Alternate Spare Area; Figure 3.2 Spare Area In Cell; Figure 3.3 Alternate Cylinder - Fujitsu MBC2073RC Product Manual

Data Format
3.1.2

Alternate spare area

The alternate spare area consists of the last track of each cell in the user space and an alternate
cylinder allocated to the last 10 cylinders of the last zone in the user space.
The spare area in each cell is placed at the end of the last track as shown in Figure 3.2. These spare
sectors are located in the end of the track logically, not necessarily located at the end physically
because of track skew or cylinder skew. (Details are explained on Subsection 3.1.3.)
Size can be specified by the MODE SELECT command.
The number of spare sectors per cell is fixed at 300. This number cannot be changed by users.
Zone 0
Cyl 0
1
USRCYL0
USRCYL: User area
ALTCYL: Alternate area
Note: This HDD manages alternate spare areas for each cell, which is a set of cylinders. One cell
consists of 40 cylinders.
The alternate cylinder is used for replacement action via the REASSIGN BLOCKS command or
automatic replacement processing. The alternate cylinder is allocated to 10 cylinders at the end of
the last zone in the user space.
Note: The number of alternate cylinders cannot be changed.
30
p
USRCYL0
Figure 3.2 Spare area in cell
Zone
Figure 3.3 Alternate cylinder
Zone n
p
ALTCELL
Change
for cell
(10 Cyl)
C141-E266