Binary delta compression
Encyclopedia
Binary delta compression (BDC) is a technology used in software deployment
for distributing patches.
) 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 to be compressed, 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, a good compression ratio
is attained.
Software deployment
Software deployment is all of the activities that make a software system available for use.The general deployment process consists of several interrelated activities with possible transitions between them. These activities can occur at the producer site or at the consumer site or both...
for distributing patches.
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-ZivLZW
Lempel–Ziv–Welch is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempel and Ziv in 1978...
) 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
Zlib
zlib is a software library used for data compression. zlib was written by Jean-Loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. Zlib is also a crucial component of many software platforms including Linux, Mac OS X,...
. The algorithm works by referring to common patterns not only in the file to be compressed, 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, a good compression ratio
Compression ratio
The 'compression ratio' of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity...
is attained.