Experimental Physics and
Industrial Control System

"Chestnut, Ronald P." <[email protected]> · Fri, 24 Mar 2006 09:38:42 -0800

At SLAC (as opposed to SPEAR at SLAC, which Stephanie has already spoken for), we use the alarm handler as a key part of what we call the Unix Watchdog. Databases for soft IOCs and alarm handler files are set up by automatic processes. Unix system monitors, IOC heartbeat monitors, and important programs themselves use the thus defined PVs to report on overall system health. Having an error state visible to operations, rather than (as previously) just one E-mail on transition has proven vital in many cases. Also, having the corrective action available on the alarm handler (for privileged users) makes fixing things almost trivial.

We do start ALH to do only logging by using a virtual X-destination (xfvb), as does Spear.

Ron Chestnut

-----Original Message-----
From: Ernest L. Williams Jr. [mailto:[email protected]] 
Sent: Thursday, March 23, 2006 8:15 PM
To: EPICS tech-talk
Cc: [email protected]; [email protected]
Subject: AlarmHandler as a daemon or service

Hi everyone,

Two questions:

(1) How many sites used the EPICS AlarmHandler.

(2) Has anyone changed the EPICS AlarmHandler to run in daemon mode or as a service?

This would be a useful mode when the logging option is used.

So, basically we would need a commandline option to enable this and give us an alhLogger, ah?

Thanks,
Ernest L. Williams Jr.
SNS Control Systems Group
ORNL

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System