Operations
6-10 C141-E218
6.3.2 Alternating processing for defective sectors The following two types of technology are used for alternating processing:
(1) Sector slip processing
In this method, defective sectors are not used (thereby avoiding the effects of
defects), and each defective sector is assigned to the next contiguous sector that is
normal.
Depending on the format defined at shipment from the plant, this processing is
performed for defective sectors.
Figure 6.5 shows an example where sector (physical) 5 with cylinder 0 and head 0
is defective.
Sector (physical)
Cylinder 0
Head 0
Defec-
tive
sector
(Not used)
778 779 780
777 778 779
Note: When an access request for sector 5 is issued, physical sector 6 must be
accessed instead of physical sector 5.
Figure 6.5 Sector slip processing
(2) Track slip processing
In this method, defective tracks not used (there by avoiding the effects of defects),
and each defective track is assigned to the next contiguous track that is normal.
Depending on the format defined at shipment from the plant, this processing is
performed for defective tracks.