2497	 Synchronizing Processors with Memory-Content-Generated Interrupts	 Implementations of the Lock-Unlock method of synchronizing processors in a multiprocessor system usually require uninterruptable memory-pause type instructions. An interlock scheme called read-interlock which does not require memory-pause instructions has been developed for a dual DEC PDP- system with real-time requirements. The read-interlock method does require a special read-interlock instruction in the repertoire of the processors and a special read-interlock cycle in the repertoire of the memory modules. When a processor examines a lock a memory location with a read-interlock instruction it will be interrupted if the lock was already set examining a lock immediately sets it if it was not already set this event sequence is a read-interlock cycle . Writing into a lock clears it. Having the processor interrupted upon encountering a set lock instead of branching is advantageous if the branch would have resulted in an effective interrupt. interrupts supervisors monitors debugging parallel processing associative memories microprogramming
