PRIMOS
Operating system
PRIMOS is a discontinued operating system developed during the 1970s by Prime Computer for its minicomputer systems. It rapidly gained popularity and by the mid-1980s was a serious contender as a mainline minicomputer operating system. Wikipedia
Programming languages: Assembly language and Fortran
Developer: Prime Computer
Latest release: 24.0.0.R52 / July 3, 1997; 26 years ago
OS family: Multics-like