Over the last few years, Apple used technologies from its Macintosh computers to create the iPhone and the iPad, building a multibillion-dollar mobile computing business that now accounts for 60 percent of its revenue.
Now Apple is doing the reverse, taking technologies like the multitouch user interface from the iPhone and the iPad and using them to refresh its Mac business.
(Read: What happened at Apple's 'Back to the Mac' event!) On Wednesday, Steven P. Jobs, the chief executive, unveiled two versions of its ultra-thin MacBook Air laptops. He also demonstrated an early version of Apple's new OS X operating system, which will be available next summer. In addition to multitouch, the new hardware and software incorporate the video phone software FaceTime, an App Store and other popular features of Apple's hand-held products.
Mr. Jobs even joked that the new MacBook Air was the offspring from the union of a Mac computer and an iPad. "We asked ourselves what would happen if a MacBook and an iPad hooked up," he said.
The new MacBook Air models are more powerful than their predecessors, which were introduced in January 2008 and have not sold well. They are also priced more aggressively, starting at $999, rather than the $1,499 starting price of the original.
Analysts predicted the new machines would be successful. "They are going to sell well," said Shaw Wu, an analyst with Kaufman Brothers. But Mr. Wu said that like the iPad, the new MacBook models are likely to have lower profit margins than Apple's average, perhaps causing concern among investors.
Still, he said that with the new machines, Apple's personal computer business would most likely grow at a faster rate than the overall industry, allowing Apple to continue to gain market share.
Indeed, while the focus over the last few years has been on the iPhone and iPad, Apple's Mac business has enjoyed a remarkable resurgence.
Apple shined a spotlight on that during the Wednesday event, which was called "Back to the Mac." Timothy Cook, Apple's chief operating officer, said that the Mac business accounted for 33 percent of Apple's revenue in the last year. And he said that the 27 percent growth in sales of Macs in the most recent quarter was about two and half times larger than the rate of growth of the personal computer business. As a result, the Mac, which a decade ago was just a tiny sliver of the PC business, now accounts for one in five computers sold to consumers in the United States.
Analysts said that the new computers were so light and priced so aggressively that they could compete with the iPad for the same customers.
In a conversation after the announcement, Mr. Cook said he was unconcerned by that risk. "If one cannibalizes the other, then so be it," he said. He said it was better for Apple to cannibalize its own business than for another company to do so.
Along with the new operating system, Apple unveiled a new App Store that would sell software for the Mac. Mr. Jobs said that it would help customers to find applications and developers to sell them. Mac users would still be able to buy programs from other sources. The new App Store will be available in 90 days, Mr. Jobs said.
The new MacBooks come in two sizes of screens, 11.6-inch and 13.3-inch. They weigh 2.3 pounds, and 2.9 pounds, respectively. For comparison, the iPad weighs 1.5 pounds. The laptops' thickness tapers from 0.68 of an inch at one end to 0.11 of an inch at the other. They have no optical or magnetic storage. Instead, like the iPad, they are built on Flash storage, which allows them to turn on instantly when powered up.
Mr. Jobs said that Apple considered putting touch-screen capabilities on its new computers, but found that for a vertical touch screen it is "ergonomically terrible." Instead, Apple put multitouch capabilities on the computer's track pad.