jh@materna.uucp (Juergen Hackenbroich) (02/24/89)
Hi all over the world, we are working on an OS-9 project with several processors and naturally processes. All of these processes communicate via a message-system based on events. Some of them also react to external interrupts (i.e. V.24). What happens is that these interrupt and event-driven processes are waiting for an event when an interrupt arrives. In this case the processes sometimes hang, because the interrupt is kept pending (procs -e) and it continues waiting for events instead of processing the interrupt. This situation is released when an event arrives, the event and the interrupt are both processed. This situation does not happen always, but it seems to happen very often on V.24 processes and relatively seldom on others (direct interrupt from controller card). We think that at certain point within the operating system, when going for sleep in event it is not checked that an interrupt is pending for this process. But this seems to be only a very short period. Has anybody experience with this problem ? Or might there be somebody who also has the solution or some tricks to come around ? Thanks hacki