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Subject: EPICS / file load interaction problem
From: Erik Johansson <erikj@keck.hawaii.edu>
To: "tech-talk (E-mail)" <tech-talk@aps.anl.gov>
Date: Thu, 10 Apr 2003 09:42:39 -1000
Hello again -

 A follow-up on my previous posting regarding the problem of reading
NFS-mounted files on an IOC while EPICS is running:

I thoroughly investigated our network to make sure that there were no
network problems causing the poor file-load performance. I also tried
running my file-load code snippet on other IOCs in our system, with no
change in behavior. Finally, and most interesting, I set up a bare-bones IOC
in our electronics lab and was able to reproduce the problem. There are 4
linked soft records, one of which is scanned at 0.5 seconds. After IOC init,
my file read routine works just fine until I run camonitor on one of the
channels. As soon as camonitor begins, the file load problems occur. I don't
understand the underlying mechanism of monitors, but I am hoping that this
is the key to the file load problems.

Does anyone understand monitors enough to explain why they would interfere
with the reading of an NFS-mounted file? And, more importantly, is there
anything I can do to fix the problem?

Any help you can give me is greatly appreciated.

Erik

****************************************
Erik M. Johansson
Adaptive Optics Software Engineer
W. M. Keck Observatory
65-1120 Mamalahoa Hwy
Kamuela, HI 96743
Tel: 808-885-7887
Fax: 808-885-4464


Replies:
RE: EPICS / file load interaction problem Jeff Hill

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