Dennis Ritchie's C language lives inside almost every modern programming language
Working with Ken Thompson at Bell Labs, Dennis Ritchie created the C language and helped build Unix, whose name began as a pun. C shaped C++, Java and C sharp, and Unix thinking runs through Linux. Ritchie also helped crack a US cipher machine, then shelved the paper at the NSA's request.
Ritchie was born in Bronxville, New York, on September 9, 1941. His father, Alistair, was a longtime Bell Labs scientist who co-wrote a book on switching circuit theory. After high school in Summit, New Jersey, Dennis studied physics and applied mathematics at Harvard, graduating in 1963. He joined the Bell Labs Computing Science Research Center in 1967 and drafted a doctoral thesis on computational complexity a year later, but never formally received the degree; the Computer History Museum tracked down the lost dissertation with both families' help in 2020.
In the 1960s he and Thompson worked on the Multics operating system. Thompson then found a neglected PDP-7 and started writing his own system from scratch, with Ritchie's help. In 1970 Brian Kernighan suggested Unix as a play on Multics. Thompson wrote the language B for system programming; Ritchie replaced it with C, and the pair rewrote Unix in C, which made the system portable across machines, one of Ritchie's key contributions. Doug McIlroy joked that their names could be assumed on anything at the lab not credited to someone else. With Kernighan, Ritchie wrote The C Programming Language, known as K&R.
C sits close to the hardware yet is not tied to any particular machine, and it remains common in operating systems and embedded devices. In 1999 Ritchie called Linux delightful, seeing it and the BSD systems as heirs of the ideas he and Thompson began. In the 1970s he, James Reeds and Robert Morris devised a method for breaking the M-209 cipher machine from ciphertext alone, but withheld it after hearing foreign governments still used the principle.
Later he worked on the Plan 9 and Inferno systems and the Limbo language, moved to Lucent Technologies in an AT&T restructuring, and retired in 2007. He and Thompson shared the 1983 Turing Award and, in 1999, received the National Medal of Technology from President Bill Clinton. Ritchie died around October 12, 2011.
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