Seagate ST31250N User manual

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Barracuda 2LP Disc Drive
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ST31250N/ND, ST31250W/WD,
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ST31250WC/DC, ST32550N/ND,
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ST32550W/WD, ST32550WC/DC
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Product Manual, Volume 1
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Barracuda 2LP Disc Drive
○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○
ST31250N/ND, ST31250W/WD,
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ST31250WC/DC, ST32550N/ND,
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ST32550W/WD, ST32550WC/DC
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Product Manual, Volume 1
○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

© 1996 Seagate Technology, Inc. All rights reserved
Publication number: 83328930, Rev. D
January 1996
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.

Note. Product Manual 83328930 is Volume 1 of a two-volume
documentwiththeSCSIinterfaceinformationinthe Volume2
SCSI-2 Interface Product Manual, Part Number 77738479.
Revision status summary sheet
Sheets
Revision Date Writer/Engineer Affected
A 7/14/94 L. Newman/J. Olson All
B 9/21/94 L. Newman/J. Olson 36, 37, 43, 51, 57, 61,
64, 66
C 3/20/95 L. Newman/J. Olson 1, 9, 12, 14, 24, 25, 26, 27,
28, 29, 33, 34, 35, 36, 39,
41, 42, 47, 48, 50, 52, 55,
57, 58, 59, 60, 61, 62, 63,
64, 66, 68, 69, 70, 71, 73,
80, 82
D 1/9/96 L. Newman/J. Olson 3, 18, 36, 39, 40, 41, 48, 50,
51, 53, 54, 57, 65, 72

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 ..................................................................................................................... 8
4.4 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
5.6 Caching write data .................................................................................................... 16
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 ............................................................................... 30
6.2.4 Service life .................................................................................................... 30
6.2.5 Service philosophy........................................................................................ 30
6.2.6 Installation..................................................................................................... 30
6.2.7 Service tools ................................................................................................. 30
6.2.8 Hot plugging Barracuda 2LP disc drives ....................................................... 30

7.0 Physical/electricalspecifications .................................................................................... 33
7.1 AC power requirements ............................................................................................ 33
7.2 DC power requirements ............................................................................................ 33
7.2.1 Conducted noise immunity............................................................................ 34
7.2.2 Power sequencing ........................................................................................ 34
7.2.3 12V current profile ........................................................................................ 35
7.3 Heat/powerdissipation.............................................................................................. 36
7.4 Environmentallimits.................................................................................................. 36
7.4.1 Temperature ................................................................................................. 36
7.4.2 Relative humidity .......................................................................................... 36
7.4.3 Effective altitude (sea level) .......................................................................... 37
7.4.4 Shock and vibration ...................................................................................... 37
7.4.5 Air cleanliness............................................................................................... 38
7.4.6 Acoustics ...................................................................................................... 38
7.5 Electromagneticcompatibility.................................................................................... 38
7.6 Mechanical specifications ......................................................................................... 39
7.6.1 Drive orientation............................................................................................ 42
7.6.2 Cooling ......................................................................................................... 42
7.6.3 Drive mounting.............................................................................................. 42
8.0 Mediacharacteristics ....................................................................................................... 43
8.1 Media description...................................................................................................... 43
9.0 Defect and error management......................................................................................... 45
9.1 Defects and errors .................................................................................................... 45
10.0 Option/configuration headers ......................................................................................... 47
10.1 Drive ID/option select headers .................................................................................. 47
10.1.1 ST31250N/ND and ST32550N/ND configuration .......................................... 47
10.1.2 ST31250W/WD and ST32550W/WD configuration ....................................... 50
10.1.3 ST31250WC/DC and ST32550WC/DC configuration.................................... 53
10.2 Synchronized spindles interface ............................................................................... 55
10.2.1 Electrical description ..................................................................................... 55
10.3 Grounding ................................................................................................................. 57
11.0 Interface requirements ..................................................................................................... 59
11.1 General description................................................................................................... 59
11.2 SCSI interface messages supported......................................................................... 59
11.3 SCSI interface commands supported........................................................................ 60
11.3.1 Inquiry data ................................................................................................... 62
11.3.2 Mode sense data .......................................................................................... 63
11.4 SCSI bus conditions and miscellaneous features supported..................................... 66
vi Barracuda 2LP Product Manual, Rev. D

11.5 Synchronous data transfer........................................................................................ 67
11.5.1 Synchronous data transfer periods supported .............................................. 67
11.5.2 REQ/ACK offset............................................................................................ 67
11.6 DC cable and connector ........................................................................................... 68
11.7 SCSI physical interface............................................................................................. 68
11.7.1 Physical characteristics ................................................................................ 70
11.7.2 Connectorrequirements ............................................................................... 71
11.7.3 Electrical description ..................................................................................... 72
11.8 SCSI non-wide physical interface ............................................................................. 76
11.9 SCSI wide physical interface..................................................................................... 79
11.10 SCSI single-connector attachment (SCA) physical interface..................................... 82
Index .......................................................................................................................................... 87
Figures
Figure 1. Barracuda 2LP disc drive (ST32550N drive shown) .................................................. 1
Figure 2. Barracuda 2LP disc drive (exploded view)................................................................. 5
Figure 3. ASA I OEM thermal calibration ................................................................................. 13
Figure 4. Synchronized drive interconnect diagram .................................................................. 17
Figure 5. Synchronized reference signal characteristics........................................................... 18
Figure 6. Air flow pattern (ST32550N drive shown) .................................................................. 23
Figure 7. WYGX temperature measurement locations.............................................................. 24
Figure 8. HYHX temperature measurement locations............................................................... 25
Figure 9. JYHX temperature measurement locations ............................................................... 26
Figure 10. KYHX temperature measurement locations ............................................................... 27
Figure 11. ZYHX temperature measurement locations ............................................................... 28
Figure 12. PYJX temperature measurement locations................................................................ 29
Figure 13. Temperature measurement location (ST32550N shown)........................................... 29
Figure 14. Barracuda 2LP drives typical +12V current profile ..................................................... 35
Figure 15. ST31250N/ND and ST32550N/ND mounting configuration dimensions..................... 39
Figure 16. ST31250W/WD and ST32550W/WD mounting configuration dimensions.................. 40
Figure 17. ST31250WC/DC and ST32550WC/DC mounting configuration dimensions.............. 41
Figure 18. Recommended mounting........................................................................................... 42
Figure 19. ST31250N/ND and ST32550N/ND jumper connectors .............................................. 47
Figure 20. ST31250W/WD and ST32550W/WD jumper connectors ........................................... 50
Figure 21. ST31250WC/DC and ST32550WC/DC jumper connectors ....................................... 53
Figure 22. SCSI reference index signal driver/receiver combination........................................... 55
Figure 23. ST31250N/ND and ST32550N/ND configuration select header ................................. 56
Figure 24. ST31250W/WD and ST32550W/WD configuration select header.............................. 56
Barracuda 2LP Product Manual, Rev. D vii

Figure 25. ST31250WC/DC and ST32550WC/DC configuration select header .......................... 57
Figure 26. ST31250N/ND and ST32550N/ND physical interface ................................................ 68
Figure 27. ST31250W/WD and ST32550W/WD physical interface ............................................. 69
Figure 28. ST31250WC/DC and ST32550WC/DC physical interface ......................................... 69
Figure 29. Single-ended transmitters and receivers.................................................................... 73
Figure 30. Typical differential I/O line transmitter/receiver and terminators................................. 74
Figure 31. Non-shielded SCSI device connector ........................................................................ 76
Figure 32. Wide SCSI device connector ..................................................................................... 79
Figure 33. Non-shielded, 80-pin I/O and DC power single-connector attachment (SCA) ............ 82
Tables
Table 1. SCSI interface messages supported ......................................................................... 59
Table 2. Supported commands............................................................................................... 60
Table 3. Barracuda 2LP family drive inquiry data–ASA I ......................................................... 62
Table 4. Barracuda 2LP family drive inquiry data–ASA II ........................................................ 62
Table 5. Mode sense data, ST31250 default values–ASA I (SCSI-1 implementation) ............. 63
Table 6. Mode sense data, ST32550 default values–ASA I (SCSI-1 implementation) ............. 63
Table 7. Mode sense data, ST31250 default values–ASA I (SCSI-2 implementation) ............. 64
Table 8. Mode sense data, ST32550 default values–ASA I (SCS-2 implementation) .............. 64
Table 9. Mode sense data, ST31250 default values–ASA II (SCSI-2 implementation) ............ 65
Table 10. Mode sense data, ST32550 default values–ASA II (SCSI-2 implementation) ............ 65
Table 11. SCSI bus conditions and other miscellaneous features ............................................. 66
Table 12. Synchronous data transfer periods ............................................................................ 67
Table 13. Mating connector parts .............................................................................................. 68
Table 14. Single-ended cable pin assignments for ST31250N and ST32550N drives ............... 77
Table 15. Differential cable pin assignments for ST31250ND and ST32550ND drives.............. 78
Table 16. Single-ended contact assignments for ST31250W and ST32550W drives ................ 80
Table 17. Differential contact assignments for ST31250WD and ST32550WD drives ............... 81
Table 18. SCA contact assignments for ST31250WC and ST32550WC drives......................... 83
Table 19. SCA contact assignments for ST31250DC and ST32550DC drives .......................... 84
Table 20. Disc drive SCSI timing ............................................................................................... 85
viii Barracuda 2LP Product Manual, Rev. D

Barracuda 2LP Product Manual, Rev. D 1
1.0 Scope
This manual describes Seagate Technology®, Inc. Barracuda™ 2LP (low
profile) disc drives.
Barracudadrivessupportthesmallcomputersysteminterface-2(SCSI-2)as
describedintheANSISCSIandSCSI-2interfacespecificationstotheextent
describedinthismanual.The SCSI-2InterfaceProductManual (partnumber
77738479)describesgeneralSCSIinterfacecharacteristicsofthisandother
families of Seagate drives.
Figure 1. Barracuda 2LP disc drive (ST32550N drive shown)

2 Barracuda 2LP Product Manual, Rev. D

Barracuda 2LP Product Manual, Rev. D 3
2.0 Applicable standard and
reference documentation
Seagatetakesallreasonablestepstoensurethatitsproductsarecertifiable
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
subsystemdesigner isresponsiblefor meeting theseconditionsof 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.
If this model has the CE Marking, it complies with the European Union
requirementsoftheElectromagneticCompatibilityDirective89/336/EECof
03 May 1989 as amended by Directive 92/31/EEC of 28 April 1992 and
Directive 93/68/EEC of 22 July 1993.
Seagateusesanindependentlaboratorytoconfirmcompliancetotheabove
directives. Drives are tested in representative systems for typical applica-
tions. The selected system represents the most popular characteristics for
test platforms. The system configurations include:
• 486, Pentium, and PowerPC Microprocessors
• 3.5-inch floppy disc drive
• Keyboard
• Monitor/display
AlthoughthetestsystemwiththisSeagatemodelcompliestothedirectives,
we cannot guarantee that all systems will comply. The computer manufac-
turer or system integrator shall confirm EMC compliance and provide CE
Marking for their product.
The Barracuda disc drive is supplied as a component part. It is the
responsibility of the subsystem designer to meet EMC/regulatory require-
ments. Engineering test characterizations of radiated emissions are avail-
able from the Seagate safety department.
2.2 Applicable reference documents
Barracuda 2LP Installation Guide
Seagate part number: 83328920
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

4 Barracuda 2LP Product Manual, Rev. D

Barracuda 2LP Product Manual, Rev. D 5
3.0 General description
Barracuda drives are low-cost, high-performance, random-access storage
devicesdesignedtomeettheneedsoftheoriginalequipmentmanufacturer
(OEM) marketplace.
The Barracuda drive’s interface supports disconnect/reconnect, multiple
initiators,self-configuringhostsoftware,andautomaticfeaturesthatrelieve
the host from knowing the physical characteristics of the targets (logical
block addressing is used).
The head and disc assembly (HDA) is sealed at the factory. Air circulates
withintheHDAthroughanon-replaceablefiltertomaintainacontamination-
free HDA environment.
RefertoFigure2foranexplodedviewofthedrive.Thisexplodedviewisfor
informationonly—neverdisassembletheHDAanddonotattempttoservice
itemsinthesealedenclosure (heads, media, actuator,etc.) as this requires
specialfacilities.Thedrivecontainsnoreplaceableparts.OpeningtheHDA
voids your warranty.
Figure 2. Barracuda 2LP disc drive (exploded view)

6 Barracuda 2LP Product Manual, Rev. D
Barracudadrivesuseadedicatedlandingzoneattheinnermostradiusofthe
mediatoeliminatethepossibilityofdestroyingordegradingdatabylanding
inthedatazone. The driveautomatically goes to thelanding zone whenthe
power is removed.
An automatic shipping lock prevents potential damage to the heads and
discs.The shipping lockdisengages whenpower isapplied tothe driveand
the head load process begins.
Barracuda drives decode track 0 location data from the dedicated servo
surface to eliminate mechanical transducer adjustments and related reli-
ability concerns.
A high-performance actuator assembly with a low-inertia, balanced, pat-
ented, straight-arm design provides excellent performance with minimal
power dissipation.

Barracuda 2LP Product Manual, Rev. D 7
4.0 Standard features
Barracuda 2LP drives have the following standard features:
• 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
• Active IC terminators (N/W models only)
• Synchronous spindle capability
• 512 Kbyte data buffer (see Section 5.5)
• Low audible noise for office environment
• Low power consumption
4.1 Performance
• 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
• Adaptive seek velocity; improved seek performance
4.1.1 Reliability
• 800,000 hour MTBF
• LSI circuitry
• Balanced low-mass rotary voice-coil actuator

8 Barracuda 2LP Product Manual, Rev. D
4.2 Unformatted and formatted capacities
Standard OEM models are formatted to have 512-byte sectors.
Barracuda 2LP drives have nine (9) spare sectors per cylinder and one (1)
spare cylinder per unit.
Formatted Unformatted
ST31250 1,020.9 Mbytes 1,205.3 Mbytes
ST32550 2,147.4 Mbytes 2,541.3 Mbytes
Users having the necessary equipment may modify the data block size
beforeissuingaformatcommandtoobtaindifferentformattedcapacities.
User-available capacity also depends on the spare reallocation scheme
selected.SeetheModeSelectcommandandtheFormatcommandinthe
SCSI-2 Interface Product Manual (part number 77738479).
4.3 Options
The capacity shown in Section 4.2 is 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 or are
available separately.
• Front panel (green lens), part number 73497151
Thestandardfrontpanelisblackplastic.Youmayorderothercolors.Each
panel has a single rectangular green LED indicator lens that, when
glowing, indicates the drive is selected.
• Barracuda 2LP Installation Guide, part number 83328920
This manual provides basic installation information for persons not
familiarwith theproduct. It also includes informationonobtainingtechni-
cal support and service for the drive.
• SCSIinterfaceterminatingresistors(N/Wmodelsonly,enabledbyjumper)
To enable internal drive termination, install a jumper on J1 pins 5 and 6.
Refer to Section 10.1.
• Single-unit shipping pack kit
The drive is shipped in bulk packaging to provide maximum protection
against transit damage. Units shipped individually require additional
protection as provided by the single-unit shipping pack.
• Adapter accessory frame kit, part number 75790701
This kit contains a frame, which allows a 3.5-inch drive to be mounted
in a 5.25-inch drive bay. It includes mounting hardware, front panel with
a green lens, an LED with cable that connects to the remote LED
connector, and installation instructions.

Barracuda 2LP Product Manual, Rev. D 9
4.4 Installation
ForoptionjumperlocationsanddefinitionsrefertoSection10.1.Drivedefault
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.
• Ifmultipledevicesare on thebus,setthedrive’sSCSIIDtoonethat is not
presently used by other devices on the bus.
• If the drive is the only device on the bus, attach it to the end of the SCSI
bus cable. Internal termination is available on ST31250N, ST31250W,
ST32550N,andST32550Wdrives byenablingthisfeaturewithajumper
(see Section10.1).
External terminators are required for ST31250ND, ST31250WD,
ST31250WC, ST31250DC, ST32550ND, ST32550WD, ST32550WC,
andST32550DCdrives.Theseexternalterminatorsmustbeprovidedby
the user, systems integrator,or host equipment manufacturer.
• If you attach the drive to a bus that contains other devices, and the new
driveisnotattachedtotheendofthebus,removeterminationfromthenew
drive.
• Setallappropriateoptionjumpers prior toapplying power tothedrive.If
you change jumpers after applying power, recycle the drive’s power to
make the new settings effective.
Formatting
• Itisnot necessary tolow-level formatthis drive. Thedrive isshipped from
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.

10 Barracuda 2LP Product Manual, Rev. D