Robert Cailliau CERN
What it is be consulted from a computer in Chicago, the SLAC pre The World-Wide Web is a client-server information print database could be interrogated from your desk in system on the Internet. Conceived as a unique way to Geneva, all without having to know anything whatsoever give particle physicists easy access to their data wherever about the remote computer systems. they worked, the Web, or W3, has grown into something much bigger. It now disseminates information from In 1993 NCSA, the US National Center for Supercom businesses, government agencies, universities, schools puting Applications, produced the X-Mosaic browser. and even individuals. This software allowed the display of coloured images, giving to the Unix platform a glamorous window on the Instead of just a single local disk, the Web has the whole Web. It stirred the exhibitionist in many Unix/Internet world as its library. programmers, and drove them to set up a Web server Documents are linked to each other, forming a single showing off scenes of the local site. NCSA also global network of information. produced versions for Apple Macintosh and Microsoft Windows, thus opening the Web to a large audience. Traffic evolution (NFS backbone, USA) The European Commission approved its first Web project (WISE) at the end of the same year, with CERN as one of 2oook r Characters the partners. I per second Prodigy& - America On Line 1994 reaiiy was rhe "Year of the -W"eb". Tne worid's First International World-Wide Web conference was held at CERN in May. This event was heavily oversubscribed. 1500k largest interactive It was attended by 400 users and developers, and was service hailed as the "Woodstock of the Web". As 1994 progressed, Web stories got into all the media. A second IOOOk conference was held in the US in October, organised by NCSA and the already created International WWW a novel per Conference Committee (IW3C2). It was attended by 500k second~ 1300 people. The next conference will be held in Darmstadt, hosted by the Fraunhofer Gesellschaft (the main contractor for the WISE project). By the end of 1994, the Web had 10,000 servers, of 1993 1994 1995 which 2,000 are commercial, and 10 million users. Traffic was equivalent to shipping the entire collected works of Shakespeare every second. Already the largest interactive service on the Internet, the Web is now driving its current phenomenal expansion. How it started The Web is an outstanding example of how basic It all began in 1989, when Tim Berners-Lee and Robert research can generate progress in a completely Cailliau proposed a distributed information system for unforseeable way: technology transfer at its best. Whilst CERN based on hypertext (see "WWW Words" at the there is no doubt that it would have appeared somewhere end). sometime, the driving force of high energy physics research and the productive working atmosphere of During 1990, the first browser and server were produced CERN have made the Web happen here and now. and although they were limited to a particular operating system, NeXTStep, their advanced information handling capabilities set the standard for everything that has followed. The Web as we know it had arrived. How it works In 1991, technical student Nicola Pellow wrote a simple The Web is a world of information available at the click browser which could be used on many different of a mouse. To use it, you need a computer, a connection computers. Its adaptability to all existing computing to the Internet, and a browser (see also "Internet & systems generated the interest needed to start a snowball WWW"). u effect. Soon the DESY (Hamburg) phone directory could 0 0 CERN WWW 1995.10.16 When you run your browser, it finds and displays a page Web. Users are to be found everywhere in the millions. of information, which might be held on your own But to publish information, you need to run a server computer (your home page), or fetched from somewhere machine, listening 24 hours a day to the incoming requests. This requires a reasonable connection and a else, you needn't know or even care where .it come~ from. It works by hiding a network hypertext hnk behmd the subscription to the Internet. While almost all academic highlighted items which appear on the screen. Certain institutes already had such connections and now run a Web service, not all businesses do. Large companies words, phrases, or even images are highlighted, and clicking on them causes the browser to go off and find with a long Internet history have their servers, both for internal and external use. Small companies usually rent another page, which probably contains more highlighted space on a commercially-run server, thus sharing the items, and so on. For example, starting from the CERN costs of a full connection. Individuals with servers are "Welcome page" in Switzerland your next click might only just appearing. fetch a document from a physics lab at the other side of the world. All the information seems to be in the little box in front of you, and in a sense it is. When you click on a piece of highlighted text your browser "orders a document" from another computer, receives it by "return Future Directions mail" and displays it. You are then free to read the new The technology of the Web is continually extended to page at leisure, without further consumption of network cater for new needs. Security, authoring, multimedia, resources. access by session and billing are the most important Browsers exist for the three most popular platforms: features now being added. Apple Macintosh, Microsoft Windows and X-Window The most important aspect of all new developments is systems. that the Web should remain an open standard for all to use and for no-one to lock up into a proprietary system. This is the avowed goal of the International World-Wide Web Consortium, a newly formed body of institutes and companies from all over the world. In 1994, CERN submitted a proposal in this spirit to the Commission of the European Union under the ESPRIT programme. But with approval of the LHC project clearly in sicrht, it was decided that further Web development was an0 activity beyond the LaboratoryI s pnmary' nuss1on.' • A new home for basic Web work was needed. The European Commission turned tv the French National Institute for Research in Computer Science and Controls, INRIA, to take up the Commission-funded "WebCore" development project in Europe. INRIA will work in collaboration with the Laboratory of Computer Science at the Massachusetts Institute of Technology, MIT, where Berners-Lee has taken up a research appointment. The The Web has its own transport protocol, HTTP, and its Consortium will be run by this collaboration. own document structure based on SGML (the Web DTD, called HTML). However, it has also integrated the With about 1,000 new servers appearing every day, the protocols of Gopher, ftp and telnet, and it has gateways to Web is set to become as familiar as the telephone, whilst others. Thus the documents available through these CERN's computer scientists concentrate on providing a earlier systems are also automatically and indistin service for the physics community. guishably visible through the Web. The Web may be used to initiate processes on either the client or the server. A request can start a database search on a server, returning a synthesised document. A document returned in an unfamiliar format can cause the browser to start a process on the client machine in order to interpret it. The Web's ability to negotiate formats between client and server makes it possible to ship any type of document from a server to a client, provided the client has the appropriate software to handle that format. This makes video, sound and anything else accessible without the need for a single application that understands everything. Starting processes means it is feasible to initiate a video conference or a terminal session entirely by a click of the mouse on a highlighted phrase in a document.
Who uses it Practically everyone on the Internet now knows about the
CERN WWW 1995.10.16 2 The Internet is not a network proper, but much more a standard for communication. If two computers want to How to bootstrap exchange data, they have to agree on a common way of behaving. This standard (the Internet protocol) is like the In order to get started as an individual user, you should traffic rules: everyone drives on the right hand side of the find out who the Internet providers are in your area. road, stops for red lights and so on: Commercial companies offer services whereby you can dial-up an Internet centre and be connected for the price of a local phone call and a monthly subscription to the service. If you are in an environment where Internet services are already available (university, large company), then it is likely that the Web is already installed by your local computing support groups. In case you do need to start from scratch, but you do have access to the Internet, you may reach the Web temporarily by doing telnet www.cern.ch which will give you automatically a free but limited access through a modest interface to the Web. From there, you can use the Web to find all instructions necessary to load software for your machine. This The Internet transfers data in little packets between service is not intended for normal Web access. Its computers, just like thousands of cars can use the same interface does not show any images. roads even if they all have different destinations. No car occupies the whole road to itself.
Internet & WWW This section explains a little more about how WWW and the Internet function, and what the difference is. First, there are the cables: they make the connections. Cables are laid down by the PTTs or by private firms. Cables are leased for prices that depend on their capacity. A single telephone line like the one leading from your home can handle about 3 kilobytes per second, the equivalent of a page of text. Optical fibres handle well into the billions of bytes per second. Even if there are many differences between the cable networks of different countries, they are all interconnected, like the roads:
The Web is one of the Internet services: it uses the Internet to transfer its information. WWW servers are like mail-order distributors of goods. They send their information to the requesting clients. The r6le of the Web protocol (HTI'P) is like that of a standardised order form.
CERN WWW 1995.10.16 3 World Wide Web Words:
Browser: a client program allowing mouse-click access to the Web. Homepage: the document you start from (usually written by you on your local machine). Not to be confused with a "Welcome page". HTML: HyperText Mark-up Language, the language in which Web documents are structured. HTTP: HyperText Transfer Protocol, the set of rules governing communication between browsers and servers .. Hypertext: a way of linking related pieces of information on a computer. Internet: the network built of existing networks through the use of a common standard. IW3C2: the International W3 Conference Committee, which organises the official Web technology conferences that are held twice a year. Server: software and/or machine delivering Web documents in response to client requests. URL: Uniform Resource Locator, the computer addresses used by the Web, "http://www.cem.ch" is the URL for CERN's Web server. WebCore: the European Web technology development project run by INRIA. Welcome page: the "first document" of a given server, what you get when you ask it for nothing specific. Often mistakenly called "home page". WWW, W3, the Web: alternative names for the World-Wide Web.
CERN, the European Laboratory for· Particle Physics, has its site straddling the French-Swiss border near Geneva. At present, its Member States are Au~tria, Belgium, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Italy, Netherlands, Norway, Poland, Portugal, the Slovak Republic, Spain, Sweden, Switzerland and the United Kingdom. Israel, the Russian Federation, Turkey, Yugoslavia (status suspended after UN embargo, June 1992), the European Commission and Unesco have observer status. Useful URLs: CERN: http://www.cem.ch/ World-Wide Web: http://www.w3.org/ INRIA: http://www. i nria.fr MIT: http://web.mit.edu/ WebCore: http://www.cern.ch/CERN/WorldWide Web/W ebCore.html
95.10.09 Robert Cailliau WWW Support ECP Division
NSF Backbone statistics : courtesy the Internet Society
CERN WNW 1995.10.16 4