| 摘要 |
The present invention provides reliable systems and methods for rapidly determining whether file data streams (146) are the same, or different, without having to make a comparison between the actual data streams (146). If the determination is made that the data streams (146) are different, the present invention can rapidly determine where the changes between the data streams (146) occur, again, without having to actually compare the entire size of the data streams (146). Such methods and systems are accomplished by generating a native data signature (NDS) (148) for each data stream (146) stored by the file system, wherein each NDS (148) is substantially smaller in size as compared to the data stream (146) corresponding thereto. The NDS (148) is generated by separating the data stream (146) into a plurality of allocation units (162), ranging in size from 4K bytes to 256K bytes; by generating a unique change identifier (UCI), one per each allocation unit (162); and by assembling the UCIs into a series of bits, typically ranging up to, and including, 64 in number. Thus, even with a UCI having 64 bits, time efficiency for comparing data streams (146) by comparing between NDSs (148) is improved on the order of 500 : 1 or 32,000 : 1, depending upon the size of the allocation unit (162).
|
