Android 3.0 has its rough spots--many rough spots, in fact. It looks good on the surface, but it needs work underneath. And around the edges. And...well, let's just say I'm glad that 3.1 is here.

We now have more information about what Android 3.1 brings to the party, thanks to the full revision notes on Google's developer site, and the changes are more far-reaching and important than Google implied.

The first big news is that this version does indeed fix 3.0's flaw that caused images to render improperly in the Gallery app. I've noted this flaw numerous times--in part because it feels like such an obvious blemish on an otherwise solid start to the Honeycomb/Android 3.x platform. While Google hasn't gone into too much detail as to what caused the issue to begin with, I do have confirmation from Google that 3.1 should fix this issue. I can hazard a few guesses, but ultimately, what matters is that it's fixed--which is why I look forward to trying out 3.1 on an array of tablets and seeing how my photos look.

Other additions to 3.1 include support for the Open Accessory and USB host APIs. By building the USB stack into Honeycomb, the platform now gets USB host abilities and tablets running Honeycomb now have operating system level-support for managing USB peripherals--including gamepads, joysticks, and storage devices--directly. Technical terms aside, this means that Android 3.1-based tablets will be able to power other gadgets through USB.

The newly introduced Open Accessory feature aims to integrate peripherals like music equipment, robotic systems, and exercise equipment into the tablet (and phone) universe, all via USB.

This is all great news, but there is one catch: Android 3.1 still isn't intended, at the operating system level, for managing external storage devices. This detail, which came out in conversations I had with Google engineers today, explains why the Android file system organization is, well, a mess, and why I've had such inconsistent experiences with Android and removable storage across the various Honeycomb tablets I've tried (and I've tried all of them that are available so far).

"We don't want to expose the user to file locations," explained Hiroshi Lockheimer, director of engineering at Google. "How do you manage that as a user? The not-good answer is with the file browser." Lockheimer says that many of the experiences I've seen so far are what individual hardware manufacturers have enabled, as opposed to what Google has provided natively. The good thing is that Lockheimer says Google is looking at ways to do this; but the problem hasn't been solved yet.

Another component of the USB connectivity update is the addition of a Media Transfer Protocol, to define how applications can be notified when external cameras are attached and removed. The MTP also governs accessing and managing the files and associated metadata stored on attached cameras. The real-world applications for this are exciting: For example, shutterbugs can now easily view and share images in the field, taking advantage of a tablet's large screen and Honeycomb's ability to show EXIF data in the Gallery app.

Performance tweaks abound as well. Google made improvements to the animation framework in Android 3.1, so that animations--such as the one you see when you tap the Apps menu button at the top-rightcorner of the home screen--flow more smoothly. And you can now scroll through the list of recently accessed apps that appears when you tap the task-switcher button. The apps most recently opened get priority; unfortunately, there's no way to manage what apps show, and in what order--you can't emove an app from this screen entirely.

Also new: The Home screen widgets can be resized horizontally or vertically, or both. This change allows for greater flexibility and customization in screen layout, and it means developers can create widgets that let you make better use of the available space.

This may sound like small tweaks, but that's where many of the improvements lie--in the small details. Like the addition of two new audio formats: ADTS AAC streaming audio and FLAC audio. The support of Real-Time Transport Protocol API for better in-app handling of on-demand data streaming for VOIP, push-to-talk, conferencing, and audio streaming applications. The ability for developers to improve how apps can locally cache data to minimize download time via a network connection. And the Web browser gains, among other minutiae, the ability to play back embedded HTML 5 video inline--with hardware acceleration where possible.

Sounds like a lot? Let's see how it looks on Honeycomb tablets. And remember--this is all just an interim OS release. Lockheimer confirms that, eventually, Honeycomb tablets will migrate to Ice Cream Sandwich--an upcoming major update to Android that will unify the tablet and smartphone versions of the OS--just as Gingerbread phones will migrate to Ice Cream Sandwich. The migration is expected to begin toward the end of 2011.