 Furthermore, Liedtke introduced the concept of the "direct process switch", where during an IPC execution an (incomplete) context switch is performed from the sender directly to the receiver.If, as in L4, part or all of the message is passed in registers, this transfers the in-register part of the message without any copying at all.Furthermore, the overhead of invoking the scheduler is avoided; this is especially beneficial in the common case where IPC is used in an RPC-type fashion by a client invoking a server.