The evolution of the operating system EMAS 2900

  title={The evolution of the operating system EMAS 2900},
  author={P. D. Stephens and J. K. Yarwood and D. J. Rees and N. H. Shelness},
  journal={Software: Practice and Experience},
As a result of experiencing problems with manufacturer's software on the early 2900 machines Edinburgh University took the bold step of attempting to move the general purpose timesharing system EMAS from an ICL 4–75 to an ICL 2970 computer. This paper describes the move together with the changes made and includes some preliminary performance figures from the new system. This implementation project has produced a major time‐sharing virtual memory operating system with a fraction of the effort… 
6 Citations
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  • W. Currie
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  • 1982


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  • 1980
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  • P. B. Hansen
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  • 1975
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