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Re: Some Questions to Xanadu

On Tue, May 26, 1998 at 03:46:35PM +0200, Soeren Grenzdoerffer wrote:
> I'm Soeren Grenzdoerffer, student of computer science and currently working
> at my diploma with the topic 'Ted Nelsons Xanadu'. 

I would be glad to help, and would also be very interested to see your

> Having read a lot about Xanadu some questions arose which I hope you can help
> me to answer:

I will do my best to answer your questions.  These are my answers, and
Ted may have better answers to your questions, but he will probably not
have time to answer them all in detail.

> a) 
> Ted Nelson wrote in several publications that there is no censorship in
> Xanadu. 

That is certainly one of the very strong goals.

> How will you handle forbi[dd]en topics like bomb-building or
> child-pornograp[h]y? 

The important question is, who says they are forbidden?  In each country
there are different laws and customs and different things are forbidden.

> In Germany they trying to disconnect server in the WWW with such topics from
> the net. I can't imagine that the government would allow Xanadu publishing
> such topics.

We hope that they will not be able to prevent it, since Xanadu is intended
to be a global system.  Of course servers in a particular country need not
carry material that would be illegal in that country, but that does not
prevent other servers in other countries from carrying the information.
This is of course exactly the existing situation with the Web.

> b) 
> Ted Nelson prefers a mouse-click-universe. 
> What about necessary text input for example in search engines?

There is nothing wrong with text input, and I don't think Ted ever said
that he wanted to get rid of text input.  He just wants to make things
easier so that they can be done with a mouse click where possible and
sensible.  (User interface design issues.)

> c) 
> In the FAQ for Xanadu you wrote in the point 2m that a 'document is
> automatically moved to physical storage appropriate to its frequency of
> access'.   In point 2o I read that 'every Xanadu service provider can charge
> their users at any rate they choose for the storage'. 
> Scenario:
> Provider A stores a huge amount of information, User X often connects to
> provider A via provider B requesting this information.
> According to point 2m this information will be automatically move to 
> provider B.
> 1) Is the fact that the provider B possibly can't handle such a huge
> amount of information neglected ?

No.  One suggested algorithm is "push-caching", where in this scenario
provider A will notice the frequent requests via provider B and send a
request to provider B to keep a local copy.  Provider B is not obliged
to accept this request; if they decline, provider A could also look
for another provider close to provider B and repeat the request.
If this other provider (call them C) accepted, Provider B would discover
the availability of the information at provider C the next time it
was requested and would presumably retrieve it from there rather than
provider A as long as it was more convenient.

> 2) Who will charge the user X for storage, retrieval and perhaps publishing
> this information (see point 2m). Provider A or provider B 

It is envisaged that the providers who store the information (which
would include provider A and possibly provider B in your example)
would charge the information publisher their storage and other fees,
which the publisher might pay partially with income from readers if they
choose to set a price on the information.  The providers who retrieve and
offer access to the information (possibly provider B in your example)
would charge the reader their fees, which would include any royalties
for the content set by the publisher (if any) and would then be paid to
the publisher's account at their home provider.

> d) 
> In Dream Machine Nelson wrote about the grand dream of Hypertext that
> everything shall be in hypertext. Point 2h in the FAQ says that the
> 'Permission to link to a document is explicitly granted by the act of
> publication.'
> If everything is in hypertext an accessible via provider, how do you handle
> restricted access for the reason of privacy or secrecy (thinking of
> corporations or gouverments) ?

Excellent point.  The FAQ is probably not clear enough on this point.
Xanadu is intended to support both private and public hypermedia.
The point 2h which you quote is intended to apply to public hypermedia,
that is information which has been published.  It of course does not
apply to private hypermedia, which may still be stored within the Xanadu
system but has not been published and is accessible only to specific users
(at least the author, presumably).

> e) 
> Referring to education Nelson wrote that there will be no need for teachers.
> The pupils will learn by exploring the Xanadu system.   I think that teachers
> and especially what their teaching can be controlled to a certain degree.
> There will be no effective control over the Xanadu system in its function as
> a teacher, especially concerning political or similar groups openly spreading
> their ideas ?

To quote Justice Brinkema in the United States:

"The answer to bad speech is more speech."

If students are exposed to wrong information, they should learn how
to determine that the information is wrong by comparing it with other
information which disagrees with it.  The linking in Xanadu is especially
designed to make sure that you can be aware when people disagree with
something on the system, since the author has already agreed to permit
all links, including dissenting ones, at the time of publication.

> f) 
> Without removing any document out of Xanadu how do you want to handle
> 'junk-information' ?

What is junk information?  This is largely subjective.
Also, we plan to have Hierarchichal Storage Management, so that
infrequently accessed information will migrate to off-line media which
will not be loaded on-line again until requested by someone.

> g) 
> The WWW is already very big. Do you want to take over the Web with Xanadu or
> do you want to build your own system which will replace the WWW ?

Both.  We envisage that Xanadu will eventually replace the Web, but only
in the sense that what we call the Web will become Xanadu.  Of course our
current designs also interoperate with the Web as far as possible, though
there is a limit to the features that can be supported without extending
the software in various ways.

> h) The WWW lives from the many young people who don't want to pay any
> royality.   Do you think that Xanadu will be alive like the WWW if you
> implement a royality system ?

Yes.  Xanadu also supports documents without any royalty; initially
we expect this will be the majority of the information available.
However, the Web currently does not offer any system for royalties, and
we believe this prevents an enormous amount of information from being
published because the publishers cannot afford to lose their income.
We believe that by allowing both free and royalty publishing, even more
information will become available than at present.

> i) What are the reasons for Ted Nelson selling Xanadu to Autodesk in 1988 and
> rebuying it in 1992?

I don't think I can answer this question; you should probably ask Ted
directly.  You can reach him at ted@xxxxxxxxxxx

I hope that helps,
		*** Xanni ***
mailto:xanni@xxxxxxxxxx                         Andrew Pam
http://www.xanadu.net/xanadu/                   Technical VP, Xanadu
http://www.glasswings.com.au/                   Technical Editor, Glass Wings
http://www.sericyb.com.au/sc/                   Manager, Serious Cybernetics
P.O. Box 26, East Melbourne VIC 8002 Australia  Phone +61 3 96511511