Editing LZMA (section)

{{Short description|Lossless data compression algorithm}}
{{For|the airport with the ICAO code "LZMA"|Martin Airport (Slovakia)}}

The '''Lempel–Ziv–Markov chain algorithm'''<ref>{{cite book |last1=Salomon |first1=David |title=Data Compression: The Complete Reference |date=March 20, 2007 |publisher=Springer London |isbn=9781846286032 |page=242}}</ref> ('''LZMA''') is an [[algorithm]] used to perform [[lossless data compression]]. It has been used in the [[7z]] format of the [[7-Zip]] archiver since 2001.<ref name="7z_format">{{cite web|author1=Igor Pavlov|title=7z Format|url=http://www.7-zip.org/7z.html|date=2001-12-05|archive-url=https://web.archive.org/web/20011205060104/http://www.7-zip.org/7z.html |archive-date=5 December 2001 }}</ref> This algorithm uses a [[Dictionary coder|dictionary compression]] scheme somewhat similar to the [[LZ77]] algorithm published by [[Abraham Lempel]] and [[Jacob Ziv]] in 1977 and features a high compression ratio (generally higher than [[bzip2]])<ref name=gzip_bzip_lzma_bench>{{cite web|author1=Lasse Collin|title=A Quick Benchmark: Gzip vs. Bzip2 vs. LZMA|url=http://tukaani.org/lzma/benchmarks.html|access-date=2015-10-21|date=2005-05-31}} - LZMA Unix Port was finally replaced by xz which features better and faster compression; from here we know even LZMA Unix Port was a lot better than gzip and bzip2.</ref><ref>{{cite web
 |url          = http://blog.i-no.de/archives/2008/05/08/index.html#e2008-05-08T16_35_13.txt
 |title        = Gzip, Bzip2 and Lzma compared
 |last         = Klausmann
 |first        = Tobias
 |date         = 2008-05-08
 |work         = Blog of an Alpha animal
 |access-date   = 2013-06-16
 |archive-url  = https://web.archive.org/web/20130106193958/http://blog.i-no.de/archives/2008/05/08/index.html#e2008-05-08T16_35_13.txt
 |archive-date = 2013-01-06
 |url-status     = dead
}}</ref> and a variable compression-dictionary size (up to 4&nbsp;[[Gigabyte|GB]]),<ref name="LZMA Format">{{cite web
| url=http://www.7-zip.org/7z.html
| title=7z Format
| year=2013
| author=Unknown
| access-date=2013-06-16}}</ref> while still maintaining decompression speed similar to other commonly used compression algorithms.<ref>
{{cite web 
| url=http://mattmahoney.net/dc/dce.html#Section_52 
|title=Data Compression Explained 
|last=Mahoney 
|first=Matt
|access-date=2013-11-13}}</ref>

'''LZMA2''' is a simple container format that can include both uncompressed data and LZMA data, possibly with multiple different LZMA encoding parameters.  LZMA2 supports arbitrarily scalable multithreaded compression and decompression and efficient compression of data which is partially incompressible.<ref name=xz-inadequate>{{cite web
 |url=http://lzip.nongnu.org/xz_inadequate.html
 |title=Xz format inadequate for long-term archiving
 |author=Antonio Diaz Diaz
 |access-date=2018-07-20}}</ref>