Seagate HAWK 4 User manual

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Product Manual,Volume 1
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HAWK 4 Family:
ST15230W/WD/WC/DC
(Wide bus)

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Product Manual,Volume 1
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HAWK 4 Family:
(Wide bus)
ST15230W/WD/WC/DC

1996 SeagateTechnology, Inc.All rights reserved
Publication Number: 77767479 Rev. E
March 1996
Seagate, SeagateTechnologyand the Seagate logo are registered trademarks of SeagateTechnology,
Inc.Hawk™, SeaFAX, SeaFone, SeaTDDand SeaBOARDare trademarks of SeagateTechnology,
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 of SeagateTechnology, Inc.

Product Manual - Hawk 4 Family (Wide) SCSI-2 (Volume 1), Rev. E v
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Revision status summary sheet
Revision Authority Date Writer/Eng. Sheets Affected
A Issue 03/13/95 D. Ashby v thru viii, 1 thru 70.
B PLD: 87201 06/26//95 D. Ashby 1/1, v and 18.
C PLD: 87236 08/30/95 D. Ashby 1/1, v and 39.
D PLD: 87305 1/24/96 D. Ashby 1/1, v, vi, 2, 12, 21 and 41
E PLD: 87334 v and 18
Notice.
Product Manual 77767479 isVolume 1 of a twoVolume document with the SCSI interface information
in theVolume 2 SCSI Interface Product Manual,P/N 77738479.
If the SCSI Interface information is needed the Volume 2 Interface Manual should be ordered, P/N
77738479.

vi Product Manual - Hawk 4 Family (Wide) SCSI-2 (Volume 1), Rev. E
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Table of contents
1.0 Scope.......................................................................................................................................... 1
2.0 Applicable standards and reference documentation.............................................................. 2
2.1 Standards ....................................................................................................................... 2
2.2 Electromagnetic Compliance for the European Union ..................................................... 2
2.3 Applicable reference documents ..................................................................................... 2
3.0 General description ................................................................................................................... 3
4.0 Standard features ...................................................................................................................... 5
4.1. Performance ................................................................................................................... 5
4.1.1 Reliability............................................................................................................ 5
4.2 Unformatted and formatted capacities ............................................................................ 6
4.3 Options (factory installed) ............................................................................................... 6
4.4 Optional accessories (user installed) .............................................................................. 6
4.5 Installation....................................................................................................................... 7
5.0 Performance characteristics ..................................................................................................... 8
5.1 Internal drive characteristics (transparent to user) .......................................................... 8
5.2 SCSI drive Seek, Read andWrite performance characteristics (Visible to User) ............ 8
5.2.1 Access time........................................................................................................ 8
5.2.2 Format drive command execution time ............................................................... 9
5.2.3 Read data command execution time................................................................... 9
5.2.4 Write data command execution time................................................................... 9
5.3 Generalized performance characteristics........................................................................ 10
5.3.1 Notes for sections 5.2 and 5.3 ............................................................................ 11
5.4 Start/stop time ................................................................................................................ 12
5.5 Prefetch/multi segmented cache control ......................................................................... 12
5.5.1 Cache operation ................................................................................................. 12
5.5.2 Prefetchoperation .............................................................................................. 13
5.6 Caching write data .......................................................................................................... 14
6.0 Reliability specifications ........................................................................................................... 15
6.1 Error rates....................................................................................................................... 15
6.1.1 Read errors........................................................................................................ 15
6.1.2 Environmentalinterference ................................................................................ 15
6.1.3 Write errors ........................................................................................................ 16
6.1.4 Seek errors ........................................................................................................ 16
6.2 Reliability and service ..................................................................................................... 16
6.2.1 Mean time between failure ................................................................................. 16
6.2.2 Preventivemaintenance..................................................................................... 16
6.2.3 Service life ......................................................................................................... 16
6.2.4 Service philosophy............................................................................................. 17
6.2.5 Installation.......................................................................................................... 17
6.2.6 Service tools ...................................................................................................... 17
6.2.7 ProductWarranty ............................................................................................... 17

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Table of contents
7.0 Physical/electrical specifications ............................................................................................. 18
7.1 AC power requirements .................................................................................................. 18
7.2 DC power requirements .................................................................................................. 18
7.2.1 Conducted noise immunity................................................................................. 19
7.2.2 Power sequencing.............................................................................................. 19
7.2.3 12V - current profile........................................................................................... 19
7.3 Heat/powerdissipation.................................................................................................... 20
7.4 Environmentallimits........................................................................................................ 20
7.4.1 Temperature....................................................................................................... 21
7.4.2 Relative humidity................................................................................................ 23
7.4.3 Effective altitude (sea level ref)........................................................................... 23
7.4.4 Shock and vibration............................................................................................ 23
7.4.5 Air cleanliness.................................................................................................... 25
7.5 Electromagneticcompatibility.......................................................................................... 25
7.5.1 Electromagneticsusceptibility ............................................................................ 25
7.6 Mechanical specifications ............................................................................................... 26
7.6.1 Drive orientation................................................................................................. 28
7.6.2 Cooling............................................................................................................... 28
7.6.3 Drive mounting................................................................................................... 28
8.0 Media characteristics ................................................................................................................ 29
8.1 Media description............................................................................................................ 29
9.0 Defect and error management .................................................................................................. 30
9.1 Drive internal defects/errors............................................................................................ 30
9.2 SCSI systems error considerations................................................................................. 30
10.0 Option/configuration headers................................................................................................... 31
10.1 Drive ID/option select header.......................................................................................... 31
10.2 Grounding....................................................................................................................... 37
11.0 Interface requirement ................................................................................................................ 38
11.1 General description......................................................................................................... 38
11.2 SCSI interface messages supported............................................................................... 38
11.3 SCSI interface commands supported ............................................................................. 39
11.3.1 Inquiry data ........................................................................................................ 41
11.3.2 Mode sense data ............................................................................................... 42
11.4 SCSI bus conditions and miscellaneous features supported........................................... 45
11.5 Synchronous data transfer .............................................................................................. 46
11.5.1 Synchronous data transfer periods supported.................................................... 46
11.5.2 REQ/ACK offset ................................................................................................. 46
11.6 Physical interface ............................................................................................................ 46
11.6.1 DC cable and connector..................................................................................... 48
11.6.2 Physical characteristics...................................................................................... 48
11.6.3 Connector requirements..................................................................................... 50
11.6.4 Electrical description .......................................................................................... 59
11.7 Disc drive SCSI timing .................................................................................................... 64

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Table of contents
12.0 Options....................................................................................................................................... 66
12.1 Front panel...................................................................................................................... 66
12.2 Single unit shipping pack ................................................................................................ 66
12.3 InstallationGuide ............................................................................................................ 66
13.0 Accessories ............................................................................................................................... 67
13.1 Front panel kit ................................................................................................................. 67
13.2 Additional Installation Guide copies ................................................................................ 67
14.0 SeagateTechnical support services......................................................................................... 68

Product Manual - Hawk 4 Family (Wide) SCSI-2 (Volume 1), Rev. E 1
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1.0 Scope
This Manual describes the Seagate Technology, Inc. Hawk 4 Family Disc Drive. This high capacity, high
performance member of the Seagate 3.5 inch rigid disc family is a companion product to the ST12400 drive
family.It has an embeddedSCSI controller.Performance information is giveninSection5.The Hawk4Family
interfaceis definedforfunctional compatibilitytoasubsetoftheSeagateSCSIInterface Specification77738479,
and the ANSI SCSI-2 and SCSI-3 standards.The Model Hawk 4 Family drives are classified as "Intelligent"
peripherals.The Hawk4FamilyprovidesLevel2conformance(highest level)with the ANSI SCSI-1 standard.
Details of the Hawk 4 Family drive SCSI implementation are provided in Section 11 of this manual, (Vol. 1)
and in the SCSI Interface Product Manual P/N 77738479 (Vol.2;Ver. 2).
The Hawk 4 family of drives consists of the ST15230W/WD/WC/DC drives.
From this point on in this Product Manual the reference to Hawk 4 Family is referred to as "the drive" (unless
reference to individual models are necessary).
The drive printed circuit board is referred to as a PCB.
* 68 pin SCSI I/O and 4 pin direct current power connector shown as used on "W" and "WD" models. "WC" and "DC"
drive models have a single 80 pin connector that contains both SCSI I/O and direct current power (see Figure 3.0-1).
Figure 1-1. Hawk 4 family (Wide) drive
SEAGATE

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2.0 Applicable standards and reference documentation
The drive has been developed as a system peripheral to the highest standards of design and construction.
The drive depends upon its host equipment to provide adequate power and environment in order to achieve
optimum performance and compliance with applicable industry and governmental regulations.Special atten-
tion must be given in the areas of safety, power distribution, shielding, audible noise control, and temperature
regulation.In particular, the drive must be securely mounted in order to guarantee the specified performance
characteristics.Mounting by bottom holes must meet the requirements of Section 7.6.3.
2.1 Standards
The Hawk 4 Family (Wide) complies with Seagate standards as noted in the appropriate sections of this
manual and the Seagate SCSI Interface Specification, P/N 77738479 (Vol.2,Version 2).
The Hawk 4 Family is a UL Recognized component per UL 1950 and a CSA Certified component per CAN/
CSA-C22.2 No. 950-M89. It also meets the requirements of DIN VDE 0805:1993 and EN60950: 1992 (IEC
950).
The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to
use. As such the drive is supplied as a subassembly and is not subject to Subpart J of Part 15 of the FCC
Rules and Regulations nor the Radio Interference Regulations of the Canadian Department of Communica-
tions.However,the unit has been tested using propershielding andgroundingand foundtobe compliantwith
Class A limits of the FCC Rules and the Regulations ofThe Canadian Department of Communications.
The physical design characteristics of the drive serve to minimize radiation when installed in an enclosure
that provides reasonable shielding. As such, the drive is capable of meeting the Class B limits of the FCC
Rulesand Regulations of the CanadianDepartmentofCommunication.However, itis theusers responsibility
to assure that the drive meets the appropriate EMI requirements in their system.Shielded I/O cables may be
required if the enclosure does not provide adequate shielding.If the I/O cables are external to the enclosure,
shielded cables should be used, with the shields grounded to the enclosure and to the host controller.
Caution. To avoid potential service problems, observe the following precautions:
TheManufacturersinstalled labels mustnot be removedfrom the driveorcoveredwith additional
labels, as they contain information required when servicing the product.
2.2 Electromagnetic Compliance for the European Union
If this model has the CE Marking it complies with the European Union requirements of the Electromagnetic
CompatibilityDirective89/336/EECof03 May1989asamendedbyDirective92/31/EEC of28April1992and
Directive 93/68/EEC of 22 July 1993.
Seagateusesan independent laboratory toconfirm compliance to theabovedirectives. The drivewastested
in a representative system for typical applications. The selected system represents the most popular
characteristics for test platforms. The system configurations include:
• 486, Pentium, and Power PC Microprocessors • Keyboard
• 3.5-inch Floppy Disc Drive • Monitor/Display
Although the test system with this Seagate model complies to the directives, we cannot guarantee that all
systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance and
provide CE Marking for their product.
2.3 Applicable reference documents
Installation Guide: Seagate P/N 77767477 Product Manual: SCSI Interface Seagate P/N 77738479
ANSI Small Computer System Interface (SCSI):Document Number ANSI3.131-1986 (X3T9/84.40 Rev. 1B)
(X3T9.2/82-2 Rev.17B), X3T9.2/86-109 Revision 10H (SCSI-2) and X3T9.2-184 Rev. 4 (SCSI-3).
Seagate PackageTest Requirements P/N 30190-001 (packages under 100 lbs)
Seagate PackageTest Requirements P/N 30191-001 (packages over 100 lbs)
In case of conflict between this document and any referenced document, this document shall take prece-
dence.

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3.0 General description
The drives are a member of a family of low cost, high performance, highly reliable, random access storage
devices designed to meet the needs of the OEM marketplace.
The drive records and recovers data on 3.7 inch (95 mm) fixed discs.
The drive supports the Small Computer System Interface-2 (SCSI) as described in the ANSI SCSI-1, SCSI-
2 and SCSI-3 Interface Specifications to the extent described in this product manual (Vol. 1), which defines
the product performance characteristics of the Hawk 4 Family of drives, and the SCSI Interface Product
Manual P/N 77738479 (Vol. 2, Version 2) which describes the general interface characteristics of this and
other families of Seagate 3.5-inch drives.
The drive interface supports multiple initiators, disconnect/reconnect, self configuring host software and au-
tomatic features that relieve the host from the necessity of knowing the physical characteristics of the targets
(logical block addressing is used).
The Head/Disc Assembly (HDA) is environmentally sealed at the factory. Air recirculates within the HDA
through a nonreplaceable filter to maintain a contamination free head/disc environment.
Referto Figure3.0-1 foranexploded viewof the drive.NEVER disassembletheHead/Disc Assembly (HDA).
This exploded view is for information only.Do not attempt to service items in the sealed environmental enclo-
sure (heads, media, actuator, etc.) as this requires special facilities.The drive contains no parts replaceable
by the user.The drive warranty is voided if the HDA is opened.
The Hawk 4 Family (Wide) drives use a dedicated landing zone at the innermost radius of the media to
eliminate the possibility of destroying or degrading data by landing in the data zone.The drive automatically
goes to the landing zone when the power is removed.
TheHawk4Family(Wide) drivesincorporatean automatic shipping lockwhich preventspotential damageto
the heads and discs that result from movement during shipping and handling.The shipping lock disengages
when power is applied to the drive and the head load process begins.
The Hawk 4 Family (Wide) drives decode Track 0 location from the dedicated servo surface to eliminate
mechanical transducer adjustments and related reliability concerns.
The Hawk 4 Family (Wide) drives use a high performance actuator assembly that consists of a low inertia,
balanced, patented, straight arm design that provides excellent performance with minimum power dissipa-
tion.

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Figure 3.0-1. Hawk 4 family (wide) drive
“W/WD” Family PCB “WC/DC” Family PCB

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4.0 Standard features
The Hawk 4 Family (Wide) has the following standard features:
•Integrated SCSI Controller
•Single Ended and Differential SCSI drivers and receivers
•Asynchronous and Synchronous data transfer protocol
•Firmware downloadable via SCSI interface
•Selectable sector size from 256 to 4096 bytes/sector
•Programmable sector reallocation scheme
•Flawed sector reallocation at format time
•Programmable auto write and read reallocation
•Reallocation of defects on command (Post Format)
•96 bit Reed-Solomon error correcting code
•Sealed Head/Disc Assembly
•No preventative maintenance or adjustment required
•Dedicated head landing zone
•Automatic shipping lock
•Automatic AdaptiveThermal Compensation
•PatentedTri-Phase Servo with embedded Grey Code track address to guarantee servo positioning.
•Self diagnostics performed at power on
•1:1 Interleave
•Zoned Bit Recording (ZBR)
•Vertical, horizontal, or top down mounting
•Dynamic spindle brake
•512 K byte data buffer
•Permanently mounted terminators (for model ST15230W only), enabled by installation of a jumper plug.
4.1 Performance
•Programmable multi-segmentable cache buffer
•5411 r/min Spindle.Average latency = 5.54 ms
•Command Queuing of up to 64 commands per initiator
•Background processing of queue
•Supports start and stop commands
•Low audible noise for office environment
•Low power consumption
4.1.1 Reliability
•800,000 hour MTBF
•Adaptive seek velocity.Improved seek performance
•LSI circuitry
•Balanced low mass rotary voice coil actuator
•5 year warranty

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4.2 Unformatted and formatted capacities
Formatted capacity depends on the number of spare reallocation sectors reserved and the number of bytes
per sector.The following table shows some typical formatted capacities.
Spare sectors or cylinders W/WD/WC/DC
reserved for reallocation MB
512 [1] 1024 [1]
No spares 4319 4596
Twelve spare sector per cylinder [2]
2 spare cylinders per Unit [3] 4294 4546
One spare sector per cylinder
2 spare cylinders per Unit [3] 4315 4590
Unformatted capacity 5170
Notes.
[1] Bytes per sector. Sector size selectable at format time. Users having the necessary equipment may
modify the data block size before issuing a format command and obtain different formatted capacities
than those listed. User available capacity depends on spare reallocation scheme selected. See Mode
Select Command and Format Command in the SCSI Interface Product Manual P/N 77738479.
[2] All twelve spare sectors are on one track.
[3] Spare cylinders are on the two inner tracks.
The standard OEM model is as follows:
Formatted Data Block Size* Unformatted
512 Byte/Sector
ST15230W/WD/WC/DC 4294 MB 5170 MB
*Twelve spare sectors per cylinder (all twelve spare sectors are on one track), two spare cylinders/unit.
Drives are shipped with Installation Guide 77767477 (unless otherwise requested), and a small bag of two
types of jumpers for the Option Select jumper headers.
4.3 Options (factory installed)
The capacities shown in Section 4.2 are available upon request.Other capacities can be ordered depending
on sparing scheme and sector size requested.
The following options are incorporated at the time of production. See Section 12.0.
•Front panel (green LED)
•Single Unit shipping pack
4.4 Optional accessories (user installed)
The following accessories are available.All kits may be installed in the field. See Section 13.0.
•Front Panel Kit (with green LED)
•Single Unit shipping pack kit
•Adapter Accessory Frame Kit P/N 75790701 (adapts 3.5-inch drives "W" and "WD" to fit in 5.25-inch drive
mounting space.Does not work for "WC" and "DC" drives which plug directly into a bulkhead connector.)

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4.5 Installation
For option jumper locations and definitions refer to Figure 10.1-1. Drive default mode parameters are not
normally needed for installation.Refer to Section 11.3.2 for default mode parameters if they are needed.
•Ensure that the SCSI ID of the drive is not the same as the host adapter.Most host adapters use SCSI ID
7, which is the highest priority on both 8 and 16 bit data busses.
•Ifmultipledevicesareonthe bussetthedriveSCSI IDto one that is not presently used byother deviceson
the bus.
•If the drive is the only device on the bus, attach it to the end of the SCSI bus cable.Permanently installed
terminators must be enabled on the drive for ST15230W models using a jumper plug (see Figure 10.1-1),
ForST15230WD/WC/DC models, terminators mustbe installed externalto the drive.These externaltermi-
nators must be provided by the user, systems integrator or host equipment manufacturer.Refer to section
11.6.4.3.
•If the drive is attached to a bus that contains other devices, and the new drive is not attached to the end of
the bus, the terminator enable jumper should be removed from the new drive.
•Set all appropriate option jumpers for desired operation prior to power on. If jumpers are changed after
power has been applied, recycle the drive power to make the new settings effective.
•Installation instructions are provided by host system documentation or with any additionally purchased
driveinstallation software.Ifnecessary see section 14.0 forSeagatesupport services telephone numbers.
•Themanufacturersinstalledlabelsmustnot be removedfrom the driveorcoveredwith additional labels,as
they contain information required when servicing the product.
Formatting
•It is not necessary to low level format this drive.The drive is shipped from the factory low level formatted in
512 byte sectors.
•Reformat the drive if one of the following occurs.
- A different sector size is selected.
- A different spare sector allocation scheme is selected.
• High level format the drive. This involves assigning one or more partitions or logical drives to the drive
volume.Follow the instructions in the system manuals for the system into which the drive is to be installed.

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5.0 Performance characteristics
5.1 Internal drive characteristics (transparent to user)
Drive Capacity 5170 MByte (UNF)
Read/Write Heads 19
Bytes/Track 68155 Bytes (UNF, Avg)
Bytes/Surface 272 Mbytes (UNF)
Tracks/Surface,Total 3992 Tracks (user accessible)
Tracks/Inch 4200 TPI
Servo Heads 1 1
Internal Data Rate 33.9 to 61.0 Mbits/sec (variable with zone)
Disc Rotational Speed 5411+0.5% r/min
Average Rotational Latency 5.54 ms
5.2 SCSI Seek, Read andWrite performance characteristics (visible to user) [8]*
Refer to Section 11.7 and to the SCSI-2 Interface Product Manual 77738479 for additional timing details.
5.2.1 Access time
Includes Controller Overhead
(without disconnect) [1] [4]
Read Write
ms
Average - Typical [3] 10.4 11.4
Max. [2] 11.9 13.4
SingleTrack- Typical [3] 2.1 2.5
Max. [2] 3.8 4.3
Full Stroke - Typical [3] 20.6 21.4
Max. [2] 23.9 24.9
*[ ] All notes are listed in section 5.3.1

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5.2.2 Format drive command execution time (minutes) [1]
Maximum (with verify) 70 Min.
Maximum (no verify) 45 Min
5.2.3 Read data command execution time [4]
(512 byte sector size, without disconnect and with read look ahead cache disabled.)
Latency time is included.
a. From CDB reception to the drive request for the first data byte to be transferred to the Host
1. Typical (Zero Stroke Seek) 7.32 ms [3]*
2. Typical (Average Seek) 16.84 ms [3]
3. Maximum (Full Stroke Seek) 31.38 ms [2]
b. Single Sector Read andTransfer of data to Host (time from receipt of last byte of the CDB to the request
for a status byte transfer to Host) [7].
1. Typical (Zero Stroke Seek) 7.42 ms [3]
2. Typical (Average Seek) 16.95 ms [3]
3. Maximum (Full Stroke Seek) 31.49 ms [2]
5.2.4 Write data command execution time [4]
(512 byte sector size, without disconnect and with read look ahead disabled.) Latency
time is included.
a. From CDB reception to the request for the first byte of write data from the Host.
1. Typical 1.49 ms 2. Maximum 1.61 ms
b. Single SectorWrite and DataTransfer from Host [7] [6]
(Time from receipt of the last byte of the CDB to the request for a completion status transfer to the Host)
1. Typical (Zero Stroke Seek) 7.72 ms [3]
2. Typical (Average Seek) 17.10 ms [3]
3. Maximum (Full Stroke Seek) 31.93 ms [2]
*[ ] All notes are listed in Section 5.3.1.

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5.3 Generalized performance characteristics
Minimum Sector Interleave 1 to 1
Data BufferTo/From Disc Media
Data transfer rate (< 1 sector) - 512 Byte Sector
Min. [4]* 4.33 MByte/sec
Avg. [4] 6.15 MByte/sec
Max. [4] 7.63 MByte/sec
Data BufferTo/From Disc Media
DataTransfer Rate (< 1Track) - 512 Byte Sector
Min. [4] 3.64 MByte/sec divided by (Interleave Factor)
Avg. [4] 5.16 MByte/sec divided by (Interleave Factor)
Max. [4] 6.41 Mbyte/sec divided by (Interleave Factor)
SCSI Interface Data
Transfer Rate (Asynchronous) [5] W/WC WD/DC
-MaximumInstantaneous 5.2 MBytes/sec [9]* 3.3 MBytes/sec
-Maximum Average 3.1 MBytes/sec [11] 2.4 MBytes/sec
Sector Sizes 512 user data blocks (default)
Variable (256 to 4096 bytes per sector) in even number of bytes per sector. If n (number of bytes
per sector) is odd, then n-1 will be used.
SynchronousTransfer Rate
From 1.25 MByte/sec to 10.0 MBytes/sec (See section 11.5.)
Read/Write consecutive sectors on a track Yes
Flaw reallocation performance impact (For flaws reallocated using the spare Negligible
sectors per track reallocation scheme.) [10]
Flaw reallocation performance impact (For flaws reallocated using the spare Negligible
sectors per cylinder reallocation scheme.) [10]
Flaw reallocation performance impact (For flaws reallocated using the spare tracks 35 ms (typical)
per volume reallocation scheme.)
Overhead time for head switch (512 byte sectors) 1 ms
Overhead time for one track cylinder switch <3 msTypical
Average rotational latency 5.54 ms
*[ ] All notes are listed in Section 5.3.1.

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5.3.1 Notes for sections 5.2 and 5.3.
[1] Execution time measured from receipt of the last Byte of the Command Descriptor Block (CDB) to the
request for a Status ByteTransfer to the Initiator (excluding connect/disconnect).
[2] Maximum times are specified over the worst case conditions of temperature, voltage margins and drive
orientation.When comparing specified access times,care should betakentodistinguish between typical
access times and maximum access times.The best comparison is obtained by system benchmark tests
conducted under identical conditions.Maximum times do not include error recovery.
[3] Typical access times are measured under nominal conditions of temperature, voltage, and horizontal
orientation as measured on a representative sample of drives.
[4] Assumes no errors and no sector has been relocated.
[5] Rate measured from the start of the first sector transfer to or from the Host.
[6] Assumes the Initiator immediately sendsWrite Data to the drive when requested.
[7] Command execution requires a data transfer phase (data to or from the disc media).Assumes the initia-
tor is instantly ready to send/receive the data when the drive generates first request for a data byte
transfer, and assumes an average data transfer rate between the drive and the Initiator as specified in
section 5.3.
[8] All performance characteristics assume that automatic adaptive temperature compensation is not in
process when the SCSI command is received.The following paragraphs give highlights of thermal cali-
brationoperation.
a. At spin-up, all heads are calibrated on the outer and inner diameter calibration tracks.
b. A timed calibration occurs 1 minute after spin-up, and every 10 minutes thereafter. During these
timed calibrations, the firmware alternates between the inner and outer diameter calibration tracks.
For example, all heads are calibrated on the inner track, then 10 minutes later all heads are cali-
brated on the outer track.Automatic adaptive temperature calibration does not interrupt SCSI com-
mands being executed.
c. Ifautomatic adaptivethermal calibrationis in process when the drivereceives a SCSIcommand, the
drive queues the command until the compensation for the specific head being compensated com-
pletes.When compensation completes for the specific head being compensated, the drive executes
the first queued command.When execution of the first queued command completes, the drive con-
tinues compensation for the remaining head(s).The above procedure continues until the drive com-
pletes compensation for all heads.
d. Whena timed calibration comes due,thedrivepostponesthe calibration until the drivehasbeen idle
for 25 to 50 milliseconds.
e. When the drive receives a Write command, the drive performs a single head calibration if a calibra-
tionhas been delayedfor 1 to5 minutes.Thedriveperforms anuninterruptiblecalibrationofall heads
if the calibration has been delayed more than 5 minutes.
f. The drive preforms a calibration of all heads prior to the first retry of any media error if a timed
calibration has been delayed for over one minute.
g. Automatic adaptive temperature compensation takes less than 0.1% of bus time.
h. Automatic adaptive temperature compensation occurs at times other than mentioned above, but
should be transparent to the user (e.g., during execution of Format, Rezero, and Reassign Block
commands).
i. A rezero command can be used to reset the Automatic adaptive temperature compensation timer
back to start so that the host can know when the interruption for timed thermal compensation will
occur.
[9] Assumes system ability to support 5.2 Mb/s and no cable loss.
[10]Simulated
[11]AssumesTypical host delays and cable losses.

12 Product Manual - Hawk 4 Family (Wide) SCSI-2 (Volume 1), Rev. E
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5.4 Start/stop time
After DC power has been applied, the drive becomes ready within 25 seconds if the Motor Start Option is
disabled (i.e.the motor starts as soon as the power has been applied).During this time the drive responds to
some commands over the SCSI interface* in less than 3 seconds.Stop time is 20 seconds from removal of
DC power.
If the Motor Start Option is enabled the internal controller accepts the commands listed in the SCSI Interface
Product Manual* less than 3 seconds after DC power has been applied.After the Motor Start Command has
been received the drive becomes ready for normal operations within 25 seconds.The Motor Start Command
can also be used to command the drive to stop the spindle*.
There is no power control switch on the drive.
5.5 Prefetch/multi-segmented cache control
The drive provides prefetch (read look-ahead) and multi-segmented cache control algorithms that in many
cases can enhance system performance. “Cache” as used herein refers to the drive buffer storage space
when it is used in“cache”operations.To select prefetch and cache features the host sends the Mode Select
command with the proper values in the applicable bytes in Mode Page 08h*. Prefetch and cache operation
are independent features from the standpoint that each is enabled and disabled independently via the Mode
Selectcommand.However,inactual operation theprefetchfeatureoverlapscache operationsomewhatasis
noted in sections 5.5.1 and 5.5.2.
All default cache and prefetch Mode parameter values (Mode Page 08h) for standard OEM versions of this
drive family are given inTables 11.3.2-1 and 11.3.2-2.
5.5.1 Cache operation
In general, 448 Kbytes of the 512 Kbytes of physical buffer space in the drive can be used as storage space
for cache operations.The buffer can be divided into logical segments (Mode Select Page 08h, byte 13) from
which data is read and to which data is written. The drive maintains a table of logical block disk medium
addresses of the data stored in each segment of the buffer. If cache operation is enabled (RCD bit = 0 in
Mode Page 08h, byte 2, bit 0.See SCSI Interface Product Manual*), data requested by the host with a Read
command is retrieved from the buffer (if it is there), before any disc access is initiated. If cache operation is
not enabled, the buffer (still segmented with required number of segments) is still used, but only as circular
buffer segments during disc medium read operations (disregarding Prefetch operation for the moment).That
is, the drive does not check in the buffer segments for the requested read data, but goes directly to the
medium to retrieve it.The retrieved data merely passes through some buffer segment on the way to the host.
For a cache miss, all data transfers to the host are in accordance with“buffer-full”ratio rules.On a cache hit
thedriveignores the bufferfull ratio.SeeexplanationsassociatedwithMode page 02h(disconnect/reconnect
control) in the SCSI Interface Product Manual*.
The following is a simplified description of a read operation with cache operation enabled:
Case A - A Read command is received and the first logical block (LB) is already in cache:
1. Drive transfers to the initiator the first LB requested plus all subsequent contiguous LB’s that are al-
ready in the cache.This data may be in multiple segments.
2. When the requested LB is reached that is not in any cache segment, the drive fetches it and any
remaining requested LB’s from the disc and puts them in a segment of the cache.The drive transfers
the remaining requested LB’s from the cache to the host in accordance with the disconnect/reconnect
specification mentioned above.
3. If the prefetch feature is enabled, refer to section 5.5.2 for operation from this point.
_________
*SCSI Interface Product Manual P/N 77738479.