Hypertext:
Are we still not there yet?
a hypertext “unkeynote”
Prof. dr. Paul De Bra
Eindhoven University of Technology
Hypertext, are we still not there yet?
• At HT’98 we asked “Are we here yet?”
• What was the answer, and why?
• if “yes”
then stop HT
else continue HT
• What was the answer really (each year), and why?
• if “yes”
then start making hypertext ubiquitous
else continue to further develop hypertext
• In fact we kept saying “No” until HT’2006
• Once we said “Yes” HT started doing well (again)
Let’s step back into history…
• Vannevar Bush inventor of hypertext?
“As We May Think” (Atlantic Monthly, 1945):
But what did he really suggest:
• The human mind … operates by association.
With one item in its grasp, it snaps instantly to the next that is
suggested by the association of thoughts, in accordance with
some intricate web of trails carried by the cells of the brain. It
has other characteristics, of course; trails that are not
frequently followed are prone to fade, items are not fully
permanent, memory is transitory.
• Selection by association, rather than indexing, may yet be
mechanized…. it should be possible to beat the mind
decisively in regard to the permanence and clarity of the items
resurrected from storage.
www.theatlantic.com/magazine/archive/1969/12/as-we-may-think/3881/
Let’s step back into history…
• What did Bush really suggest (cont.):
• If affords an immediate step, however, to associative indexing,
the basic idea of which is a provision whereby any item may be
caused at will to select immediately and automatically another.
This is the essential feature of the memex. The process of tying
two items together is the important thing.
• …he runs through an encyclopedia, finds an interesting but
sketchy article, leaves it projected. Next, in a history, he finds
another pertinent item, and ties the two together. Thus he
goes, building a trail of many items. Occasionally, he inserts a
comment of his own, either linking it into the main trail or
joining it by a side trail to a particular item…
• There is a new profession of trail blazers, those who find
delight in the task of establishing useful trails through the
enormous mass of the common record.
If Bush did not invent “hypertext”, who did?
• clue 1: who wrote
If Bush did not invent “hypertext”, who did?
• clue 2: who wrote
What is “hypertext” according to Ted Nelson?
Some Basic Hypertext Ideas
• Hypertext connects all texts
• Xanadu = magic place of literary memory
• Copying (even quoting) is evil: why quote when you
can show the original in-line?
• cross-reference links are a referral to information
elsewhere; (following the link takes you elsewhere)
• transclusions look like quotes but the original source is
shown in-line; it’s not a copy
(note: transclusion requires fine-grained addressing)
• (to avoid broken links) you can never really delete
anything; you can only create new versions
Quick look at hypertext between 1960 and 1990
• Working hypertext:
• Hypertext Editing System (1967), FRESS (1968)
• NLS, the oN-Line System (1968), successor of the
Augment project to augment the human mind
• ZOG, first hypertext system with “real” application
(1972 - 1982), used on the USS Carl Vinson
• Performance through simplicity:
• KMS let you navigate quickly (hoping to reduce
disorientation)
• Cards:
• Nodes became “cards” in NoteCards (over 50 types),
later also in HyperCard (with programmed behavior)
Quick look at hypertext between 1960 and 1990
• More and more functionality: Intermedia
• linking protocol to integrate different applications (for
different media); this is like “mash-ups”
• bidirectional links
• links not hardwired to nodes, users can create their
own web of links
• Complete programmability: HyperCard
• link is just the “goto” statement of a programming
language; link anchors are independent of content
• Link databases: Hyperties
• database of anchor-destination pairs
• open hypermedia takes this idea further
Some illustrations:
• Intermedia web view
• Intermedia create link
(and other options)
• HyperCard stacks
So hypertext systems became sophisticated!
• All functionality of all systems represented in a model:
the Dexter Model (NIST Workshop, 1990)
Essential Dexter elements/properties
• Components: atom, link, composite component
• atom is an atomic fragment
• composite:
− a page is a composite element (consists of atoms)
− an abstract composite component consists of other
(smaller) components, either abstract or atoms
(a composite with atoms is a “page”)
• link: sequence of two or more endpoints
(unidirectional, bidirectional or even undirected)
• Page selector: when a link destination is abstract
(composite) a page must be selected to be displayed
• Page constructor: after a page is selected the
presentation must be constructed from the atoms
And then…
The (early) Web
• Tim Berners Lee (1989/1990): the Web as an aid for
physicists for sharing documents
• Marc Andreessen (1992): the Mosaic browser made
the Web read-only
• Key properties/limitations in the basic Web:
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uni-directional links between single nodes
links are not objects (have no properties of their own)
links are hardwired to their source anchor
only pre-authored link destinations are possible
monolithic browser
static content, limited dynamic content through CGI
links can break
no transclusion of text, only of images
So why was this primitive Web successful?
1. Simplicity
•
Especially publishing was very simple (HTML)
2. Availability
•
“Everyone” could get it and use it (and it was free)
3. Timeliness
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The Web became available when Unix and X-Windows
became popular, and when Internet became available
4. (Pure) Client-Server Architecture
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This was fitting for the typical computing
infrastructure with powerful file servers and less
powerful workstations
Are we there yet? Take two 
• 1990 (start of the Web) threw us back to pre-1960
• Two approaches to recover:
• “This is bad, let’s build a better alternative.”
• “This is bad, let’s make it better.”
• Since 1990 we are working on the second approach:
“If you can’t beat them, join them.”
• “Are we there yet?” = “Have we integrated
everything from 1960-1990 into the Web yet?”
• but also: “Are we using everything from 1960-1990
on the Web yet?”
So how do we get “there”?
• Take the Web browser and server for granted!
Build extensions into this architecture
• browser plugins
• browser applets
• extend user interface,
• browser offers network int.
• proxy services
• change content “on the fly”
• server side scripts
• servlets
• select or compute content
• database back-end
• better storage
Example: GRAPPLE / GALE
• Overall GRAPPLE Infrastructure:
GRAPPLE Adaptive Learning Environment
Things that make GALE into “real” hypertext
• Domain Model (DM) with concepts and relations
• for each concept there may be several resources
• concepts and resources identified by URI
• User Model (UM) with for each concept certain
attributes (values)
• Links always refer to concepts:
• page selection: concept access involves (recursive)
resource selection
• page construction: page may contain
− conditionally included fragments
− conditionally included objects (object transclusion)
Things that make GALE able to get “there”
• Spring configuration lets you change most things:
• Processing is done by a pipeline of processors
(LayoutProc., Loadproc., XMLProcessor, …)
• XML adaptation is done by modules (one per tag)
− <if> for conditional fragments
− <object> for transclusion of objects (concepts)
− <a> for adaptive links
− <for> for generating a list of elements
− <variable> for selecting DM or UM info
− <view> for arbitrary generated views over DM
− <test> for multiple choice tests (specific for e-learning)
Example application: Milkyway
Are we there yet?
• Yes (for the most part) we are there. So…
• Time to look into hypertext applications more closely
• Careful not to confuse “hypertext” with “web
application”
• Time to look for new hypertext concepts that go
beyond the state of the art from 1990.
Visionaries have already done so:
− Semantic Web (web of data, leading to web of things)
− Multi-dimensional structures/browsing: ZigZag
− Mobile applications, combining on-line locationaware communication and information sources
− … what *you* will come up with!
See you all…
• at HT2011!