Seagate Barracuda ST12550W User manual

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Barracuda 1 and 2 Disc Drive
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ST11950N/ND,ST11950W/WD
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ST12550N/ND, ST12550W/WD
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Product Manual, Volume 1
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Barracuda 1 and 2 Disc Drive
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ST11950N/ND,ST11950W/WD,
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ST12550N/ND, ST12550W/WD
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Product Manual, Volume 1
○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○

© 1994 Seagate Technology, Inc. All rights reserved
Publication number: 83327780, Rev. C
November 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.

Note. Product Manual 83327780 is Volume 1 of a two-volume
documentwiththeSCSIinterfaceinformationintheVolume2
SCSI-2 Interface Product Manual, part number 77738479.
Revision status summary sheet
Sheets
Revision Date Writer/Engineer Affected
A (preliminary-01) 04/05/93 L. Newman/J. Olson All
A (preliminary-02) 04/20/93 L. Newman/J. Olson All
A (preliminary-03) 05/01/93 L. Newman/J. Olson All
A05/11/93 L. Newman/J. Olson All
B (preliminary-01) 09/15/93 L. Newman/J. Olson All
B10/18/93 L. Newman/J. Olson All
C (draft) 10/11/94 L. Newman/J. Olson All
C11/04/94 L. Newman/J. Olson All

Barracuda 1 and 2 Product Manual, Rev. C 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 ......................................................................................................................... 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............................................................................................................... 14
5.5 Prefetch/multi-segmented cache control ....................................................................... 15
5.5.1 Adaptive read lookahead..................................................................................... 16
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...................................................................................... 28
6.2.4 Service life........................................................................................................... 28
6.2.5 Service philosophy.............................................................................................. 28
6.2.6 Installation ........................................................................................................... 28
6.2.7 Service tools........................................................................................................ 28
6.2.8 Hot plugging Barracuda 1 and 2 disc drives ........................................................ 28

vi Barracuda 1 and 2 Product Manual, Rev. C
7.0 Physical/electricalspecifications ................................................................................... 31
7.1 AC power requirements ............................................................................................ 31
7.2 DC power requirements ............................................................................................ 31
7.2.1 Conducted noise immunity ............................................................................ 33
7.2.2 Power sequencing......................................................................................... 33
7.2.3 12V current profile ......................................................................................... 34
7.3 Heat/powerdissipation.............................................................................................. 35
7.4 Environmentallimits.................................................................................................. 35
7.4.1 Temperature.................................................................................................. 35
7.4.2 Relative humidity ........................................................................................... 35
7.4.3 Effective altitude (sea level)........................................................................... 36
7.4.4 Shock and vibration ....................................................................................... 36
7.4.5 Air cleanliness ............................................................................................... 37
7.4.6 Acoustics....................................................................................................... 37
7.5 Electromagneticcompatibility.................................................................................... 37
7.6 Mechanical specifications ......................................................................................... 38
7.6.1 Drive orientation ............................................................................................ 40
7.6.2 Cooling .......................................................................................................... 40
8.0 Mediacharacteristics ...................................................................................................... 41
8.1 Media description...................................................................................................... 41
9.0 Defect and error management ........................................................................................ 43
9.1 Defects and errors .................................................................................................... 43
10.0 Option/configuration headers......................................................................................... 45
10.1 Drive ID/option select headers .................................................................................. 45
10.1.1 ST11950N/ND and ST12550N/ND configuration ........................................... 45
10.1.2 ST11950W/WD and ST12550W/WD configuration ........................................ 48
10.2 Synchronized spindles interface ............................................................................... 50
10.2.1 Electrical description...................................................................................... 50
10.3 Grounding................................................................................................................. 52
11.0 Interface requirements .................................................................................................... 53
11.1 General description................................................................................................... 53
11.2 SCSI interface messages supported......................................................................... 53
11.3 SCSI interface commands supported........................................................................ 54
11.3.1 Inquiry data.................................................................................................... 56
11.3.2 Mode sense data ........................................................................................... 56
11.4 SCSI bus conditions and miscellaneous features supported..................................... 61
11.5 Synchronous data transfer........................................................................................ 62

Barracuda 1 and 2 Product Manual, Rev. C vii
11.5.1 Synchronous data transfer periods supported .............................................. 62
11.5.2 REQ/ACK offset............................................................................................ 63
11.6 DC cable and connector ........................................................................................... 63
11.7 SCSI physical interface............................................................................................. 63
11.7.1 Physical characteristics ................................................................................ 64
11.7.2 Connectorrequirements ............................................................................... 65
11.7.3 Electrical description ..................................................................................... 66
11.8 SCSI non-wide physical interface ............................................................................. 70
11.9 SCSI wide physical interface..................................................................................... 73
11.10Disc drive SCSI timing .............................................................................................. 76
Index.......................................................................................................................................... 79
Figures
1Barracuda 1 and 2 family disc drives ................................................................................ 1
2Barracuda disc drive (exploded view) ............................................................................... 5
3OEM interruptible thermal compensation implementation .................................................12
4Synchronized drive interconnect diagram .........................................................................17
5Synchronized reference signal characteristics ..................................................................18
6Air-flow pattern..................................................................................................................23
7TYFX temperature measurement locations....................................................................... 24
8UYFX temperature measurement locations ...................................................................... 25
9TYGX temperature measurement locations ......................................................................26
10 PYGX temperature measurement locations ......................................................................27
11 Temperature measurement location .................................................................................27
12 Barracuda 1 and 2 drives typical +12V current profiles ..................................................... 34
13 Mounting configuration dimensions for N/ND drives..........................................................38
14 Mounting configuration dimensions for W/WD drives ........................................................ 39
15 Recommendedmounting .................................................................................................. 40
16 ST11950N/ND and ST12550N/ND physical interface ....................................................... 45
17 ST11950N/ND and ST12550N/ND jumper connectors ..................................................... 46
18 ST11950W/WD and ST12550W/WD physical interface ....................................................48
19 ST11950W/WD and ST12550W/WD jumper connectors .................................................. 48
20 SCSI reference index signal driver/receiver combination .................................................. 50
21 ST11950N/ND and ST12550N/ND configuration select header specification.................... 51
22 ST11950W/WD and ST12550W/WD configuration select header specification ................ 51
23 ST11950N/ND and ST12550N/ND physical interface ....................................................... 63
24 ST11950W/WD and ST12550W/WD physical interface ....................................................64

viii Barracuda 1 and 2 Product Manual, Rev. C
25 Single-ended transmitters and receivers........................................................................... 67
26 Typical differential I/O line transmitters/receivers and terminators ....................................68
27 Non-shielded SCSI device connector................................................................................ 70
28 Wide SCSI device connector ............................................................................................ 73
Tables
1DC power requirements for ST11950N/ND and ST12550N/ND drives ............................. 31
2DC power requirements for ST11950W/WD and ST12550W/WD drives .......................... 32
3SCSI messages supported ............................................................................................... 53
4Supported commands.......................................................................................................54
5Barracuda 1 and 2 family drive inquiry data ......................................................................56
6Mode Sense data, ST11950 default values (SCSI-1 implementation)...............................57
7Mode Sense data, ST11950 default values (SCSI-2 implementation)...............................58
8Mode Sense data, ST12550 default values (SCSI-1 implementation)...............................59
9Mode Sense data, ST12550 default values (SCSI-2 implementation)...............................60
10 SCSI bus conditions and other miscellaneous features ....................................................61
11 Synchronous data transfer periods for ST11950N/ND and ST12550N/ND drives............. 62
12 Synchronous data transfer periods for ST11950W/WD and ST12550W/WD drives.......... 62
13 Single-ended cable pin assignments (non-shielded connector)
for ST11950N and ST12550N drives ................................................................................ 71
14 Differential cable pin assignments (non-shielded connector)
for ST11950ND and ST12550ND drives ...........................................................................72
15 Single-ended contact assignments (P cable) for ST11950W and ST12550W drives ........ 74
16 Single-ended contact assignments (P cable) for ST11950WD and ST12550WD drives ... 75
17 Disc drive SCSI timing ...................................................................................................... 76

Barracuda 1 and 2 Product Manual, Rev. C 1
1.0 Scope
This manual describes SeagateTechnology®, Inc. Barracuda™ 1 and 2
disc drives.
Barracudadrives support thesmall computersysteminterface-2(SCSI-2)
as described in theANSISCSI and SCSI-2interface specifications to the
extent described in this manual.The SCSI-2 InterfaceProductManual
(partnumber77738479)describesgeneral SCSI interfacecharacteristics
of this and other families of Seagate drives.
ST11950N/NDandST11950W/WDdrives are classifiedas Barracuda 1
family drives. ST12550N/ND and ST12550W/WD drives are classified as
Barracuda 2 family drives.
N/ND type
W/WD type
Figure 1. Barracuda 1 and 2 family disc drives

2Barracuda 1 and 2 Product Manual, Rev. C

Barracuda 1 and 2 Product Manual, Rev. C 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 assemblies, such as the
Barracuda disc drive, based on their final acceptability in the end-use
product. The subsystem designer is responsible for meeting these condi-
tions of acceptability 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 emissionsare availablefrom
the Seagate safety department.
2.2 Applicable reference documents
Barracuda Disc Drive Installation Guide
Seagate part number: 83327770
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.

4Barracuda 1 and 2 Product Manual, Rev. C

Barracuda 1 and 2 Product Manual, Rev. C 5
3.0 General description
Barracuda drives are low-cost, high-performance, random-access storage
devicesdesignedtomeettheneedsoftheoriginalequipmentmanufacturer
(OEM) marketplace.
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).
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.)asthisrequires
specialfacilities.Thedrivecontainsnoreplaceableparts.OpeningtheHDA
voids your warranty.
Figure 2. Barracuda disc drive (exploded view)

6Barracuda 1 and 2 Product Manual, Rev. C
Barracudadrivesuseadedicatedlandingzoneattheinnermostradiusofthe
mediatoeliminatethepossibilityofdestroyingordegradingdatabylanding
inthedatazone.The drive automaticallygoestothe landing zonewhenthe
power is removed.
An automatic shipping lock prevents potential damage to the heads and
discs.Theshipping lockdisengageswhen powerisapplied tothe 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.
A high-performance actuator assembly with a low-inertia, balanced, pat-
ented, straight-arm design provides excellent performance with minimal
power dissipation.

Barracuda 1 and 2 Product Manual, Rev. C 7
4.0 Standard features
Barracuda 1 and 2 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 termination with removable terminator modules
•Synchronous spindle capability
•1,024 Kbyte data buffer (N/ND/W models)
•512 Kbyte data buffer (WD models)
•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
•500,000 hour MTBF
• LSI circuitry
•Balanced low-mass rotary voice-coil actuator

8Barracuda 1 and 2 Product Manual, Rev. C
4.2 Unformatted and formatted capacities
Standard OEM models are formatted to have 512-byte sectors.
TheST11950 drive hassix (6) sparesectors per cylinderand one (1)spare
cylinder per unit.
TheST12550drivehasnine(9)sparesectorspercylinderandone(1)spare
cylinder per unit. Formatted Unformatted
ST11950N/ND 1,690 Mbytes 2,030 Mbytes
ST11950W/WD 1,690 Mbytes 2,030 Mbytes
ST12550N/ND 2,139 Mbytes 2,572 Mbytes
ST12550W/WD 2,139 Mbytes 2,572 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
The capacitiesshown in Section4.2 arenormally provided.Other capaci-
ties can be ordered depending on the sparing scheme and sector size
requested.
The following options are incorporated at the time of production or are
availableseparately.
•Front panel (green lens), part number 70869751
Thestandardfrontpanelisblackplastic.Youmayorderothercolors.Each
panel has a single rectangular green LED indicator lens that, when
glowing, indicates the drive is selected.
• Barracuda Disc Drive Installation Guide, part number 83327770
This manual provides basic installation information for persons not
familiarwiththeproduct.It alsoincludes informationonobtainingtechni-
cal support and service for the drive.
•Drive termination for single-ended drives
Removable resistor modules (SIPs) provide ST11950N and ST12550N
drive termination. Permanently mounted active terminator ICs provide
ST11950W and ST12550W drive termination; however, the ICs may be
disabledbyremovingtheEnableDriveTerminatorjumperfromJ4pins11
and 12. See Section 11.7.3.3.
•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 1 and 2 Product Manual, Rev. C 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.
•Ifmultipledevices areonthebus,setthedrive’sSCSIIDtoone thatisnot
presently used by other devices on the bus.
• If the drive is the onlydevice on the bus, attach it to the end of theSCSI
bus cable. Internal termination is available on ST11950N, ST11950W,
ST12550N, and ST12550W drives (see Sections 10.1and 11.7.3.4).
External terminators are required for ST11950ND, ST11950WD,
ST12550ND, and ST12550WDdrives.These external terminators must
beprovidedby theuser,systemsintegrator,orhostequipmentmanufac-
turer.
•If you attach the drive to a bus that contains other devices, and the new
driveisnotattachedtotheendofthebus,removeterminationfromthenew
drive.
• Set all appropriate optionjumpers prior to applying power to the drive.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.

10 Barracuda 1 and 2 Product Manual, Rev. C