It’s been said that the world hasn’t been this excited about a tablet since Moses came down the mountain. January 27, 2010, is the day Apple is slated to finally put us out of our misery and tell us what it’s all about. But imagine Steve Job moseys onto the stage, launches a forceful history of Apple’s portable record, and then announces Apple’s launching some new ipod speakers. (It happened a few years ago.) No “one more thing”. No tablet. Not even an iPhone OS 4.0.

Even if this happened (it won’t), Apple will have added huge value by sparking a conversation about the future of computing. While some say all the speculation is a waste of time, in this case, I’ve actually found some of the discourse rather fascinating. In particular, Gizmodo’s invocation of Jef Raskin and the “information appliance” dream, and John Gruber’s analysis.

I think Gruber nails it. Steve Jobs, in what many consider will be his final act at Apple, is attempting no less than the next generation of computing UI. Many people are already finding they can get by with just their iPhone for many tasks. Myself, I actually prefer to read blogs on iPhone NetNewsWire and Instapaper on iPhone Instapaper. I can read these away from the distraction of the big machine, whether at home, commuting, or in a shopping line. I’ve been trying to read stuff on mobile devices since the Palm Pilot, and now it’s truly practical. If people are finding their phone does some things better than the computer, imagine what will happen when you have a big touch-screen, let alone any secret-sauce innovations like tactile feedback or live docking into desktop equipment. I think we will find it’s more than adequate for many casual users and a valued extra device for power users.

But this is about much more than Apple. I think we can take it for granted that the medium-term future will be all about touch-screen tablets. We’ll struggle our way through questions about how to stand them up and challenges like their never-satisfying battery life. And what happens when they fall on the floor? Oh, and there will be patent wars galore. But the category will grow fast, as many people start to reap the benefits of a double whammy: better interaction, more convenient form factor.

The really interesting question is how will the UI on these tablets work? The Gizmodo and Daring Fireball articles point in the right direction - it will be more like the new “super phone” mobile generation and less like the traditional PC. Lots of sandboxing, lots of highly-customised idiosyncratic interfaces (but with common idioms), and lots of abstraction (==liberation) from the file system, lots of app stores and repositories.

Now one model for all this is iPhoneOS, the custom-built operating system Apple put together or its own phone. Is there another model?

Of course. The web.

And we can do it today. Apple won’t, others will. We have the makings of an operating system that does all that. Lots of sandboxing? Yep, the whole security model of the web assumes domains don’t trust each other, unlike traditional desktop applications. Lots of customised interfaces? Yep, with Canvas and CSS3 and SVG and WebGL and audio and video and screamingly-fast browsers and a million brilliant libraries and toolkits, yes. Lots of abstraction? Yep, the web never did like file systems, and with offline storage, it doesn’t have to. App stores? Yep, a simple system of URIs and standard HTTP security techniques can do it easily.

Most developers would rather code in technology they already know, that’s open, and has a diverse community contributing a wealth of “how-to” knowledge.

It’s all happening now. Google has ChromeOS. Palm has WebOS. Nokia and others have the W3C web widget standard. Stick these things on tablets, and a whole new generation of UI will flourish.