Seagate ST336754SS Cheetah 15K.4 SAS Product Manual - Page 28

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Cheetah 15K.4 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 automatically performs an error recovery process. If the error recovery 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 10

8

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 Cheetah disc 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 ser-

vice life of the drive. Section 8.2 provides recommended air-flow information.

5.2.1

Annualized Failure Rate (AFR)

The production disc drive shall achieve an AFR of 0.62% when operated in an environment that ensures the

HDA case temperatures specified in Section 6.4 are not exceeded. Short-term excursions up to the specifica-

tion limits of the operating environment will not affect AFR performance. Continual or sustained operation at

case temperatures above the values shown in Section 6.4.1 may degrade product reliability.

Estimated power-on operation hours means power-up hours per disc drive times the total number of disc

drives in service. Each disc drive shall have accumulated at least nine months of operation. Data shall be cal-

culated on a rolling average base for a minimum period of six months.

AFR is based on the following assumptions:

•

8,760 power-on hours per year.

•

250 average on/off cycles per year.

•

Operations at nominal voltages.

• Systems will provide adequate cooling to ensure the case temperatures specified in Section 6.4.1 are not

exceeded.

Drive failure means any stoppage or substandard performance caused by drive malfunction.

A S.M.A.R.T. predictive failure indicates that the drive is deteriorating to an imminent failure and is considered

an AFR hit.

5.2.2

Preventive maintenance

No routine scheduled preventive maintenance is required.

5.2.3

Hot plugging the drive

When a disc 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.

Section	Page
1.0 Scope	11
2.0 Standards, compliance and reference documents	13
2.1 Standards	13
2.1.1 Electromagnetic compatibility	13
2.1.1.1 Electromagnetic susceptibility	13
2.2 Compliance	14
2.2.1 Electromagnetic compliance	14
2.3 Reference documents	15
3.0 General description	17
3.1 Standard features	18
3.2 Media description	18
3.3 Performance	18
3.4 Reliability	19
3.5 Formatted capacities	19
3.6 Programmable drive capacity	19
3.7 Factory-installed accessories	19
3.8 Factory-installed options	20
3.9 User-installed accessories	20
4.0 Performance characteristics	21
4.1 Internal drive characteristics	21
4.2 Seek performance characteristics	21
4.2.1 Access time	21
4.2.2 Format command execution time (minutes)	22
4.2.3 General performance characteristics	22
4.3 Start/stop time	22
4.4 Prefetch/multi-segmented cache control	23
4.5 Cache operation	23
4.5.1 Caching write data	24
4.5.2 Prefetch operation	24
4.5.3 Optimizing cache performance for desktop and server applications	25
5.0 Reliability specifications	27
5.1 Error rates	27
5.1.1 Recoverable Errors	27
5.1.2 Unrecoverable Errors	27
5.1.3 Seek errors	28
5.1.4 Interface errors	28
5.2 Reliability and service	28
5.2.1 Annualized Failure Rate (AFR)	28
5.2.2 Preventive maintenance	28
5.2.3 Hot plugging the drive	28
5.2.4 S.M.A.R.T.	29
5.2.5 Thermal monitor	30
5.2.6 Drive Self Test (DST)	31
5.2.6.1 DST failure definition	31
5.2.6.2 Implementation	31
5.2.6.2.1 State of the drive prior to testing	32
5.2.6.2.2 Invoking DST	32
5.2.6.2.3 Short and extended tests	32
5.2.6.2.4 Log page entries	32
5.2.6.2.5 Abort	33
5.2.7 Product warranty	33
6.0 Physical/electrical specifications	35
6.1 AC power requirements	35
6.2 DC power requirements	35
6.2.1 Conducted noise immunity	37
6.2.2 Power sequencing	37
6.2.3 Current profiles	37
6.3 Power dissipation	41
6.4 Environmental limits	44
6.4.1 Temperature	44
6.4.2 Relative humidity	45
6.4.3 Effective altitude (sea level)	45
6.4.4 Shock and vibration	45
6.4.4.1 Shock	45
6.4.4.2 Vibration	47
6.4.5 Air cleanliness	47
6.4.6 Corrosive environment	47
6.4.7 Acoustics	48
6.4.8 Electromagnetic susceptibility	48
6.5 Mechanical specifications	48
7.0 Defect and error management	49
7.1 Drive internal defects/errors	49
7.2 Drive error recovery procedures	49
7.3 SAS system errors	50
8.0 Installation	51
8.1 Drive orientation	51
8.2 Cooling	52
8.3 Drive mounting	53
8.4 Grounding	53
9.0 Interface requirements	55
9.1 SAS features	55
9.1.1 task management functions	55
9.1.2 task management responses	55
9.2 Dual port support	56
9.3 SCSI commands supported	57
9.3.1 Inquiry data	61
9.3.2 Mode Sense data	61
9.3.2.1 ST3146854SS Mode Sense data	63
9.3.2.2 ST373454SS Mode Sense data	64
9.3.2.3 ST336754SS Mode Sense data	65
9.4 Miscellaneous operating features and conditions	66
9.4.1 SAS physical interface	67
9.4.2 Physical characteristics	69
9.4.3 Connector requirements	69
9.4.4 Electrical description	70
9.4.5 Pin descriptions	70
9.4.6 SAS transmitters and receivers	71
9.4.7 Power	71
9.5 Signal characteristics	71
9.5.1 Ready LED Out	71
9.5.2 Differential signals	72
9.5.2.1 Eye masks	72
9.5.2.1.1 Eye masks overview	72
9.5.2.1.2 Receive eye mask	73
9.5.2.1.3 Jitter tolerance masks	73
9.5.2.2 Transmitter signal characteristics	75
9.5.2.3 Receiver signal characteristics	76
9.5.2.3.1 Jitter	76
9.5.2.3.2 Receiver jitter tolerance	77
9.5.2.3.3 Compliant jitter test pattern (CJTPAT)	77
9.5.2.3.4 Impedance specifications	77
9.5.2.4 Electrical TxRx connections	78
9.5.2.4.1 Transmitter characteristics	78
9.5.2.5 Receiver characteristics	81
10.0 Seagate Technology support services	83
Numerics	89
A	89
B	89
C	89
D	89
E	89
F	90
G	90
H	90
I	90
J	90
L	90
M	90
N	91
O	91
P	91
Q	91
R	91
S	91
T	92
U	92
V	92
W	92

Seagate ST336754SS Cheetah 15K.4 SAS Product Manual - Page 28

Seek errors, Interface errors, Annualized Failure Rate AFR, Preventive maintenance, Hot plugging

Page 28 highlights