Experimental Physics and
Industrial Control System

Don Dohan <[email protected]> · Fri, 24 Aug 2007 14:08:39 -0500

Emmanuel
This is one of the features of the IRMIS relational database. 
IRMIS consists of, in part, all of the PVs in your system. A pv crawler
(a perl program) detects when an IOC reboots, then scans and expands
that IOC's st.cmd file to load the IRMIS database with that IOCs PVs.
This scanning is unobtrusive to the IOC.
Other crawlers have been written to scan CA clients. At the APS, we
crawl for MEDM, ALH, and SDDS clients, and we are testing the SNL
crawler written at SLAC. We intend to crawl save/restore files as well
(future). For each CA client instance, a list of resolved PVs is
generated, and inserted into the IRMIS database.
Taking the MEDM client as an example, the crawler resolves the macro
substitutions for nested MEDM screens, so that it tells you which .adl
file in the chain needs to be fixed if a given PV is removed.
Crawlers for other CA clients have been written at other facilities -
EDM, DM/2K for example.
Don Dohan
Emmanuel Mayssat wrote:

Another question about software upgrade...
Let's say that I change the name of PV in my epics database.
Potentially with this change, I could break epics extensions.
Medm of course, but also feedback system, PV backup, etc.
Is there a way to know which extensions will break if I change a PV
name? (may keeping track for each extension of the used PVs in a flat
file is the solution, but is there any other, smarter ones?)
--
Emmanuel

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System