Andrew "Tridge" Tridgell (born 28 February 1967) is an Australian

computer programmer A computer programmer, sometimes referred to as a software developer, a software engineer, a programmer or a coder, is a person who creates computer programs — often for larger computer software. A programmer is someone who writes/creates ...

. He is the author of and a contributor to the

Samba Samba (), also known as samba urbano carioca (''urban Carioca samba'') or simply samba carioca (''Carioca samba''), is a Brazilian music genre that originated in the Afro-Brazilian communities of Rio de Janeiro in the early 20th century. Havin ...

file server In computing, a file server (or fileserver) is a computer attached to a network that provides a location for shared disk access, i.e. storage of computer files (such as text, image, sound, video) that can be accessed by the workstations that are ab ...

, and co-inventor of the

rsync rsync is a utility for efficiently transferring and synchronizing files between a computer and a storage drive and across networked computers by comparing the modification times and sizes of files. It is commonly found on Unix-like operat ...

algorithm. He has analysed complex

proprietary protocol In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual. Intellectual property rights and enforcement Ownership by a single organization gives the owner the ability to place restricti ...

s and algorithms, to allow compatible

free and open source software Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software where anyone is freely licensed to use, copy, study, and change the software in any way, and the source ...

implementations.

Projects

Tridgell was a major developer of the Samba software, analyzing the

Server Message Block Server Message Block (SMB) is a communication protocol originally developed in 1983 by Barry A. Feigenbaum at IBM and intended to provide shared access to files and printers across nodes on a network of systems running IBM's OS/2. It also provides ...

protocol used for workgroup and network file sharing by

Microsoft Windows Windows is a group of several proprietary graphical operating system families developed and marketed by Microsoft. Each family caters to a certain sector of the computing industry. For example, Windows NT for consumers, Windows Server for serv ...

products. He developed th

hierarchical memory allocator, originally as part of Samba. For his PhD dissertation, he co-developed

, including the rsync algorithm, a highly efficient

file transfer File transfer is the transmission of a computer file through a communication channel from one computer system to another. Typically, file transfer is mediated by a communications protocol. In the history of computing, numerous file transfer protocol ...

and

synchronisation Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchrono ...

tool. He was also the original author of rzip, which uses a similar algorithm to rsync. He developed spamsum, based on

locality-sensitive hashing In computer science, locality-sensitive hashing (LSH) is an algorithmic technique that hashes similar input items into the same "buckets" with high probability. (The number of buckets is much smaller than the universe of possible input items.) Since ...

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

chess engine In computer chess, a chess engine is a computer program that analyzes chess or chess variant positions, and generates a move or list of moves that it regards as strongest. A chess engine is usually a back end with a command-line interface wit ...

. Tridgell was also a leader in hacking the

TiVo TiVo ( ) is a digital video recorder (DVR) developed and marketed by Xperi (previously by TiVo Corporation and TiVo Inc.) and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose fea ...

to make it work in Australia, which uses the

PAL Phase Alternating Line (PAL) is a colour encoding system for analogue television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...

video format. In April 2005, Tridgell tried to produce free software (now known as

SourcePuller SourcePuller is an open-source client for accessing the BitKeeper version control system. It was originally developed by Andrew Tridgell, who reverse engineered the BitKeeper protocol. While not widely used itself, it is best known for triggering ...

) that interoperated with the

BitKeeper BitKeeper is a software tool for distributed revision control of computer source code. Originally developed as proprietary software by BitMover Inc., a privately held company based in Los Gatos, California, it was released as open-source software ...

source code repository. This was cited as the reason that BitMover revoked a license allowing

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

developers free use of their BitKeeper product.

Linus Torvalds Linus Benedict Torvalds ( , ; born 28 December 1969) is a Finnish software engineer who is the creator and, historically, the lead developer of the Linux kernel, used by Linux distributions and other operating systems such as Android. He also c ...

, 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. Tridgell claimed his analysis started with simply

telnet Telnet is an application protocol used on the Internet or local area network to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control i ...

ing to a BitKeeper server and typing help. In 2011 Tridgell got involved with the software development of ArduPilot Mega, an open source Arduino-based UAV controller board, working on an entry for the UAV Challenge Outback Rescue.

Academic achievements

Tridgell completed a PhD at the Computer Sciences Laboratory of the

Australian National University The Australian National University (ANU) is a public research university located in Canberra, the capital of Australia. Its main campus in Acton encompasses seven teaching and research colleges, in addition to several national academies and ...

. His original doctorate work was in the area of

speech recognition Speech recognition is an interdisciplinary subfield of computer science and computational linguistics that develops methodologies and technologies that enable the recognition and translation of spoken language into text by computers with the m ...

but was never completed. His submitted dissertation 'Efficient Algorithms for Sorting and Synchronization' was based on his work on the

algorithm.

Awards and honours

* In October 2003, The Bulletin magazine judged Tridgell to be Australia's smartest

Information and Communications Technology Information and communications technology (ICT) is an extensional term for information technology (IT) that stresses the role of unified communications and the integration of telecommunications (telephone lines and wireless signals) and computers, ...

person. * In July 2008, Tridgell was named "Best Interoperator" at the Google–O'Reilly Open Source Awards, for his work on

and

. *Tridgell (along with

Jeremy Allison Jeremy Allison is a computer programmer known for his contributions to the free software community, notably to Samba, a re-implementation of SMB/CIFS networking protocol, released under the GNU General Public License. Other contributions in ...

and Volker Lendecke) has been called a "

guru Guru ( sa, गुरु, IAST: ''guru;'' Pali'': garu'') is a Sanskrit term for a "mentor, guide, expert, or master" of certain knowledge or field. In pan-Indian traditions, a guru is more than a teacher: traditionally, the guru is a reverentia ...

in its traditional Indian meaning" by IT writer, Sam Varghese. * On 11 December 2018, Tridgell was awarded the degree of Doctor of Science (

Honoris Causa An honorary degree is an academic degree for which a university (or other degree-awarding institution) has waived all of the usual requirements. It is also known by the Latin phrases ''honoris causa'' ("for the sake of the honour") or ''ad hono ...

) by the Australian National University, for authoring Samba, co-inventing rsync; and contributions to free and open source software. * On 26 January 2020, Tridgell was awarded the Medal (OAM) of the

Order of Australia The Order of Australia is an honour that recognises Australian citizens and other persons for outstanding achievement and service. It was established on 14 February 1975 by Elizabeth II, Queen of Australia, on the advice of the Australian Gove ...

in the General Division for service to Information Technology. The biographical notes for the award noted his contributions to software development and education including his work on

ArduPilot ArduPilot is an open source, unmanned vehicle Autopilot Software Suite, capable of controlling autonomous: *Multirotor drones *Fixed-wing and VTOL aircraft *Helicopters *Ground rovers *Boats * Submarines *Antenna trackers ArduPilot was original ...

, MAVProxy as well as teaching at the

References

External links

Andrew Tridgell's websiteNewer Personal Website

Andrew Tridgell's "Junk Code" collection

Efficient Algorithms for Sorting and Synchronization (PhD thesis)
– (406kB PDF)
Active Directory in Samba 4 'an old story'

FOSS folk who make us proud

Patent Defence for Free Software
January 2010 presentation transcript {{DEFAULTSORT:Tridgell, Andrew Australian computer programmers Free software programmers IBM employees 1967 births Living people People from the Australian Capital Territory University of Sydney alumni Australian National University alumni Geeknet People educated at Barker College Recipients of the Medal of the Order of Australia