MCTS nucleus
R. R. Brown · ACM SIGOPS Operating Systems Review · 1976
The goals of the total MCTS System are stated in terms of capabilities which the customer tasks should be allowed to exercise. Treating these as premises, several derivative goals were deduced for the MCTS System, and these dictated the structure of the operating system and the nucleus. The deductions are exhibited, and the structure of the nucleus is derived. The body of this paper does not reference the hardware description of the computer on which the nucleus was implemented, and indeed the structure of the MCTS nucleus is philosophically hardware independent, except that it assumes a large scale processor with virtual memory address translation hardware, as is explained in the paper.The nucleus consists of three separate modules which cooperate to provide the environment in which the MCTS system operates. In that environment the individual components of the system execute as separate subtasks within a single task, the MCTS system task. They are written in a PL/I-like language; they are interruptible, yet each is run to its completion, thereby eliminating the need to synchronize between subtasks; they are suspended during requested I/O operations thus making I/O appear to be instantaneous; and their creation, modification, and checkout proved to be easy and fast.