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ZNG dicussion

From: Pieter Van Lierop <pvanlierop@geac.fr>
Date: Wed, 26 Sep 2001 09:40:48 +0200
Message-ID: <91C02F76882CD2119EAE00805F851D850137E281@paris.geac.fr>
To: "'www-zig@w3.org'" <www-zig@w3.org>
Following Ray Denenberg's e-mail that publicly announced ZNG on July 12, a
discussion was started on the ZIG list. After a week or so, this discussion
was over, partly because of the holiday season. I think however that
important things have been said, and below I try to group them in a few
categories. This summary could be useful for discussion at the ZIG in
I have tried to summarize the contributions in a correct way and hopefully I
don't let anybody say things that he or she does not want to be put in the

There is one thing that I want to bring up although I did not find any
discussion about it - maybe because the subject was touched by Denenberg
himself: The relation between ZNG and ZIG. I think we should talk about it
in Boston Spa.

Pieter van Lierop

Discussion on the ZNG Initiative

Some people did not like the way in which ZNG was proposed.
Zeeman talks of a "fait accompli by a really quite secretive group of
Taylor replied that the group was created at the last ZIG meeting. (But I
was not there.)

The name
Kent thinks the name "ZNG" (Z39.50 - Next Generation) is both bad and good.
Bad in that it implies it's a replacement for Z39.50 (which he do not think
it is), and good in that the name will appeal to programmers.
Dovey said the name ZNG was a mistake.

What is the rationale for ZNG? (Bull)
There is no discussion of requirements. (Zeeman)
Trying to enlarge Z39.50 to a mainstream protocol is maybe not such a good
idea (Van Lierop).
Andresen asked for the long-range objective of the proposal.

ZNG and its alternatives
There is a range of alternatives to ZNG like XML Query, XQL, XML-QL, Quilt,
why would one choose ZNG? (Bull)
Zeeman: ZNG will be unable to compete with XQL.
You can also use OAI or SQL (Sanderson).
ZNG looks very much like OAI (Futrelle).
Zeeman prefers SOAP.
There was a discussion on using XER to encode protocol messages (Futrelle,

Sanderson thinks that ZNG underestimates the disadvantages of not having a

Zeeman is against putting Search and Present together.

Dropping scan?
Van Lierop is against dropping Scan.
Kent too thinks that scan should stay.

Query language
Zeeman is against leaving RPN.
CCL is English based and especially difficult to use in a non-ASCII
character set (Bull).
There was some confusion about bib-1. Sanders was happy to find out that ZNG
drops Attribute Set bib-1. But LeVan answering Zeeman said: "Who said
anything about bib-1 going away?"

XML as Record Syntax
Why no multiple record syntaxes are allowed? (Sanderson)
Against hard coding XML. (Van Lierop)
How does the client know what is inside the XML block? (Sanders)

ZNG and Z39.50
ZNG throws the baby out with the bath water (Davidson).
The parts omitted from ZNG form the heart of Z39.50; without them it is of
no use. (Sanderson)
Kent does not see ZNG as a replacement of Z39.50.
Ralph LeVan introduced a new argument. "Z39.50 Classic", as he calls it, is
too complicated, while "ZNG" is very simple. This provoked many reactions.
Davidson replied that you also could make a simple description of Z39.50
making it look easy. Sanderson: Changing the protocol for the sake of
programmer's ease is ludicrous. Taylor also did not agree with LeVan's
vision on the complexity of Z39.50: The protocol is not the problem, but
toolkits and libraries.

When Ray Denenberg replied briefly on July 13, before leaving on holiday,
one of things he said was: "This initiative is not intended to replace
Z39.50. It focuses on getting information to the user. The premise is that
Z39.50's strength is in business-to-business applications, and this
initiative is not aimed there."
Received on Wednesday, 26 September 2001 03:51:30 UTC

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