Seagate ST41201K User manual

<555>seagate
Elite Disc Drive
ST41201K
User's Manual
(/Pl Interface)

Contents
Preface........................................................................... :~.................... iii
Electrostatic discharge protection ............................ .. ....................... iii
Important safety information and precautions.................................... iv
Technical support services ............................................................... vi
Section 1. General description ........................................ .. .................... 1
Section 2. Installation ................... .. ....... .... . .. . .... . .. .. .. .............. .. ... ... ...... 7
Section 3. Operation............................................................................. 33
Section 4. Parts data .............. ... ....... .. . .. .... ...... .. ..... .. .... .. ......... ... ..... .. ... 37
Section 5. Mainienance ........................................................................
© 1992 Seagate Technology, Inc. All rights reserved
Publication Number: 83327320, Rev. B
Seagate®,SeagateTechnology®,andtheSeagatelogoareregisteredtrademarks
of SeagateTechnology, Inc. Elite™·SeaFAX™,SeaFONE™,andSeaBOARD™
aretrademarksofSeagate Technology, !nc. Otherproduct namesare registered
trademarks or trademarks of their ovJners.
No part of this publication may be reproduced in any form without wri'
permission from Seagate Technology, Inc.

ST 41201 K User's Manual iii
Preface
This manual contains information for users of the Seagate ST41201K Elite disc
drives (employing the IPI interface). It provides instructions to all personnel who
operatethe drive and to customer engineers who install and check out the drive.
Additionalinformationisavailableinthereferencemanual(publication83327330).
Electrostatic discharge protection
Caution. Removal of circuitboards by personnel not performing depot repairwill
damage components and may void the warranty.
'\II drive electronic assemblies are sensitive to static electricity due to the
ectrostatically sensitive devices used within the drive circuitry. Although
somedevicessuch as metal-oxidesemiconductors are extremelysensitive, all
semiconductors, as well as some resistors 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 acharged conductor, or by exposuretothe static fields surround-
ing charged objects. To avoid damaging drive electronic assemblies, observe
the following precautions when servicing the drive:
• Ground yourself to the drive whenever the drive electronics are or will be
exposed. Connectyourselfto ground with a wrist strap (refer to accessories in
section4forthepartnumber). Connection maybemadeto anygrounded metal
assembly. As ageneral rule, rememberthat you and the driveelectronics must
all be grounded to avoid potentially damaging static discharges.
• Turn off power before removing or installing the DC power cable.
• Do not remove any circuit boards from the drive.
• Never use an ohmmeter on any circuit boards.

iv
Important safety information and precautions
Caution. Use forced-air ventilation when bench-testing the drive to ensure
proper cooling of drive components.
Use proper safety and repair techniques for safe, reiiabie operation of this unit.
Service should be done only by qualified persons. We recommend theprocedures
in thismanual as effective ways of servicingthe unit. Some proceduresrequirethe
useofspecialtools. Forpropermaintenance and safety, you must use thesetools
as recommended.
The procedures in this manual contain warnings and cautions that must be
carefully read and followed to minimize oreliminate the risk of personal injury. The
warnings point out conditions or practices that may endanger you or others. ..,.
cautions point out conditions or practices that may damage the unit, possk ,
making it unsafe for use.
You must also understand that these warnings and cautions are not exhaustive.
We cannot possibly know, evaluate, and advise you of all the ways in which
maintenance might be performed orthe possible risk of each technique. Conse-
quently, 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.
Ahri1ays observ'e the follovving vvarnings and precautions:
• Perform all maintenance by following the procedures in this manual.
• Follow all cautions and warnings in the procedures.
Use sound safety practices when operating or repairing the unit.
• Use caution when troubleshooting a unit that has voltages present. Remove
power from the unit before servicing it.
• Wear safety shoes when removing or replacing heavy parts.
• Provide a means to isolatethedrive from the main power in case of fire orother
emergency.
• Ensure that the internal temperature of the rack or cabinet will not exceed the
limitsdefined for the drive, when the drive is mounted in an equipment rack or
cabinet. When units are stacked vertically, pay special attention to the top where
temperatures are usually highest.
Follovv the piecautions listed undei "Electiostatic dischaige piotection" above.
• Do not remove any circuit boards from the drivechassis. Return the entiredrive
for depot repair if any circuit board is defective. Removal of circuit boards '
personnel not performing depot repair will damage components and may VL
the warranty.

ST41201 K User's Manual
v
• Do not remove the head and disc assembly (HOA) from the drive chassis.
Return the entire drive for depot repair if the HOA is defective.
• Do not attemptto disassemble the HOA. It is not field repairable. If the sealed
HOA is opened by personnel not performing depot repair, this will damage
components and void the warranty.
• As a component, this drive is designed to be installed and operated in
accordance wnh UL1950, IEC950, EN60950, CSAC22.2950. and VDE0806.
• Always de-energize the drive before removing or installing cables.
• Ensure that the power supply meets the specifications in this manual and is
designed to be used in accordance with Ul1950, IEC950, EN60950, CSA
C22.2 950, and VDE0806.
..:ieagate takes all reasonable steps to ensure that its products are certifiable to
currently accepted standards. Typical applications of these disc drives include
customerpackaging and subsystemdesign Safety agenciesconditionally certify
component parts, such asthe Eme disc drive, basedon theirfinal acceptability in
the end-useproduct. Thesubsystemdesignersare responsible formeetingthese
conditions of acceptability in obtaining safety/regulatory agency compliance in
their end-use products and in certifying where required by iaw. A necessary part
ofmeeting safetyrequirements istheprovision forovercurrentprotectionon drive
SELV supply voltages.
This unn is a component assembly and as such is not meantto comply with FCC
orsimilar national requirements as a stand-alone unn. Engineering radiated and
conducted emissions test results are available through the Seagate Safety
Department to assist the subsystem designer.

vi
Technical support services
Seagate Technology provides technical support literature and diagnostic util~ies
to authorized distributors. Please contact your dealer for technical support and
installationtroubleshooting. Product technical support is available for all Seagate
products by calling the SeaFAX, SeaFONE, or SeaBOARD services. These are
toll calls if you dial from outside of the number's local dialing area.
SeaFAX: [phone]
You can use a Touch-Tone telephone to access Seagate's automated FAX
delivery system and select technical support information by return FAX. This
service is available twenty-four hours a day, seven days a week.
SeaFONE: [phone]
Theenhanced phone system provides recorded technicalinformation on select1:._
Seagate products while you are on hold. Technical support specialists are
available to answer questions from 8:00 A.M. to 5:00 P.M. PST, Monday through
Friday. Recordings are accessibletwenty-four hours a day, seven days a week.
SeaBOARD:
TheSeagateTechnical Support Bulletin Board System (BBS) is available twenty-
four hoursa day, seven days a week. A modem is required to access this service.
The communications software must be set for eight data bits no parity and one
stop bit (8N1 ). With this service you can access:
• Specifications and jumper configurations for all Seagate products
• Reprints of Seagate documentation
• Adirectory of information and helpful utilitiesthat you can downloadto your own
computer
Location Telephone Number Maximum Baud Rate
United States/Canada
[phone]
9600
England 44-62-847-8011
9600
Germany
49-89-140-9331 2400
Singapore
65-227-2217
9600
Australia
61-2- 756-2359
9600
Note. This is a toll call if you dial from outside of the number's local dialing area.

Section 1. General description
The Seagate ST41201 K Elitediscdriveisa high speed, random access digital
data storage devicethat connects to a central processor through a controller.
The ST 41201 K disc drive is shown in Figure 1, and its specifications are listed
in Table 1.
The drive is a component for installation in an enclosure designed for the drive.
The enclosure design must ensure adequate cooling for the drive, and it must
address the requirements for grounding and for shielding of emissions. The
reference manual (publication 83327330) presents guidelines for designing the
enclosure, but the design is your responsibility.
Figure 1. The ST41201K disc drive

2
Table 1. Drive specifications
Characteristics Conditions Specifications
Size Dimensions (see "Space
requirements" in section 2)
Weight 4.1 kg (9.0 lb)
(drive only)
Weight
(power supply only)
Interface IPl-2
Recording
Transfer rate
Total capacity
(unformatted)
Bytes pertrack
(unformatted)
Number of discs
Movable data heads
Servo heads
Physical heads
per surface
Cylinders per
headidisc assy
Modulation
Disc speed
at 5400 RPM
2.3 kg (5.0 lb)
1,200,055,000 bytes
33,599
10
17
2101* (0-2100 logical)
2,?code
24.2 MHz (3.0 Mbytes/sec)
• Users normally reserve two cylinders fordiagnostic use (cylinder 2100 for defect
map and cylinder 2099 for diagnostics); however, both cylinders can be used for
customer data if desired.
continued

General description
continued from previouspage
Characteristics Conditions Specifications
Seek time
(time required to move heads
to a different track address) Typical full 22.5 msec
max
Typical average 11 .5 msec max
Typical one-track 1.7 msec max
Latency
(time required to reach a
particular track address after
head positioning is complete) Average 5.55 msec
(disc rotation
at 5400 RPM)
Maximum 11.17 msec
(disc rotation
at 5373 RPM)
Start time**
60 sec max
Stop time
60 sec max
** Following the powersequence delay, once DC power is applied and start
conditions are present.
3
The drive contains all the circuits and mechanical devices necessary to record
data on and recover it from its discs. The drive requires DC voltage inputs from
an external power supply, which receives its AC input powerfrom the site main
power source. A powersupply and DC power cable are available accessories.
Thedriveconsists of a head and disc assembly(HDA) and several circuit boards
mounted on a common chassis. The circuit boards contain the electronics
required for drive operation. The HOA is a sealed unit containing the electrome-
chanical components used for data storage and retrieval. These components
include the discs, spindle, drive motor, actuator, and heads.
The ten discs provide the recording medium for the drive. These discs are
mounted on a spindle, and the spindle is coupled directlyto the drive motor. The
drive motor rotates the discs at 5400 RPM and also produces a circulation of air
within the sealed HOA.

4
All functions performed by the drive are done underdirection ofthecontroller. As
shown in Figure 2, the controiier communicates with the drive via the interface
whichconsists of a number of 1/0 lines carrying the necessary signalsto and from
the drive. Refer to the reference manual for adescription of interface functions.
Some interface lines, including those that carry commands to the drive, are not
enabled unless the drive is selected by the controller. Unit selection allows the
controller, which can be connected to more than one drive, to initiate and direct
an operation on a specific drive.
IH
Data recorded in
concentric tracks
Unit
Selection
Logic
Head
Selection
Logic Heads
Read/Write t---~
Logic I
~
~
Seek
Logic
Track
Orientation
Logic
Error
Detection
Logic
Positioning ~
Devloe If
< > Discs
Power Supply
Figure 2. Drive functional block diagram

General description 5
All driveoperationsare related to data recovery and storage (normally referred to
asreading and writing). Theactual reading and writing is performed byheadsthat
are positioned overthe rotating discs' recording surfaces. There is one head for
each data surface. The heads are positioned in such a way that data is written
in concentric tracks around the disc surfaces (see Figure 2).
Before any read or write operation can be performed, the controller must
instruct the drive to position the heads over the desired cylinder (called
seeking) and usethehead located overthe surface (head selection) where the
operation is to be performed.
The heads are mounted on the actuator, and the actuatormoves the heads over
the rotating discs. There are 18 heads-a servo head to sense actuator
,ositioning and 17 data heads used for datatransfersto and from the discs. The
actuator has avoice coil that moves in apermanent magneticfield in response to
signals from the servo positioning circuitry. The voice coil moves the heads in an
arc acrossthe rotating discs.
When the drive is not powered on, the heads rest on the disc surface in the
preassigned landing zone (beyond the data zone). The actuator automatically
iatches in thisposition, to protectthedrive in the eventthat it is moved or shipped.
When the drive is activated to bring the discs up to speed, the heads fly on a
cushion of air close to the disc surface.
After arriving at the data track and selecting a head, the controller locates the
portion of the track where the data is to be read or written. This is called track
orientation. Signals from the drive indicate the beginning of each track. The
controller uses these signals to determinethe position ofthe head on the track.
When the head is above the desired track location, the controller commands the
driveto actuallyreadorwritethedata. During aread operation, the driveretrieves
data from the discs, processes it, and transmits it to thecontroller. Duringa write
operation, the drive receives data from the controller, processes it, and stores it
on the discs.
The drive can also recognize certain errors that may occur during its operation.
When an error is detected, status information is available through the controller.

7
Section 2. Installation
The information contained in this section describes installation and initial
checkout of the drive.
Site requirements
The site requirements considered are environment, airflow, space, power,
grounding, and interface.
Environmental requirements
Table 2 lists all environmental requirements for the drive.
fable 2. Environmental requirements
Conditions
Operating environment
Temperature
Humidity
Barometric pressure
Non-operating environment
(unpacked)
Temperature
Humidity
Barometric pressure
Storage environment (packed)
Temperature
Humidity
Barometric pressure
Transit environment (packed)
Temperature
Humidity
Barometric pressure
Specifications
Range of 10°C to 45°C (50°F to 113°F) with a
maximum change of 15°C (27°F) per hour
Range of 20% to 80% relative
A maximum wet bulb temperature of 26°C (79°F)
-305 m to 2,000 m (-1,000 ft to 6,560 ft)
104 kPa to 79 kPa (30 in Hg to 23 in Hg)
Range of 10°C to 45°C (50°F to 113°F) with a
maximum change of 15°C (27°F) per hour
Range of 20% to 80% relative
A maximum wet bulb temperature of 26°C (79°F)
-305 m to 3,000 m (-1,000 ft to 10,000 ft)
104 kPa to 69 kPa (30 in Hg to 20 in Hg)
Range of -10°c to 50°C (14°F to 122°F) with a
maximum change of 15°C (27°F) per hour
Range of 5% to 95% relative
-305 m to 3,000 m (-1,000 ft to 10,000 ft)
104 kPa to 69 kPa (30 in Hg to 20 in Hg)
Range of -40°C to 60°C (-40°F to 140°F) with a
maximum change of 20°C (36°F) per hour
Range of 5% to 95% relative
-305 mto 12,192 m(-1,000 ft to 40,000 ft)
104 kPa to 19 kPa (30 in Hg to 6 in Hg)

8
Airflow requirements
The enclosure design must ensure adequate cooling forthe drive. Note that the
fan in tile power supply cools only the power supply's internal parts.
The drive's product specification (document 64403104) describes how to
evaluatethe airflow design. The evaiuation consists of ensuring that the case
temperatures of certain critical components remain within acceptable limits
during drive operation.
We recommendorienting the driveordirectingtheairflow in a way that createsthe
leastamount of airflow resistance while providing airflow above the circu~ boards
andaroundthe head and discassembly (HDA). Also, choosetheshortestpossible
pathbetweentheair inlet and exit. This minimizesthedistancetraveled by airtt'
is heated by the drive and by other nearby heat sources.
Figure 3 shows the design approach with one or more fans used to generate
airflow. The airflow patterns can be created by thefans eitherpushing ordrawing
air. It is possible to install a pair of drives side-by-side so that the air circulation
created by one or more fans ventilates both drives.
Figure4 shows the design approach when the airflowpattern is from fronttoback
orfrom back to front. Baffles can redirect aportionofthe airflowthroughthe space
between the circuit boards.

Installation
ISingle Drive I
·······>·· ...................................... ········>
·················>················ ········>
................................................ ········>
.........................................................
--·
...... ·> Airflow between
circuit boards
- - • Airflow above and below
head and disc assembly
(HDA)
--·
--·
--·
Pair of Drives
9
.................................................................................................................
........... ................................... ................ ................................... ········>
...............................................................................................................
........... .................................... ................ .................................... .... ···>
0
--·
-->--
--·
0---~--
--·
o ~
----->-----
Figure 3. Perpendicular airflow

10
IFront-to-Back Airflow I
__ .. __ I0 __ Go-·--~- : ~1-~f'-J ·-1----·---
---->- '--- __ ....,.... --- t->-1-1~\~~ ~ LI ->------ ..
I '--i:l·;~r
Ill ~ ro: I ~ 1r l I
11)\ rn/ I ~1v1: 1~11: I
- -·--tr\""\: --->---- -);?'-t->- --tr.If. tHtt-:-t----->---
l~~ I llLltllJ; I
········> Airflow between
circuit boards
- - + Airflow above and below
head and disc assembly (HDA)
FiQure 4. Lengthwise airflow
n_u1_\·~ . .-·· .. .":·~·~:.:.:.:t.:.:_:_:_:_:.~.:.:_:_:_:.~.:ii,.::
Dd.111~ "•••••·······~·············>-······

Installation
11
Space requirements
The drive is designed to be mounted in one of the three orientations shown in
Figure5. Thedrivemaybe mountedon its base or on eitherside. The physical
dimensions of the driveand optional power supply are shown in Figure 6. The
drive itself weighs 4.1 kg (9.0 lb).
Fordetailsaboutdesigning an enclosuretomatchthedrivemountingdimensions,
refer to the drive's product specification.
Figure 5. Mounting orientations

12
Figure 6. Dimensions of the drive

Installation 13
Power requirements
The voltage and current requirements for a single drive are shown in Table 3
below. Consulttheproductspecification before selecting ordesigninga power
supplyforthedrive. The product specification presents more detailed require-
ments including the types of overvoltage and overcurrent protection needed.
AC power requirements for the optional Seagate power supply are listed in
Table 4. Conversion to the different line voltages is explained in the installation
procedures.
Table 3. DC power requirements for the drive
Current
Seeking Maximum
and Power
Voltage Idle
2.7A
2.0A
Reading Seeking
+5 v
+12V
3.1 A 2.7A
2.3A 2.6A
Watts
38 w 43 w
Maximum Current Limits
Maximum operating current*
Average idle current
Maximum starting current*
Maximum seek current
45 w
+5 v
3.7A
2.7A
2.7A
2.7A
Continuous
Reading
3.7 A
2.0 A
43 w
+12V
2.9 A
2.0 A
5.4 A
3.7 A
*Instantaneous+ 12 V current peaks will exceed these values by up to 0.8 A.
Table 4. AC power requirements for the power supply
Nominal Values
Specifications 100-120 VAC
208-240VAC
Voltage range
85 to 132 V 175 to 264 V
Nominal line frequency 50/60 Hz
50/60 Hz
Frequency range 48.0 to 62.0 Hz 48.0 to 62.0 Hz
Phase requirements single phase single phase
Power consumed* 65W 63W
Line current*
0.90A
0.56A
Power factor* 0.61 0.54
*Measured at nominal values when discs are rotating and carriage is track-following.

14
Grounding requirements
A safety ground must be provided by the site AC powersystem. The green wire
(orgreen wirewithyellowstripe) in the AC powercord provides the safetyground
connectionbetweenthepowersupplyandthesiteAC powersystem. The siteAC
power system must provide the safety ground to earth ground connection.
All site AC power connection points, including convenience outlets for test
equipment, must be maintained at the same safety ground potential.
Interface requirements
This driveisatwo-portdevice, so it can be shared by two controllersifnecessary.
It is designed to be connected in a daisychain 1/0 configuration as shown ·
Figure 7. Table5 showsthepin assignments and signal namesforthe 1/0cabi.
Detailed information about interface lines is given in the reference manual
(publication 83327330}.
The two 1/0 connectors at the back of the drive accept the 1/0 cables that
connect itto thesystem. J31 (port A) and J32 (port B) arethe connectors to which
daisychain 1/0cables are attached. Eachdaisychaincable isa continuouscable
having one connector for each drive it connects to.
~ Port A --~-- Pert B ---+--
Terminator Terminator
lp.---C-cnt-rci!e-r --.~
'----.-----'
Figure 7. Daisychain configuration