It's as though an aging Henry Ford had tried to reinvent the mass-market automobile that he had, a few decades before, helped invent. Steve Jobs, a creator of the personal computer, is now creating it again, this time with the benefit of a little experience.

When Apple announced in January that it would be selling a tablet called the iPad, the question asked by a number of writers, including this one, was whether the new device would succeed as a laptop replacement. Now that the iPad is in American stores, it's clear that was the wrong question. It's best to think of the device not as the world's next laptop but as the world's first couchtop.

Much of what we do with computers these days--casually checking e-mail, grazing around the Web--we do sitting on a couch, often with a laptop, though sometimes with a phone. It's these sorts of interactions that the iPad is brilliant at--fast and light, with a bright screen full of richly saturated colors, something you can snuggle up with, just as in those iPad billboards that are suddenly everywhere.

If you need to do real work, you'll still need a "real" computer, though it will probably come to seem like meat loaf next to the sizzling steak of the iPad.

The iPad has the same three-year-old operating system as the iPhone. Five days after it began selling iPads, Apple announced its latest version of the operating system. Developing this software has been something of a catch-up game for Apple, which conceived of the iPhone primarily as a telephone rather than the general-purpose computer it has become.

For example, only this summer will iPhone and iPad users be able to run two programs at the same time, something "real" computer owners have been doing since Windows 3.1 in the early 1990s.

In developing this operating system, Jobs is shaping what computing is going to be like for millions of people for years, maybe even decades, to come--as it happens, for the second time in his career. In most cases he's making decisions opposite to those he made a generation ago.

Back then the emphasis was on freedom: the freedom to do anything with the device that you wished to do, which as a practical matter meant that the computer's programs had largely unchecked powers. It was a zeitgeist-friendly approach, but it eventually led to computers as we know them today, which are often complex, hard to use and susceptible to all manner of infections and other inconveniences.

As it creates the iPhone and iPad, by contrast, the only freedom Apple seems to be interested in is the freedom from computers that don't do what they are supposed to. You push a button and something works, just as it would on a kitchen appliance, which people have long wished computers would be like. As one writer put it, you don't "launch" an application on an iPad, you "go to it."

The tradeoff is that things are locked down. Users, for one, can't fiddle with settings the way they can on their PCs. Software programmers have far fewer tools to work with than they get on a desktop computer. Compared with the Apple programs that come standard on the devices, every other piece of software the iPad runs is a second-class citizen.

Jobs is betting that not many people will really care, and he certainly seems to be on to something. Apple is closing in on Microsoft as the most valuable tech company in the world in terms of market capitalization. It has already passed Google. It seems like only yesterday that the Internet search company was not just the rich cool kid but also the present and future of computing. Yet in the last few months the center of gravity in computing has shifted south the 9 miles between Google's headquarters in Mountain View, Calif. and Apple's in Cupertino.

Spend any time in the computer industry and you hear that just when things seem to be settling into some boring bit of doldrums, you can expect a change. But you'll never be able to predict where the shakeup is going to come from. Usually it's from a kid in a garage. But if it is courtesy of a middle-aged cancer survivor in a Learjet, well, that works just as well.

Senior editor Lee Gomes covers technology from the Silicon Valley bureau. Visit him at