The Design of the Venus Operating System The Venus Operating System is an experimental multiprogramming system which supports five or six concurrent users on a small computer. The system was produced to test the effect of machine architecture on complexity of software. The system is defined by a combination of microprograms and software. The microprogram defines a machine with some unusual architectural feature; the software exploits these features to define the operating system as simply as possible. In this paper the development of the system is described, with particular emphasis on the principles which guided the design. CACM March, 1972 Liskov, B. H. operating systems, system design, levels of abstraction, machine architecture, microprogramming, segments, semaphores, multiprogramming, virtual machines, processes, process communication, virtual devices, data sharing, resource management, deadlock 4.30 4.32 4.41 6.21 CA720302 JB January 31, 1978 3:16 PM 1828 4 2379 1854 4 2379 1877 4 2379 1960 4 2379 2150 4 2379 2228 4 2379 2280 4 2379 2280 4 2379 2317 4 2379 2319 4 2379 2377 4 2379 2342 4 2379 2376 4 2379 2379 4 2379 2379 4 2379 2379 4 2379 2424 4 2379 2482 4 2379 2482 4 2379 2482 4 2379 2500 4 2379 2618 4 2379 2632 4 2379 2704 4 2379 2723 4 2379 2738 4 2379 2740 4 2379 2740 4 2379 2741 4 2379 2851 4 2379 2867 4 2379 2920 4 2379 3184 4 2379 1749 5 2379 1877 5 2379 2228 5 2379 2379 5 2379 2379 5 2379 2379 5 2379 2704 5 2379 2867 5 2379 1247 6 2379 1552 6 2379 1749 6 2379 1749 6 2379 2247 6 2379 2356 6 2379 2379 6 2379 2379 6 2379 2673 6 2379