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+IPC stands for interprocess communication.
+
+On Unix, interprocess communication can be achieved using pipes.
+This is inefficient for large amounts of data as the data must be
+copied.  This is generally not a problem as most services are
+provided by the Unix kernel and Unix is not designed to be
+[[extensible]].
+
+[[Microkernel]] systems, on the other hand, are generally composed
+of many components.  As components are separated by their respective
+address space boundaries, unlike the kernel, they cannot arbitrarily
+examine and modify the caller's state.  The advantage is that if the
+protocol is carefully designed, the callee cannot cause the caller
+any [[destructive interference]] thereby removing the need for the
+caller to [[trust]] the callee thus reducing the former's [[tcb]].
+When done systematically, this can increase the system's [[robustness]].
+To this end, microkernels provide richer IPC semantics that include
+the ability to transfer [[capabilities]] and to use virtual memory
+mechanisms to copy data.