An Operating Systems Vade Mecum

14. We suggested that unread data might be kept in the virtual space of the writer untilthey are read. For output ports and bound ports, this design makes sense. Thisstrategy is more difficult to implement in a multicomputer for input ports or freeports. Discuss what the semantics of Read should be in those cases and what messagesmust be sent from one kernel to another to implement this design.15. The text suggests that intermediary processes are useful for allowing a server onone machine to interact with the kernel on another. A second use for intermediaryprocesses is to transmit messages between machines in a multicomputer. TheExercises alternative is to let the kernel transmit such messages. What are the advantages321ofeach alternative?16. The text suggests that if synchronous write on a port blocks the caller until a replycomes, the caller should not be preempted for another process for a while. Whenis this suggestion inapplicable?