How Jacob Ziv’s Lempel‑Ziv Algorithms Revolutionized Data Compression

IEEE announced that Jacob Ziv, a 90‑year‑old Israeli scientist, received the 2021 IEEE Medal of Honor for his pioneering work on lossless data compression.

He co‑developed the universal Lempel‑Ziv (LZ) algorithms, LZ77 and LZ78, which introduced dictionary‑based compression and laid the foundation for formats such as GIF, PNG, ZIP, WinZip, and Gzip.

In the 1970s, as the Internet and personal computers spread, the need to store more data in limited memory and bandwidth drove the rise of compression technologies. Two main types exist: lossy, which discards perceptually irrelevant information, and lossless, which perfectly reconstructs the original data.

Lossless compression was described by IEEE as “magic” because it removes redundancy without distortion, similar to a magician’s trick.

The development of compression algorithms spans over a century, starting with Morse code in 1838, followed by Shannon‑Fano coding, Huffman coding, and finally the LZ family. LZ77 (1977) introduced a sliding‑window dictionary, while LZ78 (1978) built a static dictionary, influencing Unix compress, WinZip, and image formats.

The earliest data‑compression example is the 1838 Morse code.

Shannon and Fano created probability‑based coding.

Huffman devised an optimal binary tree coding in 1951.

Ziv and Lempel’s LZ77 and LZ78 algorithms achieved near‑entropy compression without prior knowledge of the source.

Ziv’s career began in Tiberias, Palestine (now Israel) in 1931, included service in the 1948 Arab‑Israeli war, studies at the Technion, a Ph.D. at MIT, work at Bell Labs, and later collaboration with Abraham Lempel at the Israel Institute of Technology.

Beyond compression, Ziv contributed to low‑complexity decoding of error‑correcting codes and received numerous honors, including the Israel Prize (1993), IEEE Richard Hamming Medal (1995), Claude Shannon Award (1997), and the 2021 IEEE Medal of Honor.

Other Chinese recipients of the IEEE Medal of Honor include Hu Zhengming (2020) and Zhang Zhongmou (2011), noted for their contributions to microelectronics and semiconductor technology.