Seagate ST3285N, Product Manual

Page: 106 / 151

Bit
Byte
7 6 5 4 3 2 1 0
20 SSEC HSEC RMB SURF
Reserved
default 1 0 0 0
changeable 0 0 0 0 0 0 0 0
21–23 (default) Reserved (000000
H
)
changeable 000000
H
Bytes 2–3 The
tracks per zone field indicates the number of tracks the
drive allocates to each defect-management zone. Spare
sectors or tracks are placed at the end of each defect
management zone. If each zone is treated as containing one
track, the valid value for tracks per zone is 1. If each zone is
treated as containing one cylinder, the valid value is equal
to the number of read/write heads.
Bytes 4–5 The alternate sectors per zone field indicates the number
of spare sectors to be reserved at the end of each defect-
management zone. The drive defaults to one spare sector
per zone. If each zone is treated as containing one track,
the valid value for alternate sectors per zone is 1. If each
zone is treated as containing one cylinder, the valid values
are 1 through 3.
Bytes 6–7 The alternate tracks per zone field indicates the number
of spare tracks the drive reserves at the end of each
defect-management zone. A value of 0 indicates that no
spare tracks are reserved at the end of each zone for
defect management.
Bytes 8–9 The alternate tracks per volume field indicates the number
of spare tracks to be reserved at the end of the drive for
defect management.
For the ST3285N and ST3390N, the value must be a
multiple of 3 and can range from 3 through 255. For the
ST3550N and ST3655N, the value must be a multiple of
5 and can range from 5 through 255.
The default is equal to twice the number of read/write
heads.
continued from previous page
96 ST3655 Family SCSI Drives Product Manual, Rev. A