BARRACUDA 1 and 2
Disc Drive
ST11950N/ND/W/WD
ST12550N/ND/W/WD
Installation Guide
ST11950 and ST12550 Installation Guide, Rev. D
1
Preface
This manual contains information for users of the
®
Seagate ST11950N/ND,ST11950W/WD, ST12550N/ND,
and ST12550W/WD Barracuda™ SCSI disc drives. It
providessupportservices,performance specifications,
and initial setup information. Additional information is
availablein theBarracuda1and2Product Manual(part
number 83327780). Contact your Seagate sales rep-
resentative if you need to order this publication.
Electrostatic discharge protection
Caution. Removal of circuit boards by personnel not
performing depot repair will damage compo-
nents and may void the warranty.
All drive electronic assemblies are sensitive to static
electricity, duetotheelectrostaticallysensitivedevices
used within the drive circuitry. Although some devices
such as metal-oxide semiconductors are extremely
sensitive, all semiconductors, as well as some resis-
tors and capacitors, may be damaged or degraded by
exposure to static electricity.
Electrostatic damage to electronic devices may be
caused by the direct discharge of a charged conductor
or by exposure to the static fields surrounding charged
objects.Toavoiddamagingdriveelectronicassemblies,
observe the following precautions when installing or
servicing the drive:
2
ST11950 and ST12550 Installation Guide, Rev. D
• Ground yourself to the drive whenever the drive elec-
tronics are or will be exposed. Connect yourself to
ground with a wrist strap (Seagate part number
12263496).Connectionmaybemadetoanygrounded
metal assembly. As a general rule, remember that you
andthedriveelectronicsmustallbegroundedtoavoid
potentially damaging static discharges.
• TurnoffthepowerbeforeremovingorinstallingtheDC
power cable.
• Do not remove any circuit boards from the drive.
• Never use an ohmmeter on any circuit boards.
Important safety information and precautions
Caution. Useforced-airventilationwhenbench-testing
the drive to ensure proper cooling of drive
components.
Usepropersafetyandrepairtechniquesforsafe,reliable
operation of this unit. Service should be done only by
qualifiedpersons.Werecommendtheproceduresinthis
manual as effective ways of servicing the unit. Some
procedures require the use of special tools. For proper
maintenance and safety, you must use these tools as
recommended.
The procedures in this manual and labels on the unit
contain warnings and cautions that must be carefully
ST11950 and ST12550 Installation Guide, Rev. D
3
read and followed to minimize or eliminate the risk of
personal injury. The warnings point out conditions or
practicesthatmayendangeryouorothers.Thecautions
point out conditions or practices that may damage the
unit, possibly making it unsafe for use.
These warnings and cautions are not exhaustive. We
cannotpossiblyknow,evaluate,andadviseyouofallthe
ways in which maintenance might be performed or the
possible risk of each technique. Consequently, we have
not completed any such broad evaluation. If you use a
non-approved procedure or tool, first ensure that the
method you choose will not risk either your safety or unit
performance.
Alwaysobservethefollowingwarningsandprecautions:
• Performallmaintenancebyfollowingtheproceduresin
this manual.
• Follow all cautions and warnings in the procedures.
• Use sound safety practices when operating or repair-
ing the unit.
• Use caution when troubleshooting a unit that has
voltages present. Turn off power to the unit before
servicing it.
• Wear safety shoes when removing or replacing heavy
parts.
4
ST11950 and ST12550 Installation Guide, Rev. D
• Ensure that the internal temperature of the rack or
cabinetdoesnotexceedthelimitsdefinedforthedrive
when the drive is mounted in an equipment rack or
cabinet. When units are stacked vertically, pay atten-
tiontothetopwheretemperaturesareusuallyhighest.
• Follow the precautions listed above in “Electrostatic
discharge protection.”
• Do not remove any circuit boards from the drive chas-
sis. Returntheentiredrivefordepotrepairifanycircuit
board is defective. Removal of circuit boards by per-
sonnel not performing depot repair will damage com-
ponents and may void the warranty.
• Donotremovetheheadanddiscassembly(HDA)from
the drive chassis. Return the entire drive for depot
repair if the HDA is defective.
• Do not attempt to disassemble the HDA. It is not field
repairable. If the sealed HDA is opened by personnel
not performing depot repair, this will damage compo-
nents and void the warranty.
As a component, this drive is designed to be installed
and operated in accordance with UL1950, IEC950,
EN60950, CSA C22.2 950, and VDE0805.
Seagate takes all reasonable steps to ensure that its
products are certifiable to currently accepted stan-
ST11950 and ST12550 Installation Guide, Rev. D
5
dards. Typical applications of these disc drives include
customer packaging and subsystem design. Safety
agencies conditionallycertifycomponentparts,suchas
the Barracuda disc drive, based on their final accept-
abilityintheend-useproduct.Thesubsystemdesigners
are responsible for meeting these conditions of accept-
abilityinobtainingsafety/regulatoryagencycompliance
in their end-use products and for certifying where
required by law. A necessary part of meeting safety
requirements is the provision for overcurrent protection
on drive SELV supply voltages.
This unit is a component assembly and as such is not
meant to comply with FCC or similar national require-
mentsasastand-aloneunit.Engineeringradiatedemis-
sions test results are available through the Seagate
Safety Department to assist the subsystem designer.
Wichtige Sicherheitshinweise
Vorsicht. Beim Testen des Laufwerks auf dem
Prüftisch ist Fremdbelüftung vorzusehen, um eine
ausreichende Kühlung der Laufwerkkomponenten
sicherzustellen.
Verwenden Sie geeignete Sicherheits- und
Reparaturverfahren, um den sicheren, zuverlässigen
Betrieb dieser Einheit zu gewährleisten. Reparaturen
6
ST11950 and ST12550 Installation Guide, Rev. D
dürfen nur von qualifiziertem Fachpersonal
vorgenommen werden. Wir empfehlen die Verfahren in
diesem Handbuch als effektive Methoden zur
Wartung und Reparatur der Einheit. Einige Verfahren
erfordern Spezialwerkzeuge; diese müssen zur
sachgemäßen Ausführung der Wartungsarbeiten und
aus Sicherheitsgründen den Empfehlungen
entsprechend verwendet werden.
Die Verfahren in diesem Handbuch und die Aufkleber
auf dem Gerät enthalten Warn- und Vorsichtshinweise.
Diese Hinweise sind sorgfältig durchzulesen und zu
beachten, um das Risiko von Verletzungen auf ein
Mindestmaß zu beschränken oder ganz zu vermeiden.
DieWarnhinweisemachenaufSituationenoderPraktiken
aufmerksam, die Sie oder andere gefährden könnten.
Die Vorsichtshinweise machen auf Situationen oder
Praktiken aufmerksam, die die Einheit beschädigen
können, so daß deren Gebrauch mit Risiko behaftet ist.
Die Warn- und Vorsichtshinweise sind nicht
allumfassend! Es ist uns einfach nicht möglich, alle
WartungsmethodenoderdieeventuellenRisikenjeder
Methode zu kennen, zu beurteilen und Sie
entsprechend zu beraten. Aus diesem Grund haben
wir auf eine derartige umfassende Beurteilung
verzichtet. Falls Sie ein hier nicht beschriebenes
Verfahren oder Werkzeug verwenden, stellen Sie
ST11950 and ST12550 Installation Guide, Rev. D
7
zuerst sicher, daß das gewählte Verfahren weder Ihre
persönliche Sicherheit noch die Leistung der Einheit
gefährdet.
Beachten Sie in jedem Fall die folgenden Warn-und
Vorsichtshinweise:
• Führen Sie alle Wartungsarbeiten entsprechend den
Anweisungen in diesem Handbuch aus.
• Beachten Sie alle Warn- und Vorsichtshinweise in
diesem Handbuch.
• Treffen Sie beim Betrieb oder bei der Reparatur der
Einheit angemessene Sicherheitsvorkehrungen.
• Wenn eine Einheit unter Spannung steht, gehen Sie
bei der Fehlerdiagnose besonders vorsichtig vor.
Schalten Sie die Einheit aus, bevor Sie mit den
Reparaturarbeitenbeginnen.
• Tragen Sie Sicherheitsschuhe, wenn Sie schwere
Teile aus- bzw. einbauen.
• Wenn das Laufwerk in einem Einbaugestell oder
Gehäuse montiert ist, sorgen Sie dafür, daß die
Temperatur im Inneren des Gestells oder Gehäuses
die für das Laufwerk vorgegebenen Grenzwerte nicht
übersteigt. Wenn Einheiten vertikal übereinander
betestigtwerden,achtenSiebesondersaufdenoberen
Stapelbereich, da dort die Temperatur gewöhnlich am
höchsten ist.
8
ST11950 and ST12550 Installation Guide, Rev. D
• Befolgen Sie die oben unter “Electrostatic Discharge
Protection” angegebenen Sicherheitsmaßnahmen.
• NehmenSiekeinePlatinenausdemLaufwerkgehäuse.
Wenn eine Platine defekt ist, muß das gesamte
Laufwerk zur Reparatur eingeschickt werden. Die
HerausnahmevonPlatinendurchanderePersonenals
die für die werkseitige Reparatur zuständigen kann zu
einer Beschädigung der Komponenten und Erlöschen
des Garantieanspruchs führen.
• Die vormontierte Kopf- und Festplatteneinheit (HDA)
nicht aus dem Laufwerkgehäuse nehmen! Falls die
HDA beschädigt ist, schicken Sie das gesamte
Laufwerk zur Reparatur ein.
• Die HDA ist nicht vor Ort reparierbar und darf nicht
auseinandergenommen werden! Öffnen der
versiegelten HDA durch andere Personen als die für
die werkseitige Reparatur zuständigen hat eine
Beschädigung der Komponenten und Erlöschen des
Garantieanspruchs zur Folge.
Als Teilkomponente ist dieses Laufwerk für die Installa-
tion und den Betrieb in Übereinstimmung mit UL 1950,
IEC950, EN60950, CSA C22.2 950 und VDE0805
vorgesehen.
Seagate ist ständig bemüht, die Zulassungsfähigkeit
von Seagate-Produkten im Rahmen der gegenwärtig
ST11950 and ST12550 Installation Guide, Rev. D
9
geltendenStandardszugewährleisten.Zudentypischen
Anwendungen dieser Festplattenwerke zählen
Systemeinbau durch den Kunden und die Konstruktion
vonUntersystemen.Sicherheitsbehördengewähreneine
bedingte Zulassung für Komponenten wie das Barra-
cuda-Festplattenlaufwerkvorbehaltlichderendgültigen
ZulasssungimEndprodukt.DesignervonUntersystemen
sind dafür verantwortlich, die Voraussetzungen für die
Einhaltung sicherheits- oder aufsichtsbehördlicher
VorschrifteninihrenEndproduktenund-fallsgesetzlich
vorgeschrieben - für die Zulassung zu schaffen.
Eine Grundvoraussetzung zur Einhaltung der
Sicherheitsanforderungen ist die Bereitstellung
eines Überlastschutzes für die SELV-
Versorgungsspannungen des Laufwerks.
Dieses Gerät ist eine Baugruppe und unterliegt als
solchenichtdenAnforderungenderFCCoderähnlicher
nationaler Behörden für eigenständige Geräte.
Technische Testergebnisse zu elektromagnetische
Strahlung sind für Designer von Untersystemen auf
Anfrage von der Seagate-Sicherheitsabteilung
erhältlich.
10 ST11950 and ST12550 Installation Guide, Rev. D
Technical support services
Seagate Technology provides technical support litera-
ture and diagnostic utilities to authorized distributors.
Please contact your dealer for technical support and
installation troubleshooting. Producttechnicalsupport
is available for all Seagate products by calling the
SeaFAX™, SeaFONE™, SeaTDD™, or SeaBOARD™
services. These are toll calls if you dial from outside of
the number’s local dialing area.
SeaFAX
USA (408) 438-2620; England 44-62-847-7080
Use a touch-tone telephone to access Seagate’s auto-
mated FAX system and select technical support infor-
mation by return FAX. This service is available 24 hours
a day, 7 days a week.
SeaFONE (408) 438-8222
Technical support specialists are available from 8:00
A.M.to 5:00 P.M.PST, Mondaythrough Friday.Recorded
technical information on selected Seagate products is
provided while you areon hold. Recordings areacces-
sible 24 hours a day, 7 days a week.
SeaTDD (408) 438-5382
TDD is a telecommunication device for the deaf where
two people can communicate using a keyboard that is
connectedtothephoneline. ATDDdeviceisrequiredto
ST11950 and ST12550 Installation Guide, Rev. D 11
access this service, which is available from 8:00 A.M. to
5:00 P.M. PST, Monday through Friday.
SeaBOARD
The Seagate Technical Support Bulletin Board System
(BBS) is accessible by modem 24 hours a day, 7 days
a week. The communications software must be set for
eight data bits, no parity, and one stop bit (8N1). These
BBS numbers operate at 9600 baud max. With this
service you can access:
• Specifications and jumper configurations for Seagate
products
• Reprints of Seagate documentation
• A directory of information and helpful utilities that you
can download to your own computer
Telephone
Location
number
USA, Mexico, Latin America
England
(408) 438-8771
44-62-847-8011
49-89-140-9331
65-292-6973
61-2-756-2359
(416) 856-5581
33-1-40-67-1034
82-2-556-7294
Germany
Singapore
Australia
Canada
France
Korea
12 ST11950 and ST12550 Installation Guide, Rev. D
General description
Barracuda 1 and 2 SCSI disc drives are high-speed,
random-access digital-data storage devices. The
ST11950N/ND and ST12550N/ND drives are illustrated
inFigure1, and the ST11950W/WDandST12550W/WD
drives are illustrated in Figure 2. Specifications and DC
power requirements for the drive are listed in tables
following the figure.
The drive is a component for installation in an enclosure
designed for the drive. This is often a rack within the
system or an external enclosure designed to house one
or more disc drives or other peripheral units. In either
case,thediscdrivemustreceiveadequatecooling(refer
to “Providing adequate cooling”) and it must be suffi-
ciently grounded and shielded from emissions. The
Barracuda 1 and 2 Product Manual (part number
83327780) contains guidelinesforaproperlydesigned
enclosure.
ST11950 and ST12550 Installation Guide, Rev. D 13
I/O Terminator Packs
(single-ended I/O only)
SCSI I/O
Connector
J01
J4
DC Power Connector
Figure 1. Barracuda 1 and 2 disc drive (N/ND type)
SCSI I/O
Connector
Pin 1
J5
J01
J4
DC Power
Connector
Figure 2. Barracuda 1 and 2 disc drive (W/WD type)
14 ST11950 and ST12550 Installation Guide, Rev. D
Characteristics
ST11950N/ND ST11950W/WD
Interface
Fast SCSI-21
Fast & Wide SCSI-21
Multi-seg. cache
1,024 Kbytes
1,024 Kbytes (W)
512 Kbytes (WD)
Capacity
Unformatted
Formatted2
2,030 Mbytes
1,690 Mbytes
2,030 Mbytes
1,690 Mbytes
Recording
Cylinders (user)
Heads
2,706
15
2,706
15
Avg sectors/track
Avg bytes/track
Modulation
81 (51h)
49,768
RLL 1,7 code
81 (51h)
49,768
RLL 1,7 code
SCSI rate
Max burst transfer 10 Mbytes/sec 20 Mbytes/sec
Seek time3
Average read
Average write
8.0 msec
9.0 msec
8.0 msec
9.0 msec
Disc rotation
RPM
7,200
7,200
Average latency
4.17 msec
4.17 msec
1Can also be operated according to SCSI-1 protocol.
2Standard factory units are formatted as follows:
512 data bytes per sector, 6 spare sectors per cylinder
1 cylinder at the inner track reserved for spares
3Not including on-board controller overhead.
ST11950 and ST12550 Installation Guide, Rev. D 15
Characteristics
ST12550N/ND ST12550W/WD
Interface
Fast SCSI-21
Fast & Wide SCSI-21
Multi-seg. cache
1,024 Kbytes
1,024 Kbytes (W)
512 Kbytes (WD)
Capacity
Unformatted
Formatted2
2,572 Mbytes
2,139 Mbytes
2,572 Mbytes
2,139 Mbytes
Recording
Cylinders (user)
Heads
2,707
19
2,707
19
Avg sectors/track
Avg bytes/track
Modulation
81 (51h)
49,768
RLL 1,7 code
81 (51h)
49,768
RLL 1,7 code
SCSI rate
Max burst transfer 10 Mbytes/sec 20 Mbytes/sec
Seek time3
Average read
Average write
8.0 msec
9.0 msec
8.0 msec
9.0 msec
Disc rotation
RPM
7,200
7,200
Average latency
4.17 msec
4.17 msec
1Can also be operated according to SCSI-1 protocol.
2Standard factory units are formatted as follows:
512 data bytes per sector, 9 spare sectors per cylinder
1 cylinder at the inner track reserved for spares
3Not including on-board controller overhead.
16
ST11950 and ST12550 Installation Guide, Rev. D
DC power requirements
for ST11950N/ND and ST12550N/ND drives
Single-ended Differential
+5V
+12V
+5V
+12V
Voltage regulation5
± 5%
± 5%2 ± 5% ± 5%2
Amps
0.95
Maximum operating current1 1.1
1.5
0.95
0.83
Average idle current1, 12
0.76
0.83
0.79
Maximum starting current
Peak DC3, 6
1.0
−
2.18
3.1
1.1
−
1.1
2.18
3.1
Peak AC3
Delayed motor start (max)1, 4 1.06
Peak operating current
0.19
0.2
Typ DC1, 10
Max DC1
Max (peak)
1.07
1.1
1.15
0.91
0.95
1.87
1.47
1.5
1.8
0.91
0.95
1.86
Track following (DC)
at OD1
1.0
1.0
0.84
0.9
1.1
1.1
0.84
0.9
at ID1
Read track
OD DC1, 14
AC
1.1
1.2
0.85
1.2
1.6
1.8
0.85
1.2
Seeking
Typical DC1, 13
Maximum DC1
Maximum (peak) AC
1.0
1.1
1.2
1.2
1.2
1.8
1.1
1.2
1.7
1.2
1.2
1.8
ST11950 and ST12550 Installation Guide, Rev. D
17
DC power requirements
for ST11950W/WD and ST12550W/WD drives
Single-ended Differential
+5V
+12V
+5V
+12V
Voltage regulation5
± 5% ± 5%2 ± 5% ± 5%2
Amps
0.95
Maximum operating current1 1.04
1.3
0.95
0.83
Average idle current1, 12
0.76
0.83
0.83
Maximum starting current
Peak DC3, 6
1.0
−
2.18
3.1
1.1
−
1.1
2.18
3.1
Peak AC3
Delayed motor start (max)1, 4 1.0
Peak operating current
0.19
0.19
Typ DC1, 10
Max DC1
Max (peak)
1.03
1.04
1.2
0.91
0.95
1.87
1.21
1.3
2.0
0.91
0.95
1.87
Track following (DC)
at OD1
1.0
1.0
0.84
0.9
1.1
1.1
0.84
0.9
at ID1
Read track
OD DC1, 15
AC
1.1
1.3
0.85
1.2
1.4
2.0
0.85
1.2
Seeking
Typical DC1, 13
Maximum DC1
Maximum (peak) AC
1.0
1.1
1.2
1.2
1.2
1.8
1.1
1.2
2.0
1.2
1.2
1.8
1Measured with an average reading DC ammeter. Instanta-
neous +12V current peaks will exceed these values.
continued
18 ST11950 and ST12550 Installation Guide, Rev. D
continued from previous page
2 A −10% tolerance is permissible during initial start of the
spindle but must return to ±5% before reaching 7,200RPM.
The ±5% must be maintained after the drive signifies that its
power-up sequence has been completed and that the drive
is able to accept selection by the host initiator.
3 See the +12V current profile in the Product Manual .
4 This condition occurs when the Motor Start option is en-
abled and the drive has not yet received a start motor
command.
5 See “Conducted noise immunity” in the Product Manual.
The specified voltage tolerance is inclusive of ripple, noise,
and transient response.
6 At power-up, the motor current regulator limits the +12V
current to an average value of less than 2.0A, although
instantaneous peaks may exceed this value. These peaks
should measure 5 msec duration or less.
7 Minimum current loading for each supply voltage is not less
than 7% of the maximum operating current shown.
8 Use separate ground returns for +5 and +12V supplies.
9 Where power is provided to multiple drives from a common
supply, carefully consider individual-drive power require-
ments.Wheremultipleunitsarepoweredonsimultaneously,
be sure the peak starting current is available to each device.
10 Operating condition is a third-stroke seek at OD and read
one track. The command is issued every 0.07 seconds.
continued
ST11950 and ST12550 Installation Guide, Rev. D 19
continued from previous page
11No terminator power. See Section 11.7.3.4 in the Prod-
uct Manual.
12All power-saving features are enabled.
13Seeking is defined as a third-stroke seek at OD. The
command is issued every 20 msec.
14Read track is defined as repeat reads of track 15 with a
91% duty cycle.
15Read track is defined as repeat reads of track 15 with a
75% duty cycle.
Initial setup information
The following topics are presented to guide you through
the installation process. These topics are presented in
the order you should follow to properly install the drive.
• Setting the SCSI ID jumpers
• Terminating the drive
• Changing other applicable jumper options
• Synchronizing spindles
• Providing adequate cooling
• Mounting the drive and connecting cables
• Formatting the drive
Each option jumper illustration identifies the Original
Equipment Manufacturer (OEM) default factory setting.
These settings are the most common ones used but are
not necessarily the ones set for your particular system.
20 ST11950 and ST12550 Installation Guide, Rev. D
Setting the SCSI ID jumpers
EachdeviceontheSCSIchainmusthaveauniqueSCSI
ID. The host system’s SCSI controller usually uses the
highest-numbered ID available (ID7 in non-wide sys-
tems); therefore the lower-numbered SCSI IDs are nor-
mally used for the other SCSI devices such as this
Barracuda disc drive.
Note. MostSCSIcontrollers(hostadapters)allowyouto
skip a SCSI ID. For example, you can have ID0,
ID1, and ID3 (skipping ID2). Other controllers do
not allow this so be sure to refer to your system or
controller user’s manual for details about its re-
quirements for proper SCSI device installation.
Use connector J4 to set the SCSI ID on ST11950N/ND
and ST12550N/ND drives (Figure 3). Use connector J5
tosettheSCSI IDon ST11950W/WDand ST12550W/WD
drives(Figure4).MostBarracuda1and2discdrivesare
factorysetwiththeSCSIIDsetat0. TochangetheSCSI
ID, install jumpers on the appropriate pins as shown in
the illustrations.
If, after completing the installation process, the drive’s
LEDdoesnotshowon/offactivitywhenthehostistrying
to communicate with the drive, a duplicate SCSI ID may
be the problem. If this is the case, change the ID so that
each device on the SCSI chain has its own unique ID.
ST11950 and ST12550 Installation Guide, Rev. D 21
Also check your system or controller user’s manual to
ensurethatyouhavenotviolateditsSCSIIDnumbering
recommendations.
SCSI
Connector
DC Power
Connector
J01
Pin 1
J4
ID1
ID2
ID0
Select SCSI ID by placing
jumpers as shown below.
J4
SCSI ID = 0
SCSI ID = 1
SCSI ID = 2
SCSI ID = 3
SCSI ID = 4
SCSI ID = 5
SCSI ID = 6
SCSI ID = 7
Figure 3. Setting the SCSI ID on N- and ND-type drives
22 ST11950 and ST12550 Installation Guide, Rev. D
SCSI I/O
Connector
DC Power
Connector
J5 Pin 1
Pin 1
4P
3P 2P
1P
ID3 ID1
ID2 ID0
J5
SCSI ID = 0
SCSI ID = 1
SCSI ID = 2
SCSI ID = 3
SCSI ID = 4
SCSI ID = 5
SCSI ID = 6
SCSI ID = 7
SCSI ID = 8
SCSI ID = 9
SCSI ID = 10
SCSI ID = 11
SCSI ID = 12
SCSI ID = 13
SCSI ID = 14
SCSI ID = 15
Figure 4. Setting the SCSI ID on W- and WD-type drives
ST11950 and ST12550 Installation Guide, Rev. D 23
Terminating the drive
If you are installing the drive in a system that has other
SCSI devices installed, terminate only the end devices
on the SCSI chain. A SCSI “device” is any disc drive,
scanner, tape backup unit, or other piece of hardware
connected to your system using the SCSI bus.
The top example in Figure 5 shows an internal hard disc
atoneendoftheSCSIbuswiththeSCSIcontrolleratthe
other end (both are terminated). The bottom example
shows two additional SCSI devices connected exter-
nally—thismeanstheSCSIcontrollerisnolongeronthe
end of the SCSI chain and should not be terminated.
Internal SCSI cable
Internal
Internal
Controller
SCSI device SCSI device
Terminate
Internal SCSI cable
External
SCSI
cable
Internal
Internal
SCSI device SCSI device
External
External
Controller
SCSI device SCSI device
Terminate
Figure 5. SCSI bus termination
24 ST11950 and ST12550 Installation Guide, Rev. D
Refer to the appropriate section below for instructions in
terminating a drive.
Caution. Installing or removing terminator packs im-
properly can result in damage to the termina-
tors or surrounding components.
ST11950N and ST12550N drives
To terminate ST11950N and ST12550N drives, install
terminator packs as shown in Figure 6.
I/O Terminator Packs
(single-ended I/O only)
Pin 1 End
(of terminator)
Figure 6. Installing terminator packs (ST11950N shown)
ST11950 and ST12550 Installation Guide, Rev. D 25
Note. All single-ended terminators must be ANSI
SCSI-2 alternative 2 active terminators.
To install terminators, carefully insert the terminator’s
pins firmly into the socket’s holes. Note that pin 1 on the
pack is identified by a dot, a number one, or a notch.
To remove termination, remove the terminator packs by
carefully pulling them out of their sockets.
ST11950W and ST12550W drives
ST11950W and ST12550W drives are equipped with
permanently mounted IC terminators. This means you
can either enable or disable termination using jumpers
as described below.
ToterminateST11950WandST12550Wdrives(enable
termination), install a jumper on J4 pins 11 and 12 as
shown in Figure 7.
To remove termination (disable termination), remove
the jumper from J4 pins and 11 and 12.
26 ST11950 and ST12550 Installation Guide, Rev. D
J4
Pin 1
J01
EDT PAR DMS
RES RES MTR WP
J4
Enable Drive Terminators (EDT)
Enable drive terminators.
Disable drive terminators.
Figure 7. Enabling termination
on ST11950W and ST12550W drives
ST11950ND/WD and ST12550ND/WD drives
ST11950ND/WD and ST12550ND/WD drives have no
provisions for internal termination. To terminate these
drives, you must provide external termination.
ST11950 and ST12550 Installation Guide, Rev. D 27
Terminator power
Single-ended (N and W) drives have four valid configu-
rations for terminator power (see Figure 8). Differential
(ND and WD drives) must be configured with a jumper
on J01 pins 1 and 3 only.
J01 location on “N” J01 location on “W”
and “ND” drives
and “WD” drives
Pin
J01
2
J01
Pin 1
Pin 1
Pin 3
Pin
4
Terminator power options.
These jumpers determine how
termination is supplied.
J4
J4
* Terminator power from the drive. The
drive provides its own terminator power.
* Terminator power from TERMPWR on the
SCSI bus.
Terminator power to the SCSI bus. The drive
supplies power to TERMPWR on the SCSI bus.
* Terminator power to the SCSI bus and drive.
* Valid for single-ended (“N” and “W”) drives only.
Figure 8. Setting terminator power jumpers
28 ST11950 and ST12550 Installation Guide, Rev. D
Changing other applicable jumper options
Barracuda 1 and 2 drives are designed to be used in a
varietyofsystems. Uniqueinstallationsmayrequireyou
to change one or more of the other jumpers to meet
specific system requirements; however, in most cases,
you will not need to change any of these jumpers for
normal drive operation. Figures 9a and 9b provide the
information necessary to configure all N and ND drive
jumpers not discussed elsewhere in this manual.
SCSI
Connector
DC Power
Connector
J01
Pin 1
J4
WP RES
LED
RES
J4
Write Protect option (WP)
Write Protect = On (disables writing).
Write Protect = Off
(enables writing – default).
Remote LED Connector*
Pin 5 (top pin in this illustration) is negative,
Pin 6 (bottom pin) is positive.*
Reserved (RES)
Reserved for factory use.
*Note to subsystem designers: In Europe, a red LED indicates
an error or warning condition. For this reason, you may want
to use a color other than red with this connection.
Figure 9a. Additional jumper options
for ST11950N/ND and ST12550N/ND drives
ST11950 and ST12550 Installation Guide, Rev. D 29
SCSI
Connector
DC Power
Connector
J01
Pin 1
J4
MTR
PAR DMS
J4
Parity Check option (PAR)
Enable parity check of SCSI bus data
(default).
Disable parity check.
Motor Start option (MTR)
Enable motor start. This makes the
drive wait for the Start Unit command
from the host before starting the
spindle motor.
Disable motor start (default). This
causes the drive to start according to
the Delay Motor Start option setting as
described below.
Delay Motor Start option (DMS)
(valid only if the Motor Start
jumper is not connected)
Motor start delay equal to the SCSI ID
multiplied by 10 seconds. For example,
if the SCSI ID = 2, the drive will delay for
20 seconds before starting.
Disable the Delay Motor Start option
(default).
Figure 9b. Additional jumper options
for ST11950N/ND and ST12550N/ND drives
30 ST11950 and ST12550 Installation Guide, Rev. D
Figures 10a and 10b provide the information necessary
to configure all W and WD drive jumpers not discussed
elsewhere in this manual.
SCSI I/O
Connector
DC Power
Connector
J5 Pin 1
LED
J5
Remote LED Connector*
Pin 9 (top pin in this illustration) is
negative (cathode), Pin 10 (bottom pin)
is positive (anode).
*Note to subsystem designers: In Europe, a red LED
indicates an error or warning condition. For this reason, you
may want to use a color other than red with this connection.
Figure 10a. Additional jumper options
for ST11950W/WD and ST12550W/WD drives
ST11950 and ST12550 Installation Guide, Rev. D 31
J4
Pin 1
J01
RES
PAR DMS
RES MTR WP
J4
Reserved (RES)
Reserved for factory use.
Parity Check option (PAR)
Enable parity check of SCSI bus data (default).
Disable parity check of SCSI bus data.
Motor Start option (MTR)
Enable motor start. This makes the drive wait
for the Start Unit command from the host before
starting the spindle motor.
Disable motor start (default). This causes the
drive to start according to the Delay Motor
Start option setting as described below.
Delay Motor Start option (DMS)
(valid only if the Motor Start option
jumper is not connected)
Motor start delay equal to the SCSI ID multiplied
by 10 seconds. For example, if the SCSI ID = 2,
the drive will delay for 20 seconds before starting.
Disable the Delay Motor Start option (default).
Write Protect option (WP)
Write Protect = On (disables writing).
Write Protect = Off (enables writing – default).
Figure 10b. Additional jumper options
for ST11950W/WD and ST12550W/WD drives
32 ST11950 and ST12550 Installation Guide, Rev. D
Synchronizing spindles
If you are installing two or more Barracuda drives, you
may (optionally) want to synchronize their spindles to
reduce the latency associated with switching from one
drive to another. Spindle sync cables are used to con-
nect the drives.
For N- and ND-type drives, use pins 1 and 2 on the J4
connector to attach the spindle sync cable. Pin 1
provides the reference index signal (REFSIG+) and
pin 2 provides ground (GND). See Figure 11.
SCSI
Connector
DC Power
Connector
J01
Pin 1
Pin 2
J4
SSC
Spindle Sync Cable Connector
(SSC). These pins are used to
connect a spindle sync cable.
J4
Spindle sync reference index signal
(REFSIG+).
Ground (GND).
Figure 11. Spindle sync jumpers and connectors
for ST11950N/ND and ST12550N/ND drives
ST11950 and ST12550 Installation Guide, Rev. D 33
For W- and WD-type drives, use pins 11 and 12 on the
J5 connector to attach the spindle sync cable. Pin 11
provides the reference index signal (REFSIG+) and pin
12 provides ground (GND). See Figure 12.
SCSI I/O
Connector
DC Power
Connector
J5 Pin 1
SSC
Spindle Sync Cable Connector (SSC)
These pins are used to connect a
spindle sync cable.
J5
Spindle sync reference index signal
(REFSIG+).
Ground (GND).
Figure 12. Spindle sync jumpers and connectors
for ST11950W/WD and ST12550W/WD drives
34 ST11950 and ST12550 Installation Guide, Rev. D
Figure 13 illustrates a typical synchronized spindle
configuration.
After connecting each drive with spindle sync cables,
you must designate a master spindle sync reference
source. This master source is normally a disc drive
located on the same SCSI bus as the other drives you
want to synchronize with. To designate a drive as the
master, use SCSI interface commands. Refer to the
Product Manual for information about using these
commands.
Sync Interface
Sync Interface
Master Sync
Source
Master Sync
Source
J4
1
J5
11
Spindle
Control
Spindle
Control
Host
(or other drive)
Host
(or other drive)
2
12
+5V
R
Drive 1
+5V
R
Drive 1
T
T
J4
1
J5
11
System
Interface
System
Interface
Spindle
Control
Spindle
Control
2
12
+5V
+5V
R
R
T
T
Drive 2
Drive 2
J4
1
J5
11
Spindle
Control
Spindle
Control
2
12
+5V
+5V
R
R
T
T
Drive n
Drive n
ST11950N/ND and
ST12550N/ND Drives
ST11950W/WD and
ST12550W/WD Drives
Figure 13. Spindle sync diagram
ST11950 and ST12550 Installation Guide, Rev. D 35
Providing adequate cooling
The enclosure design must ensure adequate cooling
for the drive. The maximum ambient temperature is
50oC.
Thedrive’s product manual(83327780)describeshow
to evaluatetheair-flowdesign.The evaluation consists
ofensuringthatthecasetemperaturesofcertaincritical
components remain within acceptable limits during
drive operation.
We recommend orienting the drive or directing the air
flow in a way that creates the least amount of air-flow
resistance while providing air flow above the circuit
boardsand aroundthehead anddisc assembly(HDA).
Also,choosetheshortest possiblepathbetweentheair
inlet and exit. This minimizes the distance traveled by
air that is heated by the drive and by other nearby heat
sources.
Figure 14 shows two design approaches with one or
more fans used to generate air flow. The air-flow pat-
terns can be created by the fans either pushing or
drawing air. The overall flow pattern can be directed
from front to back, back to front, or side to side.
36 ST11950 and ST12550 Installation Guide, Rev. D
Kühlung des Systems
Die Gehäusekonstruktion muß eine ausreichende
Kühlung des Laufwerkes gewährleisten. Die
Umgebungstemperatur darf maximal 50oC betragen.
Die Produkthandbuch Barracuda 1 und 2 (Dokument
83327780) enthalten Anweisungen zur Beurteilung der
Luftstromkonstruktion.DieBeurteilungmußsicherstellen,
daß sich die Gehäusetemperatur bestimmter kritischer
Komponenten bei Laufwerkbetrieb innerhalb
zugelassener Grenzen hält.
Wirempfehlen, dasLaufwerksozuorientierenoderden
Luftstrom so zu lenken, daß der geringste
Luftstromwiderstand erzeugt wird und gleichzeitig ein
Luftstrom über den Platinen und um die Kopf- und
Festplatteneinheit(HDA)gegebenist.WählenSieeinen
möglichstkurzenWegzwischenLufteinlaßund-auslaß.
Dadurch wird die Strecke, die die vom Laufwerk und
anderennahegelegenenHitzequellenaufgewärmteLuft
zurücklegt, auf ein Minimum beschränkt.
Abbildung 14 zeigt zwei Konstruktionsmöglichkeiten,
bei denen ein oder mehrere Lüfter den Luftstrom
erzeugen. Der Luftstromverlauf wird durch die Lüfter
gesteuert, die entweder Luft einblasen oder abziehen.
Generell kann der Luftstrom entweder von vorne nach
hinten oder von hinten nach vorne verlaufen.
ST11950 and ST12550 Installation Guide, Rev. D 37
Above unit
Über der Einheit
Note. Air flows in the direction shown (back to front)
or in reverse direction (front to back)
Under unit
Unter der Einheit
Hinweis. Luftstrom in der angezeigten Richtung
(von vorne nach hinten) oder in umgekehrter
Richtung (von hinten nach vorne)
Above unit
Über der Einheit
Note. Air flows in the direction shown or
in reverse direction (side to side)
Under unit
Unter der Einheit
Hinweis. Luftstrom in der angezeigten Richtung oder in
umgekehrter Richtung (von Seite zu Seite)
Figure 14. Suggested air flow
Abbildung 14. Empfohlener Luftstromverlauf
38 ST11950 and ST12550 Installation Guide, Rev. D
Mounting the drive and connecting cables
Do not touch the connector pins or any components on
the control board without observing static-discharge
precautions. Always handle the drive by the frame only.
The drive may be mounted in any orientation (horizon-
tally, vertically, and any combination thereof); however,
you must ensure that the drive receives adequate air
flow for cooling.
1. Mount the drive to the host system’s chassis using
four 6-32 UNC screws. Two mounting holes are in
each side of the drive and there are four mounting
holes in the bottom of the drive. See Figure 15.
The maximum length that the screws should ex-
tend into the chassis mounting holes is 0.15 inch
(3.81 mm), measured from the outer surface of the
chassis. Tighten the screws down evenly. Do not
over-tighten or force the screw if it does not seem to
screw in easily, because this means the threads are
not properly aligned. In this case, back the screw out
and try again.
ST11950 and ST12550 Installation Guide, Rev. D 39
Installation des Laufwerkes
und Anschluß der Kabel
Beachten Sie beim Handhaben und Anfassen der
Anschlußstifte
und
Komponenten
die
Vorsichtsmaßnahmen zur Verhinderung statischer
Aufladung. FassenSiedasLaufwerknuramRahmenan.
Das Laufwerk kann in beliebiger Orientierung (horizon-
tal, vertikal oder schräg) installiert werden; jedoch muß
dafür gesorgt werden, daß ein ausreichender Luftstrom
zur Kühlung des Laufwerkes vorhanden ist.
1. Befestigen Sie das Laufwerk mit vier 6-32-UNC-
Schrauben am Gehäuse des Host-Systems. Die
beiden Seiten des Laufwerkes sind mit jeweils zwei
Befestigungslöchern versehen, die Unterseite des
Laufwerkes weist vier weitere Befestigungslöcher
auf. Siehe Abbildung 15.
GemessenvonderAußenflächedesGehäusesdürfen
die Schrauben maximal 3,81 mm in die
Befestigungslöcher des Gehüuses hineinragen. Die
Schrauben müssen gleichmäßig, jedoch nicht zu
fest, angezogen werden. Wenn sich eine Schraube
nicht ohne Widerstand einschrauben läßt, sind die
Gewinde nicht korrekt aneinander ausgerichtet. In
diesem Fall die Schraube nicht in das Gewindeloch
forcieren, sondern die Schraube herausnehmen und
erneut in das Gewindeloch einführen.
40 ST11950 and ST12550 Installation Guide, Rev. D
T
U
(1)
C
R
(3)
P
F
N
D
E
K
L
A
M
Notes:
(1)
Mounting holes two on each
side, 6-32 UNC. Max screw
length into side of drive is
0.15 in. (3.81 mm).
B
Mounting holes four on
bottom, 6-32 UNC. Max
screw length into bottom of
drive is 0.15 in. (3.81 mm).
(2)
(3)
(4)
Power and interface
connections.
Decorative front panel.
(2)
Inches
Millimeters
A
B
C
D
E
F
G
H
J
5.740
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
0.010 145.80
0.010 101.60
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
±
.25
4.000
1.615
.615
4.000
.250
1.750
3.750
2.370
5.420
5.565
5.930
.240
.25
.28
.50
.13
.13
.25
.25
.25
.50
.25
.50
.38
.38
.25
.25
.25
G
0.011
0.020
41.02
15.68
0.005 101.60
0.005
0.010
0.010
0.010
6.35
44.45
95.25
60.20
K
L
0.020 137.69
0.010 141.35
0.020 150.62
J
M
N
P
R
S
T
0.015
0.015
0.010
6.10
10.31
43.82
.410
1.725
4.100
.190
0.010 104.14
0.010 4.83
H
U
0.015 max
0.381max
(4)
S
Figure 15. Dimensions
Abbildung 15. Laufwerkabmessungen
ST11950 and ST12550 Installation Guide, Rev. D 41
2. Verify that all connections between the drive and the
host system are correctly installed.
2. Prüfen Sie, ob alle Verbindungen zwischen dem
Laufwerk und dem Host-System korrekt hergestellt
sind.
3. Verify that you have correctly installed SCSI ID jump-
ers (see Figures 3, 4, 6, and 7).
3. StellenSiesicher,daßdieKennungsbrückeninstalliert
sind. Siehe Abbildung 3, 4, 6, und 7.
4. Connect the 50-pin SCSI cable into the drive’s SCSI
connector (shown earlier in Figures 3 and 4). Take
care not to stretch or crimp this cable, and do not
block the system’s cooling air flow with the cable.
ThedrivereceivesDCpowerthrougha4-pinconnec-
tor mounted next to the SCSI connector. The output
of a power supply must meet SELV (safety extra low
voltage)asdefinedinIEC950.Figure16providesthe
pin information for the DC power connector. To con-
nect the DC power cable to the drive, insert the cable
end into the drive’s DC power connector.
4. Schließen Sie das 50-polige SCSI-Kabel an den
SCSI-SteckverbinderdesLaufwerkesan(wiebereits
in Abbildung 3 und Abbildung 4 gezeigt). Das Kabel
42 ST11950 and ST12550 Installation Guide, Rev. D
darf nicht gedehnt oder gedrückt werden und es darf
den Luftstrom zur Kühlung des Systems nicht
behindern.
Das Laufwerk wird über einen 4-poligen, neben dem
SCSI-Anschluß befestigten Steckverbinder mit
Gleichstrom versorgt. Der Ausgang eines Netzteils
muß SELV (safety extra low voltage) nach IEC 950
entsprechen.Abbildung16zeigtdieSteckerbelegung
für den Gleichstromanschluß. Zum Anschluß des
Gleichstromkabels an das Laufwerk das Kabelende
indenGleichstromanschlußdesLaufwerkesstecken.
Pin Power
Pin Gleichstrom
1
2
3
4
+12V
1
2
3
4
+12 V
+12V return
+ 5V return
+ 5V
+12 V Rückleitung
+ 5 V Rückleitung
+ 5 V
4
3
2
1
Figure 16. DC power connector
Abbildung 16. Gleichstromanschluß
ST11950 and ST12550 Installation Guide, Rev. D 43
Note. Signal ground on the power control board (PCB)
and the head and disc assembly (HDA) are con-
nected together in this drive and you cannot
separate them. The equipment in which you have
mounted the drive is connected directly to the
HDA and PCB without electrically isolating shock
mounts. Maximizing the conductive contact area
between HDA ground and system ground may
reduce radiated emissions. If you do not want the
system chassis to be connected to the HDA/PCB
ground, you must provide a nonconductive (elec-
trically isolating) method of mounting the drive in
thehostsystem.Thismayincreaseradiatedemis-
sions and is the system designer’s responsibility.
Hinweis:
DieSignalerdeaufderStromregelungskarte(PCB)
und der Kopf- und Festplatteneinheit (HDA) sind
in diesem Laufwerk miteinander verbunden und
können nicht getrennt werden. Das Gerät, in das
Sie das Laufwerk eingebaut haben, ist ohne
elektrisch isolierende Stoßdämpfer direkt an die
HDA und PCB angeschlossen. Die
elektromagnetische Strahlung kann reduziert
werden, indem Sie eine möglichst große leitende
Kontakfläche zwischen der HDA-Erdung und der
Systemerdung vorsehen. Wenn Sie das
44 ST11950 and ST12550 Installation Guide, Rev. D
Systemgehäuse nicht an die HDA/PCB-Erdung
anschließen wollen, müssen Sie das Laufwerk
auf nichtleitende Weise (galvanisch isoliert) im
Host-System einbauen. Die daraus u.U.
resultierende verstärkte elektromagnetische
Strahlung fällt in den Zuständigkeitsbereich des
Systemdesigners.
5. Replace the host system’s cover.
5. Setzen Sie das Gehäuseoberteil des Host-Systems
wieder auf.
ST11950 and ST12550 Installation Guide, Rev. D 45
Formatting the drive
Warning. Formatting a drive erases all user data. Be
sure that you understand this principle before
formatting any hard disc drive.
It is not necessary to format a drive which has
previously been used to store data, unless
your intention is to erase all user data.
1. Turn on DC power.
2. Boot the system from a system floppy disc or from a
previously installed hard disc drive if there is one.
3. Format the disc drive. The Barracuda 1 and 2 disc
drives are designed to operate with a variety of
operating systems; therefore, please refer to your
system or SCSI controller manuals for information
about formatting and setting up the drives.
Seagate Technology, Inc.
920 Disc Drive, Scotts Valley, CA 95066-4544, USA
Publication Number: 83327770, Rev. D, Printed in USA
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