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
SHARE Operating System SHARE Operating System The SHARE Operating System (SOS) was created in 1959 as an improvement on the General Motors GM-NAA I/O operating system, the first operating system, by the SHARE user group. The main target was to improve the sharing of programs over GM-NAA I/O. SHARE Operating System provided new methods to manage buffers and input/output devices, and, like GM-NAA I/O, allowed execution of programs written in assembly language. Initially, it worked on IBM 709 computer and its transistorized compatible successor the IBM 7090. A series of articles describing innovations in the system appears in the April, 1959, Journal of