Method, apparatus and system for reverting FAT cluster number to file ID and offset of non-FAT flash file system

1. A method comprising:

reverting a file allocating table (FAT) cluster number to a file ID and file offset of a non-FAT flash memory file system.

2. The method of claim 1 , the reverting comprising:

tracing a cluster number in the FAT from a first cluster number to a second cluster number;

determining a file having an end cluster equal to the second cluster number;

tracing the FAT from a starting cluster number to the first cluster number; and

determining an offset from the first cluster number and the starting cluster number.

3. The method of claim 2 , further comprising:

returning an error if the first cluster number is behind a last cluster number in a file.

4. The method of claim 1 , the reverting comprising:

determining a file ID and file offset of a file in a flash memory by an external computer supporting a FAT without tracing the FAT.

5. The method of claim 1 , the reverting comprising:

storing a FAT image file in a flash file system;

updating the FAT in an external computer; and

resetting a first cluster number, a current cluster number and a following cluster number.

6. The method of claim 1 , the reverting comprising:

setting a flag on type field of a first file if a first character of the first file is set to a predetermined value;

creating a second file having a same attribution and cluster number as the first file;

moving the first file to a destination directory,

resetting the flag on the moved first file; and

deleting the first file if FAT entries are cleared to “0”.

7. A machine-readable storage medium containing instructions that, when executed, cause a machine to:

revert a file allocating table (FAT) cluster number to a file ID and file offset of a non-FAT flash memory file system.

8. The machine-readable storage medium of claim 7 , wherein the instructions causing the machine to revert further comprising instructions that cause the machine to:

trace a cluster number in the FAT from a first cluster number to a second cluster number;

determine a file having an end cluster equal to the second cluster number;

trace the FAT from a starting cluster number to the first cluster number; and

determine an offset from the first cluster number and the starting cluster number.

9. The machine-readable storage medium of claim 8 , further comprising instructions that cause the machine to:

return an error if the first cluster number is behind a last cluster number in a file.

10. The machine-readable storage medium of claim 7 , wherein the instructions causing the machine to revert further comprising instructions that cause the machine to:

determine a file ID and file offset of a file in a flash memory by an external computer supporting a FAT without tracing the FAT.

11. The machine-readable storage medium of claim 7 , wherein the instructions causing the machine to revert further comprising instructions that cause the machine to:

store a FAT image file in a flash file system;

update the FAT in an external computer; and

reset a first cluster number, a current cluster number and a following cluster number.

12. The machine-readable storage medium of claim 7 , wherein the instructions causing the machine to revert further comprising instructions that cause the machine to:

set a flag on type field of a first file if a first character of the first file is set to a predetermined value;

create a second file having a same attribution and cluster number as the first file;

move the first file to a destination directory,

reset the flag on the moved first file; and

delete the first file if FAT entries are cleared to “0”.