list of CTSS features. Other references are likely to be found in proceedings of the Cray User Group (CUG) and the ACM SOSP (Symp. on Operating Systems Proceedings). However, owing to the fact that LANL and LLNL were nuclear weapons facilities, some aspects of security are likely to doom finding out greater detail of many of these pieces of software. See also EOS (operating system) Timeline of operating systems References Cray software Fortran software Time-sharing operating systems Proprietary operating systems Supercomputer operating systems