#### 8.2.4 Concurrent Remote Calls

It is not defined by the PCS specification whether one or more threads of control should be available to process incoming messages and to wait for their completion. But the PCS implementation is required to be reentrant, thereby allowing concurrent calls on it to service concurrent remote subprogram calls into the server partition. This means that at the implementation level the PCS manages a pool of helper tasks. This (apart from performance) is invisible to the user.