Lempel-Ziv-Welch

Lempel-Ziv-Welch, or LZW, is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv and Terry Welch, with Welch publishing the algorithm in 1984 as an improvement on the 1978 LZ78 algorithm by Lempel and Ziv. It became the first widely used universal data compression method on computers and rose to particular prominence when it was built into the GIF image format in 1987; it remains available as an option in the TIFF and PDF file formats. On typical English text LZW can compress a file to roughly half its original size, though algorithms such as DEFLATE have since overtaken it in most applications by offering better compression ratios.