178 Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
_____________________________________________________________________________________
5.2.2.7
Synchronize Cache Command (35h)
Table 5.2.2-7. Synchronize Cache Command
Bit
7
6
5
4
3
2
1
0
Byte(s)
0
0
0
1
1
0
1
0
1
1
Logical Unit No. [1]
Reserved
Immed RelAdr
[2]
[3]
2
(MSB)
:
Logical Block Address
[4]
5
(LSB)
6
Reserved
7
(MSB)
:
Number of Blocks
[5]
8
(LSB)
9
Control
[6]
The Synchronize Cache command (Table 5.2.2-7) ensures that logical blocks in the cache memory, within
the specified range, have their most recent data value recorded on the physical medium. If a more recent
data value for a logical block within the specified range exists in the cache memory than on the physical
medium, then the logical block from the cache memory shall be written to the physical medium. Logical
blocks are not necessarily removed from the cache memory as a result of the synchronize cache operation.
[1] LUN must be zero.
[2] An immediate (Immed) bit of one indicates that the drive shall return status as soon as the command
descriptor block has been validated. An Immed bit of zero indicates that the status shall not be returned
until the operation has been completed. If the Immed bit is one and the target does not support it, the
command shall terminate with CHECK CONDITION status. The sense key shall be set to ILLEGAL
REQUEST and the additional sense code shall be set to INVALID FIELD IN CDB.
[3] See paragraph 5.2.2.9 note [3] for definition of RELADR bit.
[4] The Logical block address field specifies the logical block at which the Synchronize Cache operation
begins.
[5] The number of blocks field specifies the total number of contiguous logical blocks within the range. A
number of blocks of zero indicates that all remaining logical blocks on the logical unit shall be within the
range.
A logical block within the specified range that is not in cache memory is not considered an error. Multiple
locks may be in effect from more than one initiator. Locks from different initiators may overlap. An unlock
of an overlapped area does not release the lock of another initiator.
[6] See section 4.2.6.