Some people want the Apple Tablet to run Mac OS X's user interface. Others think its UI will be something exotic. Both camps are wrong: The iPhone started a UI revolution, and the tablet is just step two. Here's why.

If you are talking hardware, you can speculate about many different features. But when it comes to the fabled Apple Tablet, there are basically three user interface camps at war. On one side there are the people who think that a traditional GUI—one built on windows, folders and the old desktop metaphor—is the only way to go for a tablet. You know, like with the Microsoft Windows-based tablets, and the new crop of touchscreen laptops.

In another camp, there are the ones who are dreaming about magic 3D interfaces and other experimental stuff, thinking that Apple would come up with a wondrous new interface that nobody can imagine now, one that will bring universal love, world peace and pancakes for everyone—even while Apple and thousands of experts have explored every UI option imaginable for decades.

And then there's the third camp, in which I have pitched my tent, who says that the interface will just be an evolution of an existing user interface, one without folders and windows, but with applications that take over the entire screen. A "modal" user interface that has been proven in the market battlefield, and that has brought a new form of computing to every normal, non-computer-expert consumer.

Yes, people, I'm afraid that the tablet will just run a sightly modified version of the iPhone OS user interface. And you should be quite happy about it, as it's the culmination of a brilliant idea proposed by a slightly nutty visionary genius, who died in 2005 without ever seeing the rise of the JesusPhone.

This guy's name was Jef Raskin.

The incredible morphing computer

Raskin was the human interface expert who lead the Macintosh project until Steve Jobs—the only guy whose gigantic ego rivaled Raskin's—kicked him out. During his time at Apple, Raskin worked on a user interface idea called the "information appliance," a concept that was later bastardized by the Larry Ellisons and Ciscos of this world.

In Raskin's head, an information appliance would be a computing device with one single purpose—like a toaster makes toast, and a microwave oven heats up food. This gadget would be so easy to use that anyone would be able to grab it, and start playing with it right away, without any training whatsoever. It would have the right number of buttons, in the right position, with the right software. In fact, an information appliance—which was always networked—would be so easy to use that it would become invisible to the user, just part of his or her daily life.

Sound familiar? Not yet? Well, now consider this. Later in his life, Raskin realized that, while his idea was good, people couldn't carry around one perfectly designed information appliance for every single task they can think of. Most people were already carrying a phone, a camera, a music player, a GPS and a computer. They weren't going to carry any more gadgets with them.

He saw touch interfaces, however, and realized that maybe, if the buttons and information display were all in the software, he could create a morphing information appliance. Something that could do every single task imaginable perfectly, changing mode according to your objectives. Want to make a call? The whole screen would change to a phone, and buttons will appear to dial or select a contact. Want a music player or a GPS or a guitar tuner or a drawing pad or a camera or a calendar or a sound recorder or whatever task you can come up with? No problem: Just redraw the perfect interface on the screen, specially tailored for any of those tasks. So easy that people would instantly get it.

Now that sounds familiar. It's exactly what the iPhone and other similar devices do. And like Raskin predicted, everyone gets it, which is why Apple's gadget has experienced such a raging success. That's why thousands of applications—which perform very specialized tasks—get downloaded daily.

The impending death of the desktop computer

Back in the '80s, however, this wasn't possible. The computing power wasn't there, and touch technology as we know it didn't even exist.

During those years, Raskin wanted the information appliance concept to be the basis of the Mac but, as we know, the Macintosh evolved into a multiple purpose computer. It was a smart move, the only possible one. It would be able to perform different tasks, and the result was a lot simpler than the command-line based Apple II or IBM PC. It used the desktop metaphor, a desk with folders to organize your documents. That was a level of abstraction that was easier to understand than typing "dir" or "cd" or "cls."

However, the desktop metaphor still required training. It further democratized computing, but despite its ease of use, many people then and today still find computers difficult to use. In fact, now they are even harder to use than before, requiring a longer learning curve because the desktop metaphor user interface is now more complex (and abstract) than ever before. People "in the know" don't appreciate the difficulty of managing Mac OS X or Windows, but watching some of my friends deal with their computers make it painfully obvious: Most people are still baffled with many of the conventions that some of us take for granted. Far from decreasing over time, the obstacles to learning the desktop metaphor user interface have increased.

What's worse, the ramping-up in storage capability and functionality has made the desktop metaphor a blunder more than an advantage: How could we manage the thousands of files that populate our digital lives using folders? Looking at my own folder organization, we can barely, if at all. Apple and Microsoft have tried to tackle this problem with database-driven software like iPhoto or iTunes. Instead of managing thousands of files "by hand," that kind of software turns the computer into an "information appliance," giving an specialized interface to organize your photos or music.

That's still imperfect, however, and—while easier than the navigate-through-a-zillion-folders alternative—we still have to live with conventions that are hard to understand for most people.

The failure of the Windows tablet

As desktop computing evolved and got more convoluted, other things were happening. The Newton came up, drawing from Raskin's information appliance concept. It had a conservative morphing interface, it was touch sensitive, but it ended being the first Personal Digital Assistant and died, killed by His Steveness.

Newton—and later the Palm series—also ran specialized applications, and could be considered the proto-iPhone or the proto-Tablet. But it failed to catch up thanks to a bad start, a monochrome screen, the lack of always-connected capabilities, and its speed. It was too early and the technology wasn't there yet.

When the technology arrived, someone else had a similar idea: Bill Gates thought the world would run on tablets one day, and he wanted them to run Microsoft software. The form may have been right, but the software concept was flawed from the start: He tried to adapt the desktop metaphor to the tablet format.

Instead of creating a completely new interface, closer to Raskin's ideas, Gates adapted Windows to the new format, adding some things here and there, like handwriting recognition, drawing and some gestures—which were pioneered by the Newton itself. That was basically it. The computer was just the same as any other laptop, except that people would be able to control it with a stylus or a single finger.

Microsoft Windows tablets were a failure, and they became a niche device for doctors and nurses. The concept never took off at the consumer level because people didn't see any advantage on using their good old desktop in a tablet format which even was more expensive than regular laptops.

The rise of the iPhone

So why would Apple create a tablet, anyway? The answer is in the iPhone.

While Bill Gates' idea of a tablet was a market failure, it achieved one significant success: It demonstrated that transferring a desktop user interface to a tablet format was a horrible idea, destined to fail. That's why Steve Jobs was never interested. Something very different was needed, and that came in the form of a phone.

The iPhone is the information appliance that Raskin imagined at the end of his life: A morphing machine that could do any task using any specialized interface. Every time you launch an app, the machine transforms into a new device, showing a graphical representation of its interface. There are specialized buttons for taking pictures, and gestures to navigate through them. Want to change a song? Just click the "next" button. There are keys to press phone numbers, and software keyboards to type short messages, chat, email or tweet. The iPhone could take all these personalities, and be successful in all of them.

When it came out, people instantly got this concept. Clicking icons transformed their new gadget into a dozen different gadgets. Then, when the app store appeared, their device was able to morph into an unlimited number of devices, each serving one task.

In this new computing world there were no files or folders, either. Everything was database-driven. The information was there, in the device, or out there, floating in the cloud. You could access it all through all these virtual gadgets, at all times, because the iPhone is always connected.

I bet that Jobs and others at Apple saw the effect this had on the consumer market, and instantly thought: "Hey, this thing changes everything. It is like the new Mac after the Apple II." A new computing paradigm for normal consumers, from Wilson's Mac-and-PC-phobic step-mom to my most computer-illiterate friends. One that could be adopted massively if priced right. A new kind of computer that, like the iPhone, could make all the things that consumers—not professionals, or office people—do with a regular computers a lot easier.

This was the next step after the punching card, the command line, and the graphical desktop metaphor. It actually feels like something Captain Picard would use.

Or, at least, that's how the theory goes.

Stretching the envelope

For the tablet revolution to happen, however, the iPhone interface will need to stretch in a few new directions. Perhaps the most important and difficult user interface problem is the keyboard. Quite simply, how will we type on the thing? It's not as easy as making the iPhone keyboard bigger. You can read our analysis of the potential solutions here. The other issues involved are:

• How would Apple and the app developers deal with the increased resolution?
• How would Apple deal with multitasking that, in theory, would be easier with the increased power of a tablet?
• Where would Apple place the home button?

The resolution dilemma

The first question has an easy answer from a marketing and development perspective.

At the marketing level, it would be illogical to waste the power that the sheer number of iPhone/iPod Touch applications give to this platform. Does this mean that the Apple Tablet would run the same applications as the iPhone, just bigger, at full screen?

This is certainly a possibility if the application doesn't contain a version of its user interface specifically tailored for the increased screen real state. It's also the easiest one to implement. The other possibility is that, in the case the application is not ready for the extra pixel space, it may run alongside other applications running at 320 x 240 pixels.

Here is a totally made-up example of home-screen icons and apps running on a tablet at full screen:

However, this would complicate the user interface way too much. My logical guess is that, if the app interface is not Tablet-ready, it would run at full screen. That's the cheapest option for everyone, and it may not even be needed in most cases: If the rumors are true, there will be a gap between the announcement of the device and the actual release. This makes sense, as it will give developers time to scramble to get their apps ready for the new resolution.

Most developers will like to take advantage of the extra pixels that the screen offers, with user interfaces that put more information in one place. But the most important thing is that the JesusTablet-tailored apps represent an opportunity to increase their sales.

From a development point of view, this represents an easily solvable challenge. Are there going to be two applications, one for the iPhone/iPod touch, and another one for the tablet? Most likely, no. If Apple follows the logic of their Mac OS X's resolution-independent application guidelines—issued during the World Wide Developers Conference in June—the most reasonable option could be to pack the two user interfaces and associated art into a single fat application.

How to multitask

Most rumors are pointing at the possibility of multitasking in the tablet (and also on the iPhone OS 4.0). This will bring up the challenge of navigation through running apps that take all over the screen. Palm's Web OS solves this elegantly, but Apple has two good options in their arsenal, all present in Mac OS X.

The app switch bar or a dock
They can implement a simple dock that is always present on the screen or is invoked using a gesture or clicking a button or on a screen icon. This is the simplest available method, and can also be made to be flashy and all eye candy.

Exposé
This is one of those features that people love in Mac OS X, but that only a few discover on their own. Once you get it, you can't live without it. I can imagine a tablet-based Exposé as an application switcher. Make a gesture or click on a corner, and get all running applications to neatly appear in a mosaic, just like Mac OS X does except that they won't have multiple windows. The apps could be updated live, ready to be expanded when you touch one of them. Plenty of opportunity for sci-fi'ish eye candy here.

A gesture makes sense for implementing Exposé on the tablet—as you can do on the MacBook Pro—but they could also use their recently-patented proximity sensing technology. In fact, I love this idea: Make the four corners of the tablet hot, making icons appear every time you get a thumb near a corner. The icons—which could be user customizable—could bring four different functions. One of them would be closing the running application. The other, call Exposé and bring up the mosaic with all running applications. The other could invoke the home screen, with all the applications. And a fourth one, perhaps, could open the general preferences. Or bring a set of Dashboard widgets that will show instant information snippets, like in Mac OS X.

Here's an illustration—again, totally hypothetical—of what this sort of Exposé interface might look like:

The trouble with the home button

The physical home button in the iPhone and the touch plays a fundamental role, and it's one of the key parts of the interface. Simply put, without it, you can't exit applications and return to the home screen. On the small iPhone, it makes sense to have it where it is. On this larger format—check its size compared to the iPhone here—things are not so clear.

Would you have a single home button? If yes, would you place it on a corner, where it could be easily pressed by one of your thumbs, as you hold the tablet? On what corner? If you add two home buttons, for easier access, wouldn't that confuse consumers? Or not? And wouldn't placing a button affect the perception of the tablet as an horizontal or vertical device? This, for me, is one of the biggest—and silliest—mysteries of the tablet.

What about if Apple decides not to use a physical button? Like I point out in the idea about Exposé, the physical button could be easily replaced by a user definable hot corner.

Revolution Part Two

With these four key problems solved, whatever extra Apple adds—like extra gestures—is just icing on the iPhone user interface cake that so many consumers find so delicious. The important thing here is that the fabled Apple Tablet won't revolutionize the computing world on its own. It may become what the Mac was to the command-line computers, but the revolution already started with the iPhone.

If Apple has interpreted its indisputable success as an indication about what consumers want for the next computing era, the new device will be more of the same, but better and more capable.

Maybe Apple ignored this experience, and they have created a magical, wondrous, an unproven, completely new interface that nobody can imagine now. You know, the one that will bring universal love, world peace and pancakes for everyone. I'm all for pancakes.

Or perhaps Steve Jobs went nuts, and he decided to emulate el Sr. Gates with a desktop operating system.

The most logical step, however, is to follow the iPhone and the direction set by Raskin years ago. To me, the tablet will be the continuation of the end for the classic windowed environment and the desktop metaphor user interface. And good riddance, is all I can say.