6.3 Defect Processing
(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.
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Automatic alternating processing is attempted for read error recovery by reaching the specified retry cycle 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
Alternate cylinder 0
Head 0
Already assigned
779 780
Defec- tive sector
(Not used) |
| 779 | 780 |
This is assigned to an unassigned sector.
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.
