Microsoft CEO Steve Ballmer has said that his company must be able to operate successfully in multiple markets – a phenomenon he called being "multi-core" – for the company to continue to grow well into the future.

Although Microsoft is best known for its desktop operating system and software business, the company has managed to carve out a successful business in server software, making it a two-core company, Ballmer said at Microsoft's annual financial analyst meeting. This is something, he argued, that no other major technology company has ever done.

But Microsoft is now fighting a war on several fronts, and Ballmer hopes it will develop more core businesses with its entertainment and online services strategies.

"There really is a Sony that lives inside of us," he said. "There's an aspiring Google or Yahoo that lives inside of us."

To create a multi-core company, Microsoft must enter new business areas, as it has with its Xbox.

"You have to confront the question: is it OK to get into some area of endeavour when you're not first?" he said. "It's always best in our business to be first. We want to be first. But are you prepared to get in and innovate and try to get growth in areas where you're not first in the market? As investors, you have to understand that we think that's important."

Even as it continues to plug away at new markets, Microsoft is also learning from mistakes it has made in its core businesses, Ballmer said.

Referring to how long it has taken the company to release Windows Vista, he said: "We will never [again] have a five-year gap between the releases of major products."