Patent ID: 7571176

Claim:
A computer-implemented method for rendering a first subset of a plurality of file data inaccessible, wherein the plurality of file data are stored on a storage medium according to a file system, and at least some of the plurality of file data is arranged in a non-contiguous manner on the storage medium, wherein a first set of metadata describing the plurality of file data are also stored on the storage medium, wherein at least a second subset of the plurality of file data, stored on the storage medium are unavailable for use unless and until an erasing operation is performed on the first subset of the plurality of file data, and wherein the first set of metadata include a first set of directory information that identifies locations on the storage medium at which the plurality of file data are stored, the method comprising: receiving an erase command that identifies the first subset of the plurality of file data comprising a first plurality of individually-identified files in the plurality of file data, all of which are to be erased as a result of the erase command, wherein the plurality of file data not identified as being in the first subset of the plurality of file data includes the second subset of the plurality of file data; creating a second set of directory information in a second set of metadata by copying directory entries corresponding to the second subset of the plurality of file data from the first set of metadata into the second set of metadata such that the second set of directory information identifies locations on the storage medium at which the second subset of the plurality of file data is stored; and erasing at least a first portion of the first set of directory information that corresponds to the first plurality of individually-identified files such that, after the erasing, at least a first portion of the first subset of the plurality of file data cannot be located on the storage medium by reading either the first set of directory information or the second set of directory information, and wherein a substantial portion of the first plurality of individually-identified files remains intact on the storage medium.