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3.1 Data Space
C141-E133-02EN 3-5
Note: This drive manages alternate spare areas for each cell, which is a set of cylinders. The
default value for the number of cylinders is four.
Figure 3.2 Spare area in cell
An alternate cylinder is used when spare sectors in a cell are used up or 0 is specified as the number
of spare sectors in a cell. 1 cylinder at the end of each zone of the user space is allocated as alternate
cylinders as shown in Figure 3.3.
The user space and the CE space share the alternate cylinders.
Zone
Figure 3.3 Alternate cylinder
Note:
Zero cannot be specified for both the number of spare sectors in each cylinder and the number of
alternate cylinders.
3.1.3 Track format
(1) Physical sector allocation
Figure 3.4 shows the allocation of the physical sectors in a track. The length in bytes of each
physical sector and the number of sectors per track vary depending on the logical data block length.
The unused area (G4) exists at the end of the track in formats with most logical data block lengths.
The interval of the sector pulse (length of the physical sector) is decided by multiple of 40MHz free
running frequency. This clock is not equal to the interval of the byte clock for each zone. Therefore,
the physical sector length cannot be described with a byte length.
Cell