internet.com
You are in the: Small Business Computing Channelarrow View Sites +
Small Business Technology
» ECommerce-Guide | Small Business Computing | Webopedia | WinPlanet |  »Close
Webopedia.com
Enter a word for a definition... ...or choose a computer category.
 
 

menu
   Home
   Term of the Day
   New Terms
   Pronunciation
   New Links
   Quick Reference
   Did You Know?
   Categories
   Tech Support
   Webopedia Jobs
   About Us
   Link to Us
   Advertising
  

talk to us
   Submit a URL
   Suggest a Term
   Report an Error

internet.com
Developer
International
Internet Lists
Internet News
Internet Resources
IT
Linux/Open Source
Personal Technology
Small Business
Windows Technology
xSP Resources
Search internet.com
Advertise
Corporate Info
Newsletters
Tech Jobs
E-mail Offers
commerce
  Be a Commerce Partner
 
 
 
 
 
 
 
 
 
 
 
 
 
 

LZW
Last modified: Friday, February 11, 2000 

Short for Lempel-Zif-Welch, a popular data compression technique developed in 1977 by J. Ziv and A Lempel, and later refined by Terry Welch. It is the compression algorithm used in the GIF graphics file format, which is one of the standard graphic formats used by CompuServe and the World Wide Web.

The patent for LZW is owned by Unisys, which for many years allowed anyone to use the algorithm for free. Then in 1995, Unisys suddenly decided to charge a license fee. There was an uproar from the Compuserve and Web communities, and Unisys backed down somewhat, though they still enforce the licensing requirement for commercial applications.

E-mail this definition to a colleague


For internet.com pages about LZW . Also check out the following links!

Related Links

The GIF Controversy: A Software Developer's Perspective 
Article on the GIF controversy seen from a software developer's perspective. Includes a collection of information from the history of the controversy to the most recent events.

League for programming freedom
Provides news, position statements and legal resouces covering software patent issues and user interface copyrights. Includes information on the LZW patent.

LZW Patent FAQs
Answers various questions about the LZW patent, including the GIF specification.

The LZW Algorithm
Detailed description of encoding and decoding algorithms as well as practical characteristics.

Unisys LZW page
Provides license information on GIF and other LZW-based technologies

related categories

Data Compression

related terms

data compression

GIF

PNG

ZIP


webopedia
Give Us Your
Feedback




JupiterWeb networks:

internet.comearthweb.comDevx.com graphics.com

Search JupiterWeb:

Jupitermedia Corporation has two divisions:
Jupiterimages andJupiterWeb


Legal Notices, Licensing, Reprints, & Permissions, Privacy Policy.

Jupitermedia Corporate Info | Newsletters | Tech Jobs | Shopping | E-mail Offers