Versions tested: 0.7
Optimal parameters: -p=2
Authors: Osman Turan
Algorithms: CM
Notable peformances: -


BIT is a command-line experimental file archiver which [has] limited capabilities for now and lacks of some essential features such as multi-volumes, solid archiving etc. In future BIT releases, there will be several codecs for trade-offs between speed vs strength. For now only LWCX (Light-Weight Context Mixing) codec is available.

LWCX stands for Light-Weight Context Mixing and it's basically a bit-wise context mixing scheme for lossless data compression. It differs from well-known compression techniques such as LZ77 which is implemented as a default algorithm in WinZip, WinRAR, 7-Zip and many other popular archivers. Rather than to find repeatation patterns in byte-wise and coding some pointers for them, LWCX collects bit-wise statistics under some context and predicts next bit by mixing collected statistics. But, top ranking context mixing compressors are generally very slow (i.e. PAQ series). So, LWCX's goal is reaching acceptable speed at extreme compression ratios. Note that, latest release of LWCX is able to outperform most of compressors with a acceptable speed already.


LWCX is a bit-wise context mixing compressor which tries to mix order 0-4, 6. Also, a match model is used for longer contexts. A neural network performs mixing after context mapping and before a 2D SSE stage. Currently, there is no any filters or preprocessing stage. I'm trying to achive acceptable speed with a good compression ratio.

the program website and documentation


(Have info that should be added here? E-mail.)

Disqualified (why) configurations (with qualification ratings)
Ver Rating CPR DPR S.E. R.E. Ratio C. kB/s D. kB/s
0.7 423 399 447 146 119 3.443 886 884
0.7 430 405 454 146 125 3.455 874 872
0.7 422 397 446 141 124 3.460 845 843
0.7 399 376 422 133 119 3.463 793 793

Version info

0.7, tar: yes, mode: 32-bit, crc32: 4bab7c5b, decoder: 51 kB, tested: 2010 Apr 19
compression: bit.exe a <args> <cfile> <src>
decompression: bit.exe e <cfile>
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