7 lock-unlock cache (10) command, Lock-unlock cache (10) command – Seagate Fibre Channel Interface User Manual
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Fibre Channel Interface Manual, Rev. D
12.7
Lock-Unlock Cache (10) command
The Lock-Unlock Cache (10) command requests that the device server disallow or allow logical blocks within
the specified range to be removed from the cache memory by the device server's cache replacement algo-
rithm. Locked logical blocks may be written to the medium when modified, but a copy of the modified logical
block shall remain in the cache memory.
Multiple locks may be in effect from more than one application client. Locks from different application clients
may overlap. An unlock of an overlapped area does not release the lock of another initiator.
Table 118: Lock-Unlock Cache (10) command (4Ch)
Field definitions (listed alphabetically)
Control
See Control Bytes in Section 11.2.1.6.
Lock
0
All logical blocks in the specified range that are currently locked into the cache memory shall be unlocked, but may
not be removed.
1
Any logical block in the specified range that is currently present in the cache memory shall be locked into cache
memory. Only logical blocks that are already present in the cache memory are actually locked.
Number of Blocks
The number of contiguous logical blocks to be written.
0
indicates that all remaining logical blocks on the block device shall be within the range.
Operation Code
4Ch
The operation code for the Lock-Unlock Cache (10) command.
RelAdr (Relative Addressing)
This function is not supported by drives described in this manual.
Bit
Byte
7
6
5
4
3
2
1
0
0
Operation Code (36h)
1
Reserved
Lock
RelAdr
2
(MSB)
3
Logical Block Address
4
5
(LSB)
6
Reserved
7
(MSB)
Number of Blocks
8
(LSB)
9
Control
36h
Table
number