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
Time Sharing Operating System Time Sharing Operating System Time Sharing Operating System, or TSOS, is a discontinued operating system for RCA mainframe computers of the Spectra 70 series. TSOS was originally designed in 1968 for the Spectra 70/46, a modified version of the 70/45. TSOS quickly evolved into the Virtual Memory Operating System (VMOS) by 1970. VMOS continued to be supported on the later RCA 3 and RCA 7 computer systems. RCA was in the computer business until 1971 when it sold its computer business to Sperry Corporation. Sperry renamed TSOS to VS/9 and continued to market it into the early 1980s. In the