Google has finally unveiled Android 4.0, the unified version of its mobile OS for smartphones and tablets best known by its "Ice Cream Sandwich" code name. The revised Android, which made its debut on a Samsung Galaxy Nexus smartphone (video) also unveiled today, features a bevy of UI enhancements, social networking integration, and other APIs meant to encourage human and application-based sharing. Android has also beefed up some of its security capabilities, though most are in the form of API support that developers can use as desired.

Google did not provide a release date for Android 4, but did say the Galaxy Nexus running it would be available in November. Available now is the updated Android SDK so developers can begin modifying or creating applications for Android 4.

Lots of new integration features

For business users, Android 4 integrates multiple mail accounts more completely, and now supports Exchange mail folders. It also lets users take screen shots from their devices. (Both are longtime iOS capabilities.) Google made some minor adjustments to Android's security and management capabilities by supporting the most recent version of Microsoft's Exchange ActiveSync (EAS) protocol, including newfound support for EAS certificate authentication, use of ABQ strings for device type and mode, an option for IT to disable automatic sync while roaming, and an option for IT to limit attachment size or disable attachments. Also added is support for disabling the device's camera via EAS.

On the security front, Android 4 adopts the better security capabilities found in the tablet version of Android ("Honeycomb") such as on-device encryption, but appears to be leaving deeper management APIs to third parties such as 3LM.

But Android 4 does have a new keychain API and underlying encrypted storage let applications store and retrieve private keys and their corresponding certificate chains. Applications can use the keychain API to install and store user certificates and certificate authorities. Android 4 also provides address space layout randomization (ASLR), a feature that has helped iOS lead in terms of onboard security capabilities, to protect system and third-party applications from exploitation due to memory-management issues.

New imaging abilities

Android 4 also borrows some features introduced in Apple's iOS 5, such as the ability to apply silly effects to video (using the Photo Booth app in iOS), to edit and adjust photos (an enhancement to iOS 5's Photos app), and to sync Chrome browser bookmarks via the cloud (one component of Apple's iCloud service). Camera enhancements include single-motion panoramic capture, automatic facial focus, and stabilised image zoom, the latter two are enhancements found in the recently released Apple iPhone 4S.

Unique capabilities in Android 4 include face identification that can be used in lieu of passwords and the ability in the Chrome browser to tell websites to provide their full desktop vesions rather than their mobile-optimized versions.

In the revised OS, a new social API lets developers create applications can integrate contacts, profile data, and calendar events from any of the user’s activities or social networks. Calendar services are also now made accessible to apps. And a new sharing API lets apps share data through a standard mechanism across the OS.

Android 4 also supports Wi-Fi Direct, a recent standard for creating ad hoc wireless networks among devices, and Bluetooth-based health care devices, such as wireless monitoring equipment. And Android 4 now supports styli with a set of APIs that can distinguish pressure, angle, and other pen-oriented input nuances. The combination of support for Bluetooth-enabled medical equipment and pen input suggests Google may be making a push into the health care market with its tablets.

As previously promised, Android 4 also supports near-field communications for use in mobile payment systems.

The UI changes appear meant to provide more customized information to users, such as sizable widgets and configurable alert displays, as well as provide more gesture controls for interacting with tasks rather than rely so heavily on Android's menus. Google has published a summary of the Android 4 changes at its website.