Spare Area; Alternating Defective Sectors; Sector Slip Processing - Fujitsu MPF3XXXAT Product Manual

6.4.1

Spare area

Following two types of spare area are provided in the user space.
1) Spare sector for sector slip:
used for alternating defective sectors at formatting in shipment (255 sectors/60 cylinder)
2) Spare cylinder for alternative assignment:
used by automatic alternative assignment. (4 cylinder/drive)
6.4.2

Alternating defective sectors

The two alternating methods described below are available:
(1)

Sector slip processing

A defective sector is not used and is skipped and a logical sector address is assigned to the
subsequent normal sector (physically adjacent sector to the defective sector).
When defective sector is present, the sector slip processing is performed in the formatting.
Figure 6.7 shows an example where (physical) sector 5 is defective on head 0 in cylinder 0.
Index
Sector (physical)
1 2
Cylinder 0
Head 0
1 2
Sector (logical)
If an access request to sector 5 is specified, the device accesses physical sector 6 instead of sector 5.
3 4 5 6
Defective
sector
3 4 5
unused
Figure 6.7 Sector slip processing
C141-E099-01EN
622
7 8 298
6 7 621 297
623 624
299 300
622 623
298 299
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