OpenBinder
OpenBinder[1] is a system for interprocess communication. It was developed at Be Inc. and then Palm, Inc.[2] and has more recently been used in the Android mobile phone platform developed by Google[3].
OpenBinder allows processes to present interfaces which may be called by other threads. Each process maintains a thread pool which may be used to service such requests. OpenBinder takes care of reference counting, recursion back into the original thread, and of course the inter-process communication itself. On the Linux version of OpenBinder the communication itself is achieved using ioctls on a given filehandle, communicating with a kernel driver.