RE: EPICS latest stable version

[Delahaye Olivier via Tech-talk <tech-talk at aps.anl.gov>]

Hi Ralph,

Thx a lot for your quick answer.

So If I understand well, we should better switch on 7.0 release. I would be quite confident about the stability since you mentionned half of the installations works now with 7.x version.

Just a few more questions (sorry if questions are not clear, EPICS is quite new to me !).

1. What do you mean by tedious small changes ? We've got about 46 IOCs running on LINUX + 20 running on VxWorks. How long would you estimate for the upgrade ?

2. You mentionned pvAcess protocol has been reviewed on 7.0 version. Our equipments rely on Channel Acess protocol. Is it the same one ? Are the "tedious small changes" you are talking about specifically related to the upgrade of the pvAccess protocol ?

 

3. You mentioned EPICS process database is backward-compatible. It's not clear to me the split between the different component in EPICS framework. But what is backward compatible and what is not ? Because if everything is backward compatible, what do the "tedious small changes" consist of ?

Thx a lot for your support,

Olivier

---

De : Ralph Lange <ralph.lange at gmx.de>
Envoyé : mardi 16 février 2021 12:55:25
À : EPICS Tech Talk
Cc : Pillon Frank; Zouaoui Djaid; Sebille Florian; Patard Charles-Henri; Delahaye Olivier
Objet : Re: EPICS latest stable version

 

Dear Olivier,

I'm not getting into the "current" vs. "stable" discussion - that depends so much on your personal definition of these two terms that I can only lose.

Let me answer it from a different angle.

• 3.14 is dead and doesn't even get bug fixes anymore. Time to move on. Not an option for new developments.
• 3.15 is supported and will get bugs fixed as they are discovered. For a new development inside an existing 3.15 context, this might be the appropriate option.
• 7.0 is being actively developed, provides the next generation network protocol pvAccess and keeps the robust 3.x IOC below. Recommended for any new developments.

Such a migration will be an effort. No rocket science, for sure, but a lot of tedious small changes and testing, testing, testing. I would not do that more often than necessary.

Most of the changes in EPICS 7 are in the new parts: the pvAccess protocol stack and its integration in the IOC. As long as you don't heavily rely on the pvAccess protocol, the migration risk is pretty low. The EPICS Process Database code is robust and gets new features carefully in a backward-compatible manner, as always.

Channel Access and its wide compatibility range will be the glue that keeps your system together. Migrating one system, even one IOC at a time should not be a big issue.

Bottom line... Don't underestimate the task. You would need good reasons to not go to a recent 7.0 release.

If I remember correctly, an audience poll at one of the last meetings showed that roughly half of the installations have EPICS 7 running somewhere. Can't be completely broken, then.

Cheers,
~Ralph

---

Préservons notre environnement, n’imprimez ce mail que si nécessaire.
Preserve our environment, print this email only if necessary.