BT's hyperlink? Don't believe the hypertext

Although BT's claim to have submitted a patent for hyperlinks in 1980 may seem to predate the Web -- which was thought up in 1989 -- hypertext and hyperlinks have been around for a lot longer. In fact, hypertext -- in the sense of texts linked together by context, rather than as linear narrative -- has been around since the middle ages, when law books surrounded text with commentaries themselves surrounded by glossaries.

The first hypertext novel is widely regarded as Laurence Sterne's Tristram Shandy, which includes documents, flashbacks, asides and even the characters discussing the novel itself. Not bad for 1760, two centuries before William S Burroughs took the idea further into the realms of the unreadable.

However, the first combination of hypertext and machinery was described in an article called As We May Think by US researcher Vannevar Bush. Writing in 1945, he predicted digital photography, speech recognition systems, and personal computers that could access hypertext databases. He called his hypertext links associative trails, and the machine a memex (memory expander), but the concept was much the same as the Web.

Bush's article inspired many in the computer field, including Douglas Engelbart who proposed in 1963 an online hypertext system that linked and cross-referenced all the documents in a workspace shared by users at different physical locations. As part of his work, he invented the computer mouse as a navigational tool.

One of the more famous attempts at creating a hypertext system is Project Xanadu, started in 1960 and still not finished. Its creator, Ted Nelson, envisaged a docuverse where all writing is permanently available, accumulating links and cross references as time goes on. Nelson is credited with coming up with the term hypertext itself, first seen in print in 1965.

As personal computers got more common, more hypertext products became available, such as Xerox's NoteCards, Owl's Guide, and Apple's HyperCard. But the big change was the blossoming of the Internet, which made it feasible for people with no organisational or physical connections to interlink each other's information.

In the early 1980s, British physicist Tim Berners-Lee was working at the CERN (European Organization for Nuclear Research) European Particle Physics Laboratory near Geneva when he wrote a personal information manager called Enquire. It could handle random associations by linking database files. The obvious next stage would be to incorporate Internet links.

Berners-Lee decided to put codes within the text that would permit both text formatting and hypertext links, all based on the newly invented SGML mark-up language. In 1989, he floated a proposal for such a system, and after some initial resistance work began in the latter part of 1990 using students as staff.

Berners-Lee wrote the first Web browser and Web server programs on his NeXT Cube, with Mosaic -- the forerunner of Netscape and Internet Explorer -- coming along from the American National Centre for Supercomputing Applications in 1993.

Looking closely at BT's patent -- US patent number 4873662 -- it's clear that it doesn't directly reference hyperlinks at all. Instead, it describes a system where text sent from a central computer to a terminal can include non-displayable information: this could be a hypertext link, colour or formatting information, even pricing data.

The patent comes from work the Post Office -- BT's forerunner -- was doing on viewdata systems such as Prestel, which was one of the first public-access information and news databases in the world. However, hidden data sent with text was in widespread use before the patent was submitted: the British system of sending TV programme and news data alongside the TV signal, Teletext, used inline attributes to set colour and graphics as early as 1974, and indeed had its display system adopted by the Post Office for use with viewdata.

To be successfully defended, a patent must be shown to be original. Prior art, where the systems described in the patent existed before the patent was submitted, will nullify a patent and ruin any chances of the holder making any money. It looks, on first glance, that prior art indeed exists on BT's patent and thus it's unlikely to survive testing in court.

BT's attempt to claim a patent on a hyperlink is just one of many bits of nostalgia which the corporation is trying to get credit for inventing. Guy Kewney is incredulous at the brass neck of BT. Go to AnchorDesk UK for the news comment.

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