The Power of Protocols

There's this friend of mine who has an idea he likes to drop into conversations now and again about the significance of teh interweb having been invented by a physicist (or somebody like one), not a computer scientist (or somebody like one). A computer scientist, you see, would never have tolerated all those dangling pointers. But the possibility of dangling pointers is one of the things that makes the Web so easy to use, and from its ease of use comes its utility. No need to wonder if the implications of this have any significance for the continued utter irrelevance of Project Xanadu to the world. Ted Nelson has stated:

The Xanadu® project did not "fail to invent HTML". HTML is precisely what we were trying to PREVENT-- ever-breaking links, links going outward only, quotes you can't follow to their origins, no version management, no rights management.

(BTW, the complete absence of any semantically useful markup whatever on the source page for this quote is a miracle of irony)

Meanwhile a retrospective air has come across certain folks in the web world. Unusually for such a neophile bunch a certain amount of harking back (with suitably cynical commentary on the present day mixed in) has gone on. And so we are presented with what's being advertised as the first ever web page. One reddit contributor makes the observation that

it's also quite reassuring to see that the page still displays exactly as it was intended in 92. a few years later i was making sites with tables, and probably naively using ie-specific markup, which now look completely heinous. Another example of why adhering to standards increases the longevity of your data.

Indeed.

It seems as if info.cern.ch no longer resolves, but if it did then some of the original hyperlinks in that page would still work. That's amazing. Microsoft have also indulged in some digging around in the archives, and present their earliest homepage. Just an image, sadly, however, the wayback machine has got a very early corporate-stylee Microsoft home page with some links on it that (after the wayback munging is removed) do still work. They don't necessarily go where they say they go, although some of them do, and that's amazing squared.

Why am I amazed? Because I can't even begin to imagine going to the server end of most other distributed information systems (certainly none of the ones that I've built) and trying to use them in exactly the way that was intended ten or more years previously and expecting to get anything sensible back. Think about trying to connect to a remote object over an ORB with ten years between client and server. How does the Web mange to do the right thing?

In several ways: firstly, (as Berners-Lee points out, but I've lost the link) there is no reason that a URI should ever go stale, being neither the address of a location in space nor a pointer to an object. Secondly, and more importantly, the web works on an open text-based protocol. Ten year old and more email servers will provide a certain level of functionality by the same means. Thirdly, browsers are very lenient in how they interpret the HTML they receive, showing the user their best effort at rendering a page. That's a lot of sloppiness, a lot of flexibility, a lot of power.

All the rambling above is an excuse to link to this presentation (pdf) by Dick Gabriel, which covers this ground in more depth and with more eloquence, most especially the remarkable benefits that come from building a system out of components communicating via protocols rather than APIs.

Gabriel is a very interesting guy, and his other essays are well worth studying.