Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017 Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017
<== Date ==> <== Thread ==>

Subject: Re: PV / record name length
From: Sebastian Marsching <sebastian@marsching.com>
To: Mark Rivers <rivers@cars.uchicago.edu>
Cc: "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Date: Fri, 28 Jul 2017 14:09:19 +0200
Hi Mark,

> Is that length restriction in the CA protocol?  If so and you change it in your IOC then they may not work with older CA clients?

You are right for clients based on EPICS Base 3.12 (and older). There, the client library restricted channel names to 39 characters (40 byte buffer). However, EPICS Base 3.13.1 (I did not check the .0 release) already increases this limit to 1007 characters (MAX_UDP of 1024 - CA header size of 16 - 1 for the null byte).

Given the fact that EPICS Base 3.13.1 was released almost 20 years ago (November 1998), I think it is unlikely that there are still clients using that version. Anyway, the limit for these clients is 39 characters, so they would already have trouble with the 60 characters that have been allowed by EPICS Base for quite a while.

Best regards,
Sebastian

Attachment: smime.p7s
Description: S/MIME cryptographic signature


Replies:
Re: PV / record name length Ralph Lange
References:
PV / record name length Sebastian Marsching
RE: PV / record name length Mark Rivers

Navigate by Date:
Prev: RE: PV / record name length Mark Rivers
Next: Re: PV / record name length Ralph Lange
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017
Navigate by Thread:
Prev: RE: PV / record name length Mark Rivers
Next: Re: PV / record name length Ralph Lange
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  <2017
ANJ, 28 Jul 2017 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·