Andrew Tridgell

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Andrew Tridgell
Tridgell in 2006
Born (1967-02-28) 28 February 1967 (age 57)
Sydney, Australia
Nationality (legal)Australian
Other namesTridge
Known forrsync, Samba, rzip, ccache, ArduPilot

Andrew "Tridge" Tridgell OAM (born 28 February 1967) is an Australian computer programmer. He is the author of and a contributor to the Samba file server, and co-inventor of the rsync algorithm.

He has analysed complex proprietary protocols and algorithms, to allow compatible free and open source software implementations.


Tridgell was a major developer of the Samba software, analyzing the Server Message Block protocol used for workgroup and network file sharing by Microsoft Windows products. He developed the talloc hierarchical memory allocator, originally as part of Samba.

For his PhD dissertation, he co-developed rsync, including the rsync algorithm, a highly efficient file transfer and synchronisation tool. He was also the original author of rzip, which uses a similar algorithm to rsync. He developed spamsum,[clarification needed] based on locality-sensitive hashing algorithms.[1]

He is the author of KnightCap, a reinforcement-learning based chess engine.

Tridgell was also a leader in hacking the TiVo to make it work in Australia, which uses the PAL video format.[2]

In April 2005, Tridgell tried to produce free software (now known as SourcePuller) that interoperated with the BitKeeper source code repository. This was cited as the reason that BitMover revoked a license allowing Linux developers free use of their BitKeeper product.[3] Linus Torvalds, the creator of the Linux kernel, and Tridgell were thus involved in a public debate about the events, in which Tridgell stated that, not having bought or owned BitKeeper – and thus having never agreed to its license – he could not violate it, and was analyzing the protocol ethically, as he had done with Samba. Tridgell's involvement in the project resulted in Torvalds accusing him of playing dirty tricks with BitKeeper.[4] Tridgell claimed his analysis started with simply telneting to a BitKeeper server and typing help.[5]

In 2011 Tridgell became involved with the software development of ArduPilot Mega,[6] an open source Arduino-based UAV controller board, working on an entry with CanberraUAV[7] for the UAV Challenge Outback Rescue.[8]

Academic achievements[edit]

Tridgell completed a PhD at the Computer Sciences Laboratory of the Australian National University. His original doctorate work was in the area of speech recognition but was never completed. His submitted dissertation 'Efficient Algorithms for Sorting and Synchronization' was based on his work on the rsync algorithm.[9]

Awards and honours[edit]


  1. ^ Jesse Kornblum (2006). "Identifying almost identical files using context triggered piecewise hashing" (PDF). DFRWS. Archived (PDF) from the original on 9 October 2022. Retrieved 23 February 2014.
  2. ^ Tridgell, Andrew. "TiVo Ethernet". Archived from the original on 14 January 2012. Retrieved 17 August 2012.
  3. ^ git []
  4. ^ Orlowski, Andrew (14 April 2005). "Torvalds knifes Tridgell: Kernel source row turns nasty". The Register.
  5. ^ "Groklaw – Tridge Speaks". Archived from the original on 27 May 2011. Retrieved 5 September 2007.
  6. ^ Andrew Tridgell's Page Archived 14 April 2012 at the Wayback Machine. DIY Drones. Retrieved on 19 September 2013.
  7. ^ "CanberraUAV – Open Source Civilian UAV Development". 3 December 2018. Retrieved 31 March 2024.
  8. ^ UAV Challenge – Outback Rescue 2013 – Home Archived 10 February 2012 at the Wayback Machine. Retrieved on 19 September 2013.
  9. ^ "Andrew Tridgell - The Mathematics Genealogy Project". Retrieved 11 December 2017.
  10. ^ The Bulletin Smart 100 Archived 18 March 2007 at the Wayback Machine
  11. ^ The Bulletin publishes for the last time Archived 9 May 2007 at the Wayback Machine
  12. ^ Google Open Source Blog: ... and the winners of the 2008 Google-O'Reilly Open Source Awards are
  13. ^ FOSS folk who make us proud, Sam Varghese, iTWire, 2007-12-25, accessed 27 September 2009
  14. ^ "ANU Graduation Ceremony 1 - from ANU Graduation Ceremony 2". Livestream. Retrieved 11 December 2018.
  15. ^ "ANU Honorary degree: Dr Andrew Tridgell". 13 December 2018.
  16. ^ "Australia Day 2020 Honours List".

External links[edit]