Fujitsu MAE3091LC SERIES, Product Manual

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C141-E064-03EN 2 - 5
2.1.4 Error rate
Errors detected during initialization and replaced by alternate block assignments are not
included in the error rate. Data blocks to be accessed should be distributed over the disk
medium equally.
(1) Unrecoverable error rate
Errors which cannot be recovered within 63 retries and ECC correction should not exceed 10
per 10
15
bits.
(2) Positioning error rate
Positioning errors which can be recovered by one retry should be 10 or less per 10
8
seeks.
2.1.5 Reliability
(1) Mean Time Between Failures (MTBF)
MTBF of the IDD during its life time is 1,000,000 hours (operating: 24 hours/day, 7
days/week average DE surface temperature: 40°C or less).
Note:
The MTBF is defined as:
Operating time (hours) at all field sites
MTBF=
The number of equipment failures from all field sites
Failure of the equipment means failure that requires repair, adjustments, or replacement.
Mishandling by the operator, failures due to bad environmental conditions, power trouble,
host system trouble, cable failures, or other failures not caused by the equipment are not
considered.
(2) Mean Time To Repair (MTTR)
MTTR is the average time taken by a well-trained service mechanic to diagnose and repair a
drive malfunction. The drive is designed for a MTTR of 30 minutes or less.