Patent ID: 7644092

Claim:
A file management system for managing read and write of a file consisting of data and management information for the data when the file is stored cluster by cluster into a memory device, the system comprising: a driver that is in charge of performing the read and write of the file into and from the memory device and that uses a preferential input/output request queue to perform the write preferentially and a non-preferential input/output request queue not to perform the write preferentially; a free-cluster queue describing cluster information indicating a cluster of the memory device in which previously written data is stored and has not been overwritten yet and will be preferentially overwritten when a file write request is received; management-information deleting means for deleting, via the driver, the management information of data in accordance with a deletion request for a file stored in the memory device; queue selecting means for selecting either the non-preferential input/output request queue or the free-cluster queue to which the cluster information of the cluster in which the file whose management information has been deleted by the management-information deleting means should be set; queue setting means for setting the cluster information of the data to which the deletion request is given, to either the non-preferential input/output request queue or the free-cluster queue, depending on selected results of the queue selecting means; and queue managing means for providing the cluster information set in the free-cluster queue to the preferential input/output request queue of the driver, when a predetermined event occurs, wherein the queue managing means comprises: a first determining means for determining whether or not the predetermined event occurs; a second determining means for determining whether or not the cluster information is in the free-cluster queue, in cases where the first determining means determines that the predetermined event occurs; and preferential deletion commanding means for providing, in cases where the second determining means determines that the cluster information is in the free-cluster queue, the determined cluster information to the preferential input/output request queue of the driver.