Fork (system call) rfork and IRIX's sproc, Linux's clone was inspired by Plan 9's rfork and can be used to implement threads (though application programmers will typically use a higher-level interface such as pthreads, implemented on top of clone). The "separate stacks" feature from Plan 9 and IRIX has been omitted because (according to Linus Torvalds) it causes too much overhead. In the original design of the VMS operating system (1977), a copy operation with subsequent mutation of the content of a few specific addresses for the new process as in forking was considered risky. Errors in the current process state may be
Chippewa Operating System preceded the Cray Operating System (also called COS) at Cray. Chippewa Operating System The Chippewa Operating System often called COS is the discontinued operating system for the CDC 6600 supercomputer, generally considered the first super computer in the world. The Chippewa was initially developed as an experimental system, but was then also deployed on other CDC 6000 machines. The Chippewa was a rather simple job control oriented system derived from the earlier CDC 3000 which later influenced Kronos and SCOPE. The name of the system was based on the Chippewa Falls research and development center of CDC in Wisconsin. This