Binary delta compression

Binary delta conversion or BDC is a technology used in software update deployment.

Explanation

Downloading large amounts of data over the internet for software updates can induce high network traffic problems, especially when a network of computers is involved. Binary Delta Compression technology allows a major reduction of download size by only transferring the difference between the old and the new files during the update process.

Implementation

In real world implementations, it is common to also use standard compression techniques (such as Lempel-Ziv) while compressing. This makes sense because LZW already works by referring back to re-used strings. ZDelta is a good example of this, as it is built from ZLib. The algorithm works by referring to common patterns not only in the file you are compressing - a target file, but also in a source file. The benefits of this are that even if there are few similarilties between the original and the new file, you will still get good standard LZW compression.

See also

Delta encoding

External links

• White paper for Microsoft's implementation of BDC technology