Dennis M. Ritchie, who made two monumental and lasting contributions to computing: “C” programming language and the Unix operating system, died last week, aged seventy. More than any other successes realized in his digital research, these two innovations have had a remarkable and lasting impact on computer science and related disciplines – permanently establishing Ritchie’s prominence in the field. The Computer History Museum, in bestowing upon Ritchie its “Fellow Award” in 1997, asserted that “both … are foundations of our modern digital world”. As a result of their work, Ritchie and research partner Ken Thompson were the recipients of the ACM (Association for Computing Machinery) Turing Award and the United States National Medal of Technology, among many other honors. And this past May, Ritchie and Thompson were named Laureates in the category of Information and Communication in receiving the Japan Prize, an annual award given by the Japan Foundation: “… to individuals whose original and outstanding achievements are not only scientifically impressive, but have also served to promote peace and prosperity for all mankind”.
The C programming language, a shorthand of words, numbers and punctuation, is still widely used today, and its successor languages, like C++ and Java, employ the same syntax. Ritchie was the leader of C development and co-authored (with fellow researcher Brian Kernighan) the definitive early book on the language entitled The C Programming Language (1978). This book, and the version of C it documents, continues to be simply called “K&R” after its authors and is a classic in the history of computer science selling millions of copies and having been translated into twenty-five languages.
And the development of Unix left an equally enduring legacy. Its free, “open-source” variant, Linux, is arguably the leading server operating system, and it runs the ten fastest supercomputers in the world. Linux’ open-source software revolutionized the computer industry because of the very nature of open source software code, which may be used, freely modified, and redistributed in both commercial and non-commercial settings. While at Bell Labs’ Computing Sciences Research Center, Ritchie and Thompson wrote and published the Unix Programmer’s Manual in November of 1971, which can be found on Ritchie’s own website.
In the course of his Unix research at Bell Labs, Ritchie made extensive use of the Gordon Bell-designed Digital Equipment Corp. PDP-11 computer. In one instance, he demonstrated that Unix could run on more than one type of computer by exporting it from the DEC. According to the Computer History Museum:
“The success of the Unix operating system is in large part due to its ability to run on a great variety of different types of computers with minimal changes. This was made possible when Unix was re-implemented in C early in its development. Prior to that, Unix, like most other operating systems, was written in the assembly language unique to each type of computer, requiring great effort. Ritchie demonstrated the flexibility that came with implementing Unix in C by porting it from the DEC PDP-11 minicomputer, on which Unix was running at the time, to an Interdata 8/32 computer”.
Later on in his career at Bell Labs, Ritchie managed a group that created a Unix-like operating system called Plan 9 (after the Ed Wood “horror” film Plan Nine from Outer Space). Ritchie retired from Bell Labs in 2007.