A multiprocessor system is configured so that each of the central processing units (CPUs) of the system have accessed at least portions of the memory of each other CPU. Interprocessor messaging is conducted by a CPU writing to, or reading from, the memory of another CPU of the system....http://www.google.de/patents/US5915088?utm_source=gb-gplus-sharePatent US5915088 - Interprocessor messaging system
