Re: Building and testing Libera EPICS

[Andrew Johnson <anj@aps.anl.gov>]

Michael Abbott wrote:
> Hmm.  This does of course depend on how EPICS has been installed on the 
> target system, and I suspect that I may have broken the rules in my 
> definition of how EPICS is installed on the Libera electron beam 
> position monitor (this is the environment Yan Ying Bing is using).
>
> If you install EPICS as I instruct Libera users:
>     1. build EPICS
>     2. run install-epics on the host
>     3. run libera-install-epics on the target
> then the following files are installed on the *target*:
>     /opt/epics/lib    <- copy of $EPICS_BASE/lib/linux-arm/*.so
>     /opt/epics/bin    <- only $EPICS_BASE/bin/linux-arm/caRepeater

> I hope this configuration is not too deviant!

I'm not very happy with it -- I don't see any significant advantage to 
using a different layout on the target, and several disadvantages:

It will cause confusion (it already did!) for anyone moving between 
architectures or trying to give help via tech-talk.

It's less flexible than using the same directory structure would be - 
/opt/epics must be installed using your scripts, it can't be an actual 
copy of EPICS Base that is NFS-mounted from a server for instance.

The /opt/epics directory will not be correctly recognized as an EPICS 
top directory by either of the makeBaseApp.pl or convertRelease.pl 
scripts, which will cause problems when creating and compiling support 
and IOC applications.  That might not be a problem for Libera boxes if 
they aren't capable of self-hosting (I don't know whether they can be), 
but there are self-hosting ARM-based Linux systems out there and I don't 
want any special rules for these.

Please seriously consider changing your installed directory structure to 
mirror the standard EPICS directory configuration, it will make life 
much easier in the long run if we keep everything homogenous.

- Andrew
--
There is considerable overlap between the intelligence of the smartest
bears and the dumbest tourists -- Yosemite National Park Ranger