<Table> Unix <Tr> <Td colspan="2"> Evolution of Unix and Unix - like systems </Td> </Tr> <Tr> <Th> Developer </Th> <Td> Ken Thompson , Dennis Ritchie , Brian Kernighan , Douglas McIlroy , and Joe Ossanna at Bell Labs </Td> </Tr> <Tr> <Th> Written in </Th> <Td> C and assembly language </Td> </Tr> <Tr> <Th> OS family </Th> <Td> Unix </Td> </Tr> <Tr> <Th> Working state </Th> <Td> Current </Td> </Tr> <Tr> <Th> Source model </Th> <Td> Historically closed - source , while some Unix projects ( including BSD family and illumos ) are open - source </Td> </Tr> <Tr> <Th> Initial release </Th> <Td> Development started in 1969 ; 49 years ago ( 1969 ) First manual published internally in November 1971 ( 1971 - 11 ) Announced outside Bell Labs in October 1973 ( 1973 - 10 ) </Td> </Tr> <Tr> <Th> Available in </Th> <Td> English </Td> </Tr> <Tr> <Th> Kernel type </Th> <Td> Varies ; monolithic , microkernel , hybrid </Td> </Tr> <Tr> <Th> Default user interface </Th> <Td> Command - line interface and Graphical ( X Window System ) </Td> </Tr> <Tr> <Th> License </Th> <Td> Varies ; some versions are proprietary , others are free / open - source software </Td> </Tr> <Tr> <Th> Official website </Th> <Td> opengroup.org/unix </Td> </Tr> </Table>
who are primarily credited with the development of the unix operating system
Ken Thompson Dennis Ritchie Brian Kernighan Douglas McIlroy Joe Ossanna