Event channels

Event channels were represented in single blocks. These blocks contained a fixed size buffer area for storing events that had been sent, but not received. They also contained the head of a circular doubly linked chain of processes which were blocked waiting for events. This chain was held together by MOT-index-unique-name style pointers, rather than absolute addresses. A single process could be on more than one such chain if it was waiting for an event from several event channels. There was an area in the representation of each process that contained these chain pointers. (In general, events could be waiting for processes, or processes could be waiting for events, but never both on the same event channel.)