EOS was the discontinued operating system developed by ETA Systems (a spin-off division of Control Data Corporation) for use in their ETA10 line of supercomputers in the 1980s. EOS was preceded by and was binary executable compatible with the CDC VSOS operating system for Cyber 205. Like VSOS, EOS had demand paged virtual memory (the VS part) with 2 pages sizes for improved virtual memory performance with the ETA's faster hardware pipelines. Though it had roots in the interactive Livermore Time Sharing System (LTSS), VSOS was focused as a batch-oriented operating system. VSOS was not run at very many institutions and its application-oriented performance, while the historic focus for supercomputing, set its features behind the times because of its limited user base.