Fujitsu 80, Scsi Logical Interface Specifications

Page: 287 / 310

6.2 Disk Media Initialization
C141-C010 6-3
• Alternate block allocation processing during FORMAT UNIT command execution
With the FORMAT UNIT command, alternate block allocation is done by sector slip processing
until all the spare sectors within the same cell have been used up for defective sectors included
in the type of defect list (P, G or D) specified in the command. When all the spare sectors in the
same cell have been used up, subsequent defective sectors in that cell are treated by allocating
spare sectors in an alternate cell by alternate sector processing.
After implementing this alternate block allocation and initializing the disk media, at times when
a data block Verify (Certification) operation is not prohibited, the IDD, reads all the initialized
data blocks and verifies their normalcy. If a defective data block is detected during this
processing, the IDD generates the C List as defect position information and allocates alternate
blocks by alternate sector processing for those defective data blocks. In this case, alternate
blocks are allocated in spare sectors in an alternate cell.
• Alternate block allocation processing by the REASSIGN BLOCKS command
With the REASSIGN BLOCKS command, alternate block allocation is performed by alternate
sector processing for defective logical data blocks specified by the INIT. In this case, alternate
blocks are allocated in spare sectors in an alternate cell.
• Auto alternate block allocation processing
If auto alternate block allocation processing is permitted by the AWRE flag or the ARRE flag of
the MODE SELECT parameters, the IDD executes alternate clock allocation automatically by
alternate sector processing for defective data blocks detected during execution of the WRITE,
WRITE EXTENDED, WRITE AND VERIFY, READ and READ EXTENDED commands.
The alternate block allocation method in this case is the same as in the case of the REASSIGN
BLOCKS command. See the description in Section 5.3.2 concerning "Auto Alternate Block
Allocation Processing".
6.2 Disk Media Initialization
6.2.1 Initialization during installation
The disk drive is initialized for the inherent (default) data format for each respective model name (model
class) when it is shipped from the factory, so ordinarily, it is not necessary to initialized (format) the disk
media when it is installed in a system. However, in cases where data attributes which differ from the
default format are necessary, initialization (formatting) of the entire disk media by the following
procedures is necessary. At this time, the INIT can change the following data format attributes.
•
The logical data block length.
•
The number of logical data blocks or the number of cylinders in the User Space.
•
The size of the spare area for alternate blocks.