Chapter 9: Viewing and Configuring System Resources
As part of normal operations, Oracle database processes constantly coordinate and communicate with system server processes. In Linux or Solaris, this type of process-to-process coordination is referred to as interprocess communication (IPC). OSs typically support three types of interprocess communication mechanisms: semaphores, shared memory, and message queues. Oracle database applications typically require significant amounts of semaphore and shared memory resources to function properly.