Seagate ST336732LC User manual

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Cheetah X15 36LP Disc Drive:
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ST336752LW/LC, ST336732LW/LC
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ST318452LW/LC, ST318432LW/LC
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Product Manual, Volume 1

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Cheetah X15 36LP Disc Drive:
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................................................
ST336752LW/LC, ST336732LW/LC
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................................................
ST318452LW/LC, ST318432LW/LC
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Product Manual, Volume 1
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©2001, 2002 Seagate Technology LLC All rights reserved
Publication number: 100139872, Rev. D
June 2002
Seagate, Seagate Technology, and the Seagate logo are registered trademarks of Seagate Technology LLC.
Cheetah, SeaFAX, SeaFONE, SeaBOARD, and SeaTDD are either registered trademarks or trademarks of
Seagate Technology LLC. 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 publica-
tion may be reproduced in any form without written permission of Seagate Technology LLC.

Revision status summary sheet
Notice.
Product Manual 100139872 is Volume 1 of a two volume document with the SCSI Interface information
in the Volume 2 SCSI Interface Product Manual, part number 75789509.
If you need the SCSI Interface information, order the Volume 2 Interface Manual, part number
75789509.
Revision Date Writer/Engineer Sheets Affected
Rev. A 06/27/01 L. Newman/J. Nowitzke All.
Rev. B 11/30/01 L. Newman/B. Hohn Pages 27, 36, 38, 39, and 56.
Rev. C 02/08/02 L. Newman/B. Hohn Pages 5, 51 and 52.
Rev. D 06/04/02 L. Newman/B. Hohn Pages 4, 67-70, 73-75.

Cheetah X15 36LP Product Manual, Rev. D 5
Contents
1.0 Scope..........................................................................1
2.0 Applicablestandardsandreferencedocumentation....................................3
2.1 Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.1 Electromagnetic compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.2 Electromagnetic susceptibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Electromagnetic compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.3 Reference documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.0 Generaldescription...............................................................5
3.1 Standard features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.2 Media characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.3 Performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.4 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.5 Unformatted and formatted capacities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.6 Programmable drive capacity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.7 Factory installed accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.8 Options (factory installed). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.9 Accessories (user installed) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.0 Performancecharacteristics.......................................................8
4.1 Internal drive characteristics (transparent to user) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2 SCSI performance characteristics (visible to user) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2.1 Access time [5] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2.2 Format command execution time (minutes) [1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2.3 Generalized performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.3 Start/stop time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.4 Prefetch/multi-segmented cache control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.5 Cache operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.5.1 Caching write data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.5.2 Prefetch operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.5.3 Optimizing cache performance for desktop and server applications . . . . . . . . . . . 11
5.0 Reliability specifications . . . . . . . . . ................................................13
5.1 Error rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.1 Environmental interference. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.2 Read errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.3 Write errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1.4 Seek errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2 Reliability and service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.1 Mean time between failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.2 Preventive maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.3 Service life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.4 Service philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.5 Service tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.6 Hot plugging Cheetah X15 36LP disc drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2.7 S.M.A.R.T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2.8 Thermal Monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2.9 Drive Self Test (DST) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2.10 Product warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.0 Physical/electricalspecifications..................................................21
6.1 AC power requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.2 DC power requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.2.1 Conducted noise immunity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.2.2 Power sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.2.3 12 V - Current profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
6.3 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6 Cheetah X15 36LP Product Manual, Rev. D
6.4 Environmental limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
6.4.1 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
6.4.2 Relative humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
6.4.3 Effective altitude (sea level) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
6.4.4 Shock and vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
6.4.5 Air cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
6.4.6 Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
6.4.7 Electromagnetic susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
6.5 Mechanical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
7.0 Defectanderrormanagement .....................................................33
7.1 Drive internal defects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
7.2 Drive error recovery procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
7.3 SCSI systems errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
8.0 Installation .....................................................................35
8.1 Drive ID/option select header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
8.1.1 Notes for Figures 14, 15, and 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
8.1.2 Function description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
8.2 Drive orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
8.3 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
8.4 Drive mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
8.5 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
9.0 Interfacerequirements............................................................43
9.1 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
9.2 SCSI interface messages supported. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
9.3 SCSI interface commands supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
9.3.1 Inquiry Vital Product data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
9.3.2 Mode Sense data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
9.4 SCSI bus conditions and miscellaneous features supported . . . . . . . . . . . . . . . . . . . . . . . . .53
9.5 Synchronous data transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
9.5.1 Synchronous data transfer periods supported. . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
9.5.2 REQ/ACK offset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
9.6 Physical interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
9.6.1 DC cable and connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
9.6.2 SCSI interface physical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
9.6.3 SCSI interface cable requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
9.6.4 Mating connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
9.7 Electrical description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
9.7.1 Multimode—SE and LVD alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67
9.8 Terminator requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
9.9 Terminator power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
9.10 Disc drive SCSI timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
9.11 Drive activity LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
10.0 Seagate Technology support services. . . ............................................73

Cheetah X15 36LP Product Manual, Rev. D 7
List of Figures
Figure 1. Cheetah X15 36LP family drive (ST336752LC shown) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 2. Typical ST336752 and ST336732 drive +12 V current profile . . . . . . . . . . . . . . . . . . . . . . . . 22
Figure 3. Typical ST336752 and ST336732 drive +5 V current profile. . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 4. Typical ST318452 and ST318432 drive +12 V current profile . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 5. Typical ST318452 and ST318432 drive +5 V current profile. . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 6. ST336752 and ST336732 DC current and power vs. IOPS (SE) . . . . . . . . . . . . . . . . . . . . . 25
Figure 7. ST336752 and ST336732 DC current and power vs. IOPS (LVD) . . . . . . . . . . . . . . . . . . . . 25
Figure 8. ST318452 and ST318432 DC current and power vs. IOPS (SE) . . . . . . . . . . . . . . . . . . . . . 26
Figure 9. ST318452 and ST318432 DC current and power vs. IOPS (LVD) . . . . . . . . . . . . . . . . . . . . 26
Figure 10. Locations of the HDA temperature check point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 11. Recommended mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 12. LW mounting configuration dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Figure 13. LC mounting configuration dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 14. J6 jumper header . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 15. J5 jumper header (on LW models only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 16. J2 option select header (on LW models only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 17. Air flow (suggested) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Figure 18. LW model drive physical interface (68-pin J1 SCSI I/O connector) . . . . . . . . . . . . . . . . . . . . 56
Figure 19. LC model drive physical interface (80-pin J1 SCSI I/O connector) . . . . . . . . . . . . . . . . . . . . 56
Figure 20. SCSI daisy chain interface cabling for LW drives. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Figure 21. Nonshielded 68 pin SCSI device connector used on LW drives . . . . . . . . . . . . . . . . . . . . . . 61
Figure 22. Nonshielded 80 pin SCSI “SCA-2” connector, used on LC drives . . . . . . . . . . . . . . . . . . . . . 62
Figure 23. Typical SE-LVD alternative transmitter receiver circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Cheetah X15 36LP Product Manual, Rev. D 1
1.0 Scope
This manual describes Seagate Technology® LLC, Cheetah® X15 36LP disc drives.
Cheetah X15 36LP drives support the small computer system interface (SCSI) as described in the ANSI SCSI
SPI-4 interface specifications to the extent described in this manual. The SCSI Interface Product Manual (part
number 75789509) describes general SCSI interface characteristics of this and other families of Seagate
drives.
From this point on in this product manual the reference to Cheetah X15 36LP models is referred to as “the
drive” unless references to individual models are necessary.
Figure 1. Cheetah X15 36LP family drive (ST336752LC shown)

2 Cheetah X15 36LP Product Manual, Rev. D

Cheetah X15 36LP Product Manual, Rev. D 3
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 opti-
mum performance and compliance with applicable industry and governmental regulations. Special attention
must be given in the areas of safety, power distribution, shielding, audible noise control, and temperature regu-
lation. In particular, the drive must be securely mounted in order to guarantee the specified performance char-
acteristics. Mounting by bottom holes must meet the requirements of Section 8.4.
2.1 Standards
The Cheetah X15 36LP family complies with Seagate standards as noted in the appropriate sections of this
Manual and the Seagate SCSI Interface Product Manual, part number 75789509 (Vol. 2).
The Cheetah X15 36LP disc drive is a UL recognized component per UL1950, CSA certified to CSA C22.2 No.
950-95, and VDE certified to VDE 0805 and EN60950.
2.1.1 Electromagnetic compatibility
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 B of Part 15 of the FCC
Rules and Regulations nor the Radio Interference Regulations of the Canadian Department of Communica-
tions.
The 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 Rules and Regu-
lations of the Canadian Department of Communications when properly packaged. However, it is the user’s
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 con-
troller.
2.1.2 Electromagnetic susceptibility
As a component assembly, the drive is not required to meet any susceptibility performance requirements. It is
the responsibility of those integrating the drive within their systems to perform those tests required and design
their system to ensure that equipment operating in the same system as the drive or external to the system
does not adversely affect the performance of the drive. See Section 5.1.1 and Table 3, DC power requirements.
2.2 Electromagnetic compliance
Seagate uses an independent laboratory to confirm compliance to the directives/standard(s) for CE Marking
and C-Tick Marking. The drive was tested in a representative system for typical applications. The selected sys-
tem represents the most popular characteristics for test platforms. The system configurations include:
• Typical current use microprocessor
• 3.5-inch floppy disc drive
• Keyboard
• Monitor/display
•Printer
• External modem
•Mouse
Although the test system with this Seagate model complies to the directives/standard(s), we cannot guarantee
that all systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance
and provide CE Marking and C-Tick Marking for their product.
Electromagnetic compliance for the European Union
If this model has the CE Marking it complies with the European Union requirements of the Electromagnetic
Compatibility Directive 89/336/EEC of 03 May 1989 as amended by Directive 92/31/EEC of 28 April 1992 and
Directive 93/68/EEC of 22 July 1993.

4 Cheetah X15 36LP Product Manual, Rev. D
Australian C-Tick
If this model has the C-Tick Marking it complies with the Australia/New Zealand Standard AS/NZS3548 1995
and meets the Electromagnetic Compatibility (EMC) Framework requirements of Australia’s Spectrum Man-
agement Agency (SMA).
Korean MIC
If this model has the Korean Ministry of Information and Communication (MIC) logo, it complies with paragraph
1 of Article 11 of the Electromagnetic Compatibility (EMC) Control Regulation and meets the Electromagnetic
Compatibility Framework requirements of the Radio Research Laboratory (RRL) Ministry of Information and
Communication Republic of Korea.
Taiwanese BSMI
If this model has two Chinese words meaning “EMC certification” followed by an eight digit identification num-
ber, as a Marking, it complies with Chinese National Standard (CNS) 13438 and meets the Electromagnetic
Compatibility (EMC) Framework requirements of the Taiwanese Bureau of Standards, Metrology, and Inspec-
tion (BSMI).
2.3 Reference documents
Cheetah X15 36LP Installation Guide Seagate P/N 100139875
Safety and Regulatory Agency Specifications Seagate P/N 75789512
SCSI Interface Product Manual Seagate P/N 75789509
Applicable ANSI small computer system interface (SCSI) document numbers:
T10/1143D Enhanced SCSI Parallel Interface (EPI)
T10/1416D Primary Commands-3 (SPC-3)
T10/1417D SCSI Block Commands (SBC-2)
T10/1157D SCSI Architectural Model-2 (SAM-2)
T10/1365D SCSI Parallel Interface - 4 (SPI-4)
SFF-8451, Specification for SCA-2 Unshielded Connections
Package Test Specification Seagate P/N 30190-001 (under 100 lb.)
Package Test Specification Seagate P/N 30191-001 (over 100 lb.)
Specification, Acoustic Test Requirements, and Procedures Seagate P/N 30553-001
In case of conflict between this document and any referenced document, this document takes precedence.

Cheetah X15 36LP Product Manual, Rev. D 5
3.0 General description
Cheetah X15 36LP drives combine giant magnetoresistive (GMR) heads, partial response/maximum likelihood
(PRML) read channel electronics, embedded servo technology, and a wide Ultra160 SCSI interface (on
ST336752 and ST318452 models) or a wide Ultra320 SCSI interface (on ST336732 and ST318432 models) to
provide high performance, high capacity data storage for a variety of systems including engineering worksta-
tions, network servers, mainframes, and supercomputers.
Ultra160 and Ultra320 SCSI use negotiated transfer rates. These transfer rates will occur only if your host
adapter supports these data transfer rates and is compatible with the required hardware requirements of the
I/O circuit type. This drive also operates at SCSI-1 and SCSI-2 data transfer rates for backward compatibility
with non-Ultra/Ultra2/Ultra160/Ultra320 SCSI host adapters.
Table 1 lists the features that differentiate the Cheetah X15 36LP models.
Table 1: Drive model number vs. differentiating features
[1] See Section 9.6 for details and definitions.
The drive records and recovers data on approximately 2.5-inch (65 mm) non-removeable discs.
The drive supports the Small Computer System Interface (SCSI) as described in the ANSI SCSI interface
specifications to the extent described in this manual (volume 1), which defines the product performance char-
acteristics of the Cheetah X15 36LP family of drives, and the SCSI Interface Product Manual (volume 2), part
number 75789509, which describes the general interface characteristics of this and other families of Seagate
SCSI drives.
The drive’s interface supports multiple initiators, disconnect/reconnect, self-configuring host software, and
automatic features that relieve the host from the necessity of knowing the physical characteristics of the targets
(logical block addressing is used).
The head and disc assembly (HDA) is sealed at the factory. Air circulates within the HDA through a non-
replaceable filter to maintain a contamination-free HDA environment.
Never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads, media, actu-
ator, etc.) as this requires special facilities. The drive contains no replaceable parts. Opening the HDA voids
your warranty.
Cheetah X15 36LP 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 power is removed.
An automatic shipping lock prevents potential damage to the heads and discs that results from movement dur-
ing shipping and handling. The shipping lock automatically disengages when power is applied to the drive and
the head load process begins.
Model number
Number
of active
heads I/O circuit type [1] Number of I/O connector pins
Interface
Ultra160 Ultra320
ST336752LW
ST318452LW
8
4
Single-ended (SE) and low
voltage differential (LVD)
68 X
ST336752LC
ST318452LC
8
4
Single-ended (SE) and low
voltage differential (LVD)
80 X
ST336732LW
ST318432LW
8
4
Single-ended (SE) and low
voltage differential (LVD)
68 X
ST336732LC
ST318432LC
8
4
Single-ended (SE) and low
voltage differential (LVD)
80 X

6 Cheetah X15 36LP Product Manual, Rev. D
Cheetah X15 36LP drives decode track 0 location data from the servo data embedded on each surface to elim-
inate mechanical transducer adjustments and related reliability concerns.
A high-performance actuator assembly with a low-inertia, balanced, patented, straight-arm design provides
excellent performance with minimal power dissipation.
3.1 Standard features
The Cheetah X15 36LP family has the following standard features:
• Multimode SCSI drivers and receivers—single-ended (SE) and low voltage differential (LVD)
• 16 bit I/O data bus
• Asynchronous and synchronous data transfer protocol
- ST336752 and ST318452 models support Ultra160 transfer rates
- ST336732 and ST318432 models support Ultra320 transfer rates
• Supports Information Unit transfer protocol
• Firmware downloadable via SCSI interface
• Selectable even byte sector sizes from 512 to 704 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)
• ECC maximum burst correction length of 240 bits with a guaranteed burst correction length of 233 bits.
• Sealed head and disc assembly
• No preventative maintenance or adjustment required
• Dedicated head landing zone
• Embedded servo design
• Self diagnostics performed when power is applied to the drive
• Zoned bit recording (ZBR)
• Vertical, horizontal, or top down mounting
• Dynamic spindle brake
• 8,192 kbytes data buffer
• Hot plug compatibility (Section 9.6.4.2 lists proper host connector needed) for LC model drives
• Drive Self Test (DST)
• Supports SCSI bus fairness
3.2 Media characteristics
The media used on the drive has an aluminum substrate coated with a thin film magnetic material, overcoated
with a proprietary protective layer for improved durability and environmental protection.
3.3 Performance
• Supports industry standard interfaces as follows:
- ST336752 and ST318452 models support the Ultra160 SCSI interface
- ST336732 and ST318432 models support the Ultra320 SCSI interface
• Programmable multi-segmentable cache buffer (see Section 4.5)
• 15k RPM spindle. Average latency = 2.0 ms
• Command queuing of up to 64 commands
• Background processing of queue
• Supports start and stop commands (spindle stops spinning)
3.4 Reliability
• 1,200,000 hour MTBF
• LSI circuitry
• Balanced low mass rotary voice coil actuator

Cheetah X15 36LP Product Manual, Rev. D 7
• Incorporates industry-standard Self-Monitoring, Analysis and Reporting Technology (S.M.A.R.T.)
• 5-year warranty
3.5 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 the standard OEM model capacities:
Notes.
[1] 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. See
Mode Select Command and Format Command in the SCSI Interface Product Manual.
[2] User available capacity depends on spare reallocation scheme selected, the number of data tracks per
sparing zone, and the number of alternate sectors (LBAs) per sparing zone.
3.6 Programmable drive capacity
Using the Mode Select command, the drive can change its capacity to something less than maximum. See the
Mode Select Parameter List table in the SCSI Interface Product Manual. Refer to the Parameter list block
descriptor number of blocks field. A value of zero in the number of blocks field indicates that the drive shall not
change the capacity it is currently formatted to have. A number in the number of blocks field that is less than
the maximum number of LBAs changes the total drive capacity to the value in the block descriptor number of
blocks field. A value greater than the maximum number of LBAs is rounded down to the maximum capacity.
3.7 Factory installed accessories
OEM Standard drives are shipped with the Cheetah X15 36LP Installation Guide, part number 100139875, and
the Safety and Regulatory Agency Specifications, part number 75789512 (unless otherwise specified). The
factory also ships with the drive a small bag of jumper plugs used for the J2, J5, and J6 option select jumper
headers.
3.8 Options (factory installed)
All customer requested options are incorporated during production or packaged at the manufacturing facility
before shipping. Some of the options available are (not an exhaustive list of possible options):
• Other capacities can be ordered depending on sparing scheme and sector size requested.
• Single unit shipping pack. The drive is normally shipped in bulk packaging to provide maximum protection
against transit damage. Units shipped individually require additional protection as provided by the single unit
shipping pack. Users planning single unit distribution should specify this option.
• The Cheetah X15 36LP Installation Guide, part number 100139875, is usually included with each standard
OEM drive shipped, but extra copies may be ordered.
• The Safety and Regulatory Agency Specifications, part number 75789512, is usually included with each
standard OEM drive shipped, but extra copies may be ordered.
3.9 Accessories (user installed)
The following accessories are available. All accessories may be installed in the field.
• Single unit shipping pack.
Formatted
data block size
512 bytes/sector [1] Unformatted
ST336752 and ST336732 445DCC9h (36.7 GB) [2] 47.5 GB
ST318452 and ST318432 222EE56h (18.4 GB) [2] 23.7 GB

8 Cheetah X15 36LP Product Manual, Rev. D
4.0 Performance characteristics
4.1 Internal drive characteristics (transparent to user)
4.2 SCSI performance characteristics (visible to user)
The values given in Section 4.2.1 apply to all models of the Cheetah X15 36LP family unless otherwise speci-
fied. Refer to Section 9.10 and to the SCSI Interface Product Manual for additional timing details.
4.2.1 Access time [5]
4.2.2 Format command execution time (minutes) [1]
4.2.3 Generalized performance characteristics
Data buffer transfer rate to/from disc media (one 512-byte sector):
SCSI interface data transfer rate (asynchronous):
Maximum instantaneous one byte wide 5.0 Mbytes/sec [4]
Maximum instantaneous two bytes wide 10.0 Mbytes/sec [4]
Synchronous formatted transfer rate Ultra160 SCSI Ultra320 SCSI
In low voltage differential (LVD) interface mode 5.0 to 160 Mbytes/sec 5.0 to 320 Mbytes/sec
ST336752 and
ST336732 ST318452 and ST318432
Drive capacity 36.7 18.4 GByte (formatted, rounded off values)
Read/write heads 8 4
Bytes/track 316,155 316,155 Bytes (average, rounded off values)
Bytes/surface 5,932.5 5,932.5 Mbytes (unformatted, rounded off values)
Tracks/surface (total) 18,497 18,497 Tracks (user accessible)
Tracks/inch 38,000 38,000 TPI
Peak bits/inch 482 482 KBPI
Internal data rate 548-706 548-706 Mbits/sec (variable with zone)
Disc rotational speed 15k 15k r/min
Average rotational latency 2.0 2.0 msec
Including controller overhead
(without disconnect) [1] [3] Not including controller overhead (without disconnect) [1] [3]
Drive level Drive level
Read Write Read Write
msec msec
Average – Typical [2] 3.8 4.4 3.6 4.2
Single Track – Typical [2] 0.5 0.6 0.3 0.4
Full Stroke – Typical [2] 7.2 8.2 7.0 8.0
ST336752 and ST336732 ST318452 and ST318432
Maximum (with verify) 90 60
Maximum (no verify) 45 30
Minimum sector interleave 1 to 1
Min. [3]* 51.8 MBytes/sec
Max. [3] 68.1 MBytes/sec

Cheetah X15 36LP Product Manual, Rev. D 9
Sector Sizes:
Default 512 byte user data blocks
Variable 512 to 704 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.
Notes for Section 4.2.
[1] Execution time measured from receipt of the last byte of the Command Descriptor Block (CDB) to the
request for a Status Byte Transfer to the Initiator (excluding connect/disconnect).
[2] Typical access times are measured under nominal conditions of temperature, voltage, and horizontal ori-
entation as measured on a representative sample of drives.
[3] Assumes no errors and no sector has been relocated.
[4] Assumes system ability to support the rates listed and no cable loss.
[5] Access time = controller overhead + average seek time.
Access to data = controller overhead + average seek time + latency time.
4.3 Start/stop time
After DC power at nominal voltage has been applied, the drive becomes ready within 20 seconds if the Motor
Start Option is disabled (i.e. the motor starts as soon as the power has been applied). If a recoverable error
condition is detected during the start sequence, the drive executes a recovery procedure which may cause the
time to become ready to exceed 20 seconds. During spin up to ready time the drive responds to some com-
mands over the SCSI interface in less than 3 seconds after application of power. Stop time is 30 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 20 seconds typically (excluding an error
recovery procedure). The Motor Start Command can also be used to command the drive to stop the spindle
(see the SCSI Interface Product Manual).
There is no power control switch on the drive.
4.4 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 (see the SCSI Interface Product Manual).
Prefetch and cache operation are independent features from the standpoint that each is enabled and disabled
independently via the Mode Select command. However, in actual operation the prefetch feature overlaps
cache operation somewhat as is noted in Section 4.5.1 and 4.5.2.
All default cache and prefetch Mode parameter values (Mode Page 08h) for standard OEM versions of this
drive family are given in Tables 8.
4.5 Cache operation
In general, 7,500 kbytes of the physical buffer space in the drive can be used as storage space for cache oper-
ations. 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 supports a maximum of 64 cache segments. The drive maintains a
table of logical block disk medium addresses of the data stored in each segment of the buffer. If cache opera-
tion is enabled (RCD bit = 0 in Mode Page 08h, byte 2, bit 0. See SCSI Interface Product Manual), data
Read/write consecutive sectors on a track Yes
Flaw reallocation performance impact (for flaws reallocated at format time using
the spare sectors per sparing zone reallocation scheme.)
Negligible
Average rotational latency 2.00 msec

10 Cheetah X15 36LP Product Manual, Rev. D
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 seg-
ment on the way to the host. On a cache miss, all data transfers to the host are in accordance with buffer-full
ratio rules. On a cache hit the drive ignores the buffer-full ratio rules. See explanations associated with Mode
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 LBs that are already 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 LBs from the disc and puts them in a segment of the cache. The drive transfers the remaining
requested LBs from the cache to the host in accordance with the disconnect/reconnect specification men-
tioned above.
3. If the prefetch feature is enabled, refer to Section 4.5.2 for operation from this point.
Case B - A Read command requests data, the first LB of which is not in any segment of the cache:
1. The drive fetches the requested LBs from the disc and transfers them into a segment, and from there to
the host in accordance with the disconnect/reconnect specification referred to in case A.
2. If the prefetch feature is enabled, refer to Section 4.5.2 for operation from this point.
Each buffer segment is actually a self-contained circular storage (wrap-around occurs), the length of which is
an integer number of disc medium sectors. The wrap-around capability of the individual segments greatly
enhances the buffer’s overall performance as a cache storage, allowing a wide range of user selectable config-
urations, which includes their use in the prefetch operation (if enabled), even when cache operation is disabled
(see Section 4.5.2). The number of segments is set dynamically by the drive and cannot be set by the host.
The size in Kbytes of each segment is not reported by the Mode Sense command page 08h, bytes 14 and 15.
The value 0XFFFF is always reported. If a size specification is sent by the host in a Mode Select command
(bytes 14 and 15) no new segment size is set up by the drive, and if the STRICT bit in Mode page 00h (byte 2,
bit 1) is set to one, the drive responds as it does for any attempt to change unchangeable parameters (see
SCSI Interface Product Manual).
4.5.1 Caching write data
Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to
be written to the medium is stored in one or more segments while the drive performs the write command.
If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made avail-
able for future read cache hits. The same buffer space and segmentation is used as set up for read functions.
The buffer segmentation scheme is set up or changed independently, having nothing to do with the state of
RCD. When a write command is issued, if RCD=0, the cache is first checked to see if any logical blocks that
are to be written are already stored in the cache from a previous read or write command. If there are, the
respective cache segments are cleared. The new data is cached for subsequent Read commands.
If the number of write data logical blocks exceeds the size of the segment being written into, when the end of
the segment is reached, the data is written into the beginning of the same cache segment, overwriting the data
that was written there at the beginning of the operation. However, the drive does not overwrite data that has not
yet been written to the medium.
If write caching is enabled (WCE=1), then the drive may return GOOD status on a write command after the
data has been transferred into the cache, but before the data has been written to the medium. If an error
occurs while writing the data to the medium, and GOOD status has already been returned, a deferred error will
be generated.