In March, 1989, a physicist and computer scientist named Tim Berners-Lee, who worked at the European nuclear research lab called CERN in Geneva, Switzerland, wrote a paper called “Information Management: A Proposal”. In that paper, which you can read here, Berners-Lee proposed a system scientists at CERN and at collaborating institutions could use to share their data and research insights. It would be always and everywhere available so that scientists could conduct their research more seamlessly and with greater cooperation. He proposed that documents would be made available through a hypertext system, an encoding technique in which snippets of text and images could be grabbed in real time from another location simply by invoking their unique, globally assigned name. Today we call those unique, globally assigned named URLs, or uniform resource locators. For example, the URL for Lewis’s homepage is unique to that page and is www.lewisu.edu. Every page on the Web has the kind of unique name Berners-Lee proposed.
Berners-Lee originally used the word “mesh” to describe the network in which these uniquely named documents would live and access each other. He didn’t decide to use the name “world wide web” until about a year later, as he continued to work on the project. He wrote the paper in the hopes of winning support from management at CERN, as he required time and funding to implement his idea. Once given the green light, Berners-Lee began designing and coding the new system.
In November, 1989, Berners-Lee demonstrated the first successful communication between a client computer requesting a document from a server computer that housed it. The client and the server communicated through a protocol Berners-Lee devised called Hypertext Transfer Protocol, or HTTP. A protocol spells out a vocabulary and the “rules of engagement” for two parties to use when communicating. For Berners-Lee’s design, when the client wanted to access a document stored on the server, it would issue a command that started with the word GET, followed by the unique name of the document it wanted. The server, provided it had the document, would then send it back to the client. What a simple – yet truly transformative – design!
Berners-Lee’s earliest implementations of this idea still required rather intimate knowledge of programming and networking to configure, and so it originally served only a small community of scientists. However, Berners-Lee laid the foundation for much broader adoption of the concept when he created Hypertext Markup Language, or HTML. HTML is the language in which all websites are coded. It enables people to populate and format the content of web pages using simple descriptors called tags. A tag is nothing more than a formatting code enclosed in angle brackets. For example, to bold something, I would put “<b>” in front of the text I wanted to bold, and I would put “</b>” to end the bolded section. There are tags for formatting text in italics, for creating tables, for including graphics, and for linking to other documents. This is yet another example of beauty in simplicity, a “no-duh” kind of innovation that somehow has fundamentally transformed how we live.
With the seminal work of Berners-Lee established, researchers just down the street from me at the University of Illinois at Urbana-Champaign built the first graphical web browser, Mosaic, in 1993. This innovation by UIUC researchers brought the power of Berners-Lee’s meshes to the masses. No longer were users of the World Wide Web limited to reading text on a black command window. They could now open up something called a web browser and see pictures and text in full color. I remember seeing Mosaic for the first time back in 1993 in the Grainger Electric Power Lab at the University of Illinois and being blown away. Of course, I had no idea how big this idea would become, and neither did my girlfriend (now wife), whom I showed this new fangled thing with what must have been remarkably nerdy pride when she visited one weekend from her school that didn’t have Internet connectivity yet. Perhaps she decided to marry me because she sensed I was on the ground floor of some world-changing movement. In reality, though, very few people had any idea what a revolution this would be.
It is difficult for us today to remember what the world was like before the Web. Heck, my students have never known a world without it. And yet, it is a system built upon the simplest of ideas. I think that is the very beauty of computer science: the combination of simple things often yields remarkable innovation. There will surely be another innovation as simple and as transformative as the one Berners-Lee started twenty-five years ago. The awesome thing for Computer Scientists is that nobody will see it coming, but we’ll all have a chance to make it happen.