1749	 The Structure of the THE -Multiprogramming System	 A multiprogramming system is described in which all activities are divided over a number of sequential processes. These sequential processes are placed at various hierarchical levels in each of which one or more independent abstractions have been implemented. The hierarchical structure proved to be vital for the verification of the logical soundness of the design and the correctness of its implementation. operating system multiprogramming system system hierarchy system structure real-time debugging program verification synchronizing primitives cooperating sequential processes system levels input-output buffering multiprogramming processor sharing multiprocessing
