Reassign Blocks Command (07H) - Seagate SCSI Interface Product Manual

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5.27

Reassign Blocks command (07h)

The Reassign Blocks command (Table 133) requests the target to reassign the defective logical blocks to an
area on the logical unit reserved for this purpose.
After sending the Reassign Blocks command, the initiator transfers a defect list that contains the logical block
addresses to be reassigned. The drive reassigns the physical medium used for each logical block address in
the list. The data contained in the logical blocks specified in the defect list is not preserved, but the data in all
other logical blocks on the medium is preserved. It is recommended that the initiator recover the data from the
logical blocks to be reassigned before issuing this command. After completion of this command, the initiator
can write the recovered data to the same logical block addresses.
The effect of specifying a logical block to be reassigned that has previously been reassigned is to reassign the
block again. Thus, over the life of the medium, a logical block can be assigned to multiple physical addresses
(until no more spare locations remain on the medium).
This command should be used by an initiator to immediately reallocate any block (sector) which requires the
drive to recover data by data correction via ECC if the automatic reallocation feature of the drive is not enabled
(see Mode Select command, Section 5.10).
For systems which support disconnection, the drive disconnects while executing this command.
Table 133: Reassign Blocks command (07h)
Bit 7
Byte
0 0
1 0
Logical Unit Number [1]
2 0
3 0
4 0
5 0
Notes.
[1] The Logical Unit Number must be zero.
[2] See "Control byte," paragraph 4.2.6.
6 5
0 0
0 0
0 0
0 0
0 0
0 0
SCSI Interface Product Manual, Rev. J
4 3
0 0
0 0
0 0
0 0
0 0
0 0
2 1
1 1
0 0
0 0
0 0
0 0
0 Flag [2] Link [2]
0
1
0
0
0
0