Fujitsu MHT2060AT Manuale Utente

C141-E192-01EN

6-11

(3)

Automatic alternating processing

This technology assigns a defective sector to a spare sector of an spare cylinder
for alternate assignment.

This device performs automatic alternating processing in the event of any of the
following errors.

•

 

Automatic alternating processing is attempted for read error recovery by
heightening the ECC correction capability while a read error retry is in
progress.

Before attempting automatic alternating processing, writing and reading of
already corrected data is repeated for the sector in which an error occurred.
If a read error does not occur during this reading operation, automatic
alternating processing is not performed.

•

 

If error recovery is not successful even if a write fault error retry is executed,
automatic alternating processing is performed.

Figure 6.6 shows an example where automatic alternating processing is applied to
sector (physical) 5 with cylinder 0 and head 0.

Sector (physical)

Cylinder 0
Head 0

Defec-
tive
sector

(Not used)

Alternate cylinder 0
Head 0

This is assigned to an unassigned sector.

Already
assigned

779       780

779       780

Notes:

1.

The alternate cylinder is assigned to an inner cylinder in each zone.

2.

When an access request for sector 5 is issued, the sector assigned for
alternating processing of the alternate cylinder must be accessed instead of
physical sector 5.

If an access request for sectors after sector 5 is issued, seek is executed to
cylinder 0, head 0 in order to continue processing.