Re: ZNG: "Z39.50 Next Generation"

Robert Sanderson wrote:

> No session support?  No separate search/present? No ASN/BER ? No multiple
> record syntaxes?  No -scan-?
> 
> Getting rid of these makes it next to useless in context. At least you
> didn't cut out search completely (which would make it almost identical to
> OAI).  Exactly how does ZNG preserve anything of the current Z protocol?

It preserves the jargon. That's it as far as I can tell.

It has one plus point -- no Bib-1.

http://www.loc.gov/z3950/agency/zng.html says:

: Flat access points will be defined, rather than utilizing
: attribute vectors as in standard Z39.50. For example, consider
: 'title - word' and 'title - phrase'. In ZNG these would be
: represented as distinct access points (rather than two attribute
: combinations with the same Use attribute and different qualifying
: attributes).

This is something that is lacking in the current standard. It is
certainly a movement in the right direction (which, IMHO, the new
attribute architecture wasn't.)

> Without sessions, resultset storage will be as little
> implemented as it is now.

I suspect Robbie is being too optimistic about this and that a
lot of developers just wont bother with result set storage. The
architecture is such it would be just oh so easy to conveniently
forget about it. A lot of developers seem to do the bare minimum
neccessary already. This wont give ZNG a reputation for being
efficient.

Database providers and service funders like sessions as it makes
usage analysis much easier and useful. A session makes it
possible to see how someone is using the system.

A search response could pass back a session-id for inclusion in
subsequent searchess, but there's no gaurantee a client would
subsequently use it. But that's what you get with a
connectionless "protocol" and no Init.

: The Z39.50 concept of record syntax is not meaningful in ZNG and
: is discarded; all ZNG records will be retrieved according to a
: single record syntax: XML.

How do you tell the client what you've packaged up in that
weighty XML envelope?

Pieter Van Lierop wrote:

> I am sceptical about the idea of trying to make a "mainstream protocol", if
> only because "mainstream" means "simplified" which means "poor". 

Have to agree with that.

Ashley.

-- 
Ashley Sanders                                a.sanders@mcc.ac.uk
COPAC: A public bibliographic database from MIMAS, funded by JISC
             http://copac.ac.uk/ - copac@mimas.ac.uk

Received on Friday, 13 July 2001 10:18:07 UTC