WorldWideWeb: Proposal for a HyperText Project
- To:
- P.G. Innocenti/ECP, G. Kellner/ECP, D.O. Williams/CN
- Cc:
- R. Brun/CN, K. Gieselmann/ECP, R.─ Jones/ECP, T.─ Osborne/CN,
P. Palazzi/ECP, N.─ Pellow/CN, B.─ Pollermann/CN, E.M.─ Rimmer/ECP
- From:
- T. Berners-Lee/CN, R. Cailliau/ECP
- Date:
- 12 November 1990
The attached document describes in more detail a Hypertext project.
HyperText is a way to link and access information of various kinds
as a web of nodes in which the user can browse at will. It provides
a single user-interface to large classes of information (reports,
notes, data-bases, computer documentation and on-line help). We propose
a simple scheme incorporating servers already available at CERN.
The project has two phases: firstly we make use of existing software
and hardware as well as implementing simple browsers for the user's
workstations, based on an analysis of the requirements for information
access needs by experiments. Secondly, we extend the application
area by also allowing the users to add new material.
Phase one should take 3 months with the full manpower complement,
phase two a further 3 months, but this phase is more open-ended, and
a review of needs and wishes will be incorporated into it.
The manpower required is 4 software engineers and a programmer, (one
of which could be a Fellow). Each person works on a specific part
(eg. specific platform support).
Each person will require a state-of-the-art workstation , but there
must be one of each of the supported types. These will cost from 10
to 20k each, totalling 50k. In addition, we would like to use commercially
available software as much as possible, and foresee an expense of
30k during development for one-user licences, visits to existing installations
and consultancy.
We will assume that the project can rely on some computing support
at no cost: development file space on existing development systems,
installation and system manager support for daemon software.
T. Berners-Lee R. Cailliau
WorldWideWeb:Proposal for a HyperText Project
T. Berners-Lee / CN, R. Cailliau / ECP
Abstract:HyperText is a way to link and access information of various kinds
as a web of nodes in which the user can browse at will. Potentially,
HyperText provides a single user-interface to many large classes of
stored information such as reports, notes, data-bases, computer documentation
and on-line systems help. We propose the implementation of a simple
scheme to incorporate several different servers of machine-stored
information already available at CERN, including an analysis of the
requirements for information access needs by experiments.
IntroductionThe current incompatibilities of the platforms and tools make it impossible
to access existing information through a common interface, leading
to waste of time, frustration and obsolete answers to simple data
lookup. There is a potential large benefit from the integration of
a variety of systems in a way which allows a user to follow links
pointing from one piece of information to another one. This forming
of a web of information nodes rather than a hierarchical tree or an
ordered list is the basic concept behind HyperText.
At CERN, a variety of data is already available: reports, experiment
data, personnel data, electronic mail address lists, computer documentation,
experiment documentation, and many other sets of data are spinning
around on computer discs continuously. It is however impossible to
"jump" from one set to another in an automatic way: once you found
out that the name of Joe Bloggs is listed in an incomplete description
of some on-line software, it is not straightforward to find his current
electronic mail address. Usually, you will have to use a different
lookup-method on a different computer with a different user interface.
Once you have located information, it is hard to keep a link to it
or to make a private note about it that you will later be able to
find quickly.
Hypertext conceptsThe principles of hypertext, and their applicability to the CERN environment,
are discussed more fully in─ [1], a glossary of technical terms is
given in [2]. Here we give a short presentation of hypertext.
A program which provides access to the hypertext world we call a browser.
When starting a hypertext browser on your workstation, you will first
be presented with a hypertext page which is personal to you : your
personal notes, if you like. A hypertext page has pieces of text
which refer to other texts. Such references are highlighted and can
be selected with a mouse (on dumb terminals, they would appear in
a numbered list and selection would be done by entering a number).
When you select a reference, the browser presents you with the text
which is referenced: you have made the browser follow a hypertext
link :
(see Fig. 1: hypertext links).
That text itself has links to other texts and so on. In fig. 1, clicking
on the GHI would take you to the minutes of that meeting. There you
would get interested in the discussion of the UPS, and click on the
highlighted word UPS to find out more about it.
The texts are linked together in a way that one can go from one concept
to another to find the information one wants. The network of links
is called a web . The web need not be hierarchical, and therefore
it is not necessary to "climb up a tree" all the way again before
you can go down to a different but related subject. The web is also
not complete, since it is hard to imagine that all the possible links
would be put in by authors. Yet a small number of links is usually
sufficient for getting from anywhere to anywhere else in a small number
of hops.
The texts are known as nodes. The process of proceeding from node
to node is called navigation . Nodes do not need to be on the same
machine: links may point across machine boundaries. Having a world
wide web implies some solutions must be found for problems such as
different access protocols and different node content formats. These
issues are addressed by our proposal.
Nodes can in principle also contain non-text information such as diagrams,
pictures, sound, animation etc. The term hypermedia is simply the
expansion of the hypertext idea to these other media. Where facilities
already exist, we aim to allow graphics interchange, but in this project,
we concentrate on the universal readership for text, rather than on
graphics.
ApplicationsThe application of a universal hypertext system, once in place, will
cover many areas such as document registration, on-line help, project
documentation, news schemes and so on. It would be inappropriate
for us (rather than those responsible) to suggest specific areas,
but experiment online help, accelerator online help, assistance for
computer center operators, and the dissemination of information by
central services such as the user office and CN and ECP divisions
are obvious candidates. WorldWideWeb (or W3 ) intends to cater for
these services across the HEP community.
Scope: Objectives and non-ObjectivesThe project will operate in a certain well-defined subset of the subject
area often associated with the "Hypertext" tag. It will aim:
- to provide a common (simple) protocol for requesting human readable
information stored at a remote system, using networks;
- to provide a protocol within which information can automatically be
exchanged in a format common to the supplier and the consumer;
- to provide some method of reading at least text (if not graphics)
using a large proportion of the computer screens in use at CERN;
- to provide and maintain at least one collection of documents, into
which users may (but are not bound to) put their documents. This collection
will include much existing data. (This is partly to give us first
hand experience of use of the system, and partly because members of
the project will already have documentation for which they are responsible)
- to provide a keyword search option, in addition to navigation by following
references, using any new or existing indexes (such as the CERNVM
FIND indexes). The result of a keyword search is simply a hypertext
document consisting of a list of references to nodes which match the
keywords. to allow private individually managed collections of documents
to be linked to those in other collections. to use public domain software
wherever possible, or interface to proprietary systems which already
exist.
- to provide the software for the above free of charge to anyone.
The project will not aim
- to provide conversions where they do not exist between the many document
storage formats at CERN, although providing a framework into which
such conversion utilities can fit;
- to force users to use any particular word processor, or mark-up format;
- to do research into fancy multimedia facilities such as sound and
video;
- to use sophisticated network authorisation systems. data will be either
readable by the world (literally), or will be readable only on one
file system, in which case the file system's protection system will
be used for privacy. All network traffic will be public.
Requirements AnalysisIn order to ensure response to real needs, a requirements analysis
for the information access needs of a large CERN experiment will be
conducted at the very start, in parallel with the first project phase.
This analysis will at first be limited to the activities of the members
of the Aleph experiment, and later be extended to at least one other
experiment. An overview will be made of the information generation,
storage and retrieval, independent of the form (machine, paper) and
independent of the finality (experiment, administration).
The result should be:
- lists of sources, depots and sinks of information,
- lists of formats,
- diagrams of flow,
- statistics on traffic,
- estimated levels of importance of flows,
- lists of client desires and / or suggested improvements,
- estimated levels of satisfaction with platforms,
- estimated urgency for improvements.
This analysis will itself not propose solutions or improvements, but
its results will guide the project.
Architecture The architecture of the hypertext world is one of data stored on server
machines, and client processes on the same or other machines. The
machines are linked by some network (fig. 2). Fig. 2: proposed model
for the hypertext world A workstation is either an independent machine
in your office or a terminal connected to a close-by computer, and
connected to the same network. The servers are active processes that
reply to requests. The hypertext data is explicitly accessible to
them. Servers can be many on the same computer system, but then each
caters to a specific hypertext base. Clients are browser processes,
usually but not necessarily on a different computer system. Information
passed is of two kinds: nodes and links.
Building blocksBrowsers and servers are the two building blocks to be provided.
A browseris a native application program running on the client machine:-
- it performs the display of a hypertext node using the client hardware
& software environment. For example, a Macintosh browser will use
the Macintosh interface look-and-feel.
- it performs the traversal of links. For example, when using a Macintosh
to browse on CERNVM FIND it will be the Macintosh browser which remembers
which links were traversed, how to go back etc., whereas the CERNVM
server just responds by handing the browser nodes, and has no idea
of which nodes the user has visited.
- it performs the negotiation of formats in dialog with the server.
For example, a browser for a VT100 type display will always negotiate
ASCII text only, whereas a Macintosh browser might be constructed
to accept PostScript or SGML.
A serveris a native application program running on the server machine:-
- it manages a web of nodes on that machine.-
- it negotiates the presentation format with the browser, performing
on-the-fly (or cached) conversions from its own internal format, if
any..
Operation A link is specified as an ASCII string from which the browser can
deduce a suitable method of contacting an appropriate server. When
a link is followed, the browser addresses the request for the node
to the server. The server therefore has nothing to know about other
servers or other webs and can be kept simple.
Once the server has located the requested node, it will know from
the node contents what the node's format is (eg. pure ASCII, marked-up,
word processor storage and which word processor etc.). The server
then begins a negotiation with the browser, in which they decide between
them what format is acceptable for display on the user's screen.
This negotiation will be based only on existing conversion programs
and formats: it is not in the scope of W3 to write new converters.
The last resort in the negotiation is the binary transfer of the
node contents to a file in the user's file space. Negotiating the
format for presentation is particular to W3.
Project phasesProvided with resources mentioned below, we foresee the first two
phases of the project as achieving the following goals:
Phase 1 -- Target: 3 months from start
- Browsers on dumb terminal to open readership to anyone with a computer
or PC.(?)
- Browsers on vt220 terminals to give cursor-oriented readership to
a very large proportion of readers; A browser on the Macintosh in
the Macintosh style; A browser on the NeXT using the NeXTStep tools,
as a fast prototype for ideas in human interface design and navigation
techniques.
- A server providing access to the world of Usenet/Internet news articles.
*
- A server providing access to all the information currently stored
on CERNVM and mentioned in the FIND index. This should include CERN
program library notes, IBM and CERN CMS help screens, CERN/CN writeups,
Computer Newsletter articles, etc.
- A server which may be installed on any machine to allow files on that
machine to be accessed as hypertext.
- The ability for users to write, using markup tags, their own hypertext
for help files. No other hypertext editing capability will necessarily
be implemented in this phase.
- A gateway process to allow access between the Internet and DECnet
protocol worlds.
- A set of guidelines on how to manage a hypertext server.
- A requirements analysis of the information access needs for a large
experiment.
At this stage, readership is universal, but the creation of new material
relies on existing systems. For example, the introduction of new material
for the FIND index, or the posting of news articles will use the
same procedures as at present. we gain useful experience in the representation
of existing data in hypertext form, and in the types of navigational
and other aids appreciated by users in high energy physics.
Phase 2 -- Target: 6 months from startIn this important phase, we aim to allow
- The creation of new links and new material by readers. At this stage,
authorship becomes universal.
- A full-screen browser on VM/XA for those using CERNVM, and other HEP
VM sites;
- An X-window browser/editor, giving the sophisticated facilities originally
prototyped under NeXTStep to the wide X-based community. (We imagine
using OSF/Motif subject to availability)
- The automatic notification of a reader when new material of interest
to him/her has become available. This is essential for news articles,
but is very useful for any other material.
The ability of readers to create links allows annotation by users
of existing data, allows to add themselves and their documents to
lists (mailing lists, indexes, etc). It should be possible for users
to link public documents to (for example) bug reports, bug fixes,
and other documents which the authors themselves might never have
realised existed.This phase allows collaborative authorship. It provides
a place to put any piece of information such that it can later be
found. Making it easy to change the web is thus the key to avoiding
obsolete information. One should be able to trace the source of information,
to circumvent and then to repair flaws in the web.
The following functions are identifiable. They do not necessarily
correspond to individuals on a one to one basis. The initials in
brackets indicate people who have already expressed an interest in
the project and who have the necessary skills but do not indicate
any commitment as yet on thier part or the part of their managers.
We are of course very open to involvement from others.
- System architect. Coordinate development, protocol definition, etc;
ensures integrity of design. (50% TBL?) Market research and product
planner. Discuss the project and its features with potential and actual
users in all divisions. Prepare criteria for feature selection and
development priority. (50% RC?)
- Hyper-Librarian. Oversees the web of available data, ensuring its
coherency. Interface with users, train users. Manages indexes and
keyword systems. Manages data provided by the project itself. (100%
KG?)
- Software engineer: NeXTStep. Provide browser/editor interface under
the NeXTStep human interface tools. Experiment with navigational aids.
Keep a running knowledge of the NeXTStep world. (50%TBL?)
- Software engineer: X-windows and human interface. Provide browser/editor
human interface under OSF/Motif. Respond to user suggestion for ease
of use improvements and options. Create an aesthetic, practical human
interface. Keep a running knowledge of the X world. (75%RJ?)
- Software engineer: IBM mainframe. Provide browser service on CERNVM
and other HEP VM sites. Maintain the FIND server software. Keep up
a running knowledge of the CMS, Rexx world. (75% BP?)
- Software engineer: Macintosh. Provide browser/editor for the mac,
using whatever tools are appropriate (Thnk-C, HyperCard, etc?). (50%RC?)
- Software engineer: C. Help write code for dumb terminal or vt100 browsers,
and portable browser code to be shared between browers. This could
include a technical student project. (100% NP? + A.N.Other?)
We foresee that a demand may arise for browsers on specific systems,
for specific customizations, and for servers to make specific existing
data available online as hypertext. We intend to enthusiastically
support such widening of the web. Of course, we may have to draw on
more manpower and specific expertise in these cases.
2. Other resources We will require the following support in the way of equipment and
services.
- We feel it is important for those involved in the project to be able
to work close to each other and exchange ideas and problems as they
work. An office area or close group of offices is therefore required.
- Each person working on the project will require a state-of-the-art
workstation. Experience shows that a workstation has to be upgraded
in some way every two years or so as software becomes more cumbersome,
and memory/speed requirements increase. This, and the cost of software
upgrades, we foresee as reasonable expenses. We imagine using a variety
of types of workstation as we provide software on a variety of machines,
but otherwise NeXTs. For VMS machines, we would like the support
of an existing VAXcluster to minimize our own system management overheads.
- We would like to be able to purchase licenses for commercial hypertext
software where we feel this could be incorporated into the project,
and save development and maintenance time, or where we feel we could
gain useful experience from its use. (Approximate examples are: Guide
license: CHF750; KMS full author license CHF1500, evaluation kit
CHF100. FrameMaker: CHF2000)
- We will require computing support. In particular, we will require
a reliable backed up NFS (or equivalent) file server support for
our development environment. We will also need to run daemon software
on machines with Internet, DECnet and BITNET connectivity, which
will require a certain amount of support from operators and system
managers.
Future paths
- The two phases above will provide an extremely useful set of tools.
Though the results seem ambitious, the individual steps necessary
are well within our abilities with available technology. Future developments
which would further enhance the project could include:
- Daemon programs which run overnight and build indexes of available
information.
- A server automatically providing a hypertext view of a (for example
Oracle) database, from a description of the database and a description
(for example in SQL) of the view required.
- Work on efficient networking over wide areas, negotiation with other
sites to provide compatible online information.
- A serious study of the use and abuse of the system, the sociology
of its use at CERN.
References
- [1]
- T. Berners-Lee/CN, HyperText and CERN . An explanation of hypertext,
and why it is important for CERN. A background document explaining
the ideas behind this project.
- [2]
- T. Berners-Lee/CN, Hypertext Design Issues . A detailed look at
hypertext models and facilities, with a discussion of choices to be
made in choosing or implementing a system.
- [3]
- Other documentation on the project is stored in hypertext form
and which leads to further references.
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