FUJITSU Disk Drives MHJ2181AT - Manual (Page 31)

Device Overview
1-10 C141-E088-01EN
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 read retries of drive 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 (the MHJ Series and
MHK Series) are formatted prior to shipment from the factory (low level format).
Thus, the hosts see a defect-free devices.
Alternate sectors are automatically accessed by the disk drive. The user need not
be concerned with access to alternate sectors.