PPT Slide
Message-passing variations
- Some useful lessons come out of tweaking the basic message passing SOS system calls.
- First variation: rather than have anonymous message queues that any process can send/receive, have messages go directly to a process via the processes’ PID. Note this is less flexible - Figure 8.10 (a).
- Second variation: Message passing with non-blocking receives. What if you want to be able to receive from multiple queues? The original ReceiveMessage() call only allowed you to look at one queue at a time; it would block the caller if a message wasn’t available. If we make the system call non-blocking, then the process can “poll”.