The inventors of Unix, one of whom also created the first master-level chess-playing machine, have been awarded the prestigious Japan Prize for their work in building the Unix operating system in 1969.

Ken Thompson, who is now a distinguished engineer at Google, and Dennis Ritchie, who is retired, were researchers at Bell Labs four decades ago when they "developed the Unix operating system which has significantly advanced computer software, hardware and networks over the past four decades, and facilitated the realisation of the Internet," the Japan Prize Foundation said Tuesday in awarding them the 2011 prize.

"I did it as a backlash against the bad operating systems of the day," Thompson, 67, told the San Francisco Chronicle. "We were just trying to get something better to get our own work done."

The Japan Prize, started in 1985 to honor great achievements in science and technology, has in previous years been awarded to Vint Cerf and Tim Berners-Lee for their contributions to the Internet and World Wide Web.

In addition to developing Unix, Thompson also played a key role in building Belle, the first chess-playing computer to achieve a master-level rating and five time winner of the now-defunct North American Computer Chess Championship in the 1970s and 1980s. Ritchie and Thompson have also been credited with developing the C programming language, a process that occurred in conjunction with the development of Unix.

"Compared to other operating systems prevailing around that time, their new and advanced OS was simpler, faster and featured a user-friendly hierarchical file system," the Japan Prize Foundation said.

"UNIX was developed in conjunction with the programming language, C, which is still widely used... and dramatically improved the readability and portability of UNIX source code. As a result, UNIX has come to be used by various systems such as embedded systems, personal computers and supercomputers. UNIX was also a major driving force behind the development of the Internet."

"[The] University of California, Berkeley developed Berkeley Software Distribution (BSD), an extended version of UNIX that was implemented with the Internet protocol suite TCP/IP. The development was based on the sixth edition of UNIX that Bell Labs distributed along with its source code to universities and research institutions in 1975, which led to the beginning of an 'open source' culture. BSD UNIX helped the realisation of the Internet."

Unix, of course, also led to the development of Linux by Linus Torvalds in 1991.

Ritchie, 69 years old, retired from Bell Labs in 2007. Ritchie and Thompson previously won the Turing Award from the Association for Computing Machinery in 1983, and the US National Medal of Technology and Innovation in 1998, presented to them by President Bill Clinton.

Thompson became a distinguished engineer at Google in 2006, where he has worked on developing the Go programming language.

Thompson and Ritchie will each receive $300,000 for winning the Japan Prize.