Jim Gray, Butler Lampson, Bruce Lindsay, and Howard Sturgis
Citation: IBM Research Report RC3949, July 1972.
CAL is an operating system based on the concepts of capabilities and of implementation via machine extension. We first present some brief comments on our design philosophy and our experience with this approach. Extensions to the capability (descriptor) mechanism are described. The remainder of the paper concerns the control structure for (a) intra-process communication: creation and display of processes, domains and gates, various forms of domain activation, and the fielding of traps; and (b) inter-process communication: messages, events, interrupts, and locks.