Alternate Spare Area - Fujitsu MAG3182FC SERIES Product Manual

The default number of cylinders in the user space is 10,200 for MAF3364FC and 9,866 for MAG
series. The user, however, can select the number of cylinders to be allocated in the user space by
specifying 10,200 for MAF3364FC and 9,866 for MAG series as the maximum and the number
of alternate cylinders + 1 as the minimum. The user can also specify the number of logical data
blocks to be placed in the user space with the MODE SELECT or MODE SELECT EXTENDED
command. When the number of logical data blocks is specified, as many cylinders as required to
place the specified data blocks are allocated in the user space.
A number starting with 0 is assigned to each cylinder required in the user space in ascending
order. If the number does not reach 10,200 (MAF3364FC) and 9,866 (MAG series), the rest of
the cylinders will not be used.
Always one alternate cylinders can be established in the user space. Alternate cylinders will be
used for alternate blocks when primary cylinders in the user space are used up. See Subsections
3.1.2 and 3.3.2 for details.
(2) Internal test space
The Internal test space is an area for diagnostic purposes only and its data block length is always
512 byte. The internal test space consists of only 1 cylinder and outer-host cylinder (–37) is
always assigned. The user cannot change the number of cylinders in the internal test space or
their positions.
The IDD reads or writes the data block in the CE space during the self-diagnostic test specified
with the setting terminal (diagnostic mode) or a SEND DIAGNOSTIC command.
(3) System space
The system space is an area for exclusive use of the IDD itself and the following information are
recorded. The length of the data block is always 512 bytes.
•
Defect list (P list and G list)
•
MODE SELECT parameter (saved value)
•
Statistical information (log data)
•
Controller control information
The above information are duplicated in several different locations for safety.
Note:
The system space is also called SA space.
3.1.2

Alternate spare area

The alternate spare area is provided in the last track of each primary cylinder in the user space,
and in the last track of the cylinder and the alternate cylinder.
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