October 12, 2012 / IST / Science & Technology, Story.

Dennis MacAlistair Ritchie (born September 9, 1941; found dead October 12, 2011)

American computer scientist, Dennis Ritchie invented the programming language called C, a major and important piece of software. Together with Ken Thompson, Dennis Ritchie co-invented the UNIX operating system. He was the author of two books, the Unix Programmer’s Manual (1971), and The C Programming Language (1978).

Both Unix and C can be considered essential parts of infrastructure software that shapes the design and abilities of today’s modern computers. Unless you are an advanced programmer, you probably do not realize when and where Unix and C are being used, but if you use a computer in any way you have been affected by these two tools.

All major important operating system is written in ‘C’. Such as UNIX, Linux etc.


  • Harvard University, Bachelor’s degrees in physics and applied mathematics, 1963
  • Harvard University, PhD, 1968


  • Dennis Ritchie and Ken Thompson were co-awarded the Turing Award from the ACM in 1983 for the implementation of the UNIX operating system.
  • Dennis Ritchie and Ken Thompson were co-awarded the Hamming Medal from the IEEE in 1990 for the origination of the UNIX operating system and the C programming language.
  • Dennis Ritchie and Ken Thompson became Fellows of the Computer History Museum in 1997 for co-creation of the UNIX operating system, and for development of the C programming language.
  • Dennis Ritchie and Ken Thompson were co-awarded the National Medal of Technology from President Clinton in 1998 for co-inventing the UNIX operating system and the C programming language.
  • Dennis Ritchie and Ken Thompson were co-awarded the Japan Prize for Information and Communications in 2011 for the development of Unix operating system.

Dennis Ritchie Biography:

Dennis Ritchie was born on September 9, 1941, in Bronxville, New York. His father was a noted Bell Labs scientist, Alistair E. Ritchie, who co-authored The Design of Switching Circuits, a book about just that. Dennis Ritchie grew up in Summit, New Jersey, where he attended Summit High School.Following in his father’s footsteps, Dennis Ritchie began working at the Bell Labs Computing Sciences Research Center in 1967. Most of Dennis Ritchie career was spent at Bell Labs, one of the largest American phone providers in the U.S. Their research lab was considered an extremely prestigious facility.In 1968, he received his PhD from Harvard University under the supervision of Patrick C. Fischer, his doctoral dissertation was entitled “Program Structure and Computational Complexity”.


Dennis Ritchie and Ken Thompson worked together at Bell Labs to create the Unix operating language, which was released for the minicomputer, DEC PDP-7 in 1971.The original version of Unix was written in machine language, by 1973, Ritchie and Thompson had rewritten Unix in C, in order to increase its functionality. The kernel was published in the same year.


C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system.C was the descendent of CPL (Combined Programming Language and BCPL (Basic CPL). Ken Thompson and Dennis Ritchie decided to use BCPL to rewrite Unix, and together they came up with a version of the language called B. However, it was Dennis Ritchie who wrote the improved and portable version named C, that could run on any machine. By virtue of C’s portability, Unix rewritten in 1973 was also a portable operating system that could work on different computers.


In 2007, Dennis Ritchie retired as the head of Lucent Technologies System Software Research Department.


Dennis Ritchie died on October 12, 2011, at the age of 70 at home in Berkeley Heights, New Jersey. The exact cause of his death is unknown, hower, Ritchie was a survivor of prostate cancer and heart disease.