Seagate 15K.5 - Cheetah - Hard Drive, Руководство по эксплуатации продукта

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Cheetah 15K.5 SCSI Product Manual, Rev. D 19
zero) whenever the error rate is acceptable. This counter is referred to as the Failure History Counter. There is
a separate Failure History Counter for each attribute. Should the counter continually be incremented such that
it reaches the predictive threshold, a predictive failure is signaled.
5.2.5 Thermal monitor
Cheetah 15K.5 SCSI 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 exceed the threatening temperature value.
A temperature sensor monitors the drive temperature and issues a warning over the interface when the tem-
perature 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 speci-
fied limit in compliance with the SCSI standard. The drive temperature is reported in the FRU code field of
mode sense data. You can use this information to determine if the warning is due to the temperature exceeding
the drive threatening temperature or the user-specified temperature.
This feature is controlled by the Enable Warning (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 reference temperature parameter in the temperature log page (see Table 2) 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.
When the first temperature trip point is exceeded, S.M.A.R.T. data is collected and a frame is saved to the disc.
5.2.6 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
The most thorough option is the extended test that performs various tests on the drive and scans every logical
block address (LBA) of the drive. The short test is time-restricted and limited in length—it does not scan the
entire media surface, but does some fundamental tests and scans portions of the media.
If DST encounters an error during either of these tests, it reports a fault condition. If the drive fails the test,
remove it from service and return it to Seagate for service.
Table 2: Temperature Log page (0Dh)
Parameter Code Description
0000h
Primary Temperature
0001h
Reference Temperature