LZX

Source: Wikipedia, the free encyclopedia.
This article is about the compression algorithm. For the programming language, see OpenLaszlo.

LZX is an

file archiver with the same name. Both were invented by Jonathan Forbes and Tomi Poutanen
in the 1990s.

Instances of use of the LZX algorithm

Amiga LZX

LZX was publicly released as an Amiga file archiver in 1995, while the authors were studying at the University of Waterloo in Canada. The software was shareware, which was common for compression software at the time. The registered version contained fixes and improvements that were not available in the evaluation version. In 1997, the authors gave away a free keyfile, which allowed anyone to use the registered version, as they had stopped work on the archiver and stopped accepting registrations.

Microsoft Cabinet files

In 1996, Forbes went to work for

80x86 "CALL" instructions, converting their operands
from relative addressing to absolute addressing, thus calls to the same location resulted in repeated strings that the compressor could match, improving compression of 80x86 binary code. (This technique is later generalized as Branch-Call-Jump [BCJ] filtering.)

Microsoft Compressed HTML Help (CHM) files

When Microsoft introduced

Microsoft Compressed HTML Help
, the replacement for their classic Help file format, they chose to compress all of the HTML data with the LZX algorithm. However, in order to improve random access speed, the compressor was altered to reset itself after every 64 kilobyte (65,536 bytes) interval and re-align to a 16-bit boundary after every 32 kilobyte interval. Thus, the HTMLHelp software could immediately seek the nearest 64 kilobyte interval and start decoding from there, rather than decoding from the beginning of the compressed datastream at all times.

Microsoft Reader (LIT) files

Microsoft LIT files for Microsoft Reader are simply an extension of the CHM file format, and thus also use LZX compression.

Windows Imaging Format (WIM) files

Windows Imaging Format, the installation/drive image file format of Windows Vista and Windows 7, uses LZX as one of the compression methods.[3]

CompactOS NTFS file compression

In Windows 10, LZX compression from Windows Imaging Format is used for the new CompactOS NTFS file compression.

Xbox Live Avatars

Microsoft uses LZX compression on

Xbox Live Avatars to reduce their disk and bandwidth requirements.[4]

Decompressing LZX files

The unlzx program and

CHM article. LIT files can be unpacked using the Convert LIT software.[6]

See also

References

  1. ^ [wimlib: the open source Windows Imaging (WIM) library - Compression algorithm https://wimlib.net/compression.html]
  2. ^ "Jonathan Forbes - LinkedIn". Archived from the original on 2010-03-23.
  3. ^ "APC Magazine » Build your own Vista install DVD". Archived from the original on 2006-08-19. Retrieved 2006-08-19.
  4. ^ "Xbox.com | Engineering Blog - Xbox Engineering Blog: Avatar Technology". Archived from the original on 2010-04-11.
  5. ^ "cabextract: Free Software for extracting Microsoft cabinet files". Retrieved 17 March 2020.
  6. ^ "Converting .LIT files for fun and profit". www.kyzer.me.uk.

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=LZX&oldid=1196143647"
This page is based on the copyrighted Wikipedia article: LZX. Articles is available under the CC BY-SA 3.0 license; additional terms may apply.Privacy Policy