Product manual

Barracuda 9FC Product Manual, Rev. C 15
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 inter-
val 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 firm-
ware keeps a running count of the number of times the error rate for each attribute is unacceptable. To accom-
plish 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 pre-
dictive 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.
5.3 Reliability and service
The reliability of Barracuda 9FC disc drives can be enhanced by ensuring that the drive receives adequate
cooling. This section provides recommended air-flow information, temperature measurements, and other infor-
mation, which you can use to enhance the service life of the drive.
5.3.1 Mean time between failure (MTBF)
The production disc drive achieves an MTBF of 1,000,000 hours when operated in an environment that
ensures the case temperature does not exceed 45°C. Short-term excursions up to the specification limits of the
operating environment will not affect MTBF performance. Operating the drive at case temperatures above
these values may adversely affect the drive’s ability to meet specifications. See Section 6.4, “Environmental
limits” on page 18.
The following expression defines MTBF:
Estimated power-on operating hours means the estimated total power-on hours for all drives in service. Drive
failure means any stoppage or substandard performance caused by drive malfunction.
Data is calculated on a rolling-average base for a minimum period of six months.
Drive failure means any stoppage or substandard performance caused by drive malfunction.
5.3.2 Preventive maintenance
No routine scheduled preventive maintenance is required.
5.3.3 Service life
The drive has a useful service life of five years. Depot repair or replacement of major parts is permitted during
the lifetime.
5.3.4 Service philosophy
Special equipment is required to repair the drive HDA. To achieve the above service life, repairs must be per-
formed only at a properly equipped and staffed Seagate service and repair facility. Troubleshooting and repair
of PCBs in the field is not recommended because of the extensive diagnostic equipment required for effective
servicing. The drive warranty is voided if the HDA is opened.
5.3.5 Service tools
No special tools are required for site installation or recommended for site maintenance. The depot repair phi-
losophy of the drive precludes the necessity for special tools. Field repair of the drive is not practical because
users cannot purchase individual parts for the drive.
MTBF = Estimated power-on operating hours in the period
Number of drive failures in the period