Apple is making an early version of Mac OS X Lion available to registered Mac developers to allow them to incorporate the operating system's new capabilities into forthcoming applications.
In keeping with its effort to de-emphasize disc-based software distribution and to encourage online software delivery, Apple has made Mac OS X Lion Developer Preview available exclusively through the Mac App Store.
The Mac App Store remains controversial among developers because while it improves the experience of buying, installing, and maintaining software for users, it costs developers 30% of revenue, limits the technologies they can use, and requires them to seek Apple's approval to sell their applications.
Underscoring the extent to which Apple's business has shifted away from desktop and notebook computers toward its iPhone, iPod, and iPad products, Apple SVP Phil Schiller said that the iPad was the source of inspiration for many of the features in Mac OS X Lion.
Several API enhancements make it easier to create applications that operate with full-screen user interfaces. This shows the impact of iOS and the iPad, where applications take over the screen and don't allow users to toggle back and forth between other apps running at the same time.
Lion also brings several iOS-inspired user-interface elements, such as overlay scrollbars and support for Multi-Touch gestures -- pinch-to-zoom, for example -- and animations. Users of the new MacBook Pro can utilize Multi-Touch gestures through its Multi-Touch trackpad. Whether Apple will ever bring touch-screens to its MacBooks and MacBook Pros remains to be seen.
A feature called Mission Control combines previously released workflow and UI apps Expose, Dashboard, and Spaces into a single view for organizing and navigating through all active apps and windows. Another feature called Launchpad presents all installed Mac apps in a full-screen layout for easier launching and organization.
A new AV Foundation framework simplifies audio and video file editing and encoding in Mac apps and adds real-time manipulation capabilities.
Lion makes the version saving capabilities found in Apple's Time Machine backup software available to any document-oriented Mac app. Documents from applications that support Auto Save and Versions can be browsed like Time Machine snapshots, so that any saved iteration can be accessed.
Lion will also automatically save the state of apps when the user logs out or shuts down, allowing those applications to be resumed when the user restarts his or her computer.
Several security enhancements will arrive with Lion, including app sandboxing and privilege separation. These additions will provide a way to deny malware disk access and use of network resources.
Lion also includes a thread and process management system called File Coordinator, which oversees file access across multiple threads and processes.
Other features and enhancements include a new iPad-inspired version of Mail and AirDrop, a way to transfer files between Macs.
Apple is also planning to release Mac OS X Lion Server this summer, featuring easier server setup and iOS device management.