Seagate ST3300457FC Cheetah 15K.6 SAS Product Manual - Page 48

44

Cheetah 15K.6 SAS Product Manual, Rev. B

The drive firmware error recovery algorithms consists of 13 levels for read recoveries and five levels for write.

Each level may consist of multiple steps, where a step is defined as a recovery function involving a single re-

read or re-write attempt. The maximum level used by the drive in LBA recovery is determined by the read and

write retry counts.

Table 18 equates the read and write retry count with the maximum possible recovery time for read and write

recovery of individual LBAs. The times given do not include time taken to perform reallocations. Reallocations

are performed when the ARRE bit (for reads) or AWRE bit (for writes) is one, the RC bit is zero, and the recov-

ery time limit for the command has not yet been met. Time needed to perform reallocation is not counted

against the recovery time limit.

When the RC bit is one, reallocations are disabled even if the ARRE or AWRE bits are one. The drive will still

perform data recovery actions within the limits defined by the Read Retry Count, Write Retry Count, and

Recovery Time Limit parameters. However, the drive does not report any unrecovered errors.

[1]

These values are subject to change.

Setting these retry counts to a value below the default setting could result in degradation of the unrecov-

ered error rate which may exceed the value given in this product manual. A setting of zero (0) will result in

the drive not performing error recovery.

For example, suppose the read/write recovery page has the RC bit set to 0, read retry count set to 4, and

the recovery time limit field (Mode Sense page 01, bytes 10 and 11) set to FF FF hex (maximum). A four

LBA Read command is allowed to take up to 253.11 msec recovery time for each of the four LBAs in the

command. If the recovery time limit is set to 00 C8 hex (200 msec decimal) a four LBA read command is

allowed to take up to 200 msec for all error recovery within that command. The use of the Recovery Time

Limit field allows finer granularity on control of the time spent in error recovery. The recovery time limit

only starts counting when the drive is executing error recovery and it restarts on each command. There-

fore, each command’s total recovery time is subject to the recovery time limit. Note: A recovery time limit

of 0 will use the drive’s default value of FF FF. Minimum recovery time limit is achieved by setting the

Recovery Time Limit field to 00 01.

Table 18:

Read and write retry count maximum recovery times

Read retry count

1

Maximum recovery time per

LBA (cumulative, msec)

Write retry count

1

Maximum recovery time per

LBA (cumulative, msec)

0

51.87

0

23.94

1

59.85

1

35.91

2

203.49

2

55.86

3

219.45

3

67.83

4

231.42

4

119.79

5

297.38

5 (default)

147.72

6

323.62

7

355.54

8

439.39

9

507.39

10

539.31

11

567.24

12

1,460.85

13 (default)

1,468.74

Section	Page
1.0 Scope	5
2.0 Standards, compliance and reference documents	7
2.1 Standards	7
2.1.1 Electromagnetic compatibility	7
2.1.1.1 Electromagnetic susceptibility	7
2.2 Compliance	8
2.2.1 Electromagnetic compliance	8
2.3 European Union Restriction of Hazardous Substances (RoHS)	8
2.4 Reference documents	9
3.0 General description	11
3.1 Standard features	12
3.2 Media description	12
3.3 Performance	12
3.4 Reliability	13
3.5 Formatted capacities	13
3.6 Programmable drive capacity	13
3.7 Factory-installed options	13
4.0 Performance characteristics	15
4.1 Internal drive characteristics	15
4.2 Seek time	15
4.2.1 Access time	15
4.2.2 Format command execution time (minutes)	16
4.2.3 General performance characteristics	16
4.3 Start/stop time	16
4.4 Prefetch/multi-segmented cache control	17
4.5 Cache operation	17
4.5.1 Caching write data	18
4.5.2 Prefetch operation	18
5.0 Reliability specifications	19
5.1 Error rates	19
5.1.1 Recoverable Errors	19
5.1.2 Unrecoverable Errors	19
5.1.3 Seek errors	20
5.1.4 Interface errors	20
5.2 Reliability and service	20
5.2.1 Annualized Failrue Rate (AFR) and Mean time between failure (MTBF)	20
5.2.2 Preventive maintenance	20
5.2.3 Hot plugging the drive	20
5.2.4 S.M.A.R.T.	21
5.2.5 Thermal monitor	22
5.2.6 Drive Self Test (DST)	23
5.2.6.1 DST failure definition	23
5.2.6.2 Implementation	23
5.2.6.2.1 State of the drive prior to testing	23
5.2.6.2.2 Invoking DST	24
5.2.6.2.3 Short and extended tests	24
5.2.6.2.4 Log page entries	24
5.2.6.2.5 Abort	25
5.2.7 Product warranty	25
6.0 Physical/electrical specifications	27
6.1 AC power requirements	27
6.2 DC power requirements	27
6.2.1 Conducted noise immunity	31
6.2.2 Power sequencing	31
6.2.3 Current profiles	31
6.3 Power dissipation	34
6.4 Environmental limits	40
6.4.1 Temperature	40
6.4.2 Relative humidity	41
6.4.3 Effective altitude (sea level)	41
6.4.4 Shock and vibration	41
6.4.4.1 Shock	41
6.4.4.2 Vibration	43
6.4.5 Acoustics	43
6.4.6 Air cleanliness	43
6.4.7 Corrosive environment	43
6.4.8 Electromagnetic susceptibility	44
6.5 Mechanical specifications	44
7.0 Defect and error management	47
7.1 Drive internal defects/errors	47
7.2 Drive error recovery procedures	47
7.3 SAS system errors	49
7.4 Background Media Scan	49
7.5 Media Pre-Scan	49
7.6 Deferred Auto-Reallocation	50
7.7 Idle Read After Write	50
8.0 Installation	51
8.1 Drive orientation	51
8.2 Cooling	51
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	62
9.3.2.1 ST3450856SS/ST3450056SS Mode Sense data	63
9.3.2.2 ST3300656SS/ST3300056SS Mode Sense data	64
9.3.2.3 ST3146356SS/ST3146756SS Mode Sense data	65
9.4 Miscellaneous operating features and conditions	66
9.4.1 SAS physical interface	66
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	85
A	85
B	85
C	85
D	85
E	85
F	86
G	86
H	86
I	86
J	86
L	86
M	86
N	86
O	87
P	87
Q	87
R	87
S	87
T	88
U	88
V	88
W	88

Seagate ST3300457FC Cheetah 15K.6 SAS Product Manual - Page 48

Recovery Time Limit field to 00 01.

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