Re: Z39.50 diagnostics in Init response

Guys,

If we were to deprecate (and, more importantly, remove from the published 
ASN.1) an element of the core ASN.1 spec for which there was no negotiation 
mechanism, then I could imagine interoperability problems. But since Diag-1 
is carried in an EXTERNAL, I don't really see any major problems.. the 
decoding layer itself oughtn't crash just because it encounters an unknown 
EXTERNAL (if it did, the addinfo extensibility mechanism would be in trouble).

My toolkit has decoders for Diag-1, but to my knowledge, no-one has *ever* 
used them for anything. Moreover, I don't think the majority of client 
applications (no matter what toolkit) really bother to check whether a 
diagnostic is the old-fashioned kind or a Diag-1. That means that if any 
server out there was to start producing Diag-1, then THAT would be a lot 
more troublesome than a deprecation of Diag-1.

That's the reality... I would suggest that deprecating Diag-1 is as good a 
way as any of warning new implementors that this is, in fact, the state of 
affairs, and save them a lot of time staring despondently at all that 
well-meaning but sadly over-engineered ASN.1.

--Sebastian

At 16:07 22-05-01 -0400, Ray Denenberg wrote:
>Rob Bull wrote:
>
> > For example, in our cases, the Diag 1 is supported by our toolkits, ....
>
>We won't depricate it then. I was waiting for someone to step forward and say
>they have implemented it.
>
>But we need to know: have you implemented it in general, or more specifically,
>have you implemented it as specified in the implementor agreement "Returning
>diagnostics in an InitResponse"
>http://lcweb.loc.gov/z3950/agency/agree/initdiag.html.
>
>I am integrating that agreement into the revision and what I would like to 
>do is
>substitute the new format for Diag-1, as in the draft revised appendix 4,
>available at http://www.loc.gov/z3950/agency/revision/parts/appx4.doc
>
>I'm also planning on not including the definition of Diag-1 in the 
>revision text
>(it was included in Z39.50-1995).
>
>So, taking these two steps would be far short of deprication.   Would that 
>cause
>any problems?
>
>--Ray
>
>
>
>
>--
>Ray Denenberg
>Library of Congress
>rden@loc.gov
>202-707-5795

--
Sebastian Hammer        <quinn@indexdata.dk>            Index Data ApS
Ph.: +45 3341 0100    <http://www.indexdata.dk>    Fax: +45 3341 0101

Received on Tuesday, 22 May 2001 17:31:26 UTC