Eric S. Raymond

Eric Steven Raymond (born December 4, 1957) (often referred to by his initials, ESR) is the author of "The Cathedral and the Bazaar" and the present maintainer of the "Jargon File" (also known as "The New Hacker's Dictionary"). Though the Jargon File established his original reputation as a historian/anthropologist of the hacker culture, after 1997 he became a "leading figure" in the open source movement, and is today one of the most famous (and controversial) characters.

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  2004 at Linucon
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  2005 at FISL 6.0
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  2006
  looks like this one was taken with a little cameraphone
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  The Glider: A Universal Hacker Emblem by Eric S. Raymond