On Mon, 2007-02-26 at 13:18 -0600, Andrew Johnson wrote:
> Hi Michael,
>
> Michael Abbott wrote:
> > Is there any way to request the orderly shutdown of an IOC, waiting for
> > all IOC threads to terminate (I'm guessing not).
>
> Probably not in the way you're looking for. You can type 'exit' into
> the ioc shell which will stop the IOC, but you may not regard the
> resulting shutdown as 'orderly'.
>
> > I have a lot of resources open which I would like to close cleanly: but
> > if IOC threads are still running then I have to synchronise with them to
> > ensure closed resources aren't used by calls from IOC threads.
> >
> > Am I better off just pulling the plug, leaving everything running and
> > relying on exit to do the right thing?
> >
> > I can (and do) shut my own threads down in an orderly fashion, but the
> > IOC threads seem to be out of reach.
>
> The problem is that the IOC extensibility mechanisms (record, device and
> driver support etc.) were designed before the idea of porting to
> non-vxWorks systems came up, and the original concept for the vxWorks
> systems was that they boot up on power up, and then they run until they
> get turned off. As a result there's nothing in the record support or
> device support interfaces to ask them to shut down nicely, and
> retro-fitting such an interface would be a major re-engineering effort
> (which we want to do anyway for other reasons too, but the results
> cannot be backwards-compatible and it's hard for APS to justify spending
> effort on such work). We already know that the internal CA client that
> handles links has issues with IOC shutdown; I think there's 'string and
> sealing wax' in that code to try and be as tidy as possible, but it's
> not great.
>
> You can use the epicsAtExit() facility to get callbacks when shutdown is
> occurring, but the current state of the other threads when this happens
> is not well-defined, meaning your I/O thread may be active at the time
> and there's nothing we can do about that.
Andrew, is this the same as iocConsole from SLAC?
What happen to this utility? I no longer see it on the APS download
page.
-- Ernest
>
> > I'm running an EPICS 3.14 IOC as a Linux process, using iocsh(filename)
> > to load databases and get things rolling, and then running as a daemon
> > the rest of the time.
>
> I hope you've heard of the GNU Screens program, which is a wonderful way
> of attaching to IOC consoles to provide simultaneous access to the
> console session, a history buffer and the ability to disconnect and
> reconnect at will. We use this for both soft and hard IOCs here.
>
> - Andrew
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