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<== Date ==> <== Thread ==>

Subject: RE: Channel access problem on cygwin IOC
From: "Mark Rivers" <rivers@cars.uchicago.edu>
To: "Mark Rivers" <rivers@cars.uchicago.edu>, "Jeff Hill" <johill@lanl.gov>, <tech-talk@aps.anl.gov>
Date: Fri, 30 Sep 2005 16:07:53 -0500
Jeff,
 
I just learned a little more about the caRepeater problem.  When I did the tests in my previous message I had not run any Windows CA clients that would have started a Windows caRepeater task.  When I started the IOC it started a caRepeater task that appears with "ps -a" in cygwin, but did not appear in the Windows Task Manager.  I got the error saying that CA could not find the caRepeater.  The copy of caRepeater that was started under cygwin had the unfortunate property that it had a file open that my IOC application had opened, and that file could not be deleted until that copy of caRepeater was killed.
 
I then started medm on the Windows machine, which created a caRepeater task that shows up in the Windows Task Manager.  That time starting the IOC did not start a caRepeater task, since it must have found the one that was running under Windows.  However, I still got the following error at the IOC:
***
epics> CA client library is unable to contact CA repeater a
Silence this message by starting a CA repeater daemon
or by calling ca_pend_event() and or ca_poll() more often.
****
 
But at least this copy of caRepeater does not have the file locked that needs to be deleted!
 
Do you understand what is going on?
 
Thanks,
Mark

 
________________________________

From: Mark Rivers
Sent: Fri 9/30/2005 3:33 PM
To: Jeff Hill; tech-talk@aps.anl.gov
Subject: RE: Channel access problem on cygwin IOC



Jeff,

The think the problem might have been caused by EPICS launching a second copy of my IOC instead of caRepeater one time.  So there were two copies of the IOC application running, causing the IP problem?

There is something else I don't understand about caRepeater behavior on this IOC.

Here is a list of cygwin processes before I start my IOC. 
$ ps -a
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1364       1    1364       1364    ?   18 20:29:52 /usr/bin/cygrunsrv
     1660    1364    1660       1672    ?   18 20:29:57 /usr/sbin/sshd
I     460       1     460        460    0 11092 20:31:24 /usr/bin/bash
     2280       1    2280       2280    1 11092 14:02:41 /usr/bin/bash
     3808    2280    3808       2740    1 11092 14:03:38 /usr/bin/ps

Now I start the IOC. Note that the path to caRepeater in EPICS base is in my cygwin PATH.  Now list the processes again.

$ ps -a
      PID    PPID    PGID     WINPID  TTY  UID    STIME COMMAND
     1364       1    1364       1364    ?   18 20:29:52 /usr/bin/cygrunsrv
     1660    1364    1660       1672    ?   18 20:29:57 /usr/sbin/sshd
      460       1     460        460    0 11092 20:31:24 /usr/bin/bash
     2280       1    2280       2280    1 11092 14:02:41 /usr/bin/bash
I    2112     460    2112       3008    0 11092 14:03:49 /cygdrive/j/epics/devel/dxp/2-4beta/bin/cygwin-x86/xmapApp
      736    2112    2112       3284    0 11092 14:04:49 /cygdrive/h/epics/base/bin/cygwin-x86/caRepeater
     3932    2280    3932       3456    1 11092 15:14:12 /usr/bin/ps


xmapApp is the IOC process.  Note that starting the IOC has started the caRepeater, as it should have.

However, I get the following message from iocsh on the IOC after iocInit is complete.
*****
CA client library is unable to contact CA repeater after 50
Silence this message by starting a CA repeater daemon
or by calling ca_pend_event() and or ca_poll() more often.
******

This does not seem right.  Why am I getting that error message even though caRepeater was in fact successfully started?

Thanks,
Mark





Replies:
RE: Channel access problem on cygwin IOC Jeff Hill

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