CES saw the long-rumored appearance of Apple’s convergent device, the keyless phone that runs OS X. As you can see from this size comparison supplied by Sizeasy (thanks, engadget!), the iPhone is nearly as large as the Nokia N800 Internet Tablet.

For the last 18 months, we’ve been saying that not every person wants the identical thing from their tablet, and that different vendors would emphasize different aspects as they entered this device zone. The UMPC went for traditional computer features (hard disk drive, Windows operating system), Sony for a proprietary marketing model for e-books and slideout keyboard for its Mylo. And Apple chooses cellphone and camera as its prime features.

Nokia long ago gave highest priority to size, weight, cost and internetability when designing its internet tablets, making possible the walkaround web. If you keep the cost below $400, make the screen 800 pixels wide and need to carry it in a pocket, well, your device can’t also include a cellphone, 2MB camera, hard disk drive, keyboard, Windows, and so on and so on.

With this announcement, Apple officially retired the word “Computer” from its name. iPods and iPhones aren’t computers and that’s where Apple is positioned. But its computer orientation is what enabled Apple to blow off the cellphone OS approach and put its own Unix-rooted OS X into the iPhone. Think Steve Jobs isn’t prepared for really, really rapid advance in capabilities for the pocket communicator?

Perhaps the most reassuring part of Apple’s approach for the Nokians is Jobs’ determination to have it his way. So, as others have noted, the iPhone isn’t a smart phone, onto which you can plunk your own applications to make the device ever more your own. No, you’ll get only what Steve permits you (which is still more expansive than Sony or Microsoft, come to think of it).

It’s only Nokia that says, yes, the CPU in your pocket should do everything you want, and every user is going to want a unique blend of capabilities. And most of those are going to be software-based. And that door is wide open. Maybe Ari Jaaksi and his crew chose this path for other reasons. But as of now, Nokia seems to be the only vendor willing to grow the carryaround device in conjunction with its customers and who isn’t anticipating fleecing them.

Welcome to convergence, Apple! Better fasten your seat belts. It looks to be a very bumpy ride because of the speed!

Update: The report at Good Morning, Silicon Valley! included an analyst’s saying he thought sales of 10 million iPhones this year was low. I’ve just got to believe that kind of heat will transfer to the N800 as people wrap their heads around this concept of a small, keyless, great-screen carryaround computer.

GMSV quotes Time’s Lev Grossman, and it’s so apt I’ve got to repeat it:

The iPhone breaks two basic axioms of consumer technology. One, when you take an application and put it on a phone, that application must be reduced to a crippled and annoying version of itself. Two, when you take two devices — such as an iPod and a phone — and squish them into one, both devices must necessarily become lamer versions of themselves. The iPhone is a phone, an iPod, and a mini-Internet computer all at once … without taking a hit in performance. In a way iPhone is the wrong name for it. It’s a handheld computing platform that just happens to contain a phone.

Right on, Lev!

Added later: So why does it matter that the iPhone is nearly as big as the N800? Two reasons:

People get used to the size/form factor. Plus you know imitation phones will come out, enlarging the pool of devices this size. The more devices there are, the less odd the Internet Tablets seem to those who need help understanding why they’re so great.

Apple’s going to match the 800×480 resolution. They may be able to squeeze in the screen in the current size or maybe the next model is slightly bigger. But a single derogatory comment — “I’d rather surf on a UMPC” (also 800×480) — and Jobs will make it happen. Then the Internet Tablet will need something other than price to make it stand apart.