Browse Definitions :
Definition

LZW compression

LZW compression is the compression of a file into a smaller file using a table-based lookup algorithm invented by Abraham Lempel, Jacob Ziv, and Terry Welch. Two commonly-used file formats in which LZV compression is used are the GIF image format served from Web sites and the TIFF image format. LZW compression is also suitable for compressing text files.

A particular LZW compression algorithm takes each input sequence of bits of a given length (for example, 12 bits) and creates an entry in a table (sometimes called a "dictionary" or "codebook") for that particular bit pattern, consisting of the pattern itself and a shorter code. As input is read, any pattern that has been read before results in the substitution of the shorter code, effectively compressing the total amount of input to something smaller. Unlike earlier approaches, known as LZ77 and LZ78, the LZW algorithm does include the look-up table of codes as part of the compressed file. The decoding program that uncompresses the file is able to build the table itself by using the algorithm as it processes the encoded input.

This was last updated in April 2005

Continue Reading About LZW compression

Join the conversation

1 comment

Send me notifications when other members comment.

Please create a username to comment.

It says "the LZW algorithm does include the look-up table of codes". Shouldn't it be "does not include"?
Cancel

-ADS BY GOOGLE

File Extensions and File Formats

SearchCompliance

  • Whistleblower Protection Act

    The Whistleblower Protection Act of 1989 is a law that protects federal government employees in the United States from ...

  • smart contract

    A smart contract, also known as a cryptocontract, is a computer program that directly controls the transfer of digital currencies...

  • risk map (risk heat map)

    A risk map, also known as a risk heat map, is a data visualization tool for communicating specific risks an organization faces. A...

SearchSecurity

  • access control

    Access control is a security technique that regulates who or what can view or use resources in a computing environment.

  • ethical hacker

    An ethical hacker, also referred to as a white hat hacker, is an information security expert who systematically attempts to ...

  • two-factor authentication (2FA)

    Two-factor authentication (2FA), sometimes referred to as two-step verification or dual factor authentication, is a security ...

SearchHealthIT

SearchDisasterRecovery

  • virtual disaster recovery

    Virtual disaster recovery is a type of DR that typically involves replication and allows a user to fail over to virtualized ...

  • tabletop exercise (TTX)

    A tabletop exercise (TTX) is a disaster preparedness activity that takes participants through the process of dealing with a ...

  • risk mitigation

    Risk mitigation is a strategy to prepare for and lessen the effects of threats faced by a data center.

SearchStorage

  • Flash Storage

    Flash storage is any type of drive, repository or system that uses flash memory to keep data for an extended period of time.

  • optical disc

    An optical disc is an electronic data storage medium that can be written to and read from using a low-powered laser beam.

  • RAID 0 (disk striping)

    RAID 0 (disk striping) is the process of dividing a body of data into blocks and spreading the data blocks across multiple ...

Close