Apple has pushed back the release of Leopard, the next major upgrade of its Macintosh operating system, until October, explaining it had to divert resources to getting the iPhone out on time.

The company may be feeling the effects of trying to be a maker of proprietary computers, digital music players, and mobile phones. "Obviously, they're not big enough or experienced enough yet to properly manage multiple operating systems," observes IDC analyst Richard Shim.

Apple had planned to issue Leopard in June at its Worldwide Developers Conference. Instead, developers will get a beta release at the conference, with the final code four months later. "Life often presents tradeoffs, and in this case, we're sure we've made the right ones," Apple said in a written statement.

The delay means Apple will miss the back-to-school shopping season that runs from mid-July to mid-September. In terms of computer sales, only the year-end holiday season is bigger. Says Shim, "They're going to have to manage the development of these operating systems more closely."