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This paper describes the design philosophy of HYDRA—the kernel of an operating system for C.mmp, the Carnegie-Mellon Multi-Mini-Processor. This philosophy is realized through the introduction of a generalized notion of “resource,” both physical and virtual, called an “object.” Mechanisms are presented for dealing with objects,(More)
The extent to which resource allocation policies are entrusted to user-level software determines in large part the degree of flexibility present in an operating system. In Hydra the determination to separate mechanism and policy is established as a basic design principle and is implemented by the construction of a kernel composed (almost) entirely of(More)
Over the last 15 years, CMOS scaling simplified the task of the microprocessor architect. With each new process technology, frequency increased by -50%, and transistor density increase by 100 percent. Also, the improvements in manufacturing technology (larger wafers and higher yields) allowed for increasing die sizes without increasing cost. Projections of(More)
In this paper, we describe how the memory management mechanisms of the Intel iAPX-432 are used to implement the visibility rules of Ada. At any point in the execution of an Ada® program on the 432, the program has a protected address space that corresponds exactly to the program's accessibility at the corresponding point in the program's source. This(More)
The Intel iAPX 432 is an object-based microcomputer which, together with its operating system iMAX, provides a multiprocessor computer system designed around the ideas of data abstraction. iMAX is implemented in Ada and provides, through its interface and facilities, an Ada view of the 432 system. Of paramount concern in this system is the uniformity of(More)
A unified facility for interprocess communication and processor dispatching on the Intel 432 is described. The facility is based on a queuing and binding mechanism called a port. The goals and motivations for ports, both abstract and implementation views of them, and their absolute and comparative performance are described.
This paper describes interprocess communication and process dispatching on the Intel 432. The primary assets of the facility are its generality and its usefulness in a wide range of applications. The conceptual model, supporting mechanisms, available interfaces, current implementations, and absolute and comparative performance are described. The Intel 432(More)
As part of the ongoing research program in conversational programming an APL system has been Implemented for the PDP-10. Since this system Is to be a base for extensive study In conversational programming the system was programmed entirely In Bliss, a high-level programming language specifically designed for the writing of systems programs. A few extensions(More)