Write Safety; Data Buffer Test; Error Recovery; Automatic Reallocation - IBM IC25N040ATCS04 - Travelstar 40 GB Hard Drive Specifications

5.4 WRITE safety

The drive ensures that the data is written into the disk media properly. The following conditions are moni-
tored during a write operation. When one of these conditions exceeds the criteria, the write operation is
terminated and the automatic retry sequence is invoked.
! Head off track
! External shock
! Low supply voltage
! Spindle speed out of tolerance
! Head open/short

5.5 Data buffer test

The data buffer is tested at power on reset and when a drive self-test is requested by the host. The test
consists of a write/read '00'x and 'ff'x pattern on all buffers.

5.6 Error recovery

Errors occurring on the drive are handled by the error recovery procedure.
Errors that are uncorrectable after application of the error recovery procedure are reported to the host
system as nonrecoverable errors.

5.7 Automatic reallocation

The sectors that show some errors may be reallocated automatically when specific conditions are met.
The drive does not report any auto reallocation to the host system. The conditions for auto reallocation are
described below.

5.7.1 Nonrecovered write errors

When a write operation cannot be completed after the Error Recovery Procedure (ERP) is fully carried out,
the sectors are reallocated to the spare location. An error is reported to the host system only when the
write cache is disabled and the auto reallocation has failed.

5.7.2 Nonrecoverable read error

When a read operation fails after ERP is fully carried out, a hard error is reported to the host system. This
location is registered internally as a candidate for the reallocation. When a registered location is specified
as a target of a write operation, a sequence of media verification is performed automatically. When the
result of this verification meets the required criteria, this sector is reallocated.

5.7.3 Recovered read errors

When a read operation for a sector fails and is recovered at the specific ERP step, the sector is real-
located automatically. A media verification sequence may be run prior to the reallocation according to the
predefined conditions.
Travelstar 60GH & 40GN hard disk drive specifications
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