An Apple spokesman declined to comment.

The new effort faces plenty of hurdles, and people familiar with Apple's plans don't expect internally designed chips to emerge until next year at the earliest. Still, Apple's aggressive hiring is another sign of how the company's recent success has allowed it to expand while other tech giants have trimmed their work forces in the recession.

Apple's strategy also marks a break from a long-term trend among most big electronics companies to outsource the development of chips and other components to external suppliers.

STEVE JOBS

Last spring, Apple Chief Executive Steve Jobs explained the purchase of Silicon Valley start-up P.A. Semi as a way to acquire expertise and technology to help run increasingly sophisticated software on iPhones and iPods. "You can't just go out and buy the chips off the shelf to do that," said Mr. Jobs in an interview.

Most cellphones are based on chip designs licensed by ARM Holdings PLC to others. For the iPhone, Samsung Electronics Co. supplies an ARM-based microprocessor with custom features developed by Apple, analysts say.

People familiar with Apple's thinking say executives have expressed concern that some information shared with outside vendors could find its way into chips sold to Apple competitors. A Samsung spokeswoman declined comment.