Access control apparatus and access control method

1. An access control apparatus controlling an access to a recording area of a recording medium on a command with a command completion time limit requiring completing the command in a predefined period of time, the access control apparatus comprising:

a writable and readable memory;

a command executor executing an access process on the command with the command completion time limit, storing an address of an inaccessible recording area in the memory when an access error is caused, obtaining data attempted to be written on the inaccessible recording area, storing the data associating to the address of the inaccessible recording area in the memory;

an automated alternate processor executing an automated alternate process of the inaccessible recording area in a predefined period of time after the process executed by the command executor is completed; and

a memory updater deleting the address of the inaccessible recording area whose automated alternate process has succeeded and the data attempted to be written in the recording area at the address from the memory.

2. The access control apparatus according to claim 1 , wherein the command executor searches in the memory on a write command with time limit and where an address of the recording area to be accessed on the write command is stored in the memory, the data attempted to be written in the recording area at the address are stored in the memory.

3. The access control apparatus according to claim 1 , wherein the command executor searches in the memory on the write command with time limit, and when the address of the recording area to be accessed on the write command is not stored in the memory, the recording medium is accessed.

4. The access control apparatus according to claim 1 , wherein the command executor searches in the memory on a read command with time limit, and when an address of a recording area to be accessed on the read command and data attempted to be written in a recording area at the address are stored in the memory, the data are read from the memory.

5. The access control apparatus according to claim 1 , wherein the command executor searches in the memory on the read command with time limit, and when the address of the recording area to be accessed on the read command is not stored in the memory or the data attempted to be written in the recording area at the address are not stored in the memory, the recording medium is accessed.

6. The access control apparatus according to claim 1 , wherein the command executor repeatedly accesses to the recording medium at the maximum number of times predefined when the access on the write command with time limit is failed, and when the access has succeeded when retrying the access more than a threshold and less than the predefined times, the address of the recording area and the data attempted to be written in the recording area at the address are stored in the memory, and when the access has succeeded when retrying the access less than the threshold, the address and the data are not stored in the memory.

7. An access control method controlling an access to a recording area on a recording medium on a command with a time limit requiring completing the command in a predefined period of time, the access control method comprising:

executing an access process on the command with the time limit,

associating an address of an inaccessible recording area with data attempted to be written in the inaccessible recording area at the address;

storing the address and the data in a memory when an access error is caused;

executing an automated alternate process of the inaccessible recording area in the predefined period of time; and

deleting the address of the recording area whose automated alternate process has succeeded and the data attempted to be written in the recording area at the address from the memory in response to the success of the automated alternate process.

8. The access control method according to claim 7 , further comprising:

searching the memory on a write command with a time limit, and

storing the data to be stored in the recording area at the address in the memory when the address of the recording area to be accessed on the write command is stored in the memory.

9. The access control method according to claim 7 , further comprising:

searching the memory on the write command with the time limit, and

accessing the recording medium when the address of the recording area to be accessed on the write command is not stored in the memory.

10. The access control method according to claim 7 , further comprising:

searching the memory on a read command with a time limit,

storing the address of the recording area to be accessed on the read command and data attempted to be written in the recording area at the address in the memory, and

reading the data from the memory.

11. The access control method according to claim 7 , further comprising:

searching the memory on the read command with the time limit, and

accessing the recording medium when the address of the recording area to be accessed on the read command is not stored in the memory or the data attempted to be written in the recording area at the address are not stored in the memory.

12. The access control method according to claim 7 , further comprising:

accessing the recording medium repeatedly at the maximum number of predefined times when the access to the recording medium on the write command with time limit is failed in the command execution operation;

storing the data attempted to be written in the recording area at the address in the memory when the access has succeeded when retrying the access less than the predefined times; and

not storing the address and the data in the memory when the access has succeeded when retrying the access less than the threshold.