APPENDIX
106
bad sectors without external help using cyclic redundancy check
(CRC) checksums stored at the end of each sector.
SATA drives perform automatic defect re-assignment for both
read and write errors. Writes are always completed - if a location
to be written is found to be defective, the drive will automatically
relocate that write command to a new location and map out the
defective location. If there is a recoverable read error, the cor-
rect data will be transferred to the host and that location will be
tested by the drive to be certain the location is not defective. If
it is found to have a defect, data will be automatically relocated,
and the defective location is mapped out to prevent future write
attempts.
In the event of an unrecoverable read error, the error will be re-
ported to the host and the location will be agged as being po-
tentially defective. A subsequent write to that location will initiate
a sector test and relocation should that location prove to have
a defect. Auto Reassign Sector does not affect disk subsystem
performance because it runs as a background task. Auto Reassign
Sector discontinues when the operating system makes a request.
Data Protection
• RECOVERY ROM
The SATA RAID controller rmware is stored on the ash ROM
and is executed by the I/O processor. The rmware can also be
updated through the PCIe bus port without the need to replace
any hardware chips. During the controller rmware upgrade ash
process, it is possible for a problem to occur resulting in corrup-
tion of the controller rmware. With our Redundant Flash Image
feature, the controller will revert back to the last known version of
rmware and continue operating. This reduces the risk of system
failure due to rmware crash.
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