Hyperformance in the Hyperfuture
Presented at the John Moores University Multimedia Conference,
Liverpool, May 1994.
Xanadu publishing is a long-standing proposal for a new literary and
communication medium for all purposes--pluralist, populist on-line
publishing on a vast scale. Many different Xanadu implementations are
possible, and several have been attempted(1).
The ideas of Xanadu publishing include hypertext and hypermedia; open
contributions and linkages publishable by anyone; and quotation from
other documents without negotiation or red tape. These ideas have now
been validated by the spectacular success of World Wide Web--an Internet
service originally inspired by Xanadu(2). However, the two systems are
in various respects different, built on different ideas of data storage,
delivery, ownership and payment(3).
Xanadu publishing is principally based on selling copyrighted materials
in small amounts. All material may be re-used and quoted without
special arrangement, provided the re-use is virtual (by transclusion--a
pointer indicates material to be virtually included), so that the
material is bought from the original publisher at the time of delivery.
Xanadu has its own detailed contracts and business model for
fine-grained ownership, sale, royalty and storage payment.
All Xanadu links and transclusions are bivisible (visible from each end
of the connection) and bifollowable (followable from each end of the
connection). The design cleans up copyright and rights issues by
finely-detailed business tracking and the elimination of red tape.
Client Programs and the Purchase Model
The Xanadu usage model assumes a reader buying fragments from many
different publishers on a rapid-fire basis(4).
Many front-end client programs are possible for this, in many variegated
styles. These can vary from simple, "vanilla" windowing to colorful and
even baroque viewing systems. We encourage other software developers to
create client programs in their own styles for presentation and
exploration of this new medium.
In addition, we intend to permit Xanadu use from the popular Mosaic,
formatting Xanadu output into Mosaic's HTML on the fly, even though this
format represents a different model of the world from ours.
Needed: A High Performance Client
Thus there needs to be a high-performance client language, which we are
calling Hyperformance(TM). It is still under design, and our principal
concerns at the moment are with getting servers up, not with these later
embellishments, but it is time to start thinking about them. What
structures, what synchronizations, what pieces to connect in new
non-sequential ways, must be specified in the virtual document?
So I would like to say a few words on the ideal, high-performance Xanadu
client front end. Now that we have a high-speed network (the Internet
on a good day), what will top performance look like?
Consider the 3D workstations, especially those of Silicon Graphics, and
how they offer top-speed zooming, rotation and 3D roving. Consider also
the high-performance software specs of some of the newer programs,
especially "Live Picture," a high-performance competitor for Photoshop
now about to appear on the market. Live Picture allows high-speed
panning and zooming where Photoshop was glacially slow. But it should
also be noted that Live Picture is said to require a Macintosh with 64
megabytes of RAM, and 128 megabytes are recommended. So software comes
with a hardware price.
Nevertheless, these levels of performance are what the world is moving
toward. So what will high-performance Xanadu look like?
Xanadu server performance will look the same regardless of speed.
So it is Xanadu client performance that will be able to vary in
What It Should Do
High performance views are those which involve interactive
zooming and panning, interactive animation, video (possibly video in
several windows), video with alpha channel (permitting moving figures
to be superimposed, as allowed by MacroMedia Director); 3-dimensional
movement; the wrapping of pictures or "textures" onto surfaces in real
time. As well as:
Pan, scroll and zoom. Text and graphics should be able to pan,
scroll and zoom at high speed.
Reversibility of operations. Xanadu connections are
bidirectional and bifollowable, and correspondingly, all movements by
the user through the docuverse should be reversible. Supporting
reversible operations at high speed is highly desirable.
Appropriate compressions. For transmission of pictures and
video, compression is important; some compressions, such as MPEG, do not
map well to the Xanadu model of purchasing arbitrary sections. We are
particularly interested in other forms of compression, especially
fractal, that will improve performance in the client.
Animation in real time (rather than received as canned video or
digital frames) is a key capability that the high performance client
should have. Not only is this desirable to meet varied user needs, but
it also saves on transmission time and precious bandwidth.
Fast simulations are important for similar reasons.
Vamping. In musical theater, the pianist is often given the
instruction "Vamp till ready;" this means that the music should
plausibly continue until the performers arrive onstage. Corresponding
vamping methods must provide fulfilling animations and screen events
until materials arrive over the network. So these too must be
specifiable in the high-performance client. (Note that similar
techniques are available in such environments as Director.)
Benefits of high screen performance. There has always been a
tradeoff between screen area and resolution and fast performance. The
more performance, the bigger the screen will seem to be.
The High-Performance Client Language
The Xanadu model of sale assumes that portions bought from a variety of
documents are recomposited into new structures and objects in the
client. This is very like the Edit Decision List (EDL), the final list
of what is to be put together in a video production: the succession of
shots and audio pieces to be assembled for the final production. But in
the Xanadu model these must in principle be bought from different
sources and co-presented in real time. Thus the high-performance client
system must be able to composite various data sources into a seamless,
high-performance data structure in real time.
The formatting and presentational specification for such
high-performance works or documents must be rich. The high-performance
client language must allow the definition of visible and virtual units
and objects, their possible movements and mutations, actions upon them
and interactions with them. (More conventional formatting, like SGML's
hierarchical template formatting on the basis of similarities, will also
be needed--but for objects composited on the fly from different
Unfortunately we cannot use the existing "standard" tools, such as SGML
and HTML, because they are inside-out from the Xanadu model of
transclusion. Recommended Xanadu data structures are optimized for
fragmentary re-use and re-embedding of all materials in any new
contexts, in any possible structures. Thus the materials do not have
internal markers, as does HTML, and so the Xanadu internals are
inside-out from those of World Wide Web and Mosaic.
Xanadu hot front ends will need a specification system, or language,
that will be of a generally new kind, although it will borrow from many
sources. It will have to deal with new arbitrary data composites having
many owners, and very different contexts of origin, and they will have
to dance, zoom and array themselves as if they had been carefully
preformatted for the purpose.
- Theodor Holm Nelson, Literary Machines. Mindful Press, 3020
Bridgeway #295, Sausalito CA 94965.
- Tim Berners-Lee, personal communication.
- T. Nelson, "Xanadu and World Wide Web," unpublished.
- T. Nelson, "Publishing in the Point-and-click Universe." Presented
at the National Convergence Conference '94, Sydney, Australia, April
Copyright (c) 1994 Theodor Holm Nelson, Project Xanadu, 3020 Bridgeway #295,
Sausalito CA 94965. Tel. 415/ 331-4422, fax 415/ 332-0136.
"Xanadu," "Hyperformance," "Point-and-Click Universe" and the
Eternal-Flaming-X symbol are trademarks of Project Xanadu. "Live
Picture" is a trademark of HSC. "Photoshop" is a trademark of Aldus.
"Macintosh" is a trademark of Apple. "Director" is a trademark of