Thermal Monitor - Seagate ST600MP0005 Product Manual

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 hour subject to an idle period on the drive interfaces. The process of measuring off-line attribute data and
saving data to the disk is interruptable. The maximum on-line only processing delay is summarized below:
Maximum processing delay
Fully-enabled delay DEXCPT = 0
S.M.A.R.T. delay times 70 milliseconds
Reporting control
Reporting is controlled by the MRIE bits in the Informational Exceptions Control mode page (1Ch). Subject to the reporting method. For
example, if the MRIE is set to one, the firmware will issue to the host an 01-5D00 sense code. The FRU field contains the type of predictive
failure that occurred. 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 rate of degraded errors increases to an
unacceptable level. To determine rate, error events are logged and compared to the number 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.
Error rate is the number of errors per operation. The algorithm that S.M.A.R.T. uses to record rates of error is 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.
5.2.5

Thermal monitor

Enterprise Performance 15K HDD and Enterprise Turbo SSHD drives implement a temperature warning system which:
1. Signals the host if the temperature exceeds a value which would threaten the drive.
2. 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.
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).
Table 1 Temperature Log Page (0Dh)
Parameter Code
0000h
0001h
[a]. Do not reset the log parameter.
[b]. Do not make any requested changes in any field in any log parameter in any log page.
S E P
EAGATE NTERPRISE ERFORMANCE
Description
Primary Temperature
Reference Temperature
15K HDD 5 T
V AND URBO
Resettable or Support
Changeable Required
[a] [b]
Never Mandatory
[a] [b]
Never Optional
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