SAN FRANCISCO - Personal computer sales have been in a slump for years, as customers flock to increasingly powerful smartphones, tablets and other mobile devices. Now Hewlett-Packard, the Silicon Valley stalwart that was once the world's biggest seller of personal computers, is splitting off its PC and printing businesses. It's the latest shakeup in a tech industry that's being reshaped by the mobile revolution.

IBM sold its PC business years ago. Dell took its struggles private. Can an HP spinoff focused on personal computing thrive?

"There's a significant transformation going on in that industry, and maybe now HP can make its move," said Forrester tech analyst Peter Burris, one of several analysts who say the iconic tech giant will need to get better at building and selling mobile gadgets if it wants the new spinoff to succeed. HP has stumbled in previous efforts to sell those devices.

HP's split is a sign that CEO Meg Whitman sees more growth and profit opportunity in selling commercial tech products, including data-center hardware, business software and cloud services, some analysts say. That's the business she plans to lead, as chief executive of a new company dubbed Hewlett-Packard Enterprise.

That puts more pressure on the HP Inc. spinoff, which will be led by current PC and printing executive Dion Weisler as CEO. Though it was once the world leader in both segments, HP is now No. 2 to China's Lenovo in PC sales.

Tablets now out-sell laptop computers. And no other major U.S. tech company is focused on selling only PCs. Apple Inc.'s growth in recent years has been fueled by the phenomenal success of its iPhone and iPad devices. Dell also sells commercial computer hardware and software. Even Lenovo is purchasing IBM's server business and taking over the Motorola smartphone division from Google Inc.

PC sales aren't going away entirely, to be sure. There are still some cases where PCs are more useful than smaller-screen devices, especially in the workplace, said Bob O'Donnell of TECHnalysis Research. The industry sold more than 310 million desktop and laptop computers last year, and one out of six were sold by Palo Alto, Calif.-based HP. But global sales fell 10 percent in 2013 and are likely to fall another 4 percent this year, according to the IDC research firm. PC sales should level off in 2015, forecasts O'Donnell.