Re: CA protocol documentation.

["Bob Dalesio" <ldalesio@lanl.gov>]

It sounds like there will be good support at the 
laboratories when we make a plea to acquire funding for a 
dedicated EPICS support group.
Good :)
Bob

On Thu, 14 Nov 2002 08:23:43 -0600
 Brian Tieman <tieman@aps.anl.gov> wrote:
> Ralph,
>
> You can apologize for the rough tone all you want, but I 
> find this attitude towards documentation appaling. 
> That's not to say I think the documentation should be 
> widely availiable--in fact, I think it should not be for 
> the exact reasons you specify.
>
> However, knowing that there is one and only one guru who 
> knows what's going on scares the begeezes out of me.  As 
> someone who implements Epics based systems--primarily 
> with the PCAS, but with iocCore as well, I find it 
> disconcerting every time a problem is posted to this 
> list.  The first few responses--if any--are from well 
> meaning, knowledgable, experienced users offering what 
> amounts to an educated guess--it can't be much more than 
> that because the internals of CA are unknown.  Then, 
> perhaps a week later, the guru responds with the only 
> answer I find I can trust.
>
> I know Jeff is busy and I'm not saying he has to offer 
> 24-7 tech support, but knowing he is the only guy who 
> understands the CA protocol--the hing-pin of EPICS--makes 
> me wonder what shape the community would be in were, God 
> forbid, something to happen to him.  Is that the point 
> where Epics ceases to exist?  Does someone step in to do 
> their best only to have the "official" Epics CA libraries 
> become buggy due to lack of knowledge/experience?  Do we 
> then get an open protocol where people who need to can 
> muck about?
>
> Again, I'm not saying the protocol specification needs to 
> be generally distributed, but I would sleep better at 
> night if I knew it were written down somewhere and there 
> was at least one other individual spending some amount of 
> time developing with it.
>
> Sorry for my tone, but I manage several projects on which 
> I am the only person who knows how they work.  I've 
> fought for years to try and get someone else involved to 
> understand them in case I leave.  Having failed that, I 
> have at least documented my efforts to the best of my 
> ability such that someone else might have a fighting 
> chance to take over after me--it's the only responsible 
> thing to do.
>
> Brian Tieman
>
> Ralph Lange wrote:
>
> > >> I'm not sure if the information exists anywhere else 
> > >> but in the source code and with Jeff Hill. I don't 
> > recall
> >
> > > That is what I thought at first place.
> >
> > >> (over ten years) seeing a document that describes 
> > >> the internals of the protocol - unless Jeff alluded 
> > >> to it in some collaboration meeting.
> >
> > > Is there any interest on such a document? Or a soruce 
> > code may be enough.
> >
> > There is some intention in this.
> >
> > Since the CA protocol is not well documented, everyone is 
> > forced to use
> > the CA libraries that come with base. Thus we are able to 
> > develop and
> > improve details of the network protocol without the 
> > overhead of an
> > official protocol change.
> >
> > As soon as documentation exists, people will start 
> > writing their own
> > libraries. In contrast to the original libraries these 
> > will be buggy,
> > unstable and not compatible with older/newer versions of 
> > CA.
> >
> > Nevertheless, the authors will blame CA for this, flood 
> > tech talk with
> > their questions and absorb valueable manpower to solve 
> > problems that
> > wouldn't exist if they used the original libraries.
> >
> > Use the CA libraries from base. Don't start writing your 
> > own. Just don't.
> >
> > I think leaving the source code as the only documentation 
> > keeps the
> > scare-off factor on an adequate level. We're open source, 
> > not open
> > protocol.
> >
> > Cheers,
> > Ralph
> >
> > ps. Sorry for the rough tone, but I think opening this 
> > would really be a
> > serious danger. If CA gets suspected of being a flaky 
> > protocol, we're in
> > trouble.

Bob Dalesio
ldalesio@lanl.gov
410 557 0297 Maryland
505 667 3414 Los Alamos
505 699 1632 Cell Phone
505 667 6087 Our Secretary (Lisa Marie)