Experimental Physics and
Industrial Control System

Mark Rivers <[email protected]> · Fri, 25 May 2012 18:18:16 +0000

Lewis,

I think your point and Dirk's are rather different.  You are saying "don't support old releases of modules you are responsible for".  Fine.  But Dirk is saying "do write your module X so it supports old versions of module Y that someone else is responsible for".  In the case of streamDevice that means old versions of base and asyn.

In the case of more complex modules like areaDetector, it would potentially mean I should support old versions of base, asyn, calc, busy, sscan, and autosave.

I just don't think that's realistic or a good use of my limited time.

Mark

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of J. Lewis Muir
Sent: Friday, May 25, 2012 12:01 PM
To: Andrew Johnson
Cc: Eric Norum; [email protected]
Subject: Re: "@init handler failed" , "Record initialization failed" and "No reply fro device within 1000 ms"

On 5/25/12 11:07 AM, Andrew Johnson wrote:
> Hi Dirk,
> 
> On 2012-05-25 Dirk Zimoch wrote:
>> Eric Norum wrote:
>>> I'm actually kind of surprised that StreamDevice 2-5 (the latest, right?)
>>> even works with ASYN from over five years ago.
>>
>> With every change in StreamDevice I am very careful not to break
>> compatibility with earlier versions of asyn and base. You can run the
>> current StreamDevice version with asyn 4-6 and base 3.14.7 (or even
>> 3.13.9 with some tricks) if you like. Sometimes I wish other people
>> would spend that effort too.
> 
> I regard new features and bug fixes as an incentive to get people to upgrade 
> their IOCs to newer versions of Base.  Otherwise we have to continue to 
> support ancient versions of the code, and they keep hitting old bugs.

Hi, Andrew.

I think Dirk's approach is very nice.  Any change to a system
increases the chance of introducing some kind of problem.  If I
want to keep a system as stable as possible, I don't change it
(or I change it as little as possible).  Dirk's approach enables
me to do that.

Of course, I understand your desire to get people to upgrade.
If I were you, I would simply state what releases of EPICS Base
you support.  Outside of that, people are on their own, and you
don't have to waste your time fixing, or helping people with,
old bugs.  It's completely reasonable that you can't support a
ton of old releases, so don't.  As an example, the OpenBSD
project releases every six months.  They support the current
release and the previous one--that's it. They do this because
they don't have the resources to support more than that, and
they'd rather focus on new features.

Lewis

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System