San Francisco: More than a year after igniting the tablet computing craze, Apple Inc prepares to unveil the second version of its blockbuster iPad - possibly minus lead showman Steve Jobs.

Plenty has changed over the course of the year. The iPad became a bona fide smash, essentially creating the tablet category and triggering a wave of me-too products that are just starting to hit the market.

Now, as rivals Motorola and Research in Motion race to catch up, Apple itself is going through a transformation. There is as much speculation about whether iconic Chief Executive Jobs will take the stage at Wednesday's event in San Francisco as there is about the new device.

Jobs traditionally launches major products with a pizzazz and style that reflect his eye for detail and design. But he took indefinite medical leave last month and Apple has not revealed details of the cancer survivor's medical condition.

His absence is bound to spark a fresh round of speculation on his condition. And his presence will be scrutinized equally closely for any signals on his health.

Many in Silicon Valley and on Wall Street doubt he will return to the company he co-founded in 1976.

In his absence, it is a good bet that Tim Cook, the company's operations chief and Jobs' heir apparent, or marketing head Phil Schiller, will lead Wednesday's show.

If Cook does appear, investors will scrutinize his performance. While Wall Street has grown comfortable with Cook's leadership, Wednesday would provide the first major test of his showmanship skills -- a key asset for marketing maestro Apple.

Regardless, the company is in little danger of losing its massive lead in the tablet market in the near term. With a big first-mover advantage, the company is rolling out the second-generation iPad just as its rivals are bringing their first offerings to consumers.

iPAD, PART DEUX

The new model will sport the same 10-inch screen but should be lighter, thinner and faster, according to a plethora of analyst and blog reports. Apple is expected to add a camera to enable video chat using the FaceTime application.

Some industry watchers believe it may also sport a chip that enables it to run on networks that use both GSM and CDMA technologies.

Consumer appetite for tablets seems sizable, and businesses are also piloting the devices for a variety of uses, including retail and healthcare. But Apple no longer has the tablet market to itself.

Motorola has just launched the well-reviewed Xoom. Research in Motion, which specializes in corporate customers with its BlackBerry, will begin selling the PlayBook. And Hewlett-Packard Co will bring the TouchPad this summer.

Companies like Samsung Electronics and Dell Inc are already selling tablets, but neither seems to have slowed the iPad's momentum.

Apple set a high bar with the first iPad, so the company will have a harder time creating a "wow-factor" with the second iteration. It sold nearly 15 million iPads in 2010 after an April launch, three or even four times as many as some analysts had predicted. The tablet added more than $9 billion in revenue for the company last year.

It became a must-have for the holiday season, embraced by taste arbiters such as Oprah Winfrey. Analysts expect the company to sell more than 30 million iPads this year, as the overall tablet market explodes to more than 50 million units.

Jobs' absence comes at a crucial time. Apple is engaged in a battle in the smartphone market with Google Inc, whose Android operating system was installed on more devices than Apple's for the first time in 2010. Its usually gravity-defying stock has fluctuated this year.

Shares in the world's most valuable technology company are up roughly 8.5 per cent this year, but slid nearly 7 per cent over three trading days from Feb. 17 to 22.