Dennis Ritchie Biography

Dennis MacAlistair Ritchie (born 1941) is best known for his work on computer languages and operating systems ALTRAN, B, BCPL, C, Multics, and especially Unix. For a man who did not start out in the computer industry, he has had a profound influence on the entire computer programming world. He told Investor's Business Daily , "It's not the actual programming that's interesting. But it's what you can accomplish with the end results that are important." And if that is the case, then Ritchie has had an important effect on most, if not all, computer users today.

Early Fascination with Harvard's Univac I

Ritchie was born on September 9, 1941, in Bronx-ville, New York. He was born to Alistair Ritchie, a switching systems engineer for Bell Laboratories, and Jean McGee Ritchie, a homemaker. Ritchie grew up in New Jersey, and after a childhood in which he did very well academically, he went on to attend Harvard University. There he studied science and graduated with a bachelor's degree in physics. While he was still going to school, Ritchie happened to go to a lecture about how Harvard's computer system, a Univac I, worked. He was fascinated by what he heard and wanted to find out more. Outside of his Harvard studies, Ritchie began to explore computers more thoroughly, and was especially interested in how they were programmed.

While still at Harvard, Ritchie got a job working at the Massachusetts Institute of Technology (MIT). At that time computer programming was not a degree, and computer labs were looking for anyone with potential to help on their computers. Ritchie, with his unflagging curiosity, seemed perfect for the job. Ritchie worked at MIT for many years helping develop, alongside other scientists, more advanced computer systems and software.

Began Work on Operating Systems

He also began work on developing an operating system for more portable computers. Most computers at the time took up entire rooms and had limited dial-in access, but smaller desktop computers were being developed, and these did not have easy to use operating systems. Ritchie decided that one was needed. MIT, Honeywell, and General Electric agreed, and administered his project. Other scientists from colleges and private companies came to help build the system, one that was able to handle up to a thousand users at once and could be run 24 hours a day. Ritchie never saw programming as a problem but rather as a puzzle to be solved.

After the project was finished, just about the time that he graduated, Ritchie determined that computers, rather than physics, would be his career. He got a job at Bell Labs, where his father had worked for years. At the time, in 1967, it was the nation's primary phone provider, and it had one of the best labs in the world, one that was responsible for developing a multiplicity of technical advances, from new switching devices to transistors, as well as new computer advances. Ritchie told Investor's Business Daily , "Instead of focusing on specific projects, I wanted to be around people with a lot of experience and ideas. So I started working on various projects to learn my way around the profession."

Built Unix to Fulfill Computer Needs

Ritchie began working with Kenneth Thompson, who had joined Bell Labs in 1966. Both men had been watching how the minicomputer was becoming more and more popular in the early 1970s. What was needed, they thought, was a simpler and more feasable interaction between various computers. It took them months to come up with a solution, but when they were finished they had written the Unix operating system. An operating system is necessary for a user to copy, delete, edit, and print data files. It allows a person to move data around from disk to screen to printer and back to disk for storage. Without an operating system computers would not be accessible to anyone but an expert few. Before the creation of Unix, operating systems had been complex and expensive. Unix was comparatively cheap and simple, and it could be used on just about any machine, which meant buyers were not stuck with the cumbersome software that came with their computers. They could buy and install a variety of software systems, because Unix was compatible with all of them. This had not been possible before.

Ritchie and his team released Unix to the public at a symposium on Operating Systems Principles that was hosted by IBM, and it was an immediate success. Ritchie and Thompson then set out to improve the system.

Development of C Programming Language

Unix was written in machine language, which had a small vocabulary and did not deal well with multiple computers and their memories. So Ritchie combined some aspects of the older systems with aspects of the new one, and came up with the "C" programming language. In the early twenty-first century, "C" is still the dominant language of computer programming. It was such a simple, concise language that almost every single computer maker at the time switched to it.

"C" uses very little syntax and few instructions, but it is extremely structured and modular. Because of this it was easy to use in different computers. There were large blocks of "C" functions that were already written that programmers could copy whole into their own programs without having to start from scratch, making it faster and easier to implement. These blocks were easily accessible, available in libraries so programmers could access them. By the middle of the 1980s "C" had become one of the most popular programming languages in the world. Because of the speed with which "C" could be used to write programs and run them, companies began using "C" to develop their own software.

Continued Drive to Improve Computer Functionality

By 1973 Ritchie and Thompson had re-written the Unix operating system, using "C" instead of machine language, and had done massive testing on it. It was so simple to use that programmers all over were switching to smaller machines to do their programming, giving up the larger computers they thought they would never want to leave. Bell Labs became Lucent Technologies Inc., and began to sell Unix to developers, creating a whole new division for the company. Ritchie has credited his success in part to the fact that he did not have a computer background and therefore had an open mind to possibilities that others might not have thought existed.

Ritchie became the leader of the Computing Techniques Research Department at Lucent Technologies in 1990. In that role he wrote applications and managed the growth of already released operating systems. Over the years Ritchie has received numerous awards, including the ACM award for the outstanding paper of 1974 in systems and languages, the IEEE Emmanuel Piore Award in 1982, a Bell Laboratories Fellow in 1983, an Association for Computing Machinery Turing Award in 1983, an ACM Software Systems Award in 1983, and an IEEE Hamming Medal in 1990. He was also elected to the United States National Academy of Engineering in 1988. In April of 1999 he was the recipient of the United States National Medal of Technology. All of the awards Ritchie received were in conjunction with Thompson. Ritchie is now the head of Lucent Technologies' Systems Software Research Department, and is still striving to make computers work better and more easily for users.

Personal Life Mirrored Professional

Asked what he liked to do in his personal life, Ritchie admitted that his personal and professional lives are mixed together. He said in an interview on the Old Unix website, "I've done a reasonable amount of traveling, which I enjoyed, but not for too long at a time. I'm a home-body and get fatigued by it fairly soon, but enjoy thinking back on experiences when I've returned and then often wish I'd arranged a longer stay in the somewhat exotic place."


Almanac of Famous People , 8th edition, Gale Group, 2003.

Newsmakers 2000 , Issue 1, Gale Group, 2000.

Notable Scientists: From 1900 to the Present , Gale Group, 2001.

World of Computer Science , 2 volumes, Gale Group, 2002.


Economist , June 12, 2004.

Investor's Business Daily , January 27, 2003.


"Dennis M. Ritchie," Bell Laboratories , (January 2, 2007).

"Dennis M. Ritchie," Bell Laboratories , (January 2, 2007).

"Interview-Dennis Ritchie," Unix , (January 2, 2007).

User Contributions:

Comment about this article, ask questions, or add new information about this topic: