Andrew Tridgell

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Andrew Tridgell
Andrew Tridgell.jpg
Born (1967-02-28) 28 February 1967 (age 51)
Nationality Australian
Other names Tridge
Occupation Programmer
Known for rsync, Samba, rzip

Andrew "Tridge" Tridgell (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 also was 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 got involved with the software development of ArduPilot Mega,[6] an open source Arduino-based UAV controller board, working on an entry for the UAV Challenge Outback Rescue.[7]

Academic achievements[edit]

Attending Barker College Hornsby, NSW, Tridgell completed his Higher School Certificate in 1984. Tridgell completed a degree with majors in applied mathematics and physics at the University of Sydney in 1988, before moving to Canberra to complete an Honours degree at the Australian National University, in which he received first class honours in theoretical physics.

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.[8]


Tridgell started his career working for Efam Resources from 1987 to 1988, designing computer models of financial markets. His work led to a product named The Options Analyst, which he marketed and sold for five years.

From 1988 to 1989, Tridgell worked as a software developer for a company named Sonartech Pty Ltd (now Sonartech Atlas), which developed sonar technologies for Australian submarines. He worked on passive sonar technology.

Between 1989 and 1990, Tridgell was employed at the Research School of Biological Sciences in the Australian National University, making computer models of physical and biological events and environments such as bushfire spread and population dynamics.

From 1991 to 1999, Tridgell held various other positions at the Australian National University, such as UNIX administration, satellite control, and supercomputer research. During this period he was seconded to the Cooperative Research Centre for Advanced Computational Systems, where he headed the PIOuS (Parallel Input/Output System) project—later HiDIOS (High-performance Distributed Input/Output System)—for parallel file systems on the Fujitsu AP1000 and AP+ supercomputers. Tridgell also went on to lecture, first as an associate lecturer, and then as a casual lecturer, in the university's Computer Science division. He remains a Visiting Fellow of the University.

In mid-1999, Tridgell joined the LinuxCare company's office in Canberra as their first Australian employee. He helped to assemble 14 staff for a research and development team known as OzLabs. Linux and open-source companies were quite a new concept at this stage. Tridgell was made a research fellow of LinuxCare in 2000.

In March 2001, Tridgell joined VA Linux Systems. He worked in the network-attached storage division for VA Linux Systems, making enhancements to Samba and the Linux kernel to provide enhanced performance for their network-attached storage device range.

Tridgell continued his work with network-attached storage technologies when he joined Quantum Corporation as a Senior Engineer in the Storage Systems Group. His role once again involved developing functionality and efficiency modifications into Samba to enhance Quantum's GuardianOS-powered Snap Server network-attached storage device. One of the features that he added to Samba at this time was support for Microsoft's Active Directory technology, a new authentication system introduced with Microsoft's Windows 2000 Server product range.

In 2004, Tridgell was employed by IBM working remotely for the Almaden Research Center. In January 2005, he joined the OSDL on a one-year fellowship;[9] he then returned to IBM.[10] As of 2015 he no longer works for IBM.[11]

Since 2009, Tridgell has co-taught a course titled Free and Open Source Software Development at the Australian National University.[12]

Awards and honours[edit]


  1. ^ Jesse Kornblum (2006). "Identifying almost identical files using context triggered piecewise hashing" (PDF). DFRWS. Retrieved 23 February 2014. 
  2. ^
  3. ^ git []
  4. ^ Orlowski, Andrew (14 April 2005). "Torvalds knifes Tridgell: Kernel source row turns nasty". The Register. 
  5. ^ Groklaw – Tridge Speaks
  6. ^ Andrew Tridgell's Page. DIY Drones. Retrieved on 19 September 2013.
  7. ^ UAV Challenge – Outback Rescue 2013 – Home Archived 10 February 2012 at the Wayback Machine.. Retrieved on 19 September 2013.
  8. ^ "Andrew Tridgell - The Mathematics Genealogy Project". Retrieved 2017-12-11. 
  9. ^ News & Media | The Linux Foundation. Retrieved on 19 September 2013.
  10. ^ News & Media | The Linux Foundation. Retrieved on 19 September 2013.
  11. ^ As per the IBM Employee Directory, retrieved on 2 October 2015.
  12. ^ COMP8440 – ANU – College of Engineering and Computer Science. Retrieved on 19 September 2013.
  13. ^ The Bulletin Smart 100 Archived 18 March 2007 at the Wayback Machine.
  14. ^ The Bulletin publishes for the last time Archived 9 May 2007 at the Wayback Machine.
  15. ^ Google Open Source Blog: ... and the winners of the 2008 Google-O'Reilly Open Source Awards are
  16. ^ FOSS folk who make us proud, Sam Varghese, iTWire, 2007-12-25, accessed 27 September 2009

External links[edit]