W3C home > Mailing lists > Public > w3c-sgml-wg@w3.org > December 1996

Re: unmarked linkend awareness by XML engines

From: Martin Bryan <mtbryan@sgml.u-net.com>
Date: Tue, 31 Dec 1996 11:19:08 +0000
Message-Id: <1.5.4.32.19961231111908.006c4bfc@mail.u-net.com>
To: "Steven R. Newcomb" <srn@techno.com>, w3c-sgml-wg@www10.w3.org
At 14:15 30/12/96 -0500, Steven R. Newcomb wrote:
>> >Upon arrival at the read-only asset,
>> >the BOS is still pretty much guaranteed to include the session-start
>> >document; otherwise, the user couldn't have arrived at the read-only
>> >asset.
>
>> This only works if your read-only asset inherits the BOS of all the
>> documents in the chain used to reach it, or the BOS of a start point
>> document that covers the whole of a document set.
>
>Yes, but it is literally impossible for such inheritance NOT to take
>place without deliberate user intervention.  

Why? Can't I have a history file that automatically records all the BOS
entries that I have traversed to in the session? (Let the computer do the
work, not the user.) 

We seem to be talking at cross purposes again. What you call "the BOS" seems
to be what I call the History - the list of entities visited during a
session. To me a Bounded Object Set is the set of things that _could be_
accessed from a page, not the list that _has been_ accessed. Is this what
you are recording?

>If a user is in a
>document, then that document is by definition in the BOS.  If a user
>traverses to another document, he can only get there by adding that
>document to the BOS.  When he arrives at the traversed-to document,
>removal of the traversed-from document from the BOS can only be done
>deliberately and consciously.  There is no automatic removal of items
>from the BOS.

If you are saying that at each document you should add to your session BOS
references to all entities pointed to by the current document then you are
going to end up with horrendous BOS configurations if you use the web in the
way I do. Typically I access 100+ documents from anything up to 50 servers
at a session.
I need the BOS to be segmented, perhaps on a per server basis, not as a
whole. When I return to a particular document I would expect my BOS list to
be truncated accordingly.

>Because the session-start (hub) document was in fact browsed by the
>user, the links it contains are known to the application, and their
>linkends in other documents, when the user stumbles across them for
>whatever reason, are therefore also known to the application, full
>stop.  There is no need to look anything up.

The presumption that every user will come to the session-start (hub)
document goes totally against the way the Web is used. You cannot guarantee
where users will start looking at a document set accessible via the web.
They may arrive at a set of XML links to a particular "document" from a link
within a non-XML document. This is not their session-start point: it is
simply the start point for the traversal of a document set defined from a
particular set of links. (We need to define what we mean by a session - I
suspect you are using it in terms of "arriving at a known set of related
files that have a HyTime hub document": this is obviously not my definition!)

>When you use the BOS concept, the only thing that matters is the
>user's decisions as to which documents (and therefore, which link
>sets) are known to the application.  As I said before, upon arrival at
>any document, the user has the option of adding that document's BOS to
>the actual BOS in effect for this session, or of replacing the active
>BOS with that document's BOS (which means that the application will
>"forget" about the links that exist in documents that are not present
>in the new BOS).  At any time, the user can create and/or use *any*
>BOS.  If the user fails to use any suggested BOS, the user does so at
>his own risk.

How can the user (who have no overall view of the data they are using)
assess such a risk?

The scenarios you provided were great. The only problem I have is if I
publish my annotations is monthly part, and my users subscribe to my
annotations and choose one of these parts to start from. How can I arrange
for them to see all of the annotations from all of the monthly commentaries
unless I share an updatable BOS between them. If the BOS is separated from
the annotations I have no problems. If it has to be part of the annotations
I am in difficulty. 
----
Martin Bryan, The SGML Centre, Churchdown, Glos. GL3 2PU, UK 
Phone/Fax: +44 1452 714029   WWW home page: http://www.u-net.com/~sgml/
Received on Tuesday, 31 December 1996 06:20:36 EST

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