Experimental Physics and
Industrial Control System

Maintaining EPICS Build Host Backward Compatibility

In order to maintain compatibility across multiple RHEL OS versions (e.g. RHEL6 & RHEL7) at the beamlines, BCDA must use a workstation with the oldest OS version available when building software (e.g. EPICS base & synApps) for distribution on the shared dserve's. If this is not done, then utilities that use OS shared runtime libraries (e.g., EPICSbase's "antelope") will be built with links to newer versions of libraries that do not reside on workstations with older OS versions. When workstations with the older OS run that utility, they fail. The assumption with this method is that newer OS versions will always be backward compatible with the older version.

Hi All,

I would like some input from the community regarding the organization of EPICS build for multiple OS targets (not cross-compiling), e.g. RHEL (5, 6, 7), Debian and other flavors available to coexist in a shared directory structure.

How is the community handling cases similar to rhel7-x86_64 versus rhel6-x86_64 given that "EPICS_HOST_ARCH" returns "linux-x86_64" for both?

One possible solutions would be to use something like:

       <shared_path>/<os_version>/base/.../<EPICS_HOST_ARCH>/...

       - where os_version would be: rhel5, rhel6, deb7, deb8, etc.

Another solution would be to apply a local patch to the EPICS building system to return a specific value for EPICS_HOST_ARCH including the <os_version>, e.g. rhel6-x86_64, resulting in something like this:
       <shared_path>/base/.../<NEW_EPICS_HOST_ARCH>/...

Thanks,

Hugo