|Born|| September 9, 1941 |
Bronxville, New York, U.S.
|Died||c. October 12, 2011 70) (aged|
|Alma mater||Harvard University (Ph.D., 1968)|
|Known for|| ALTRAN |
|Awards|| IEEE Emanuel R. Piore Award (1982) |
Turing Award (1983)
National Medal of Technology (1998)
IEEE Richard W. Hamming Medal (1990)
Computer Pioneer Award (1994)
Computer History Museum Fellow (1997)
Harold Pender Award (2003)
Japan Prize (2011)
|Institutions|| Lucent Technologies |
Dennis MacAlistair Ritchie (September 9, 1941 – c. October 12, 2011) was an American computer scientist.He is most well-known for creating the C programming language and, with long-time colleague Ken Thompson, the Unix operating system and B programming language. Ritchie and Thompson were awarded the Turing Award from the ACM in 1983, the Hamming Medal from the IEEE in 1990 and the National Medal of Technology from President Bill Clinton in 1999. Ritchie was the head of Lucent Technologies System Software Research Department when he retired in 2007. He was the "R" in K&R C, and commonly known by his username dmr.
Dennis Ritchie was born in Bronxville, New York. His father was Alistair E. Ritchie, a longtime Bell Labs scientist and co-author of The Design of Switching Circuitson switching circuit theory. As a child, Dennis moved with his family to Summit, New Jersey, where he graduated from Summit High School. He graduated from Harvard University with degrees in physics and applied mathematics.
In 1967, Ritchie began working at the Bell Labs Computing Sciences Research Center, and in 1968, he defended his PhD thesis on "Computational Complexity and Program Structure" at Harvard under the supervision of Patrick C. Fischer. However, Ritchie never officially received his PhD degree as he did not submit a bound copy of his dissertation to the Harvard library, a requirement for the degree.In 2020, the Computer History Museum worked with Ritchie's family and Fischer's family and found a copy of the lost dissertation.
During the 1960s, Ritchie and Ken Thompson worked on the Multics operating system at Bell Labs. Thompson then found an old PDP-7 machine and developed his own application programs and operating system from scratch, aided by Ritchie and others. In 1970, Brian Kernighan suggested the name "Unix", a pun on the name "Multics".To supplement assembly language with a system-level programming language, Thompson created B. Later, B was replaced by C, created by Ritchie, who continued to contribute to the development of Unix and C for many years.
During the 1970s, Ritchie collaborated with James Reeds and Robert Morris on a ciphertext-only attack on the M-209 US cipher machine that could solve messages of at least 2000–2500 letters.Ritchie relates that, after discussions with the National Security Agency, the authors decided not to publish it, as they were told that the principle was applicable to machines still in use by foreign governments.
Ritchie was also involved with the development of the Plan 9 and Inferno operating systems, and the programming language Limbo.
As part of an AT&T restructuring in the mid-1990s, Ritchie was transferred to Lucent Technologies, where he retired in 2007 as head of System Software Research Department.
Ritchie is best known as the creator of the C programming language, one of the developer of the Unix operating system, and co-author of the book The C Programming Language ; he was the 'R' in K&R (a common reference to the book's authors Kernighan and Ritchie). Ritchie worked together with Ken Thompson, who is credited with writing the original version of Unix; one of Ritchie's most important contributions to Unix was its porting to different machines and platforms.They were so influential on Research Unix that Doug McIlroy later wrote, "The names of Ritchie and Thompson may safely be assumed to be attached to almost everything not otherwise attributed."
Ritchie liked to emphasize that he was just one member of a group. He suggested that many of the improvements he introduced simply "looked like a good thing to do", and that anyone else in the same place at the same time might have done the same thing.
Nowadays, the C language is widely used in application, operating system, and embedded system development, and its influence is seen in most modern programming languages. C is a low level language with constructs closely translating to the hardware's instruction set. However, it is not tied to any particular hardware—making it easy to write programs on any machine that supports C.Moreover, C is a high level language with constructs mapping to the application's data structures.
C influenced several other languages and derivatives as C++, Objective-C used by Apple, C# used by Microsoft, and Java extensively used in corporate environment and also by Android. Ritchie and Thompson used C to write UNIX. Unix has been influential establishing computing concepts and principles that have been widely adopted.
In an interview from 1999, Ritchie clarified that he saw Linux and BSD operating systems as a continuation of the basis of the Unix operating system, and as derivatives of Unix:
I think the Linux phenomenon is quite delightful, because it draws so strongly on the basis that Unix provided. Linux seems to be among the healthiest of the direct Unix derivatives, though there are also the various BSD systems as well as the more official offerings from the workstation and mainframe manufacturers.
In the same interview, he stated that he viewed both Unix and Linux as "the continuation of ideas that were started by Ken and me and many others, many years ago."
In 1983, Ritchie and Thompson received the Turing Award "for their development of generic operating systems theory and specifically for the implementation of the UNIX operating system".Ritchie's Turing Award lecture was titled "Reflections on Software Research". In 1990, both Ritchie and Thompson received the IEEE Richard W. Hamming Medal from the Institute of Electrical and Electronics Engineers (IEEE), "for the origination of the UNIX operating system and the C programming language".
In 1997, both Ritchie and Thompson were made Fellows of the Computer History Museum, "for co-creation of the UNIX operating system, and for development of the C programming language."
On April 21, 1999, Thompson and Ritchie jointly received the National Medal of Technology of 1998 from President Bill Clinton for co-inventing the UNIX operating system and the C programming language which, according to the citation for the medal, "led to enormous advances in computer hardware, software, and networking systems and stimulated growth of an entire industry, thereby enhancing American leadership in the Information Age".
In 2005, the Industrial Research Institute awarded Ritchie its Achievement Award in recognition of his contribution to science and technology, and to society generally, with his development of the Unix operating system.
In 2011, Ritchie, along with Thompson, was awarded the Japan Prize for Information and Communications for his work in the development of the Unix operating system.
Ritchie was found dead on October 12, 2011, at the age of 70 at his home in Berkeley Heights, New Jersey, where he lived alone.First news of his death came from his former colleague, Rob Pike. He had been in frail health for several years following treatment for prostate cancer and heart disease. News of Ritchie's death was largely overshadowed by the media coverage of the death of Apple co-founder Steve Jobs, which occurred the week before.
Following Ritchie's death, computer historian Paul E. Ceruzzi stated:
Ritchie was under the radar. His name was not a household name at all, but... if you had a microscope and could look in a computer, you'd see his work everywhere inside.
In an interview shortly after Ritchie's death, long time colleague Brian Kernighan said Ritchie never expected C to be so significant.Kernighan told The New York Times "The tools that Dennis built—and their direct descendants—run pretty much everything today." Kernighan reminded readers of how important a role C and Unix had played in the development of later high-profile projects, such as the iPhone. Other testimonials to his influence followed.
Reflecting upon his death, a commentator compared the relative importance of Steve Jobs and Ritchie, concluding that "[Ritchie's] work played a key role in spawning the technological revolution of the last forty years—including technology on which Apple went on to build its fortune."Another commentator said, "Ritchie, on the other hand, invented and co-invented two key software technologies which make up the DNA of effectively every single computer software product we use directly or even indirectly in the modern age. It sounds like a wild claim, but it really is true." Another said, "many in computer science and related fields knew of Ritchie’s importance to the growth and development of, well, everything to do with computing,..."
The Fedora 16 Linux distribution, which was released about a month after he died, was dedicated to his memory.FreeBSD 9.0, released January 12, 2012, was also dedicated in his memory.
Asteroid 294727 Dennisritchie, discovered by astronomers Tom Glinos and David H. Levy in 2008, was named in his memory. M.P.C. 78272).The official naming citation was published by the Minor Planet Center on 7 February 2012 (
Ritchie has been the author or contributor to about 50 academic papers, books and textbooks and which have had over 15,000 citations.
Here are some of his most cited works:
Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by multinational company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world.
Brian Wilson Kernighan is a Canadian computer scientist.
B is a programming language developed at Bell Labs circa 1969 by Ken Thompson and Dennis Ritchie.
Plan 9 from Bell Labs is a distributed operating system which originated from the Computing Science Research Center (CSRC) at Bell Labs in the mid-1980s and built on UNIX concepts first developed there in the late 1960s. Since 2000, Plan 9 has been free and open-source. The final official release was in early 2015.
QED is a line-oriented computer text editor that was developed by Butler Lampson and L. Peter Deutsch for the Berkeley Timesharing System running on the SDS 940. It was implemented by L. Peter Deutsch and Dana Angluin between 1965 and 1966.
troff, short for "typesetter roff", is the major component of a document processing system developed by Bell Labs for the Unix operating system. troff and the related nroff were both developed from the original roff.
Yacc is a computer program for the Unix operating system developed by Stephen C. Johnson. It is a Look Ahead Left-to-Right Rightmost Derivation (LALR) parser generator, generating a LALR parser based on a formal grammar, written in a notation similar to Backus–Naur Form (BNF). Yacc is supplied as a standard utility on BSD and AT&T Unix. GNU-based Linux distributions include Bison, a forward-compatible Yacc replacement.
A Commentary on the UNIX Operating System by John Lions is a highly influential 1976 publication containing analytical commentary on the source code of the 6th Edition Unix computer operating system "resident nucleus" software, plus copy formatted and indexed by Lions, of said source code obtained from the authors at AT&T Bell Labs. It is also commonly referred to as the Lions Book.
Joseph Frank Ossanna, Jr. worked as a member of the technical staff at the Bell Telephone Laboratories in Murray Hill, New Jersey. He became actively engaged in the software design of Multics, a general-purpose operating system used at Bell.
Malcolm Douglas McIlroy is a mathematician, engineer, and programmer. As of 2019 he is an Adjunct Professor of Computer Science at Dartmouth College. McIlroy is best known for having originally proposed Unix pipelines and developed several Unix tools, such as spell, diff, sort, join, graph, speak, and tr. He was also one of the pioneering researchers of macro processors and programming language extensibility. He participated in the design of multiple influential programming languages, particularly PL/I, SNOBOL, ALTRAN, TMG and C++.
The Unix philosophy, originated by Ken Thompson, is a set of cultural norms and philosophical approaches to minimalist, modular software development. It is based on the experience of leading developers of the Unix operating system. Early Unix developers were important in bringing the concepts of modularity and reusability into software engineering practice, spawning a "software tools" movement. Over time, the leading developers of Unix established a set of cultural norms for developing software; these norms became as important and influential as the technology of Unix itself, and have been termed the "Unix philosophy."
The C Programming Language is a computer programming book written by Brian Kernighan and Dennis Ritchie, the latter of whom originally designed and implemented the language, as well as co-designed the Unix operating system with which development of the language was closely intertwined. The book was central to the development and popularization of the C programming language and is still widely read and used today. Because the book was co-authored by the original language designer, and because the first edition of the book served for many years as the de facto standard for the language, the book was regarded by many to be the authoritative reference on C.
Inferno is a distributed operating system started at Bell Labs and now developed and maintained by Vita Nuova Holdings as free software under the MIT License. Inferno was based on the experience gained with Plan 9 from Bell Labs, and the further research of Bell Labs into operating systems, languages, on-the-fly compilers, graphics, security, networking and portability. The name of the operating system, many of its associated programs, and that of the current company, were inspired by Dante Alighieri's Divine Comedy. In Italian, Inferno means "hell", of which there are nine circles in Dante's Divine Comedy.
The Unix Programming Environment, first published in 1984 by Prentice Hall, is a book written by Brian W. Kernighan and Rob Pike, both of Bell Labs and considered an important and early document of the Unix operating system.
The history of Unix dates back to the mid-1960s, when the Massachusetts Institute of Technology, AT&T Bell Labs, and General Electric were jointly developing an experimental time-sharing operating system called Multics for the GE-645 mainframe. Multics introduced many innovations, but also had many problems. Bell Labs, frustrated by the size and complexity of Multics but not its aims, slowly pulled out of the project. Their last researchers to leave Multics – among them Ken Thompson, Dennis Ritchie, Doug McIlroy, and Joe Ossanna – decided to redo the work, but on a much smaller scale.
The term "Research Unix" refers to early versions of the Unix operating system for DEC PDP-7, PDP-11, VAX and Interdata 7/32 and 8/32 computers, developed in the Bell Labs Computing Sciences Research Center (CSRC).
Unix is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others.
Kenneth Lane Thompson is an American pioneer of computer science. Thompson worked at Bell Labs for most of his career where he designed and implemented the original Unix operating system. He also invented the B programming language, the direct predecessor to the C programming language, and was one of the creators and early developers of the Plan 9 operating system. Since 2006, Thompson has worked at Google, where he co-developed the Go programming language.
In Unix and operating systems inspired by it, the file system is considered a central component of the operating system. It was also one of the first parts of the system to be designed and implemented by Ken Thompson in the first experimental version of Unix, dated 1969.
Rudd Canaday is an American computer systems engineer and a previous member of the technical staff at the Bell Telephone Laboratories in Murray Hill, New Jersey, credited to co-develop the initial design of the Unix file system. In 2015 he joined a Palo Alto based tech startup, Entefy, as a Senior Architect & Engineer.
Dennis M. Ritchie, who helped shape the modern digital era by creating software tools that power things as diverse as search engines like Google and smartphones, was found dead on Wednesday at his home in Berkeley Heights, N.J. He was 70. Mr. Ritchie, who lived alone, was in frail health in recent years after treatment for prostate cancer and heart disease, said his brother Bill.
Pioneering computer scientist Dennis Ritchie has died after a long illness. ... The first news of Dr Ritchie's death came via Rob Pike, a former colleague who worked with him at Bell Labs. Mr Ritchie's passing was then confirmed in a statement from Alcatel-Lucent which now owns Bell Labs.
I just heard that, after a long illness, Dennis Ritchie (dmr) died at home this weekend. I have no more information.
Dennis MacAlistair Ritchie, computer scientist, born 9 September 1941; died 12 October 2011
Members of the Technical Staff, Bell Telephone Laboratories
Ritchie, 69, has lived in Berkeley Heights for 15 years. He was born in Bronxville, New York, grew up in Summit and attended Summit High School before going to Harvard University.
NOT KNOWN: Alcatel-Lucent confirmed his death to The Associated Press but would not disclose the cause of death or when Ritchie died.
Q Did Dennis Ritchie or you ever think C would become so popular? [Kernighan] I don't think that at the time Dennis worked on Unix and C anyone thought these would become as big as they did. Unix, at that time, was a research project inside Bell Labs.
Dennis Ritchie, the inventor of the C language and co-inventor of the Unix operating system, died a few days after Steve Jobs. He was far more influential than Jobs.
The book came off the shelf in service of teaching another generation a simple, elegant way to program that allows the developer to be directly in touch with the innards of the computer. The lowly integer variable—int—has grown in size over the years as computers have grown, but the C language and its sparse, clean, coding style live on. For that we all owe a lot to Dennis Ritchie.
NOW that digital devices are fashion items, it is easy to forget what really accounts for their near-magical properties. Without the operating systems which tell their different physical bits what to do, and without the languages in which these commands are couched, the latest iSomething would be a pretty but empty receptacle. The gizmos of the digital age owe a part of their numeric souls to Dennis Ritchie and John McCarthy.
Four decades ago, Ken Thompson, the late Dennis Ritchie, and others at AT&T's Bell Laboratories developed Unix, which turned out to be one of the most influential pieces of software ever written. Their work on this operating system had to be done on the sly, though, because their employer had recently backed away from operating-systems research.
UNIX, to the development of which Ritchie greatly contributed, and whose C made it possible it to be ported to other machines, is, even today, in its different avatars, the de facto OS for anything that is mission critical. Solaris, AIX, HP-UX, Linux—all these are derived from UNIX.