13. A trap semaphore for interprocess communication as recited in claim 12 wherein said second means includes an event processing demand device for establishing an interest in at least a first type event occurrence which is certain to occur in at least a second of said processes.
13. A trap semaphore for interprocess communication as recited in claim 12 wherein said second means includes an event processing demand device for establishing an interest in at least a first type event occurrence which is certain to occur in at least a second of said processes. 14. A trap semaphore as recited in claim 13 wherein said second means includes a trap event processing demand device for establishing an interest in at least a second type event occurrence which is not certain to occur in at least a second of said processes.