US 6,934,700 B1 · File systems supported data sharing

Abstract

A storage file system is provided for data stored on a storage medium, and particularly for storage of data on optical disc storage medium. Each successive or alternate file of data included in the storage medium is represented by a respective allocation extent list with each allocation extent identifying locations of data segments for each file. Data in some data segments or portions of data segments may be shared by two or more files with each file having a respective allocation extent list entry referencing that segment and each such allocation extent maintaining byte-accurate pointers to the start and end of the data relevant to each file within the data segment. An allocation space table containing respective entries for each reference to a data segment or portion of a data segment, and optionally a free-space table identifying those data segments or portions of data segments available for rewriting, may be provided to allow for rapid reclamation of free within the storage medium.

Claims27

Dependent claims

A storage device comprising:

a first area subdivided into segments for the recording of sequential data, portions of which when read in a predetermined sequence comprise a data file;
a second area containing a list of allocation extents, each of which identifies the start and end of a contiguous portion of the first area, and a pointer file containing a list of pointers to respective entries in the list of allocation extents;
and
wherein the device carries at least two files defined in respective pointer files having a portion of a segment less than an entire segment that is common to the two files, with each of the at least two files having a respective allocation extent for that segment and each allocation extent indicating the start and end points within the portion of the segment used in that respective file.

1 more element

A data processing apparatus operable to manipulate data on a storage medium comprising:

a data processor coupled with storage medium read/write means, the data processor configured to receive and access said storage medium, the storage medium having:
a first area subdivided into segments for the recording of sequential data, portions of which when read in a predetermined sequence comprise a data file;
a second area containing a list of allocation extents, each of which identifies the start and end of a contiguous portion of the first area and a pointer file containing a list of pointers to respective entries in the list of allocation extents;
and
wherein the device carries at least two files defined in respective pointer files and a portion of a segment less than a full segment is common to the two files, with each file having a respective allocation extent for that segment and each allocation extent indicating the start and end points within the segment for that part of the segment;
and
the data processor adapted to receive data identifying those segments or parts of segments comprising a file, the processor generating and storing a pointer together with a list of allocation extents for the segment data, the allocation extents including an indication of physical locations of start and end points for each segment used in the file.

4 more elements

Dependencies are inferred from the claim text.

File systems supported data sharing

Life of this patent

File systems supported data sharing

Life of this patent

Abstract

Claims27