Native data signatures in a file system
US5978814A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1998 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Jan 21, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99954
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides reliable systems and methods for rapidly determining whether file data streams are the same, or different, without having to make a comparison between the actual data streams. If the determination is made that the data streams are different, the present invention can rapidly determine where the changes between the data streams occur, again, without having to actually compare the entire size of the data streams. Such methods and systems are accomplished by generating a native data signature (NDS) for each data stream stored by the file system, wherein each NDS is substantially smaller in size as compared to the data stream corresponding thereto. The NDS is generated by separating the data stream into a plurality of allocation units, ranging in size from 4K bytes to 256K bytes; by generating a unique change identifier (UCI), one per each allocation unit; 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 by comparing between NDSs is improved on the order of 500:1 or 32,000:1, depending upon the size of the allocation unit…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.