Re: (LONG) Detailed notes on URL6.TXT

Marc Andreessen (marca@ncsa.uiuc.edu)
Thu, 14 Oct 93 08:30:11 -0700

Date: Thu, 14 Oct 93 08:30:11 -0700
From: marca@ncsa.uiuc.edu (Marc Andreessen)
Message-Id: <9310141530.AA26289@wintermute.ncsa.uiuc.edu>
To: mitra@path.net (Mitra)
Subject: Re: (LONG) Detailed notes on URL6.TXT
In-Reply-To: <9310131154.aa06645@pandora.sf.ca.us>
<timbl@www3.cern.ch>

Mitra writes:
> Hmm - we use the standard unix nntp distribution (not INN) and I do
> not think it can return you an article in response to a message-id.

Your news server is not conforming to RFC 977.

That said, there needs to be group/article number news URLs if ever a
URL-based system is going to be a standard news reader (handling
standard .newsrc files, etc.). There is indeed an implicit
restriction in the scope of the validity of such a URL, but without
them we don't fit into NNTP very well at all.

> } >10) Wais - pg 12
> } >A client does not need to know the length to retrieve an object, the bytes
> } >to be retrieved may (but are not neccessarily) encoded in docid. The type is
> } >carried seperately, and is required for retrieval since a docid can refer
> } >to a number of seperate objects with different types.
> } You are right in that since the paper was written, wais
> } source has been fixed to wrok without a length specified.
> } I guess we have to keep the field there for
> } back-compatibility.
>
> Back compatibility with what?

Existing clients that expect wais: URLs to have the structure they
currently have in WWW. (That said, Mosaic 2.0 [at least] already
completely ignores the length in the URL.)

> } I am not aware (perhaps ignorance) of a way of deriving
> } the list of types available from the wais docid. The set
> } of types is returned only with the serach result, and
> } so must be regarded as part of the URL.
>
> Thats what I said - we need the type, not the length

As a side note to this, freeWAIS (at least) is capable of associating
multiple types with a single docid. The latest Mosaic 2.0 prerelease
(pre5) has code to recognize multiple types and encode them in the
type field of a wais: URL as "type1,type2,type3". Suggest this be
codified as part of the URL spec.

One other piddly detail -- it needs to be clear somewhere [dunno
where] that when MIME types are used by WAIS servers (as is coming),
the slash in the MIME type needs to be escaped inside the WAIS URL.
Methinks slashes are used for too much these days..

Cheers,
Marc