Apple released a preview version of its new Macintosh operating system on Thursday, bringing some features of the iPad to the personal computer.

The Cupertino, California-based company said the updated operating system, called Mountain Lion, will be available to Macintosh developers immediately and Mac owners can upgrade to the new software in late summer.

Apple said Mountain Lion includes a new Messages application which replaces iChat and allows a user to send unlimited messages, photos and video from a Mac to another Mac or a device running iOS software such as the iPad or iPhone.

It also includes integration with Twitter allowing users to sign in and tweet directly from Safari, Photo Booth and third-party applications, Apple said.

Game Center allows for live multiplayer games to be played across iPhone, iPad or iPod Touch devices.

Mountain Lion is the first Mac operating system built with the Internet "cloud" in mind, Apple said.

"More than 100 million users have iCloud accounts, and Mountain Lion makes it easier than ever to set up iCloud and access documents across your devices," Apple said.

A new security feature called Gatekeeper protects the computer against malicious software by giving the user control over what applications can be installed and downloaded, Apple said.

With AirPlay Mirroring, a Mac user can wirelessly send video from a Mac to an HDTV using Apple TV.

Apple chief executive Tim Cook told The Wall Street Journal in an interview that the new Macintosh operating system takes advantage of features popular on the iPad and iPhone.

"We see that people are in love with a lot of apps and functionality here," Cook said of the iPhone. "Anywhere where that makes sense, we are going to move that over to Mac."

Apple sold 5.2 million Macs last quarter.