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The Lempel-Ziv-Markov chain-Algorithm (LZMA) is an algorithm for data compression in development since 1998[1] and used in the 7z format of the 7-Zip archiver. In Mathematics, Computing, Linguistics and related subjects an algorithm is a sequence of finite instructions often used for Calculation 7z is a compressed Archive file format that supports several different Data compression, Encryption and pre-processing filters 7-Zip is a Free software / Open source File archiver designed originally for Microsoft Windows. It uses a dictionary compression scheme somewhat similar to LZ77 and features a high compression ratio (generally higher than bzip2) and a variable compression-dictionary size (up to 4 GB). A dictionary coder, also sometimes known as a substitution coder, is a class of Lossless data compression algorithms which operate by searching for matches between LZ77 and LZ78 are the names for the two Lossless data compression Algorithms published in papers by Abraham Lempel and Jacob Ziv in bzip2 is a free and open source Lossless data compression Algorithm and program developed by Julian Seward. [2]

Contents

Overview

The LZMA uses an improved LZ77 compression algorithm, backed by a range encoder. LZ77 and LZ78 are the names for the two Lossless data compression Algorithms published in papers by Abraham Lempel and Jacob Ziv in Range encoding is a Data compression method defined by G N N Martin in his 1979 paper on "Range encoding an algorithm for removing redundancy from a digitized

Streams for data, repeated-sequence size and repeated-sequence location seem to be compressed separately.

7-Zip reference implementation

The reference implementation of LZMA is included as part of the 7z and 7-Zip suite of tools. 7z is a compressed Archive file format that supports several different Data compression, Encryption and pre-processing filters 7-Zip is a Free software / Open source File archiver designed originally for Microsoft Windows. Source code is distributed under the terms of the GNU LGPL license with a special exception for linked binaries. The GNU Lesser General Public License (formerly the GNU Library General Public License) or LGPL is a Free software license published by the Free Software The special exception allows redistribution of binaries linked to unmodified LZMA to be free of any LGPL requirements (e. g. , they do not need to allow reverse engineering or binary modifications. )

The reference open source LZMA compression library is written in C++ and has the following properties:

The 7-Zip implementation uses several variants of hash chains, binary trees and Patricia tries as the basis for its dictionary search algorithm. In Computer security, a hash chain is a method to produce many one-time keys from a single key or Password. In Computer science, a binary tree is a tree data structure in which each node has at most two children. A radix tree, Patricia trie / tree, or crit bit tree is a specialized Set data structure based on the Trie that is used to store a set

Decompression-only code for LZMA generally compiles to around 5kB and the amount of RAM required during decompression is principally determined by the size of the sliding window used during compression. Sliding Window Protocol is a bi-directional Data transmission Protocol in the Data link layer ( OSI model) Small code size and relatively low memory overhead, particularly with smaller dictionary lengths, make the LZMA decompression algorithm well-suited to embedded applications. An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints

Algorithm

The documentation in the SDK is very limited, providing no design information.

For that, rely on third-party discussion, e. g. , its user forum. [3] Digesting that (or some other source), Paul Sladen summarizes the algorithm:[4]

LZMA is effectively deflate (zlib, gzip, zip) with a larger dictionary size, 32MB instead of 32kB. LZMA stands for Lempel-Ziv-Markov chain-Algorithm, after string back-references have been located, values are reduced using a Markov chain range-encoder (aka arithmetic coding) instead of huffman. Lempel-Ziv-Welch ( LZW) is a universal Lossless data compression Algorithm created by Abraham Lempel, Jacob Ziv, and Terry In Mathematics, a Markov chain, named after Andrey Markov, is a Stochastic process with the Markov property. Range encoding is a Data compression method defined by G N N Martin in his 1979 paper on "Range encoding an algorithm for removing redundancy from a digitized Arithmetic coding is a method for Lossless data compression. Normally a string of characters such as the words "hello there" is represented using a fixed number of History In 1951 David A Huffman and his MIT information theory classmates were given

Users

Software that uses or supports LZMA:

Notes

  1. ^ The SDK history file states that it was in development from 1996, and first used in 7-zip 2001-08-30. 7-Zip is a Free software / Open source File archiver designed originally for Microsoft Windows. Aside from some unreferenced comments about 1998, the algorithm appears to have been unpublished before its use in 7-zip. 7-Zip is a Free software / Open source File archiver designed originally for Microsoft Windows.
  2. ^ Overview of the LZMA format 7z Format
  3. ^ RE: LZMA Algorithm. SF. net » Projects » 7-Zip » Forum. Retrieved on 2007-10-06. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 105 BC - Battle of Arausio: The Cimbri inflict the heaviest defeat on the Roman army of Gnaeus Mallius Maximus
  4. ^ Paul Sladen. Comment on 7-zip, LZMA and blah. Retrieved on 2007-10-06. Year 2007 ( MMVII) was a Common year starting on Monday of the Gregorian calendar in the 21st century. Events 105 BC - Battle of Arausio: The Cimbri inflict the heaviest defeat on the Roman army of Gnaeus Mallius Maximus

External links

gzip is a Software application used for File compression. gzip is short for GNU zip; the program is a Free software replacement for the bzip2 is a free and open source Lossless data compression Algorithm and program developed by Julian Seward.
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