Seek Errors; Reliability And Service; Mean Time Between Failure; Preventive Maintenance - Seagate ST34520N - Medalist 4.55 GB Hard Drive Product Manual

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5.1.4

Seek errors

A seek error is defined as a failure of the drive to position the heads to the addressed track. There shall be no
more than one recoverable seek errors in 10
drive automatically reseeks to the addressed track up to 3 times. If a reseek is successful, the Extended Sense
reports a seek positioning error (15h), no seek complete error (02h), or track follow error (09h), and the sense
key reports a recovered error (1h). If all three reseeks fail, a seek positioning error (15h) is reported with a
Medium error (3h) or Hardware error (4h) reported in the Sense Key. This is an unrecoverable seek error. Unre-
coverable seek errors are classified as failures for MTBF calculations. Refer to Section 5.1.1.2 of the SCSI
Interface Product Manual (part number 77738479) for Request Sense information. Appendix A of this manual
lists the sense keys and additional sense codes supported by the drives of this manual.
5.2

Reliability and service

You can enhance the reliability of Medalist Pro disc drives by ensuring that the drive receives adequate cooling.
Section 6.4.1 provides temperature measurements and other information that may be used to enhance the ser-
vice life of the drive. Section 8.3.1 provides recommended air-flow information.
5.2.1

Mean time between failure

The production disc drive shall achieve an MTBF of 800,000 hours when operated in an environment that
ensures the case temperatures specified in Section 6.4.1 are not exceeded. Short-term excursions up to the
specification limits of the operating environment will not affect MTBF performance.
The following expression defines MTBF
MTBF per measurement period
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 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.
5.2.2

Preventive maintenance

No routine scheduled preventive maintenance shall be required.
5.2.3

Service life

The drive shall have a useful service life of five years. Depot repair or replacement of major parts is permitted
during the lifetime (see Section 5.2.4).
5.2.4

Service philosophy

Special equipment is required to repair the drive HDA. In order to achieve the above service life, repairs must
be performed only at a properly equipped and staffed 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. Also, there are no spare parts available for this drive. Drive warranty is voided if the HDA is opened.
5.2.5

Service tools

No special tools are required for site installation or recommended for site maintenance. Refer to Section 5.2.4.
The depot repair philosophy of the drive precludes the necessity for special tools. Field repair of the drive is not
practical since there are no user purchasable parts in the drive.
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physical seek operations. After detecting an initial seek error, the
Estimated power-on operating hours in the period
=
Number of drive failures in the period
Medalist Pro Product Manual, Rev. D