- published: 30 Jan 2015
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Deflate is a lossless data compression algorithm that uses a combination of the LZ77 algorithm and Huffman coding. It was originally defined by Phil Katz for version 2 of his PKZIP archiving tool and was later specified in RFC 1951.
The original algorithm as designed by Katz was patented as US patent 5051745 and assigned to PKWARE. Deflate is widely thought to be free of any subsisting patents and was so at a time before the patent on LZW (which is used in the GIF file format) expired.[citation needed] This has led to its use in gzip compressed files and PNG image files in addition to the ZIP file format for which Katz originally designed it.
A Deflate stream consists of a series of blocks. Each block is preceded by a 3-bit header:
Most blocks will end up being encoded using method 10
, the dynamic Huffman encoding, which produces an optimised Huffman tree customised for each block of data individually. Instructions to generate the necessary Huffman tree immediately follow the block header.
William Sanford "Bill" Nye (born November 27, 1955), popularly known as Bill Nye the Science Guy, is an American science educator, comedian, television host, actor, mechanical engineer, and scientist. He is best known as the host of the Disney/PBS children's science show Bill Nye the Science Guy (1993–1998) and for his many subsequent appearances in popular media as a science educator.
William Sanford Nye was born in Washington, D.C., the son of Jacqueline (née Jenkins; c. 1920–2000), a codebreaker during World War II, and Edwin Darby "Ned" Nye (died 1997), also a World War II veteran whose experience in a Japanese prisoner of war camp led him to become a sundial enthusiast. Nye is a fourth-generation Washington, D.C. resident on his father's side of the family. After attending Lafayette Elementary and Alice Deal Junior High in the city, he was accepted to the private Sidwell Friends School on a partial scholarship, graduating in 1973. He studied mechanical engineering at Cornell University, where one of his professors was Carl Sagan, and graduated with a Bachelor of Science in 1977. He was awarded an honorary doctorate by The Johns Hopkins University in May 2008. In May 2011, Nye was awarded an Honorary Doctor of Science degree from Willamette University where he was the keynote speaker for that year's commencement exercises.
William Stephen "Bill" Belichick (pronounced /ˈbɛlɨtʃɪk/; born April 16, 1952) is an American football head coach for the New England Patriots of the National Football League. Coaching continuously in various roles in the NFL since 1975, Belichick earned his first head coaching job with the Cleveland Browns in 1991. Following his firing in 1995, he did not serve as a head coach again until 2000 with the Patriots. Since then, Belichick has coached the Patriots to five Super Bowl appearances: victories in Super Bowls XXXVI, XXXVIII, and XXXIX, and subsequent losses in Super Bowl XLII and Super Bowl XLVI. He was named the AP NFL Coach of the Year for the 2003, 2007 and 2010 seasons. He is the NFL's second-longest tenured active head coach, behind Andy Reid.
Bill Belichick was born in Nashville, Tennessee, and raised in Annapolis, Maryland, where his father Steve Belichick was an assistant football coach at the United States Naval Academy. He graduated from Annapolis High School in 1970. While there, he played American football and lacrosse, with the latter being his favorite sport. He enrolled at Phillips Academy in Andover, Massachusetts for a postgraduate year, with the intention of improving his grades and test scores in order to be admitted into a quality college. The school would honor him forty years later by inducting him into its Athletics Hall of Honor in 2011.