UPDATES: This is a developing story.

UPDATES: This is a developing story.

10:40 a.m. PDT (1:25 p.m. EDT)

New updates to Apple's Mac operating system include the ability to run multiple apps in split-screen mode. It allows people to take advantage of the computer's full screen. You could have done that before by resizing windows, but that takes more time. The feature has similarities to what Microsoft offers in Windows 8.

Other updates include:

the ability to pin frequently visited sites on a bar at the top of the Safari browser

the ability to compose multiple emails in the Mail app through the use of tabs, similar to what Web browsers now have

improved searching across the entire computer

tools for faster graphical performance

The new system is called El Capitan, a landmark within Yosemite National Park. Last year's update was called Yosemite, so the use of El Capitan is an indication that the upcoming version is largely a refinement of Yosemite.

___

10:25 a.m. PDT (1:25 p.m. EDT)

Apple says this fall's update to its Mac operating system will be called El Capitan the name of a landmark in Yosemite National Park.

It follows a recent practice of Apple naming the Mac operating system after geographical locations in California. The 2013 update was called Mavericks, the name of a surfing area in the San Francisco Bay area. Last year's version was called Yosemite.

Before, Apple named its Mac systems after big cats, including Lion and Tiger, but the company was running out of animals. Apple now makes Mac updates available for free.

Apple says 55 percent of Mac users have upgraded to Yosemite, much better than the adoption for Microsoft's Windows 8.1

The new Mac system will be more formally known as OS X 10.11, as it's the 11th update to a system adapted from the NeXT operating system that co-founder Steve Jobs brought to Apple when he returned in 1997 after an exile.

___

10:10 a.m. PDT (1:10 p.m. EDT)

Apple's conference for software developers is kicking off with CEO Tim Cook declaring the event "the epicenter of change" for both Apple and the industry.

The crowd is cheering as Cook unveils new tools for Apple Watch apps.

The Worldwide Developers Conference in San Francisco is Apple's chance to preview software updates for Macs, iPhones, iPads and the Apple Watch. The company is also expected to use the show to unveil a new music-subscription service based on the Beats service it purchased last year.

The show began with a comedic video skit purportedly of the event's director planning the special effects and other elements. The director was played by actor Bill Hader.

___

9:40 a.m. PDT (12:40 p.m. EDT)

Apple's penchant for secrecy extends to the agenda for its annual gathering of app developers this week.

The Worldwide Developers Conference in San Francisco begins with a keynote. Apple isn't saying anything ahead of time, though it's widely expected the company will unveil updates to its mobile and Mac operating systems, along with a new music service.

For now, sessions for the rest of the week have mysterious titles such as "Pins and needles," ''Patience is a virtue" and "You'll be talking about this one." Another goes by "Hmmmm." and yet another is "Surprise!" Apple says details will be posted after the keynote.

The conference runs through Friday at the Moscone convention center in San Francisco.

___

9:25 a.m. PDT (12:25 p.m. EDT)

Apple isn't the only company to be previewing its plans for this fall.

Nearly two weeks ago, Google held its annual I/O conference for app developers. It's similar to Apple's Worldwide Developers Conference in that it gives Google the stage for showcasing upcoming features and products.

Google unveiled a mobile payment system called Android Pay to rival Apple Pay and an upcoming service from Samsung. Google also says its Google Now virtual assistant will get better in bringing information users might want based on context, such as the song they are listening to or the article they are reading.

The next version of the Android operating system doesn't have a name yet. It's known for now as M, as Google names systems after desserts in alphabetical order.

___

9 a.m. PDT (noon EDT)

Crowds are starting to form outside San Francisco's Moscone convention center ahead of Apple's annual gathering for app developers. Apple uses the Worldwide Developers Conference to preview new features for Macs, iPhones and other devices.

Apple is expected to announce a new music-subscription service incorporating a similar service from Beats, which Apple bought last year for $3 billion.

Apple also might announce new tools for Apple Watch. Apple has said software developers will be able to design apps specifically for the watch this year. For now, all third-party watch apps are dependent on a companion iPhone.

The two-hour keynote begins at 10 a.m. PT.

___

AP Technology writers Anick Jesdanun, Ryan Nakashima and Brandon Bailey are contributing to this report.