Google's Android 4.0 "Ice Cream Sandwich" mobile OS release, which is expected to debut this evening, has developers hoping for resolution of longstanding platform fragmentation problems and critical bug fixes.

Android application developers now deal with multiple versions of the operating system, geared for either phones or tablets but not both. They also have had to cope with customized interfaces, making it tough to build applications to run across the variety of Android units on the market. "I'm anticipating [the operating system upgrade] hotly," said Brian Hardy, a software engineer and instructor at mobile software developer Big Nerd Ranch. "It's always nice to see what's new, but it will be refreshing to be able to develop on one platform at some point in the future."

Currently, developers can use the Android 2.x platform for smartphones and 3.x platform for tablets. Google has released a compatibility library for sharing some functionality between 3.x and 2.x systems, but does not solve all problems, Hardy said. As an example, he cited that the action bar functionality is not available in the library.

Another developer chimed in that unification would bring Google in line with competitor Apple. "It's exactly what Apple did when they came out with the iPad," said Nick Farina, CTO at developer Meridian. "Google is doing the same, which I think is good." As a result, Android tablets and phones will share the same UI, simplifying development, he said.

Fragmentation has even affected Android's WebKit browser engine, said Mike Burns, a developer at Thoughtbot. "This is part of the fragmentation problem. They fix bugs in one version and introduce bugs in another version," he noted.

Android 4's arrival is anticipated as part of a Samsung Galaxy Nexus smartphone debut in Hong Kong scheduled for this evening in U.S. time zones. Google has emphasized the unity the operating system upgrade is supposed to bring to the fragmented Android landscape. "Our goal with Ice Cream Sandwich is to deliver one operating system that works everywhere, regardless of device. Ice Cream Sandwich will bring everything you love about [the Honeycomb release of Android] on your tablet to your phone, including the holographic user interface, more multitasking, the new launcher, and richer widgets," wrote Hugo Barra, Google's product management director for Android, in a May blog post.

But Ice Cream Sandwich will not solve all problems with the platform, said David Cao, organizer of the Silicon Valley Android Developer Group and vice president of mobile at BeyondSoft. He is not a developer himself, but said Android still has problems in which Google controls the release of code and some device vendors get the code before others, he said. "Android is somewhat open, but it's not completely open."

Fragmentation is not the only issue hurting developers. "I look forward to the bug fixes more than anything else," said Thoughtbot's Burns. Android has had issues with bugs in widgets and HTTP as well, not just in WebKit, said Burns. The widget issues are the most prevalent, he said -- in particular, issues with rotating the device and screen pages. Screen fragments, such as the tab bar, do not get updated when pages are swiped left to right, he said. "I'm hoping that they've gone through and fixed all these kinds of situations."

Burns also wants to see improvements in caching data from the Web. "It's all manual. I have to maintain my own cache, and every application has to do this. So if [Google] could give us something, that would be great," he said.

Meridian's Farina cited issues with software-based graphics rendering related to pre-Android 3.0 releases. He said, "The way that graphics are drawn to the screen is using a software technology that basically as old as Windows 3.1."

Big Nerd Ranch's Hardy adds that he anticipates some new APIs but that Google has said little about Ice Cream Sandwich, making it hard to know what to truly expect. Google has not yet released a software development kit for Ice Cream Sandwich, so even when Android 4.0 is released, it will be some time before developers can write one Android 4.0 application that runs on multiple systems, he said. Plus, cellular carriers and device makers have to update the operating systems on their devices.