Steve Jobs likes to say that Apple is the last company that makes "the whole widget." But it doesn't, not really. Sure, Apple makes software and designs hardware — but inside its gadgets are silicon brains from the likes of Samsung and Intel. Jobs is adept at bullying chipmakers for lower prices and faster delivery, but he can't order around their engineers like he does his own employees. That must rile him. Jobs's ego, therefore, is the best explanation for Apple's $278 million acquisition of PA Semi, a microprocessor design startup. But is Apple getting into the ruthlessly competitive semiconductor business?