Andrew Tridgell
Encyclopedia
Andrew "Tridge" Tridgell (born 28 February 1967) is an Australia
n computer programmer best known as the author of and contributor to the Samba
file server
, and co-inventor of the rsync
algorithm.
He is known for his analysis of complex proprietary protocol
s and algorithms
, to allow compatible free and open source software
implementations.
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 thesis, he co-developed rsync
, including the rsync algorithm, a highly efficient file transfer and synchronization
tool. He also was the original author of rzip
, which uses a similar algorithm to rsync.
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.
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. 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, having not bought or owned BitKeeper and agreed to its license, he couldn't violate it, and was merely analysing the protocol ethically, as he had done with Samba. Tridgell's involvement in the project resulted in Linus accusing him of playing dirty tricks with BitKeeper.
Tridgell claimed his analysis started with simply telnet
ing to a BitKeeper server and typing
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 thesis 'Efficient Algorithms for Sorting and Synchronization' was based on his work on the rsync
algorithm.
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 submarine
s. 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; he then returned to IBM.
In 2009 and 2010, Andrew Tridgell (with Bob Edwards) taught a course titled COMP8440 Free and Open Source Software Development at the Australian National University
.
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n computer programmer best known as the author of and contributor to the Samba
Samba (software)
Samba is a free software re-implementation, originally developed by Andrew Tridgell, of the SMB/CIFS networking protocol. As of version 3, Samba provides file and print services for various Microsoft Windows clients and can integrate with a Windows Server domain, either as a Primary Domain...
file server
File server
In computing, a file server is a computer attached to a network that has the primary purpose of providing a location for shared disk access, i.e. shared storage of computer files that can be accessed by the workstations that are attached to the computer network...
, and co-inventor of the rsync
Rsync
rsync is a software application and network protocol for Unix-like and Windows systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found in most similar...
algorithm.
He is known for his analysis of complex proprietary protocol
Proprietary protocol
In telecommunications, a proprietary protocol is a communications protocol owned by a single organization or individual.-Enforcement:Proprietors may enforce restrictions through patents and by keeping the protocol specification a trade secret...
s and algorithms
Proprietary software
Proprietary software is computer software licensed under exclusive legal right of the copyright holder. The licensee is given the right to use the software under certain conditions, while restricted from other uses, such as modification, further distribution, or reverse engineering.Complementary...
, to allow compatible free and open source software
Free and open source software
Free and open-source software or free/libre/open-source software is software that is liberally licensed to grant users the right to use, study, change, and improve its design through the availability of its source code...
implementations.
Projects
Tridgell was a major developer of the Samba software, analysing the Server Message BlockServer Message Block
In computer networking, Server Message Block , also known as Common Internet File System operates as an application-layer network protocol mainly used to provide shared access to files, printers, serial ports, and miscellaneous communications between nodes on a network. It also provides an...
protocol used for workgroup
Workgroup
A Workgroup may refer to* a peer-to-peer computer network. See Workgroup * a group of people working together toward a common goal, also known as a working group...
and network file sharing by Microsoft Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
products. He developed the talloc hierarchical memory allocator, originally as part of Samba.
For his PhD thesis, he co-developed rsync
Rsync
rsync is a software application and network protocol for Unix-like and Windows systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found in most similar...
, including the rsync algorithm, a highly efficient file transfer and synchronization
File synchronization
File synchronization in computing is the process of ensuring that computer files in two or more locations are updated via certain rules....
tool. He also was the original author of rzip
Rzip
The rzip program is huge-scale data compression software designed around initial LZ77-style string matching on a 900 MB dictionary window, followed by bzip2-based Burrows–Wheeler transform and entropy coding on 900 kB output chunks....
, which uses a similar algorithm to rsync.
He is the author of KnightCap, a reinforcement-learning
Reinforcement learning
Inspired by behaviorist psychology, reinforcement learning is an area of machine learning in computer science, concerned with how an agent ought to take actions in an environment so as to maximize some notion of cumulative reward...
based chess engine.
Tridgell was also a leader in hacking the TiVo
TiVo
TiVo is a digital video recorder developed and marketed by TiVo, Inc. and introduced in 1999. TiVo provides an on-screen guide of scheduled broadcast programming television programs, whose features include "Season Pass" schedules which record every new episode of a series, and "WishList"...
to make it work in Australia, which uses the PAL
PAL
PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...
video format.
In April 2005, Tridgell tried to produce free software (now known as SourcePuller) that interoperated with the BitKeeper
BitKeeper
BitKeeper is a software tool for distributed revision control of computer source code. A distributed system, BitKeeper competes largely against other systems such as Git and Mercurial...
source code repository. This was cited as the reason that BitMover revoked a license allowing Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
developers free use of their BitKeeper product. Linus Torvalds
Linus Torvalds
Linus Benedict Torvalds is a Finnish software engineer and hacker, best known for having initiated the development of the open source Linux kernel. He later became the chief architect of the Linux kernel, and now acts as the project's coordinator...
, the creator of the Linux kernel, and Tridgell were thus involved in a public debate about the events, in which Tridgell stated that, having not bought or owned BitKeeper and agreed to its license, he couldn't violate it, and was merely analysing the protocol ethically, as he had done with Samba. Tridgell's involvement in the project resulted in Linus accusing him of playing dirty tricks with BitKeeper.
Tridgell claimed his analysis started with simply telnet
TELNET
Telnet is a network protocol used on the Internet or local area networks to provide a bidirectional interactive text-oriented communications facility using a virtual terminal connection...
ing to a BitKeeper server and typing
HELP.Academic achievements
Attending Barker CollegeBarker College
Barker College is an independent Anglican, day and boarding school, located in Hornsby, a North Shore suburb of Sydney, New South Wales, Australia. Founded in 1890 by the Reverend Henry Plume at Kurrajong Heights, Barker is an all-boys school from Kindergarten to Year 9, and co-educational from...
Hornsby, NSW, Tridgell completed his Higher School Certificate in 1984. Tridgell completed a degree
Bachelor's degree
A bachelor's degree is usually an academic degree awarded for an undergraduate course or major that generally lasts for three or four years, but can range anywhere from two to six years depending on the region of the world...
with majors in applied mathematics
Applied mathematics
Applied mathematics is a branch of mathematics that concerns itself with mathematical methods that are typically used in science, engineering, business, and industry. Thus, "applied mathematics" is a mathematical science with specialized knowledge...
and physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
at the University of Sydney
University of Sydney
The University of Sydney is a public university located in Sydney, New South Wales. The main campus spreads across the suburbs of Camperdown and Darlington on the southwestern outskirts of the Sydney CBD. Founded in 1850, it is the oldest university in Australia and Oceania...
in 1988, before moving to Canberra
Canberra
Canberra is the capital city of Australia. With a population of over 345,000, it is Australia's largest inland city and the eighth-largest city overall. The city is located at the northern end of the Australian Capital Territory , south-west of Sydney, and north-east of Melbourne...
to complete an Honours degree at the Australian National University
Australian National University
The Australian National University is a teaching and research university located in the Australian capital, Canberra.As of 2009, the ANU employs 3,945 administrative staff who teach approximately 10,000 undergraduates, and 7,500 postgraduate students...
, in which he received first class honours in theoretical physics
Theoretical physics
Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...
.
Tridgell completed a PhD
PHD
PHD may refer to:*Ph.D., a doctorate of philosophy*Ph.D. , a 1980s British group*PHD finger, a protein sequence*PHD Mountain Software, an outdoor clothing and equipment company*PhD Docbook renderer, an XML renderer...
at the Computer Sciences Laboratory of the Australian National University
Australian National University
The Australian National University is a teaching and research university located in the Australian capital, Canberra.As of 2009, the ANU employs 3,945 administrative staff who teach approximately 10,000 undergraduates, and 7,500 postgraduate students...
. His original doctorate work was in the area of speech recognition
Speech recognition
Speech recognition converts spoken words to text. The term "voice recognition" is sometimes used to refer to recognition systems that must be trained to a particular speaker—as is the case for most desktop recognition software...
but was never completed. His submitted thesis 'Efficient Algorithms for Sorting and Synchronization' was based on his work on the rsync
Rsync
rsync is a software application and network protocol for Unix-like and Windows systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found in most similar...
algorithm.
Employment
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
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
technologies for Australian submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s. 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
Population dynamics
Population dynamics is the branch of life sciences that studies short-term and long-term changes in the size and age composition of populations, and the biological and environmental processes influencing those changes...
.
From 1991 to 1999, Tridgell held various other positions at the Australian National University, such as UNIX
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
administration, satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
control, and supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
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
Levanta
Levanta was a company based in San Mateo, California, United States, that created products for Linux management and data virtualization.-Company history:...
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
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
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
Linux kernel
The Linux kernel is an operating system kernel used by the Linux family of Unix-like operating systems. It is one of the most prominent examples of free and open source software....
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
Snap Server
The Snap Server is a network attached storage computer appliance currently sold by Overland Storage.All modern Snap Servers include an embedded operating system called GuardianOS. The GuardianOS is a UNIX-like operating system based on the mainstream Linux kernel, and is used on the Snap Server...
network-attached storage device. One of the features that he added to Samba at this time was support for Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
's Active Directory
Active Directory
Active Directory is a directory service created by Microsoft for Windows domain networks. It is included in most Windows Server operating systems. Server computers on which Active Directory is running are called domain controllers....
technology, a new authentication system introduced with Microsoft's Windows 2000 Server
Windows 2000
Windows 2000 is a line of operating systems produced by Microsoft for use on personal computers, business desktops, laptops, and servers. Windows 2000 was released to manufacturing on 15 December 1999 and launched to retail on 17 February 2000. It is the successor to Windows NT 4.0, and is the...
product range.
In 2004, Tridgell was employed by IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
working remotely for the Almaden Research Center
Almaden Research Center
The IBM Almaden Research Center is in San Jose, California, and is one of IBM's nine worldwide research labs. Its scientists perform basic and applied research in computer science, services, storage systems, physical sciences, and materials science and technology. The center opened in 1986, and...
. In January 2005, he joined the OSDL
OSDL
Open Source Development Labs was a non-profit organization supported by a global consortium tasked to "accelerate the deployment of Linux for enterprise computing." Founded in 2000, its goals included "to be the recognized center-of-gravity for the Linux industry."On January 22, 2007, OSDL and the...
on a one-year fellowship; he then returned to IBM.
In 2009 and 2010, Andrew Tridgell (with Bob Edwards) taught a course titled COMP8440 Free and Open Source Software Development at the Australian National University
Australian National University
The Australian National University is a teaching and research university located in the Australian capital, Canberra.As of 2009, the ANU employs 3,945 administrative staff who teach approximately 10,000 undergraduates, and 7,500 postgraduate students...
.
Awards and honours
- In October 2003, The BulletinThe BulletinThe Bulletin was an Australian weekly magazine that was published in Sydney from 1880 until January 2008. It was influential in Australian culture and politics from about 1890 until World War I, the period when it was identified with the "Bulletin school" of Australian literature. Its influence...
magazine judged Tridgell to be Australia's smartest Information and Communications Technology person. - In January 2006, the Free Software FoundationFree Software FoundationThe Free Software Foundation is a non-profit corporation founded by Richard Stallman on 4 October 1985 to support the free software movement, a copyleft-based movement which aims to promote the universal freedom to create, distribute and modify computer software...
awarded Tridgell its 2005 Award for the Advancement of Free Software, for his work on Samba, the Linux kernel, and rsync. Tridgell was considered to have furthered an important goal of the free software movement since the founding of GNUGNUGNU is a Unix-like computer operating system developed by the GNU project, ultimately aiming to be a "complete Unix-compatible software system"...
, analyzing ways for free software to interact with widespread proprietary systems to allow people to more easily move away from those systems. - In July 2008, Tridgell was named "Best Interoperator" at the Google-O'Reilly Open Source Awards, for his work on SambaSamba (software)Samba is a free software re-implementation, originally developed by Andrew Tridgell, of the SMB/CIFS networking protocol. As of version 3, Samba provides file and print services for various Microsoft Windows clients and can integrate with a Windows Server domain, either as a Primary Domain...
and RsyncRsyncrsync is a software application and network protocol for Unix-like and Windows systems which synchronizes files and directories from one location to another while minimizing data transfer using delta encoding when appropriate. An important feature of rsync not found in most similar...
.
- Tridgell (along with Jeremy AllisonJeremy AllisonJeremy 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....
and Volker Lendecke) has been called a "guruGuruA guru is one who is regarded as having great knowledge, wisdom, and authority in a certain area, and who uses it to guide others . Other forms of manifestation of this principle can include parents, school teachers, non-human objects and even one's own intellectual discipline, if the...
in its traditional Indian meaning" by IT writer, Sam Varghese.
External links
- Andrew Tridgell's website
- 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