Dennis Ritchie, a chief architect of Unix, has died

Dennis Ritchie, the American computer scientist who had a significant hand in creating the Unix operating system and the C programming language, has died aged 70, following a long illness.

The C programming language simplified software writing, and was created at Bell labs in the early 1970s; it is regarded as one of the most powerful programming languages around. It was created in the early 1970s, and a decade later spawned the C++ language created by Bjarne Stroustrup, also at Bell labs.

C was ported to just about every hardware system, meaning a program written in C could run on any machine.

Unix is an open standard operating system that has been in wide circulation since the 1980s. Among all variants of Unix, Linux is the most widely used, powering everything from huge datacentres and desktop systems to mobile phones and embedded devices such as routers.

In addition, Apple's OS X, the operating system that underpins the Apple Mac operating system, is based on Unix. There are more than 55 million systems currently in use.

Ritchie joined the programming division of Bell Labs in 1967 after he studied physics and applied mathematics for a bachelor's degree and computer science for a PhD at Harvard.

Ritchie got early recognition for his work when he received the 1983 Turing award from the Association of Computing Machinery.

He was also awarded the National Medal of Science by President Clinton in 1998.