One wonders how the evolution of hypertext in general might have gone,
had the Web not been so pre-eminent in the 1990s.
> We should work toward a universal linked information system, in which
> generality and portability are more important than fancy graphics
> techniques and complex extra facilities.
And, one wonders how we've managed to stray from generality and
portability just enough that fancy graphics techniques and complex extra
facilities are the main thing driving the Web today, nine years after
the following proposal was written...
Written in March 1989; provided for historical interest only. The
diagrams are missing. The text has not been changed, even to correct
errors such as misnumbered figures or unfinished references. This
document was Tim Berners-Lee's attempt to persuade CERN management that
a global hypertext system was in CERN's interests.
Information Management: A Proposal
Tim Berners-Lee, CERN
March 1989, May 1990
This proposal concerns the management of general information about
accelerators and experiments at CERN. It discusses the problems of loss
of information about complex evolving systems and derives a solution
based on a distributed hypertext system.
Many of the discussions of the future at CERN and the LHC era end with
the question - "Yes, but how will we ever keep track of such a large
project?" This proposal provides an answer to such questions. Firstly,
it discusses the problem of information access at CERN. Then, it
introduces the idea of linked information systems, and compares them
with less flexible ways of finding information.
It then summarises my short experience with non-linear text systems
known as "hypertext", describes what CERN needs from such a system, and
what industry may provide. Finally, it suggests steps we should take to
involve ourselves with hypertext now, so that individually and
collectively we may understand what we are creating.
Losing Information at CERN
CERN is a wonderful organisation. It involves several thousand people,
many of them very creative, all working toward common goals. Although
they are nominally organised into a hierarchical management
structure,this does not constrain the way people will communicate, and
share information, equipment and software across groups.
The actual observed working structure of the organisation is a multiply
connected *web: whose interconnections evolve with time. In this
environment, a new person arriving, or someone taking on a new task, is
normally given a few hints as to who would be useful people to talk to.
Information about what facilities exist and how to find out about them
travels in the corridor gossip and occasional newsletters, and the
details about what is required to be done spread in a similar way. All
things considered, the result is remarkably successful, despite
occasional misunderstandings and duplicated effort.
A problem, however, is the high turnover of people. When two years is a
typical length of stay, information is constantly being lost. The
introduction of the new people demands a fair amount of their time and
that of others before they have any idea of what goes on. The technical
details of past projects are sometimes lost forever, or only recovered
after a detective investigation in an emergency. Often, the information
has been recorded, it just cannot be found.
If a CERN experiment were a static once-only development, all the
information could be written in a big book. As it is, CERN is constantly
changing as new ideas are produced, as new technology becomes available,
and in order to get around unforeseen technical problems. When a change
is necessary, it normally affects only a small part of the
organisation. A local reason arises for changing a part of the
experiment or detector. At this point, one has to dig around to find out
what other parts and people will be affected. Keeping a book up to date
becomes impractical, and the structure of the book needs to be
The sort of information we are discussing answers, for example,
* Where is this module used?
* Who wrote this code? Where does he work?
* What documents exist about that concept?
* Which laboratories are included in that project?
* Which systems depend on this device?
* What documents refer to this one?
The problems of information loss may be particularly acute at CERN, but
in this case (as in certain others), CERN is a model in miniature of the
rest of world in a few years time. CERN meets now some problems which
the rest of the world will have to face soon. In 10 years, there may be
many commercial solutions to the problems above, while today we need
something to allow us to continue.
Linked information systems
In providing a system for manipulating this sort of information, the
hope would be to allow a pool of information to develop which could grow
and evolve with the organisation and the projects it describes. For this
to be possible, the method of storage must not place its own restraints
on the information. This is why a "web" of notes with links (like
references) between them is far more useful than a fixed hierarchical
system. When describing a complex system, many people resort to diagrams
with circles and arrows. Circles and arrows leave one free to describe
the interrelationships between things in a way that tables, for example,
do not. The system we need is like a diagram of circles and arrows,
where circles and arrows can stand for anything.
We can call the circles nodes, and the arrows links. Suppose each node
is like a small note, summary article, or comment. I'm not over
concerned here with whether it has text or graphics or both. Ideally, it
represents or describes one particular person or object. Examples of
nodes can be
* Software modules
* Groups of people
* Types of hardware
* Specific hardware objects
The arrows which links circle A to circle B can mean, for example, that A...
* depends on B
* is part of B
* made B
* refers to B
* uses B
* is an example of B
These circles and arrows, nodes and links, have different significance
in various sorts of conventional diagrams: Family treeDataflow
diagramDependencyPERT chartOrganisational chart
Diagram Nodes are Arrows mean
People "Is parent of"
Software modules"Passes data to"
Module "Depends on"
Tasks "Must be done before"
People "Reports to"
The system must allow any sort of information to be entered. Another
person must be able to find the information, sometimes without knowing
what he is looking for.
In practice, it is useful for the system to be aware of the generic
types of the links between items (dependences, for example), and the
types of nodes (people, things, documents..) without imposing any
The problem with trees
Many systems are organised hierarchically. The CERNDOC documentation
system is an example, as is the Unix file system, and the VMS/HELP
system. A tree has the practical advantage of giving every node a unique
name. However, it does not allow the system to model the real world. For
example, in a hierarchical HELP system such as VMS/HELP, one often gets
to a leaf on a tree such as
HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS
only to find a reference to another leaf: "Please see
HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS"
and it is necessary to leave the system and re-enter it. What was needed
was a link from one node to another, because in this case the
information was not naturally organised into a tree.
Another example of a tree-structured system is the uucp News system (try
'rn' under Unix). This is a hierarchical system of discussions
("newsgroups") each containing articles contributed by many people. It
is a very useful method of pooling expertise, but suffers from the
inflexibility of a tree. Typically, a discussion under one newsgroup
will develop into a different topic, at which point it ought to be in a
different part of the tree. (See Fig 1).
Article 93 of alt.hypertext:
>From: firstname.lastname@example.org (Scott Duncan)
Subject: Re: Threat to free information networks
Date: 10 Mar 89 21:00:44 GMT
References: <1784.2416BB47@isishq.FIDONET.ORG> <email@example.com...
Reply-To: firstname.lastname@example.org (Scott Duncan)
Organization: Computer Technology Transfer, Bellcore
Doug Thompson has written what I felt was a thoughtful article on
censorship -- my acceptance or rejection of its points is not
particularly germane to this posting, however.
In reply Greg Lee has somewhat tersely objected.
My question (and reason for this posting) is to ask where we might
logically take this subject for more discussion. Somehow alt.hypertext
does not seem to be the proper place.
Would people feel it appropriate to move to alt.individualism or even
one of the soc groups. I am not so much concerned with the specific
issue of censorship of rec.humor.funny, but the views presented in
Speaking only for myself, of course, I am...
Scott P. Duncan (email@example.com OR ...!bellcore!ctt!duncan)
(Bellcore, 444 Hoes Lane RRC 1H-210, Piscataway, NJ...)
(201-699-3910 (w) 201-463-3683 (h))
Fig 1. An article in the UUCP News scheme.
The Subject field allows notes on the same topic to be linked together
within a "newsgroup". The name of the newsgroup (alt.hypertext) is a
hierarchical name. This particular note is expresses a problem with the
strict tree structure of the scheme: this discussion is related to
several areas. Note that the "References", "From" and "Subject" fields
can all be used to generate links.
The problem with keywords
Keywords are a common method of accessing data for which one does not
have the exact coordinates. The usual problem with keywords, however, is
that two people never chose the same keywords. The keywords then become
useful only to people who already know the application well.
Practical keyword systems (such as that of VAX/NOTES for example)
require keywords to be registered. This is already a step in the right
direction. A linked system takes this to the next logical step. Keywords
can be nodes which stand for a concept. A keyword node is then no
different from any other node. One can link documents, etc., to
keywords. One can then find keywords by finding any node to which they
are related. In this way, documents on similar topics are indirectly
linked, through their key concepts. A keyword search then becomes a
search starting from a small number of named nodes, and finding nodes
which are close to all of them.
It was for these reasons that I first made a small linked information
system, not realising that a term had already been coined for the idea:
A solution: Hypertext
Personal Experience with Hypertext
In 1980, I wrote a program for keeping track of software with which I
was involved in the PS control system. Called Enquire, it allowed one to
store snippets of information, and to link related pieces together in
any way. To find information, one progressed via the links from one
sheet to another, rather like in the old computer game "adventure". I
used this for my personal record of people and modules. It was similar
to the application Hypercard produced more recently by Apple for the
Macintosh. A difference was that Enquire, although lacking the fancy
graphics, ran on a multiuser system, and allowed many people to access
the same data.
Documentation of the RPC project (concept)
Most of the documentation is available on VMS, with the two
principle manuals being stored in the CERNDOC system.
1) includes: The VAX/NOTES conference VXCERN::RPC
2) includes: Test and Example suite
3) includes: RPC BUG LISTS
4) includes: RPC System: Implementation Guide
Information for maintenance, porting, etc.
5) includes: Suggested Development Strategy for RPC Applications
6) includes: "Notes on RPC", Draft 1, 20 feb 86
7) includes: "Notes on Proposed RPC Development" 18 Feb 86
8) includes: RPC User Manual
How to build and run a distributed system.
9) includes: Draft Specifications and Implementation Notes
10) includes: The RPC HELP facility
11) describes: THE REMOTE PROCEDURE CALL PROJECT in DD/OC
Help Display Select Back Quit Mark Goto_mark Link Add Edit
Fig 2. A screen in an Enquire scheme.
This example is basically a list, so the list of links is more important
than the text on the node itself. Note that each link has a type
("includes" for example) and may also have comment associated with
it. (The bottom line is a menu bar.)
Soon after my re-arrival at CERN in the DD division, I found that the
environment was similar to that in PS, and I missed Enquire. I therefore
produced a version for the VMS, and have used it to keep track of
projects, people, groups, experiments, software modules and hardware
devices with which I have worked. I have found it personally very
useful. I have made no effort to make it suitable for general
consumption, but have found that a few people have successfully used it
to browse through the projects and find out all sorts of things of their
Meanwhile, several programs have been made exploring these ideas, both
commercially and academically. Most of them use "hot spots" in
documents, like icons, or highlighted phrases, as sensitive
areas. touching a hot spot with a mouse brings up the relevant
information, or expands the text on the screen to include it. Imagine,
then, the references in this document, all being associated with the
network address of the thing to which they referred, so that while
reading this document you could skip to them with a click of the mouse.
"Hypertext" is a term coined in the 1950s by Ted Nelson [...], which has
become popular for these systems, although it is used to embrace two
different ideas. One idea (which is relevant to this problem) is the
concept: *Hypertext:: Human-readable information linked together in an
The other idea, which is independent and largely a question of
technology and time, is of multimedia documents which include graphics,
speech and video. I will not discuss this latter aspect further here,
although I will use the word "Hypermedia" to indicate that one is not
bound to text.
It has been difficult to assess the effect of a large hypermedia system
on an organisation, often because these systems never had seriously
large-scale use. For this reason, we require large amounts of existing
information should be accessible using any new information management
To be a practical system in the CERN environment, there are a number of
clear practical requirements.
Remote access across networks.
CERN is distributed, and access from remote machines is essential.
Access is required to the same data from different types of system
(VM/CMS, Macintosh, VAX/VMS, Unix)
Information systems start small and grow. They also start isolated and
then merge. A new system must allow existing systems to be linked
together without requiring any central control or coordination.
Access to existing data
If we provide access to existing databases as though they were in
hypertext form, the system will get off the ground quicker. This is
discussed further below.
One must be able to add one's own private links to and from public
information. One must also be able to annotate links, as well as nodes,
Bells and Whistles
Storage of ASCII text, and display on 24x80 screens, is in the short
term sufficient, and essential. Addition of graphics would be an
optional extra with very much less penetration for the moment.
An intriguing possibility, given a large hypertext database with typed
links, is that it allows some degree of automatic analysis. It is
possible to search, for example, for anomalies such as undocumented
software or divisions which contain no people. It is possible to
generate lists of people or devices for other purposes, such as mailing
lists of people to be informed of changes. It is also possible to look
at the topology of an organisation or a project, and draw conclusions
about how it should be managed, and how it could evolve. This is
particularly useful when the database becomes very large, and groups of
projects, for example, so interwoven as to make it difficult to see the
wood for the trees.
In a complex place like CERN, it's not always obvious how to divide
people into groups. Imagine making a large three-dimensional model, with
people represented by little spheres, and strings between people who
have something in common at work.
Now imagine picking up the structure and shaking it, until you make some
sense of the tangle: perhaps, you see tightly knit groups in some
places, and in some places weak areas of communication spanned by only a
few people. Perhaps a linked information system will allow us to see
the real structure of the organisation in which we work.
The data to which a link (or a hot spot) refers may be very static, or
it may be temporary. In many cases at CERN information about the state
of systems is changing all the time. Hypertext allows documents to be
linked into "live" data so that every time the link is followed, the
information is retrieved. If one sacrifices portability, it is possible
so make following a link fire up a special application, so that
diagnostic programs, for example, could be linked directly into the
Discussions on Hypertext have sometimes tackled the problem of copyright
enforcement and data security. These are of secondary importance at
CERN, where information exchange is still more important than secrecy.
Authorisation and accounting systems for hypertext could conceivably be
designed which are very sophisticated, but they are not proposed here.
In cases where reference must be made to data which is in fact
protected, existing file protection systems should be sufficient.
The following are three examples of specific places in which the
proposed system would be immediately useful. There are many others.
Development Project Documentation.
The Remote procedure Call project has a skeleton description using
Enquire. Although limited, it is very useful for recording who did
what, where they are, what documents exist, etc. Also, one can keep
track of users, and can easily append any extra little bits of
information which come to hand and have nowhere else to be
put. Cross-links to other projects, and to databases which contain
information on people and documents would be very useful, and save
duplication of information.
The CERNDOC system provides the mechanics of storing and printing
documents. A linked system would allow one to browse through concepts,
documents, systems and authors, also allowing references between
documents to be stored. (Once a document had been found, the existing
machinery could be invoked to print it or display it).
The "Personal Skills Inventory".
Personal skills and experience are just the sort of thing which need
hypertext flexibility. People can be linked to projects they have worked
on, which in turn can be linked to particular machines, programming
The State of the Art in Hypermedia
An increasing amount of work is being done into hypermedia research at
universities and commercial research labs, and some commercial systems
have resulted. There have been two conferences, Hypertext '87 and '88,
and in Washington DC, the National Institute of Standards and Technology
(NST) hosted a workshop on standardisation in hypertext, a followup of
which will occur during 1990.
The Communications of the ACM special issue on Hypertext contains many
references to hypertext papers. A bibliography on hypertext is given in
[NIST90], and a uucp newsgroup alt.hypertext exists. I do not,
therefore, give a list here.
Much of the academic research is into the human interface side of
browsing through a complex information space. Problems addressed are
those of making navigation easy, and avoiding a feeling of being "lost
in hyperspace". Whilst the results of the research are interesting,
many users at CERN will be accessing the system using primitive
terminals, and so advanced window styles are not so important for us
Interconnection or publication?
Most systems available today use a single database. This is accessed by
many users by using a distributed file system. There are few products
which take Ted Nelson's idea of a wide "docuverse" literally by allowing
links between nodes in different databases. In order to do this, some
standardisation would be necessary. However, at the standardisation
workshop, the emphasis was on standardisation of the format for
exchangeable media, nor for networking. This is prompted by the strong
push toward publishing of hypermedia information, for example on optical
disk. There seems to be a general consensus about the abstract data
model which a hypertext system should use.
Many systems have been put together with little or no regard for
portability, unfortunately. Some others, although published, are
proprietary software which is not for external release. However, there
are several interesting projects and more are appearing all the
time. Digital's "Compound Document Architecture" (CDA), for example, is
a data model which may be extendible into a hypermedia model, and there
are rumours that this is a way Digital would like to go.
Incentives and CALS
The US Department of Defence has given a big incentive to hypermedia
research by, in effect, specifying hypermedia documentation for future
procurement. This means that all manuals for parts for defence equipment
must be provided in hypermedia form. The acronym CALS stands for
*Computer-aided Acquisition and Logistic Support).
There is also much support from the publishing industry, and from
librarians whose job it is to organise information.
What will the system look like?
Let us see what components a hypertext system at CERN must have. The
only way in which sufficient flexibility can be incorporated is to
separate the information storage software from the information display
software, with a well defined interface between them. Given the
requirement for network access, it is natural to let this clean
interface coincide with the physical division between the user and the
remote database machine.
This division also is important in order to allow the heterogeneity
which is required at CERN (and would be a boon for the world in
*** original image omitted **
Fig 2. A client/server model for a distributed hypertext system.
Therefore, an important phase in the design of the system is to define
this interface. After that, the development of various forms of display
program and of database server can proceed in parallel. This will have
been done well if many different information sources, past, present and
future, can be mapped onto the definition, and if many different human
interface programs can be written over the years to take advantage of
new technology and standards.
Accessing Existing Data
The system must achieve a critical usefulness early on. Existing
hypertext systems have had to justify themselves solely on new data. If,
however, there was an existing base of data of personnel, for example,
to which new data could be linked, the value of each new piece of data
would be greater.
What is required is a gateway program which will map an existing
structure onto the hypertext model, and allow limited (perhaps
read-only) access to it. This takes the form of a hypertext server
written to provide existing information in a form matching the standard
interface. One would not imagine the server actually generating a
hypertext database from and existing one: rather, it would generate a
hypertext view of an existing database.
orginal picture not converted
Fig 3. A hypertext gateway allows existing data to be seen in hypertext form
by a hypertext browser.
Some examples of systems which could be connected in this way are
This is a Unix electronic conferencing system. A server for uucp news
could makes links between notes on the same subject, as well as showing
the structure of the conferences.
This is Digital's electronic conferencing system. It has a fairly wide
following in FermiLab, but much less in CERN. The topology of a
conference is quite restricting.
This is a document registration and distribution system running on
CERN's VM machine. As well as documents, categories and projects,
keywords and authors lend themselves to representation as hypertext
This would allow any file to be linked to from other hypertext
The Telephone Book
Even this could even be viewed as hypertext, with links between people
and sections, sections and groups, people and floors of buildings, etc.
The unix manual
This is a large body of computer-readable text, currently organised in
a flat way, but which also contains link information in a standard
format ("See also..").
A generic tool could perhaps be made to allow any database which uses a
commercial DBMS to be displayed as a hypertext view.
In some cases, writing these servers would mean unscrambling or
obtaining details of the existing protocols and/or file formats. It may
not be practical to provide the full functionality of the original
system through hypertext. In general, it will be more important to allow
read access to the general public: it may be that there is a limited
number of people who are providing the information, and that they are
content to use the existing facilities.
It is sometimes possible to enhance an existing storage system by coding
hypertext information in, if one knows that a server will be generating
a hypertext representation. In 'news' articles, for example, one could
use (in the text) a standard format for a reference to another
article. This would be picked out by the hypertext gateway and used to
generate a link to that note. This sort of enhancement will allow
greater integration between old and new systems.
There will always be a large number of information management systems -
we get a lot of added usefulness from being able to cross-link
them. However, we will lose out if we try to constrain them, as we will
exclude systems and hamper the evolution of hypertext in general.
We should work toward a universal linked information system, in which
generality and portability are more important than fancy graphics
techniques and complex extra facilities.
The aim would be to allow a place to be found for any information or
reference which one felt was important, and a way of finding it
afterwards. The result should be sufficiently attractive to use that it
the information contained would grow past a critical threshold, so that
the usefulness the scheme would in turn encourage its increased use.
The passing of this threshold accelerated by allowing large existing
databases to be linked together and with new ones.
A Practical Project
Here I suggest the practical steps to go to in order to find a real
solution at CERN. After a preliminary discussion of the requirements
listed above, a survey of what is available from industry is obviously
required. At this stage, we will be looking for a systems which are
* portable, or supported on many platforms,
* Extendible to new data formats.
We may find that with a little adaptation, pars of the system we need
can be combined from various sources: for example, a browser from one
source with a database from another.
I imagine that two people for 6 to 12 months would be sufficient for
this phase of the project.
A second phase would almost certainly involve some programming in order
to set up a real system at CERN on many machines. An important part of
this, discussed below, is the integration of a hypertext system with
existing data, so as to provide a universal system, and to achieve
critical usefulness at an early stage.
(... and yes, this would provide an excellent project with which to try
our new object oriented programming techniques!) TBL March 1989, May
Nelson, T.H. "Getting it out of our system" in Information Retrieval: A
Critical Review", G. Schechter, ed. Thomson Books, Washington D.C.,
Smish, J.B and Weiss, S.F,"An Overview of Hypertext",in Communications
of the ACM, July 1988 Vol 31, No. 7,and other articles in the same
special "Hypertext" issue.
Campbell, B and Goodman, J,"HAM: a general purpose Hypertext Abstract
Machine",in Communications of the ACM July 1988 Vol 31, No. 7
Akscyn, R.M, McCracken, D and Yoder E.A,"KMS: A distributed hypermedia
system for managing knowledge in originations", in Communications of
the ACM , July 1988 Vol 31, No. 7
Hypertext on Hypertext, a hypertext version of the special Comms of the
ACM edition, is avialble from the ACM for the Macintosh or PC.
Under unix, type man rn to find out about the rn command which is used
for reading uucp news.
Under VMS, type HELP NOTES to find out about the VAX/NOTES system
On CERNVM, type FIND DOCFIND for infrmation about how to access the
J. Moline et. al. (ed.) Proceedings of the Hypertext Standardisation
Workshop January 16-18, 1990, National Institute of Standards and
Technology, pub. U.S. Dept. of Commerce
Power corrupts; obsolete power corrupts obsoletely.
-- Ted Nelson, hypertext pioneer, on Microsoft