Bsdiff

Revision as of 07:37, 29 September 2025

Bsdiff is an open-source utility for generating diffs of binary files which can be distributed as patches or updates without having to send the entire set of binary data each time the package is updated. While one might think the need for such things is reduced with the much-improved bandwidth of modern times, software has also increased in size (the "bloatware" phenomenon), so the need for tools like this continues. Supposedly bsdiff generates more compact diff files than the high-priced proprietary RTPatch system.

bsdiff uses a technique called delta encoding to encode the differences between two binary objects.

bzip2 is used for compression.

There have been some forks and variant versions of bsdiff, and slightly-divergent forms are used for some platforms and software systems; for instance, there is an adapted version used for Mozilla updates (which, in turn, get put into Mozilla Archive files).

Code and downloads

• BSDIFF page with link to download
• An 2012 fork of bsdiff
• Golang implementation of bsdiff based on Percival's original

Links and references

• bsdiff for Windows
• bsdiff Python extension
• BSDIFF format information
• Paper on algorithm used
• Doctoral thesis by author describing more sophisticated algorithm
• Blog discussion
• BSDIFF: Technological Solutions for Reversible Pre-conditioning of Complex Binary Objects
• Revisiting bsdiff as a tool for digital preservation