Download Bzip2 ((EXCLUSIVE))
Irma Wave
bzip2 is suitable for power users. The command line enabled file compression program has fifteen options. Initiating and running the program is a cakewalk. Every option is well explained. The program can be used in batch files. It cannot recover from syntax errors but it can force compression and even decompress damaged archives. There are specific options to overwrite files, to suppress errors and compel compression. The simple operation and quick decompression or extraction would suit many heavy users. As per the information published by the developer, the file compression program is capable of compressing files down to 15% or 10% of other available techniques and operates at twice the compression speed and six times the decompression speed than gzip. Although not an archiving tool, the program can extract undamaged files in disks or tapes that have errors.
The file compression program can be downloaded and installed for free. It is compatible with Windows 2000 and XP, subsequently all later versions. There are no specific requirements or additional specifications that must be satiated. The total size of the file to be downloaded is 76KB. You would use the bzip2-105-x86-win32.exe file to install. bzip2 is used by a few million people around the world. bzip2 file compression can convert almost everything that you may test it with. The simplicity and reliability of the program have earned it many laurels but there has been some criticism for its lack of archiving ability. The efficacy of the program to extract some damaged parts of files in otherwise inaccessible tapes or discs is worthwhile. This blog was created as an informational portal on bzip2. Scott Chow has a good guide on how to start a blog that is suitable for beginners if you are looking to start your own blog on file compression or any other topic.
There has been no major update to the file compression program in recent years. This is partly because such updates have been unnecessary. It can still work on all popular files and can compress or decompress with utmost ease. The space you can save with files compressed using bzip2 is sufficient when you factor in heavy documents or materials. There is no premium version of the file compression program so you can bid adieu to the recurrent messages prompting you to pay up and upgrade. There is no advanced or full version. You get everything there is in the free and open source version of bzip2. In fact, there is only one version you can download and use. It has been criticized by some for having only one algorithm powering the compression.
bzip2 became quite popular in the late nineties and the subsequent updates made it more widespread. The program is more effective than Deflate and LZW programs but is also slower. The LZW or .z and the Deflate algorithms such as .gz and .zip are less effective but they operate quickly. As a result they end up taking more space than what bzip2 can achieve. The bzip2 compression program facilitates considerably faster decompression compared to its pace of compression.
bzip2 is similar to gzip. Both are data compressors. bzip2 is not like zip or tar. Those have archiving ability. bzip2 is also only meant for single files. It cannot work on multiple files, archive splitting or encryption. It can work with external utilities like GnuPG and tar to facilitate such tasks. In a way, bzip2 stays true to its UNIX tradition.
The initial run length encoding has a sequence of four to two hundred and fifty five duplicate symbols. The consecutive sequence is then replaced by four symbols with a repeat length varying from zero to two hundred and fifty one. For instance, AAAAAAABBBBCCCD sequence gets replaced by AAAA\3BBBB\0CCCD. The 3 and 0 are byte values. The symbols are transformed only after the first four symbols so the run length is zero and the transformation is reversible. bzip2 can cause an expansion of a file in worst case scenarios but up to 1.25. In best case scenarios, the reduction is less than 0.02. This run length encoding has been criticized and even Julian Seward had admitted that it was a mistake and was only applicable to avert pathological instances.
The algorithm has gone through multiple maintainers since its initial release, with Micah Snyder being the maintainer since June 2021. There have been some modifications to the algorithm, such as pbzip2, which uses multi-threading to improve compression speed on multi-CPU and multi-core computers.
Seward made the first public release of bzip2, version 0.15, in July 1996. The compressor's stability and popularity grew over the next several years, and Seward released version 1.0 in late 2000.[not verified in body] Following a nine-year hiatus of updates for the project since 2010, on 4 June 2019 Federico Mena accepted maintainership of the bzip2 project.[4] Since June 2021, the maintainer is Micah Snyder.[5]
Because of the first-stage RLE compression (see above), the maximum length of plaintext that a single 900 kB bzip2 block can contain is around 46 MB (45,899,236 bytes). This can occur if the whole plaintext consists entirely of repeated values (the resulting .bz2 file in this case is 46 bytes long). An even smaller file of 40 bytes can be achieved by using an input containing entirely values of 251, an apparent compression ratio of 1147480.9:1.
The compressed blocks in bzip2 can be independently decompressed, without having to process earlier blocks. This means that bzip2 files can be decompressed in parallel, making it a good format for use in big data applications with cluster computing frameworks like Hadoop and Apache Spark.[8]
bzip2 compresses most files more effectively than the older LZW (.Z) and Deflate (.zip and .gz) compression algorithms, but is considerably slower. LZMA is generally more space-efficient than bzip2 at the expense of even slower compression speed, while having much faster decompression.[9]
bzip2 performance is asymmetric, as decompression is relatively fast. Motivated by the long time required for compression, a modified version was created in 2003 called pbzip2 that used multi-threading to encode the file in multiple chunks, giving almost linear speedup on multi-CPU and multi-core computers.[12] As of May 2010[update], this functionality has not been incorporated into the main project.
Like gzip, bzip2 is only a data compressor. It is not an archiver like tar or ZIP; the bzip2 file format does not support storing the contents of multiple files in a single compressed file, and the program itself has no facilities for multiple files, encryption or archive-splitting. In the UNIX tradition, archiving could be done by a separate program producing an archive which is then compressed with bzip2, and un-archiving could be done by bzip2 uncompressing the compressed archive file and a separate program decompressing it. Some archivers have built-in support for compression and decompression, so that it is not necessary to use the bzip2 program to compress or decompress the archive. GnuPG also has built-in support for bzip2 compression and decompression.
bzip2 is a freely available, patent free (see below),high-quality data compressor. It typically compresses files towithin 10% to 15% of the best available techniques (the PPMfamily of statistical compressors), whilst being around twice asfast at compression and six times faster at decompression.
The code is organised as a library with a programminginterface. The bzip2 program itself is a client of the library.You can use the library in your own programs, to directly readand write .bz2 files, or even just to compress data in memoryusing the bzip2 algorithms.
There are many compression algorithms around, and bzip2 is one of the slower ones. Plain gzip tends to be significantly faster, at usually not much worse compression. When speed is the most important, lzop is my favourite. Poor compression, but oh so fast.
If the 16 cores of your server are idle enough that all can be used for compression, pbzip2 will probably give you a very significant speed-up. But you need more speed still and you can tolerate 20% larger files, gzip is probably your best bet.
Update: Added lbzip2 (see gmathts comment) and zstd (Johnny's comment) to the table, and sorted it by compression speed. lbzip2 puts the bzip2 family back in the running by compressing three times as fast as pbzip2 with a great compression ratio! zstd also looks reasonable but is beat by brotli (q1) in both ratio and speed.
pbzip2 is a parallel implementation of the bzip2 block-sorting file compressor that uses pthreads and achieves near-linear speedup on SMP machines. The output of this version is fully compatible with bzip2 v1.0.2 or newer (ie: anything compressed with pbzip2 can be decompressed with bzip2).
Comparison: Brotli vs deflate vs zopfli vs lzma vs lzham vs bzip2
- If you're looking for compression speed, then what you're looking for is which lines are further right on this chart. (The entries to the top of this chart show tight compression ratio. Higher=tighter. However, if compression speed is your priority, then you'll want to pay more attention to what lines reach further right on the chart.)
On a more serious note, it's actually pretty good. I use it for everything now because it just works, and it lets you trade speed for ratio on a large scale (most often, speed matters more than size anyway since storage is cheap, but speed is a bottleneck).
At compression levels that achieve comparable overall compression as bzip2, it's significantly faster, and if you are willing to pay some extra in CPU time, you can almost achieve results similar to LZMA (although then it will be slower than bzip2). At sligthly worse compression ratios, it is much, much faster than bzip2 or any other mainstream alternative.
On macOS Big Sur, to get pyenv ( via homebrew ) to work I had to install zlib and bzip2 via homebrew and then add the exports in my /.zshrc ( or /.bashrc for bash I guess). The answer above by luislhl leads the way to my solution.
df19127ead