Patent ID: 7401092

Claim:
A method for replacing a first sub-hierarchy of at least two sub-hierarchies of a hierarchical file system (HFS) with a second sub-hierarchy of the at least two sub-hierarchies, the HFS having a single parentless root directory and being accessible by at least one processor, wherein the HFS provides a mapping between a disk sector and user data, further wherein the HFS is a New Technology File System (NTFS) implementation, the HFS is provided with file records storing directory attribute data corresponding with the first and second sub-hierarchies, the method comprising the steps of: providing for the first sub-hierarchy to include a first root directory located in a first location of the HFS associated with the single parentless root directory of the HFS through at least one internal pointer, wherein the first sub-hierarchy includes a first plurality of files configured to branch from the first root directory and at least one special system file which is exclusive to the parentless root directory; providing for the second sub-hierarchy to include a second root directory located in a second location of the HFS, wherein the second sub-hierarchy includes a second plurality of files configured to branch from the second root directory and the second root directory is provided with at least one placeholder file which corresponds to each of special system files; providing the first and second root directories with at least one file entry, each of which are provided with corresponding owning directories, and respective owning directories are provided with corresponding back-pointers; and replacing the first sub-hierarchy with the second sub-hierarchy comprising the step of: associating the second root directory and the single parentless root directory of the HFS through the at least one internal pointer, wherein the associating step further comprises the steps of: configuring the first plurality of files to branch from the first root directory once the first root directory is accessed through the second location; exchanging owning directories corresponding to the file entries of the first root directory with owning directories corresponding to the file entries of the second root directory; exchanging owning directory back-pointers of the first root directory with corresponding owning directory back-pointers of the second root directory; exchanging at least one directory pointer corresponding to the at least one special system file with at least one directory pointer corresponding to the at least one placeholder file; and exchanging directory attribute data of file record associated with the first root directory with directory attribute data associated with the second root directory.