state of QNX messaging on restarts

what happens to the IPC state (QNX native message passing) if the machine restarts in the middle of communication ? Can we be able to restore the previous states of IPC when the machine restarts ?


Look at HAM. Maybe this is what you need.

If you take this request literally, HAM would be useless as there would be no HAM left. A good first question is whether you mean inter or intra processor IPC. If you are communicating across a network, and one cpu resets while a message is being transmitted, it will either be completely sent, or not at all. You would probably have to modify the kernel and provide application support to restart a message that was in transit. A better model would be one where after a request for data fails, you re-request the data.

If you mean within a single processor or SMP group, then there is a lot more state information to be restarted than just the IPC transmission states. I once worked on a gambling machine that had to very stiff requirements along these lines. If you yanked the power plug at any time, you had to be able to plug it back in and expect the machine to return to an identical state. This required non-volatile ram as well as a special un-corruptable database.

Strange, you’d think a gambling company would be willing to roll-the-dice ;-)

LOL, well the gambling company might have been willing. The requirements came from the gambling commission in Nevada.