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1.9 Media Defects
C141-E042-01EN 1-9
(3) Service life
In situations where management and handling are correct, the disk drive requires
no overhaul for five years when the DE surface temperature is less than 48°C.
When the DE surface temperature exceeds 48°C, the disk drives requires no
overhaul for five years or 20,000 hours of operation, whichever occurs first.
Refer to item (3) in Subsection 3.2 for the measurement point of the DE surface
temperature.
(4) Data assurance in the event of power failure
Except for the data block being written to, the data on the disk media is assured in
the event of any power supply abnormalities. This does not include power supply
abnormalities during disk media initialization (formatting) or processing of
defects (alternative block assignment).
1.8 Error Rate
Known defects, for which alternative blocks can be assigned, are not included in
the error rate count below. It is assumed that the data blocks to be accessed are
evenly distributed on the disk media.
(1) Unrecoverable read error
Read errors that cannot be recovered by maximum 126 times read retries without
user’s retry and ECC corrections shall occur no more than 10 times when reading
data of 10
14
bits. Read retries are executed according to the disk drive’s error
recovery procedure, and include read retries accompanying head offset
operations.
(2) Positioning error
Positioning (seek) errors that can be recovered by one retry shall occur no more
than 10 times in 10
7
seek operations.
1.9 Media Defects
Defective sectors are replaced with alternates when the disk is formatted prior to
shipment from the factory (low level format). Thus, the host sees a defect-free
device.
Alternate sectors are automatically accessed by the disk drive. The user need not
be concerned with access to alternate sectors.