STORAGE SYSTEM THAT INCLUDES A PLURALITY OF ROUTING CIRCUITS AND A PLURALITY OF NODE MODULES CONNECTED THERETO

1 . A storage system, comprising:

a storage unit having a plurality of routing circuits networked with each other, each of the routing circuits configured to route packets to a plurality of node modules that are connected thereto, each of the node modules including nonvolatile memory; and

a plurality of connection units, each coupled with one or more of the routing circuits for communication therewith, and configured to access each of the node modules through one or more of the routing circuits, wherein

when a first connection unit transmits to a target node module a lock command to lock a memory region of the target node module for access thereto, and then a second connection unit transmits a write command to the target node module before the first connection unit transmits to the target node module an unlock command to unlock the memory region, the target node module is configured to return an error notice to the second connection unit.

2 . The storage system according to claim 1 , wherein

the write command is for writing data into the memory region of the target node module.

3 . The storage system according to claim 1 , wherein

the write command is for writing data into another memory region of the target node module.

4 . The storage system according to claim 1 , wherein

when the first connection unit transmits the lock command to the target node module, and then the second connection unit transmits to the target node module a read command to read data from the memory region before the first connection unit transmits to the target node module a write command to write data into the memory region, the target node module is configured to return data read from the target node module to the second connection unit.

5 . The storage system according to claim 1 , wherein

when the first connection unit transmits the lock command to the target node module, and then the second connection unit transmits to the target node module a read command to read data from the memory region after the first connection unit transmits to the target node module a write command to write data into the memory region, the target node module is configured to return an error notice to the second connection unit.

6 . The storage system according to claim 1 , wherein

when the second connection unit transmits to the target node module an access command after each memory region of the target node module becomes unlocked, the target node module is configured to allow access to a memory region thereof in accordance with the access command.

7 . The storage system according to claim 1 , wherein

when the first connection unit accesses a plurality of memory regions of the target node modules during a single access operation with respect to the target node module, the first connection unit sequentially transmits, to the target node module, a plurality of lock commands, each corresponding to one of the memory regions, and then a plurality of write commands, each corresponding to one of the memory regions.

8 . The storage system according to claim 7 , wherein

after transmitting the plurality of write command, the first connection unit further sequentially transmits, to the target node module, a plurality of unlock commands.

9 . A storage system, comprising:

a storage unit having a plurality of routing circuits networked with each other, each of the routing circuits configured to route packets to a plurality of node modules that are connected thereto, each of the node modules including nonvolatile memory; and

a plurality of connection units, each coupled with one or more of the routing circuits for communication therewith, and configured to access each of the node modules through one or more of the routing circuits, wherein

when a first connection unit transmits to a target node module a lock command to lock a memory region of the target node module for access thereto, and then a second connection unit transmits to the first connection unit a write request to write data into the memory region before the first connection unit transmits to the target node module an unlock command to unlock the memory region, the first connection unit is configured to access the target node module in accordance with the write request, in place of the second connection unit.

10 . The storage system according to claim 9 , wherein

the first connection unit accesses the target node module in accordance with the write request before the first connection unit transmits the unlock command to the target node module.

11 . The storage system according to claim 9 , wherein

when the first connection unit transmits the lock command to the target node module, and then the second connection unit transmits to the first connection unit a read request to read data from the memory region before the first connection unit transmits the unlock command to the target node module, the first connection unit is configured to return data read from the memory region to the second connection unit.

12 . The storage system according to claim 11 , wherein

the data read from the memory region are data that have been stored therein before the first connection unit writes data therein, when data writing into each memory region of the target node module through an access from the first connection unit has not completed.

13 . The storage system according to claim 11 , wherein

the data read from the memory region are data that have been written through an access from the first connection unit, when data writing into each memory region of the target node module through the access from the first connection unit has completed.

14 . A storage system, comprising:

a storage unit having a plurality of routing circuits networked with each other, each of the routing circuits configured to route packets to a plurality of node modules that are connected thereto, each of the node modules including nonvolatile memory; and

a plurality of connection units, each coupled with one or more of the routing circuits for communication therewith, and configured to access each of the node modules through one or more of the routing circuits, wherein

when a first connection unit transmits to a target node module a lock command to lock a memory region of the target node module for access thereto, and then a second connection unit transmits to the target node module an access command before the first connection unit transmits to the target node module an unlock command to unlock the memory region, the target node module is configured to transfer the access command to the first connection unit.

15 . The storage system according to claim 14 , wherein

the first connection unit is further configured to access the target node module in accordance with the access command.

16 . The storage system according to claim 15 , wherein

the first connection unit accesses the target node module in accordance with the access command before the first connection unit transmits the unlock command to the target node module.

17 . The storage system according to claim 16 , wherein

when the access command is a write command to write data into the memory region, the first connection unit accesses the target node module in accordance with the write command after data writing initiated by the first connection unit has completed.

18 . The storage system according to claim 16 , wherein

when the access command is a read command to read data from the memory region, the first connection unit is configured to transmit data read from the memory region to the second connection unit.

19 . The storage system according to claim 18 , wherein

the data read from the memory region are data that have been stored therein before the first connection unit writes data therein, when data writing initiated by the first connection unit has not completed.

20 . The storage system according to claim 18 , wherein

the data read from the memory region are data that have been written through data writing initiated by the first connection unit, when data writing initiated by the first connection unit has completed.