................................... 45
11.1 General description................................................................................................... 45
11.2 SCSI interface messages supported......................................................................... 45
11.3 SCSI interface commands supported........................................................................ 46
11.3.1 Inquiry data.................................................................................................... 48
11.3.2 Mode sense data ........................................................................................... 48
11.4 SCSI bus conditions and miscellaneous features supported..................................... 51
11.5 Synchronous data transfer........................................................................................ 52
11.5.1 Synchronous data transfer periods supported .............................................. 52
11.5.2 REQ/ACK offset............................................................................................ 52
11.6 DC cable and connector ........................................................................................... 52

ST12450W/WD Product Manual, Rev. A vii
11.7 SCSI physical interface............................................................................................. 53
11.7.1 Physical characteristics ................................................................................ 53
11.7.2 Connectorrequirements ............................................................................... 54
11.7.3 Electrical description ..................................................................................... 54
11.8 SCSI wide physical interface..................................................................................... 59
12.0 Options.............................................................................................................................. 65
12.1 Front panel................................................................................................................ 65
12.2 Single-unit shipping pack .......................................................................................... 65
12.3 Drive termination....................................................................................................... 65
12.4 Barracuda 2, 2HP Installation Guide ......................................................................... 65
13.0 Accessories ..................................................................................................................... 67
13.1 Adaptor accessory frame kit ..................................................................................... 67
Index.......................................................................................................................................... 69
Figures
Figure 1. Barracuda 2, 2HP disc drive ...................................................................................... 1
Figure 2. Barracuda 2, 2HP disc drive (exploded view) ............................................................ 5
Figure 3. OEM interruptible thermal calibration implementation ................................................ 12
Figure 4. Synchronized drive interconnect diagram .................................................................. 17
Figure 5. Synchronized reference signal characteristics........................................................... 18
Figure 6. Air flow....................................................................................................................... 23
Figure 7. GYHX temperature measurement locations .............................................................. 24
Figure 8. RYGX temperature measurement locations .............................................................. 25
Figure 9. Temperature measurement location .......................................................................... 25
Figure 10. Typical Barracuda 2, 2HP drive +12V current profile ................................................. 29
Figure 11. Mounting configuration dimensions............................................................................ 33
Figure 12. Recommendedmounting........................................................................................... 34
Figure 13. Barracuda 2, 2HP drive physical interface ................................................................. 39
Figure 14. Barracuda drive ID and option select headers ........................................................... 40
Figure 15. SCSI reference index signal driver/receiver combination........................................... 42
Figure 16. J5 configuration select header specification............................................................... 43
Figure 17. Barracuda 2, 2HP physical interface.......................................................................... 53
Figure 18. Single-ended transmitters and receivers.................................................................... 55
Figure 19. Typical differential I//O line transmitter/receiver and terminators................................ 57
Figure 20. Wide SCSI device connector ..................................................................................... 59

ST12450W/WD Product Manual, Rev. A 1
1.0 Scope
This manualdescribes Seagate Technology®, Inc. Barracuda™ 2, 2HP
(2 head parallel) disc drives.
Barracuda drives support the Small Computer SystemInterface-2 (SCSI-
2)asdescribedintheANSISCSIandSCSI-2interfacespecificationstothe
extent described in this manual. This manualdefines the performance
characteristics of the Barracuda 2, 2HP drives. The SCSI-2 Interface
ProductManual (partnumber77738479)describesgeneralSCSIinterface
characteristics of this and other families of Seagate drives.
Figure 1. Barracuda 2, 2HP disc drive

ST12450W/WD Product Manual, Rev. A 3
2.0 Applicable standard and
reference documentation
Seagatetakesallreasonablesteps to insurethatits products arecertifiable
to currently accepted standards. Typical applications of these disc drives
include customer packaging and subsystem design.
Safety agencies conditionally certify component parts, such as the Barra-
cudadiscdrive,basedontheirfinalacceptabilityintheend-useproduct.The
subsystem designer is responsible for meeting these conditions of accept-
ability in obtaining safety/regulatory agency compliance in their end-use
product and certifying where required by law.
2.1 Standards
The Barracuda disc drive is a UL recognized component per UL1950, CSA
certified to CSA C22.2 No. 950-M89, and VDE certified to VDE 0805 and
EN60950.
The Barracuda disc drive is supplied as a component part. It is the respon-
sibility of the subsystem designer to meet EMC/regulatory requirements.
Engineeringtest characterizations ofradiated emissionsareavailablefrom
the Seagate safety department.
2.2 Applicable reference documents
Barracuda 2, 2HP Installation Guide
Seagate part number: 83328890
SCSI-2 Interface Product Manual (volume 2)
Seagate part number: 77738479
ANSI small computer system interface (SCSI) documents
ANSIX3.131-1986 (SCSI-1)
X3T9.2/86-109 Rev. 10H (SCSI-2)
X3T9.2/91-010 Rev. 10 (SCSI-3) Parallel Interface
Incaseofconflictbetweenthisdocumentandanyreferenceddocument,this
document takes precedence.

ST12450W/WD Product Manual, Rev. A 5
3.0 General description
Barracuda drives are low-cost, high-performance, random-access storage
devicesdesignedtomeettheneedsoftheoriginalequipmentmanufacturer
(OEM) marketplace.
TheBarracuda2,2HPdrivehastworead/writechannelsonthecircuitboard.
The SCSI-2 controller chip is modified to process data for two read/write
channels at once. This technology effectively doubles the internal data
transfer rate when compared to a conventional Barracuda 2 disc drive.
The Barracuda drive’s interface supports multiple initiators, disconnect/
reconnect, self-configuring host software, and automatic features that re-
lievethehostfromknowingthephysicalcharacteristicsofthetargets(logical
block addressing is used).
Theheadanddiscassembly(HDA)isenvironmentallysealedatthefactory.
Air circulates within the HDA through a non-replaceable filter to maintain a
contamination-free HDA environment.
RefertoFigure2foranexplodedviewofthedrive.Thisexplodedviewisfor
informationonly—neverdisassembletheHDAanddonotattempttoservice
itemsinthesealedenclosure(heads, media, actuator,etc.)asthisrequires
specialfacilities.Thedrivecontainsnoreplaceableparts.OpeningtheHDA
voids your warranty.
Figure 2. Barracuda 2, 2HP disc drive (exploded view)

6ST12450W/WD Product Manual, Rev. A
Barracudadrivesuseadedicatedlandingzoneattheinnermostradiusofthe
mediatoeliminatethepossibilityofdestroyingordegradingdatabylanding
inthedatazone.The drive automaticallygoestothe landing zonewhenthe
power is removed.
An automatic shipping lock prevents potential damage to the heads and
discsthatresultsfrommovementduringshippingandhandling.Theshipping
lock disengages when power is applied to the drive and the head load
process begins.
Barracuda drives decode track 0 locationdata from the dedicated servo
surface to eliminate mechanical transducer adjustments and related reli-
ability concerns.
Ahigh-performance actuator assembly with a low-inertia, balanced, pat-
ented, straight-arm design provides excellent performance with minimal
power dissipation.

ST12450W/WD Product Manual, Rev. A 7
4.0 Standard features
Barracuda 2, 2HP drives have the following standard features:
•2 head parallel technology
•Integrated SCSI controller
•Single-ended or differential SCSI drivers and receivers
•Asynchronous and synchronous data-transfer protocols
•Firmware downloadable using a SCSI interface
•Selectable sector size from 180 to 4,096 bytes per sector
•Programmable sector-reallocation scheme
•Flawed sector reallocation at format time
•Programmable auto-write and auto-read reallocation
•Reallocation of defects on command (post format)
•96-bit Reed-Solomon error-correction code
•Sealed head and disc assembly (HDA)
•No preventive maintenance or adjustments required
•Dedicated head-landing zone
•Automatic shipping lock
•Automatic thermal compensation
•Embedded Grey Code track address to eliminate seek errors
•Self-diagnostics performed at power-on
•1:1 interleave
•Zone bit recording (ZBR)
•Vertical, horizontal, or top-down mounting
•Dynamic spindle brake
•Permanently mounted IC terminators (ST12450W models only)
•Synchronous spindle capability
•1,024 Kbyte data buffer (see Section 5.5)
4.1 Performance
•Simultaneously processes data for two read/write channels (heads)
•Programmable multi-segmentable cache buffer
•7,200 RPM spindle; average latency = 4.17 msec
•Command queuing of up to 64 commands
•Background processing of queue
•Supports start and stop commands
•Provides synchronized spindle capability
•Low audible noise for office environment
•Low power consumption
4.1.1 Reliability
•500,000 hour MTBF
•Adaptive seek velocity; improved seek performance
• LSI circuitry
•Balanced low-mass rotary voice-coil actuator

8ST12450W/WD Product Manual, Rev. A
4.2 Unformatted and Formatted Capacities
Standard OEM models are formatted to have 512-byte sectors.
ST12450 drives have nine (9) spare sectors per cylinder and one (1) spare
cylinder per unit.
Formatted Unformatted
1,849 Mbytes 2,437 Mbytes
Users having the necessary equipment may modify the data block size
before issuing aformat command to obtain different formatted capacities.
User-available capacity also depends on the spare reallocation scheme
selected.Seethe ModeSelect command and the Format command inthe
SCSI-2 Interface Product Manual (part number 77738479).
4.3 Options (factory installed)
The capacityshown in Section 4.2is normally provided. Other capacities
can be ordered depending on the sparing scheme and sector size re-
quested.
The following options are incorporated at the time of production. See
Sections 12.0 and 13.0.
•Front panel (green lens), part number 70869751
• Barracuda 2, 2HP Installation Guide, part number 83328890
4.4 Optional accessories
Thefollowingaccessoriesareavailable.Allkitsmaybeinstalledinthefield.
See Section 13.0.
•Front -panel kit (with green lens)
•Single-unit shipping pack kit
•Adapter accessory frame kit, part number 75790701 (adapts a 3.5-inch
drive to fit in a 5.25-inch drive mounting space)

ST12450W/WD Product Manual, Rev. A 9
4.5 Installation
For option jumper locations and definitions refer to Figure 14. Drive default
mode parameters are not normally needed for installation. Refer to
Section 11.3.2 for default mode parameters if you need them.
•Ensure that the SCSI ID of the drive is not the same as the host adapter.
•Ifmultipledevicesareonthebus,setthedrive’sSCSIIDtoonethatisnot
presently used by other devices on the bus.
•Ifthedriveistheonlydeviceonthebus,attachittotheendoftheSCSIbus
cable. Internal termination is available on single-ended (ST12450W)
drives by enabling this feature with a jumper (see Figure 14). External
terminators are required for differential (ST12450WD) drives. These
externalterminatorsmustbeprovidedbytheuser,systemsintegrator,or
hostequipment manufacturer.
•If you attach the drive to a bus that contains other devices, and the new
driveisnotattachedtotheendofthebus,removeterminationfromthenew
drive.
• Set allappropriateoptionjumpers prior to applying power to thedrive.If
you change jumpers after applying power, recycle the drive’s power to
makethe new settings effective.
Formatting
•Itisnot necessary tolow-levelformat this drive.The drive isshippedfrom
the factory low-level formatted in 512-byte sectors.
•Reformat the drive if:
a. You select a different sector size.
b. You select a different spare-sector allocation scheme.