Seagate ST3400755SS User Manual

Product Manual
Cheetah® NS SAS
ST3400755SS
100453994 Rev . B August 2007
in the United States and/or other countries. Cheetah, SeaTools and SeaTDD are either trademarks or reg­istered trademarks of Seagate Technology LLC or one of its affiliated companies in the United States and/ or other countries. All other trademarks or registered trademarks are the property of their respective own­ers.
One gigabyte, or GB, equals one billion bytes when referring to hard drive capacity. Accessible capacity may vary depending on operating environment and formatting. Quantitative usage examples for various applications are for illustrative purposes. Actual quantities will vary based on various factors, including file size, file format, features and application software. Seagate reserves the right to change, without notice, product offerings or specifications.
Cheetah NS SAS Product Manual, Rev. B
i
Contents
1.0 Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0 Standards, compliance and reference documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1 Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1.1 Electromagnetic compatibility. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.1 Electromagnetic compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Reference documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.0 General description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Standard features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Media description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.3 Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.4 Reliability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.5 Formatted capacities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.6 Programmable drive capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.7 Factory-installed options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.0 Performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Internal drive characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2 Seek performance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2.1 Access time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2.2 Format command execution time (minutes) . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.2.3 General performance characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.3 Start/stop time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.4 Prefetch/multi-segmented cache control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.5 Cache operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.5.1 Caching write data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.5.2 Prefetch operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.0 Reliability specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1 Error rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1.1 Recoverable Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1.2 Unrecoverable Errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1.3 Seek errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.1.4 Interface errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2 Reliability and service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2.1 Annualized Failure Rate (AFR) and Mean Time Between Failures (MTBF) . . . 16
5.2.2 Preventive maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2.3 Hot plugging the drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2.4 S.M.A.R.T. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2.5 Reporting control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2.6 Thermal monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2.7 Drive Self Test (DST). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.2.8 Product warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6.0 Physical/electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.1 AC power requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.2 DC power requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
6.2.1 Conducted noise immunity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.2.2 Power sequencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.2.3 Current profiles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
6.3 Power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
6.4 Environmental limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
6.4.1 Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
ii
Cheetah NS SAS Product Manual, Rev. B
6.4.2 Relative humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.4.3 Effective altitude (sea level) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.4.4 Shock and vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.4.5 Acoustics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.4.6 Air cleanliness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.4.7 Corrosive environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.4.8 European Union Restriction of Hazardous Substances (RoHS) Directive . . . . . 30
6.4.9 China Restriction of Hazardous Substances (RoHS) Directive . . . . . . . . . . . . . 30
6.4.10 Electromagnetic susceptibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.5 Mechanical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.0 Defect and error management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.1 Drive internal defects/errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.2 Drive error recovery procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.3 SAS system errors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.4 Background Media Scan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.5 Media Pre-Scan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
7.6 Deferred Auto-Reallocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
7.7 Idle Read After Write . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
8.0 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.1 Drive orientation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
8.2 Cooling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
8.3 Drive mounting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8.4 Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.0 Interface requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.1 SAS features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.1.1 task management functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.1.2 task management responses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.2 Dual port support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.3 SCSI commands supported. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.3.1 Inquiry data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
9.3.2 Mode Sense data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
9.4 Miscellaneous operating features and conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
9.4.1 SAS physical interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
9.4.2 Physical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
9.4.3 Connector requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
9.4.4 Electrical description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.4.5 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.4.6 SAS transmitters and receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.4.7 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.5 Signal characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.5.1 Ready LED Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.5.2 Differential signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
10.0 Seagate Technology support services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Cheetah NS SAS Product Manual, Rev. B
1
List of Figures
Figure 1. Typical ST3400755SS drive +5V and +12V current profiles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Figure 2. ST3400755SS (3 Gbit) DC current and power vs. input/output operations per second . . . . . . . . . . . . . . . . .25
Figure 3. Locat i o n of th e HDA te mp e r a ture check point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Figure 4. Recommended mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Figure 5. Physi ca l d i me n si o n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Figure 6. Physi ca l i n te r fa ce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Figure 7. Air flo w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Figure 8. Physic a l inte r fa ce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Figure 9. SAS connector dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Figure 10. SAS connector dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Figure 11. SAS transmitters and receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Figure 12 . Receive e ye ma sk. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Figure 13 . Receive to l e r a n ce e ye ma sk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Figure 14 . Sinusoid a l j i tte r ma sk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58
Figure 15. Compliance interconnect test load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
Figure 16. Zero-length test load. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
Figure 17 . ISI loss exa mp l e a t 3 .0 G b p s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
Figure 18 . ISI loss exa mp l e a t 1 .5 G b p s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
2
Cheetah NS SAS Product Manual, Rev. B
Cheetah NS SAS Product Manual, Rev. B
1

1.0 Scope

This manual describes Seagate Technology® LLC, Cheetah® NS SAS (Serial Attached SCSI) disk drives. Cheetah drives support the SAS Protocol specifications to the extent described in this manual. The SAS Inter-
face Manual (part number 100293071) describes the general SAS characteristics of Cheetah NS and other Seagate SAS drives.
2
Cheetah NS SAS Product Manual, Rev. B
Cheetah NS SAS Product Manual, Rev. B
3

2.0 Standards, compliance and reference documents

The drive has been d evelope d as a system p eriphe ral to the hig hest st and ards of desig n and constru c tion. The drive depends on its host equipment to provide adequate power and environment for optimum 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 regulation. In particular, the drive must be securely mounted to guarantee the specified performance characteristics. Mounting by bot­tom holes must meet the requirements of Section 8.3.

2.1 Standards

The Cheetah NS SAS family complies with Seagate standards as noted in the appropriate sections of this manual and the Seagate SAS Interface Manual, part number 100293071.
The Cheetah disk drive is a UL recognize d compo nent per UL 1950 , CSA certifi ed to CAN /CSA C22.2 N o. 95 0­95, and VDE or TUV certified to EN60950.

2.1.1 Electromagnetic compatibility

The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to use. 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 Communications.
The design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides reasonable shielding. The drive is capable of meeting the Class B limits of the FCC Rules and Regulations 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 controller.
2.1.1.1 Electromagn etic susc ept ibili ty
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 Table 2 for DC power requirements.
4
Cheetah NS SAS Product Manual, Rev. B

2.2 Compliance

2.2.1 Electromagn etic complia nce

Seagate uses an independent laboratory to confirm compliance with the directives/standards for CE Marking and C-Tick Marking. T he dr ive was tested in a r epre sent ative system for typica l applications. The select ed sys­tem represents the most popular characteristics for test platforms. The system configurations include:
• Typical current use microprocessor
• 3.5-inch floppy disk drive
• Keyboard
• Monitor/display
•Printer
• External mo dem
•Mouse Although the test system with th is Seag ate mo del comp lies with the dir ectives/st and ards, we cannot gu aran tee
that all systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance and provide the appropriate 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.
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 Man­agement Agency (SMA).
Korean MIC
If this model has the Korean Min ist ry of Infor mat ion and Com munication (MIC) logo, it complie s with par agr aph 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 num­ber, 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 Inspec­tion (BSMI).
Cheetah NS SAS Product Manual, Rev. B
5

2.3 Reference documents

SAS Installation Guide Seagate part number: 100453998 SCSI Commands Reference Manual Seagate part number: 100293068 SAS Interface Manual Seagate part number: 100293071 Applicable ANSI SAS documents
SFF-8323 3.5” Drive Form Factor with Serial Connector SFF-8460 HSS Backplane Design Guidelines SFF-8470 Multi Lane Copper Connector SFF-8482 SAS Plug Connector ANSI INCITS.xxx Serial Attached SCSI (SAS) Standard (T10/1562-D) ISO/IEC 14776-xxx SCSI Architecure Model-3 (SAM-3) Standard (T10/1561-D) ISO/IEC 14776-xxx SCSI Primary Commands-3 (SPC-3) Standard (T10/1416-D) ISO/IEC 14776-xxx SCSI Block Commands-2 (SBC-2) Standard (T10/1417-D)
ANSI Small Computer System Interface (SCSI) Documents X3.270-1996(SCSI-3) Architecture Model Specification for Acoustic Test Requirement and Procedures Seagate part number: 30553-001 Package Test Specification Seagate P/N 30190-001 (under 100 lb.) Package Test Specification Seagate P/N 30191-001 (over 100 lb.)
In case of conflict between this document and any referenced document, this document takes precedence.
6
Cheetah NS SAS Product Manual, Rev. B
Cheetah NS SAS Product Manual, Rev. B
7

3.0 General description

Cheetah drive s combin e Tunneling Ma gneto resistive (T M R) head s and a S er ial Att ach ed S CSI (SAS ) inter face to provide high pe rfor mance , high cap acity d at a sto rage for a va riety o f system s includ ing en gineer ing worksta­tions, network servers, mainframes, and supercomputers. The Serial Attached SCSI interface is designed to meet next-generation computing demands for performance, scalability, flexibility and high-density storage requirements.
Cheetah drives are random access storage devices designed to support the Serial Attached SCSI Protocol as described in the ANSI specifications, this document, and the SAS Interface Manual (part number 100293071) which describes the general interface characteristics of this drive. Cheetah drives are classified as intelligent peripherals and provide level 2 conformance (highest level) with the ANSI SCSI-1 standard. The SAS connec­tors, cables and electrical interface are compatible with Serial ATA (SATA), giving future users the choice of populating their syste ms with eithe r S AS or SATA har d d isk drives. This allo ws you to continue to levera ge yo ur existing investment in SCSI while gaining a 3Gb/s serial data transfer rate.
The head and disk assembly (HDA) is sealed at the factory. A ir recirculates within the HDA through a non­replaceable filter to maintain a contamination-free HDA environment.
Note. Never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads,
media, actuator, etc.) as this requires special facilities. The drive does not contain user-replaceable parts. Opening the HDA for any reason voids your warranty.
Cheetah drives use a de dicated landing zone a t the innermost radius of the media to e liminate the p ossibility of destroying or de grad i ng d at a b y l and ing in the data zone. Th e h eads autom atical ly go t o the landing zone when power is removed from the drive.
An automatic shipping lock prevents potential damage to the heads and disks that results from movement dur­ing shipping and handling. The shipping lock disengages and the head load process begins when power is applied to the drive.
The drives also use a high-performance actuator assembly with a low-inertia, balanced, patented, straight arm design that provides excellent performance with minimal power dissipation.
8
Cheetah NS SAS Product Manual, Rev. B

3.1 Standard featu re s

Cheetah NS SAS drives have the following standard features:
• Perpendicular recording technology
• 1.5 / 3 Gbit Serial Attached SCSI (SAS) interface
• Integrated dual port SAS controller
• Support for SAS expanders and fanout adapters
• Downloadable firmware using the SAS interface
• 128 - deep task set (queue)
• Supports up to 32 initiators
• Jumperless configuration.
• User-selectable logical block size (512, 520, 524, or 528 bytes per logical block)
• Programmable logical block reallocation scheme
• Flawed logical block reallocation at format time
• Programmable auto write and read reallocation
• Reallocation of defects on command (Post Format)
• ECC maximum burst correction length of 400 bits
• No preventive maintenance or adjustments required
• Dedicated head landing zone
• Embedded servo design
• Automatic shipping lock
• Self diagnostics performed when power is applied to the drive
• Zone bit recording (ZBR)
• Vertical, horizontal, or top down mounting
• Dynamic spindle brake
• 16 Mbyte data buffer (see Section 4.5).
• Drive Self Test (DST)
• Background Media Scan (BGMS)
• Power Save

3.2 Media desc ription

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

• Firmware-controlled multisegmented cache designed to dynamically adjust segments for enhanced system performance.
• 300 Mbytes/sec maximum instantaneous data transfers.
• 10k RPM spindle. Average latency = 2.98 msec
• Command queuing of up to 128 commands
• Background processing of queue
• Supports start and stop commands (spindle stops spinning)
• Adaptive seek velocity; improved seek performance

3.4 Reliability

• Annualized Failure Rate (AFR) of 0.62%
• Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.)
• 5-year warranty
Cheetah NS SAS Product Manual, Rev. B
9

3.5 Formatted ca pacities

Standard OEM models are formatted to 512 bytes per block. The block size is selectable at format time and must be a multiple of 4 bytes. Users having the necessary equipment may modify the data block size before issuing a format command and obtain different formatted capacities than those listed.
To provide a stable target capacity environment and at the same time provide users with flexibility if they choose, Seagate recommends product planning in one of two modes:
1. Seagate designs specify capacity points at certain block sizes that Seagate guarantees current and future products will meet. We recommend customers use this capacity in their project planning, as it ensures a stable operating point with backward and forward compatibility from generation to generation. The current guaranteed operating points for this product are:
ST3400755SS
Sector Size
Decimal
512 781,422,768 520 769,230,777 524 752,213,841 528 749,632,385
2. Seagate drives also may be used at the maximum available capacity at a given block size, but the excess capacity above the guaranteed level will vary between other drive families and from generation to genera­tion, depending on how each block size actually formats out for zone frequencies and splits over servo bursts. This added capacity potential may range from 0.1 to 1.3 percent above the guaranteed capacities listed above. Using the drives in this manner gives the absolute maximum capacity potential, but the user must determine if the extra capacity potential is useful, or whether their assurance of backward and for­ward compatibility takes precedence.

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 (6) parameter list table in the SAS Interface Manual, part number 100293071. A value of zero in the Number of Blocks field indicates that the drive will not change the capacity it is currently formatted to have. A number other than zero and less than the maximum number of LBAs in the Number of Blocks field changes the total drive cap acity to the value in the Nu mber of Blocks field. A value gre ater t han th e maxim um nu mbe r of LBAs is rounded down to the maximum capacity.

3.7 Factory-installed options

Yo u may order the following items which are incorporated at the manufacturing facility d uring production or packaged 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. U nit s shipped individually require add itional pro tection as pr ovided by th e singl e unit shipping pack. Users planning single unit distribution should specify this option.
• The Safety and Regulatory Agency Specifications, part number 75789512, is usually included with each
standard OEM drive shipped, but extra copies may be ordered.
10
Cheetah NS SAS Product Manual, Rev. B
Cheetah NS SAS Product Manual, Rev. B
11

4.0 Performance characteristics

This section provides detailed information concerning performance-related characteristics and features of Cheetah NS SAS drives.

4.1 Internal drive characteristics

ST3400755SS
Drive capacity 400.0 Gbytes (formatted, rounded off value) Read/write data heads 8 Tracks per surface (total) 92,200 Tracks (user accessible) Tracks per inch 155,000 TPI Peak bits per inch 979k BPI Areal Density 151.7 Gbits/inch Internal data rate 725 to 1,211 Mbits/sec (variable with zone) Disk rotation speed 10k rpm Avg rotational latency 2.98 msec
*One Gbyte equals one billion bytes when referring to hard drive capacity. Accessible capacity may vary depending on operating environment
and formatting.
2
*

4.2 Seek performance

See Section 9.4.1, "SAS physical interface" on page 51 and the SAS Interface Manual (part number
100293071) for additional timing details.

4.2.1 Access time

Not Including controller overhead Read Write
Average Typical 3.9 4.2 Single track Typical 0.35 0.52 Full stro ke Typical 6.8 7.5
1, 2
(msec)
1. Typical access times are measured under nominal conditions of temperature, voltage, and
horizontal orientation as measured on a representative sample of drives.
2. Access to data = access time + latency time.
12
Cheetah NS SAS Product Manual, Rev. B

4.2.2 Format command execution time (minutes)

ST3400755SS
Maximum (wi th verify) Maximum (without verify)
180 100
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).

4.2.3 General performance characteristics

Sustainable disk transfer rate*:
Minimum 54 Mbytes/sec Maximum 97 Mbytes/sec
SAS Interface maximum instantaneous transfer rate 300 Mbytes/sec* per port
Logical block sizes
Default is 512-byte data blocks Sector sizes variable to 512, 520, 524, and 528 kbytes.
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.)
*Assumes no errors and no relocated logical blocks. Rate measured from the start of the first logical block transfer to or from the host.
(dual port = 600 Mbytes/sec*)
Negligible

4.3 Start/stop time

The drive accepts the commands listed in the SAS Interface Manual less than 3 seconds after DC power has been applied.
If the drive receives a NOTIFY (ENABLE SPINUP) primitive through either port and has not received a START STOP UNIT command with the START bit equal to 0, the drive becomes ready for normal operations within 30 seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit equal to 0 before receiving a NOTIFY (ENABLE SPINUP ) pri mitive, the drive waits for a S TART STOP UNIT com mand wi th th e START bit equal to 1. After receiving a START STOP UNIT command with the START bit equal to 1, the drive waits for a NOTIFY (ENABLE SPINUP) primitive. After receiving a NOTIFY (ENABLE S PINUP) primitive through either port, the drive becomes ready for normal operations within 30 seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit and IMMED bit equal to 1 and does not receive a NOTIFY (ENABLE SPINUP) primitive within 5 seconds, the drive fails the START STOP UNIT command.
The START ST OP UN IT comm and m ay be used to comm and the dr ive to st op the spi ndle. Stop time is 30 sec­onds (maximum) from removal of DC power.
There is no power control switch on the drive.
Cheetah NS SAS Product Manual, Rev. B
13

4.4 Prefetc h / m ulti-segmented ca che control

The drive provides a prefetch (read look-ahead) and multi-segmented cache control algorithms that in many cases can enhance system performance. Cache refers to the drive buffer storage space when it is used in cache operations. To select this feature, the host sends the Mode Select command with the proper values in the applicable bytes in page 08h. Prefetch and cache operations are independent features from the standpoint that each is enabled and disabled independently using the Mode Select command; however, in actual opera­tion, the prefetch feature overlaps cache operation somewhat as described in sections 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 Section 9.3.2.1.

4.5 Cache operation

Note. Refer to the SAS Interface Manual for more detail concerning the cache bits.
Of the 16 Mbytes physical buffer sp ace in the drive, approximately 13,000 kbytes can be used as a cache. The buffer is divided into logical segments from which data is read and to which data is written.
The drive keeps track of the logical block addresses of the data stored in each segment of the buffer. If the cache is enabled (see RCD bit in the SAS Interface Manual ), data requested by the host w ith a rea d comm and is retrieved from the buf fe r, if possible, before any disk access is initiated . If cach e oper ation is not en abled, the buffer is still used, but only as circular buffer segments during disk 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 i t. The retrieved data merely passes through some buf fer segment on the way to the host. All data transfers to the host are in accordance with buffer-full ratio rules. See the explanation provided with the information about Mode Page 02h (disconnect/reconnect control) in the SAS Interface Manual.
The following is a simplified description of the prefetch/cache operation: Case A—read command is received and all of the requested logical blocks are already in the cache:
1. Drive transfers the requested logical blocks to the initiator.
Case B—A Read command requests data, and at least one requested logical block is not in any segment of the cache:
1. The drive fetches the requested logical blocks from the disk and transfers them into a segment, and then from there to the host in accordance with the Mode Select Disconnect/Reconnect parameters, page 02h.
2. If the prefetch feature is enabled, refer to section 4.5.2 for operation from this point.
Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical blocks. The drive dynamically creates and removes segments based on the workload. The wrap-around capa­bility of the individual segments greatly enhances the cache’s overall performance.
Note. The size of each segment is not reported by Mode Sense command page 08h, bytes 14 and 15.
The value 0XFFFF is always reported regardless of the actual size of the segment. Sending a size specification using the Mode Select command (bytes 14 and 15) does not set up a new segment size. 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 an unchangeable parameter.

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 while the drive performs the Write command.
14
Cheetah NS SAS Product Manual, Rev. B
If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made avail­able 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 dat a logical blo cks excee d the size o f the segm ent b eing wr itten into, wh en th e en d of the segment is reached, the data is written i nto the b eginning of the same cache segment, overwriting the dat a 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.
The Synchronize Ca che command may be used to force the drive to write all cached wri te dat a to the med ium. Upon completion of a Synchronize Cache command, all data received from previous write commands will have been written to the medium.
Table 9.3.2.1 shows the mode default settings for the drive.

4.5.2 Prefetch operation

If the Prefetch feature is enabled, data in contiguous logical blocks on the disk immediately beyond that which was requested by a Read command are retrieved and stored in the buffer for immediate transfer from the buffer to the host on subsequent Read commands that request those logical blocks (this is true even if cache operation is disabled). Though the prefetch operation uses the buffer as a cache, finding the requested data in the buffer is a prefetch hit, not a cache operation hit.
To enable Prefetch, use Mode Select page 08h, byte 12, bit 5 (Disable Read Ahead - DRA bit). DRA bit = 0 enables prefetch.
The drive does not use the Max Prefetch field (bytes 8 and 9) or the Prefetch Ceiling field (bytes 10 and 11). When prefetch (read look-ahead) is enabled (enabled by DRA = 0), the drive enables prefetch of contiguous
blocks from the disk when it senses that a prefetch hit will likely occur. The drive disables prefetch when it decides that a prefetch hit is not likely to occur.
Cheetah NS SAS Product Manual, Rev. B
15

5.0 Reliability specifications

The following reliability specifications assume correct host and drive operational interface, including all inter­face timings, power supply voltages, environmental requirements and drive mounting constraints.
Seek error rate: Less than 10 errors in 108 seeks Read Error Rates
Recovered Data Less than 10 errors in 1012 bits transferred (OEM default settings) Unrecovered Data Less than 1 sector in 1016 bits transferred
Miscorrected Data Less than 1 sector in 1021 bits transferred Interface error rate: Less than 1 error in 1012 bits transferred MTBF 1,400,000 hours Annualized Failure Rate (AFR) 0.62% Preventive maintenance: None required
1. Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.

5.1 Error rate s

The error rates stated in this manual assume the following:
• The drive is operated in accordance with the manual using DC power as defined in Section 6.2.
• Errors caused by host system failures are excluded from error rate computations.
• Assume random data.
• Default OEM error recovery settings are applied. This includes AWRE, ARRE, full read retries, full write retries and full retry time.
1

5.1.1 Recoverable Errors

Recoverable errors are those detected and corrected by the drive, and do not require user intervention. Recoverable Data errors will use correction, although ECC o n-the-fly is not considered fo r purposes o f recov-
ered error specifications. Recovered Data error rate is determined using read bits transferred for recoverable errors occurring during a
read, and using write bits transferred for recoverable errors occurring during a write.

5.1.2 Unrecoverable Errors

Unrecoverable Data Errors (Sense Key = 03h) are specified at less than 1 sector in error per 1016 bits trans­ferred. Unrecoverable Data Errors resulting from the same cause are treated as 1 error for that block.
16
Cheetah NS SAS Product Manual, Rev. B

5.1.3 Seek errors

A seek error is defined as a failure of the drive to position the heads to the addressed track. After detecting an initial seek error, the drive automaticall y perf orms an error recovery process. If the error recover y process fails, a seek positioning error (Error code = 15h or 02h) will be reported with a Hardware error (04h) in the Sense Key. Recoverable seek errors are specified at Less than 10 errors in 108 seeks. Unrecoverable seek errors (Sense Key = 04h) are classified as drive failures.

5.1.4 Interface errors

An interface error is defined as a failure of the receiver on a port to recover the data as transmitted by the device port connected to the receiver. The error may be detected as a running disparity error, illegal code, loss of word sync, or CRC error.

5.2 Reliability and service

You can enhance the reliability of disk drives by ensuring that the drive receives adequate cooling. Section 6.0 provides temperature measurements and other information that may be used to enhance the service life of the drive. Section 8.2 provides recommended air-flow information.

5.2.1 Annualized Failure Rate (AFR) and Mean Time Between Failures (MTBF)

These drives shal l ach ieve an A FR of 0.62 % ( MTBF of 1,400,000 hours) w he n op erate d in an en vi ronm ent that ensures the HDA case temperatures do not exceed the values specified in Section 6.4.1.
Operation at case temperatures outside the specifications in Section 6.4.1 may increase the AFR (decrease the MTBF).
AFR and MTBF statistics are poplulation statistics that are not relevant to individual units. AFR and MTBF specifications are based on the following assumptions for Enterprise Storage System environments:
• 8,760 power-on hours per year
• 250 average on/off cycles per year
• Operating at nominal voltages
• System provides adequate cooling to ensure the case temperatures specified in Section 6.4.1 are not exceeded.

5.2.2 Preventive mainte nan ce

No routine scheduled preventive maintenance is required.

5.2.3 Hot plugging the drive

When a disk is powered on by switching the power or hot plugged, the drive runs a self test before attempting to communicate on its’ interfaces. When the self test completes successfully, the drive initiates a Link Reset starting with OOB. An attached device should respond to the link reset. If the link reset attempt fails, or any time the drive looses sync, the drive initiated link reset. The drive will initiate link reset once per second but alternates between port A and B. Therefore each port will attempt a link reset once per 2 seconds assuming both ports are out of sync..
If the self-test fails, the does not respond to link reset on the failing port. Note. It is the responsibility of the systems integrator to assure that no temperature, energy, voltage haz-
ard, or ESD potential hazard is presented during the hot connect/disconnect operation. Discharge the static electricity from the drive carrier prior to inserting it into the system.
Caution. The dr ive motor must come to a complete stop prior to changing the plane of operation. Thi s time i s
required to insure data integrity.
Cheetah NS SAS Product Manual, Rev. B
17

5.2.4 S.M.A.R.T.

S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended to recognize conditions that indicate imminent drive failure and is designed to provide sufficient warning of a failure to allow you to back up the data before an actual failure occurs.
Note. The drive’s firmwar e m onitor s specif ic attr ibutes for degr adati o n ove r tim e b ut can ’t pr edict in sta nta-
neous drive failures.
Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating per­formance of the drive and the thresholds are optimized to minimize “false” and “failed” predi ctions.
Controlling S.M.A.R.T.
The operating mode of S.M.A.R. T. is controlled by the DEXCPT and PERF bits on the Informational Exce ptions Control mode page (1Ch). Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEX­CPT bit disables all S.M.A.R.T. functions. When enab led, S .M. A.R.T. collects on -line d ata as the drive p erfor ms normal read and write operations. When the PERF bit is set, the drive is considered to be in “On-line Mode Only” and will not perform off-line functions.
You can measure off-line attributes and force the drive to save the data by using the Rezero Unit command. Forcing S.M.A.R.T. resets the timer so that the next scheduled interrupt is in two hours.
You can interrogate the drive through th e host t o dete rmine the time remaining b efore the ne xt schedu l ed me a­surement and d at a logg i ng p rocess occur s . To accomplish this, i ssue a Log Sense command to log page 0x3E. This allows you to control when S.M.A.R.T. interruptions occur. Forcing S.M.A.R.T. with the RTZ command resets the timer.
Performance impact
S.M.A.R.T. attribute data is saved to the disk so that the events that caused a predictive failure can be recre­ated. The drive measures and saves parameters once every two hours subject to an idle period on the drive interfaces. The process of measuring off-line attribute data and saving data to the disk is uninterruptable. The maximum on-line only processing delay is summarized below:
Maximum processing delay
On-line only delay DEXCPT = 0, PERF = 1
S.M.A.R.T. delay times 42 milliseconds 163 milliseconds
Fully-enabled delay DEXCP T = 0, PE R F = 0

5.2.5 Reporting control

Reporting is controlled by the MRIE bits in the Informational Exceptions Control mode page (1Ch). Subject to the reporting method, the firmware will issue to the host an 01-5Dxx sense code. The error code is preserved through bus resets and power cycles.
Determining rate
S.M.A.R.T. monitors the rate at which errors occur and signals a predictive failure if the rat e of degrad ed err ors increases to an unacceptabl e level. To determine rate, error events are logged and com pa red to the num ber of total operations for a given attribute. The interval defines the number of operations over which to measure the rate. The counter that keeps track of the current number of operations is referred to as the Interval Counter.
S.M.A.R.T. measures error rates. All errors for each monitored attribute are recorded. A counter keeps track of the number of errors for the current interval. This counter is referred to as the Failure Counter.
18
Cheetah NS SAS Product Manual, Rev. B
Error rate is the number of errors per oper ation. The algori thm tha t S .M.A.R .T. uses to record rate s of err or i s to set thresholds for the number of errors and their interval. If the number of errors exceeds the threshold before the interval expires, the error rate is considered to be unacceptable. If the number of errors does not exceed the threshold before the interval expires, the error rate is considered to be acceptable. In either case, the inter­val and failure counters are reset and the process starts over.
Predictive failures
S.M.A.R.T. signals predictive failures when the drive is performing unacceptably for a period of time. The firm­ware keeps a running count of the number of times the error rate for each attribute is unacceptable. To accom­plish this, a counter is incremented each time the error rate is unacceptable and decremented (not to exceed zero) whenever the error rate is acceptable. If the counter continually increments such that it reaches the pre­dictive threshold, a predictive failure is signaled. This counter is referred to as the Failure History Counter. There is a separate Failure History Counter for each attribute.

5.2.6 Thermal monitor

Cheetah drives implement a temperature warning system which:
1. Signals the host if the temperature exceeds a value which would threaten the drive.
2. Signals the host if the temperature exceeds a user-specified value.
3. Saves a S.M.A.R.T. data frame on the drive which exceeds the threatening temperature value.
A temperature sensor monitors the drive temperature and issues a warning over the interface when the tem­perature exceeds a set threshold. The temperature is measured at power-up and then at ten-minute intervals after power-up.
The thermal monitor system generates a warning code of 01-0B01 when the temperature exceeds the speci­fied limit in compliance with the SCSI standard. The drive temperature is reported in the FRU code field of mode sense dat a. You can use this infor matio n to deter mine if the warning i s due to t he tem per atur e excee ding the drive threatening temperature or the user-specified temperature.
This feature is controlled by the En able W a rni ng (EWasc) bit, and the reporting mechanism is controlled by the Method of Reporting Informational Exceptions field (MRIE) on the Informational Exceptions Control (IEC) mode page (1Ch).
The current algorithm implements two temperature trip points. The first trip point is set at 68°C which is the maximum temperature limit according to the drive specification. The second trip point is user-selectable using the Log Select command. The re feren ce tempe ratur e p aram eter in the tempera ture log page (see Table 1) can be used to set this trip point. The default value for this drive is 68°C, however, you can set it to any value in the range of 0 to 68°C. If you specify a temperature greater than 68°C in this field, the temperature is rounded down to 68°C. A sense code is sent to the host to indicate the rounding of the parameter field.
Table 1: Temperature Log Page (0Dh)
Parameter Code Description
0000h Primary Temperature 0001h Reference Temperature

5.2.7 Drive Self Test (DST)

Drive Self Test (DST) is a technology designed to recognize drive fault conditions that qualify the drive as a failed unit. DST validates the functionality of the drive at a system level.
There are two test coverage options implemented in DST:
1. Extended test
2. Short text
Loading...
+ 56 hidden pages