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
Security-evaluated operating system in August, 1987. The Unisys OS 2200 operating system includes an implementation of the DoD Orange Book B1, Labeled security protection level specification. OS 2200 first obtained a successful B1 evaluation in September, 1989. Unisys maintained that evaluation until 1994 through the National Computer Security Center Rating Maintenance Phase (RAMP) of the Trusted Product Evaluation Program. Security-evaluated operating system In computing, security-evaluated operating systems have achieved certification from an external security-auditing organization, the most popular evaluations are Common Criteria (CC) and FIPS 140-2. Trusted Solaris 8 was a security-focused version of the Solaris Unix operating system. Aimed primarily at the