Computing device with relatively limited storage space and operating/file system thereof
A computing device includes a storage device having a file and a file system for storing and retrieving the file on the storage device. The file includes a plurality of segments, where each of at least some of the segments is null data and each of at least some of the segments is substantive data. The file has space allocated therein for each null data segment but such allocated space is not actually filled with information, and the file has space allocated therein for each substantive data segment and such allocated space is actually filled with information. Each null data segment is not actually physically stored on the storage device and each substantive data segment is actually stored on the storage device.
1. A computing device including a storage device having contents of a file and a file system for storing and retrieving the contents of the file on the storage device, the file comprising a file header and a plurality of file segments, each of at least some of the file segments being null data and each of at least some of the file segments being substantive data, the file system constructing a segment allocation table, the segment allocation table referenced from the file header, the segment allocation table having an entry for each file segment, wherein the file system stores at least one substantive file segment, wherein the entry in the segment allocation table for the at least one substantive file segment comprises a reference to a location of the at least one substantive file segment, wherein the file system does not store each null file segment, wherein a null data segment of the file represents data removed from the file, wherein the entry in the segment allocation table for each null file segment does not contain a reference to any location, wherein the file system stores the segment allocation table as a plurality of non-contiguous segment allocation table fragments on the storage device, and wherein the file header comprises a plurality of references to locations of the non-contiguous segment allocation table fragments.
2. The computing device of claim 1 wherein the entries in the segment allocation table are ordered according to the order of the segments within the file.
3. The computing device of claim 1 wherein a null data segment of the file represents data not yet placed within the file.
4. A storage device on a computing device, the storage device having contents of a file, the file comprising a file header and a plurality of file segments, each of at least some of the file segments being null data and each of at least some of the file segments being substantive data, the file system constructing a segment allocation table, the segment allocation table referenced from the file header, the segment allocation table having an entry for each file segment, the file system constructing a segment allocation table, the segment allocation table referenced from the file header, the segment allocation table having an entry for each file segment, wherein the file system stores at least one substantive file segment, wherein the entry in the segment allocation table for the at least one substantive file segment comprises a reference to a location of the at least one substantive file segment, wherein the file system does not store each null file segment, wherein a null data segment of the file represents data removed from the file, wherein the entry in the segment allocation table for each null file segment does not contain a reference to any location, wherein the file system stores the segment allocation table as a plurality of non-contiguous segment allocation table fragments on the storage device, and wherein the file header comprises a plurality of references to locations of the non-contiguous segment allocation table fragments.
5. The storage device of claim 4 wherein the entries in the segment allocation table are ordered according to the order of the segments within the file.
6. The storage device of claim 4 wherein a null data segment of the file represents data not yet placed within the file.