Apple today released a developer preview of OS X Mountain Lion, the ninth major release of the world’s most advanced operating system, which brings popular apps and features from iPad to the Mac and accelerates the pace of OS X innovation. Mountain Lion introduces Messages, Notes, Reminders and Game Center to the Mac, as well as Notification Center, Share Sheets, Twitter integration and AirPlay Mirroring. Mountain Lion is the first OS X release built with iCloud in mind for easy setup and integration with apps. The developer preview of Mountain Lion also introduces Gatekeeper, a revolutionary security feature that helps keep you safe from malicious software by giving you complete control over what apps are installed on your Mac. The preview release of Mountain Lion is available to Mac Developer Program members starting today. Mac users will be able to upgrade to Mountain Lion from the Mac App Store in late summer 2012. Further information is available here.
Messages App – Replaces iChat and allows you to send unlimited messages, high-quality photos and videos directly from your Mac to another Mac or iOS device. Messages will continue to support AIM, Jabber, Yahoo! Messenger and Google Talk. Starting today Lion users can download a beta of Messages from Apple.com, and the final version will be available with Mountain Lion. Reminders and Notes help you create and track your to-dos across all your devices. Game Center lets you personalize your Mac gaming experience, find new games and challenge friends to play live multiplayer games, whether they’re on a Mac, iPhone, iPad or iPod touch.
Notification Center – Provides easy access to alerts from Mail, Calendar, Messages, Reminders, system updates and third party apps. System-wide Share Sheets make it easy to share links, photos and videos directly from Apple and third party apps. Twitter is integrated throughout Mountain Lion so you can sign on once and tweet directly from Safari, Quick Look, Photo Booth, Preview and third party apps. Mountain Lion also introduces AirPlay Mirroring, an easy way to wirelessly send a secure 720p video stream of what’s on your Mac to an HDTV using Apple TV.
iCloud – Access documents across your devices. Mountain Lion uses your Apple ID to automatically set up Contacts, Mail, Calendar, Messages, FaceTime® and Find My Mac. The new iCloud Documents pushes any changes to all your devices so documents are always up to date, and a new API helps developers make document-based apps work with iCloud.
Gatekeeper – A revolutionary new security feature that gives you control over which apps can be downloaded and installed on your Mac. You can choose to install apps from any source, just as you do on a Mac today, or you can use the safer default setting to install apps from the Mac App Store, along with apps from developers that have a unique Developer ID from Apple. For maximum security, you can set Gatekeeper to only allow apps from the Mac App Store to be downloaded and installed.