Dennis Ritchie

American computer scientist, co-inventor of the Unix operating system and the C programming language

Dennis MacAlistair Ritchie (September 9, 1941 – c. October 12, 2011) was an American computer scientist and winner, with Kenneth Thompson, of the 1983 Turing Award. He created the C programming language and, with Thompson, the Unix operating system, which have had pervasive and lasting influence on subsequent programming languages and operating systems.

Dennis Ritchie


  • What we wanted to preserve was not just a good environment in which to do programming, but a system around which fellowship could form. We knew from experience that the essence of communal computing, as supplied by remote-access, time-shared machines, is not just to type programs into a terminal instead of a keypunch, but to encourage close communication.
    • In a 1980 lecture "The Evolution of the UNIX Time-sharing System", as quoted in Christopher Negus, Linux Bible 2010 Edition (2010),
  • I am not now, nor have I ever been, a member of the demigodic party.

Reflections on Software Research (1984)


1983 Turing Award Lecture[1], Communications of the ACM 27 (8), August 1984, pp. 758-760.

  • Computer science research is different from these more traditional disciplines. Philosophically it differs from the physical sciences because it seeks not to discover, explain, or exploit the natural world, but instead to study the properties of machines of human creation. In this it as analogous to mathematics, and indeed the "science" part of computer science is, for the most part mathematical in spirit. But an inevitable aspect of computer science is the creation of computer programs: objects that, though intangible, are subject to commercial exchange.
  • The greatest danger to good computer science research today may be excessive relevance. Evidence for the worldwide fascination with computers is everywhere, from the articles on the financial, and even the front pages of the newspapers, to the difficulties that even the most prestigious universities experience in finding and keeping faculty in computer science. The best professors, instead of teaching bright students, join start-up companies.
  • Another danger is that commercial pressures of one sort or another will divert the attention of the best thinkers from real innovation to exploitation of the current fad, from prospecting to mining a known lode.
  • The working examples of important new systems seem to have come either from entrepreneurial efforts (Visicalc is a good example) or from large companies, like Bell Labs and most especially Xerox, that were much involved with computers and could afford research into them, but did not regard them as their primary business.

On Unix and Unix-like systems (1999)

  • I think the Linux phenomenon is quite delightful, because it draws so strongly on the basis that Unix provided. Linux seems to be the 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.
  • My own computational world is a strange blend of Plan 9, Windows, and Inferno. I very much admire Linux's growth and vigor. Occasionally, people ask me much the same question [about Linux], but posed in a way that seems to expect an answer that shows jealousy or irritation about Linux vs. Unix as delivered and branded by traditional companies. Not at all; I think of both as the continuation of ideas that were started by Ken and me and many others, many years ago.

On Unix, Linux, and open-source (2001)

  • I think one of the interesting things about the Linux phenomenon is that [Linus] has been able to keep some kind of control over such an amazingly extended development environment. I’m certainly glad that I didn’t have to develop C in public, because you get more suggestions than you really want. Being in this nice, small group, you can control that sort of thing. I honestly don’t know the dynamics and the details of the Linux kernel project. However, one of the knocks on Linux is that it is undisciplined. But I think probably the fairer observation is that it is amazingly disciplined, compared to what you would expect, given the nature of the endeavor.
  • I don’t really distinguish between Linux and things that are more or less direct descendants of Unix. I think they’re all the same at some level. Often, people ask me, "Do you feel jealous about Linux being the big thing." And the answer is no, for the same reason. I think they’re the same.

Quotes about Dennis Ritchie

  • Ritchie and Thompson made an amazing team; and they played Unix and C like a fine instrument. They sometimes divided up work almost on a subroutine-by-subroutine basis with such rapport that it almost seemed like the work of a single person. In fact, as Dennis has recounted, they once got their signals crossed and both wrote the same subroutine. The two versions did not merely compute the same result, they did it with identical source code! Their output was prodigious. Once I counted how much production code they had written in the preceding year − 100,000 lines! Prodigious didn’t mean slapdash. Ken and Dennis have unerring design sense. They write code that works, code that can be read, code that can evolve.
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