Apple, the world's most valuable company, made available the latest version of its OS, dubbed Mountain Lion, for developers Thursday so that it will be able to ship new products by the third quarter.

Apple shares, on a record-setting tear lately, largely shrugged off the news, although they rose $5.46 to $503.13 in late trading, only $14 below their record high set Wednesday.

The reason Cupertino, Calif.-based Apple introduced the new software now and made CEO Tim Cook available for selected interviews is competition: About the same time as new Apple products based on what is technically version 10.8 of the Mac's OS X operating system are ready, Microsoft will finally roll out Windows 8.

Battles between Apple and Microsoft, the No. 1 software provider aren't new. Indeed, as Microsoft CEO Steve Ballmer said at last month's Consumer Electronics Show, It's Windows, Windows, Windows for the Bellevue, Wash.-based developer.

That means Microsoft will soon have its own smartphones running on Windows 8 as well as Nokia's new line of Lumia phones and perhaps more. Meanwhile, new ultralight laptops with Intel's Ultrabook chips have already been introduced by Hewlett-Packard, Samsung Electronics, Dell, Sony and others.

To add to the competition, Google any day will close its $12.5 billion acquisition of Motorola Mobility, a sure boost for Google's Android OS.

In short, to protect its share as No. 1 in smartphones, with a 23.8 percent fourth-quarter share, as researcher Gartner reported this week, with a 19 percent full-year share, Apple will have to behave like a mountain lion.

Banking on the enormous popularity of the iPhone and the latest iPhone 4S, Mountain Lion will essentially converge some of the most popular iPhone features into the Mac. For example, the address book will be renamed contacts and iCal will be renamed Calendar.

There will also be a new feature, AirPlayMirroring, to allow customers to see what's on their Mac, iPhone and TV screen, presumably hooked up to Apple TV.

I don't really think anything Microsoft does puts pressure on Apple, CEO Cook told the Wall Street Journal in a pre-announcement interview. In reality, everything does.

Apple's PC share with the Mac is tiny, with only about 5 percent of the global PC market in the fourth quarter, estimates researcher IDC. Mac revenue in the quarter slipped to only 14.3 percent of the record revenue of $46.3 billion.

Meanwhile, with new competition from Google and Microsoft in the tablet and smartphone sector, as well as legacy users running Research in Motion's BlackBerry OS and Europe's Symbian, Apple needs to keep refreshing its product line, with new services from the iCloud as well as new sales from upgrades of the iPhone 4S and the iPad2.

Apple hasn't announced any of these yet. But there will be two ideal venues to show them off.

Next Thursday is Apple's annual meeting, where there will be a memorial to founding Chairman Steve Jobs and a review of business. Cook and senior executives such as Senior VP Phil Schiller would be crazy not to tweak shareholders and potential customers.

Starting Feb. 27, the annual Mobile World Congress begins in Barcelona, where the entire mobile industry introduces products. As usual, no one from Apple is among the keynote speakers.

Plenty of Apple's rivals will be keynoters, though, including Google Chairman Eric Schmidt and Nokia CEO Steve Elop, so it's likely Apple executives and marketers will be there unofficially.

Meanwhile, Apple has plenty of resources to stay ahead. Spending on research and development surged 32 percent to $758 million last quarter. Cash and investments soared 20 percent to $97.6 billion in the last 14 weeks of 2011.

In late trading, Apple's market value was $468.9 billion, compared with Microsoft's $264 billion and Google's $197.7 billion.