Patent ID: 7676504

Claim:
An information processing device for processing content and a related information file relating to the content, the device comprising: a memory for storing the related information file, the related information file comprising: file format identifying information identifying the a file format of the related information file; file version information indicating a version of the related information file, the file version information comprising a first piece of the file version information and a second piece of the file version information, wherein the second piece of the file version information indicates a change to the file format that is smaller than the change indicated by the first piece of the file version information; one or more information blocks; number of information blocks information indicating the a number of the information blocks; block identifying information identifying the information blocks; and block position information indicating the position of the information blocks, the information blocks comprising block identifying information for identifying the block itself; and a processor for: determining agreement or disagreement of the file version information and a file version determining information at the time of writing to the related information file, wherein the file version determining information is predefined in the information processing device at the time of reading the related information file, wherein the file version determining information comprises a first piece of the file version determining information and a second piece of the file version determining information, and wherein determining agreement or disagreement of the file version information and the file version determining information comprises determining agreement or disagreement of the first piece of the file version information and the first piece of the file version determining information, and controlling reading of the related information file according to the block identifying information or the block position information upon determining agreement of the file version information and the file version determining information, wherein the processor determines agreement or disagreement of the file version information and the file version determining information only upon determining agreement of the file format identifying information and a file format identifying determining information, wherein the processor controls writing to the related information file according to the block identifying information or the block position information upon determining agreement of the file version information and the file version determining information, and wherein the processor adds the information block and block position information indicating the position of the information block to the related information file and updates the related information file by updating the file version information when it is determined that the file version information and the file version determining information do not agree with each other.