MIX07 Despite the early batch of criticism that Microsoft’s Silverlight has already generated, there is still much to interest applications developers in its arrival as a beta product, as well as issues for them to ponder, not least being whether Flash is still the better option for now.
The key interest, particularly in Microsoft’s world, is that the Common Language Runtime (CLR) is going cross-platform. That is the big news at Microsoft’s Mix07 conference, where delegates have seen demos of .NET code running on both Windows and the Mac, hosted in a future version of Silverlight, the video streaming browser plug-in now in beta.
The announcement itself is no surprise, but many of the details are new and worth considering from the developer point of view. For example, cross-platform in this context means Windows, Mac, and in due course Windows Mobile. Microsoft appears uninterested in Linux, though program manager Keith Smith told me “there is nothing to preclude it.” There is talk of supporting other mobile platforms such as Symbian in future.
According to Smith, the Silverlight-hosted CLR will have no access to local storage beyond what the browser chooses to cache, and will be sandboxed to disallow invocation of native platform APIs. Silverlight runs only in the browser, so there is no cross-platform equivalent to Adobe’s Apollo, which uses the Flash runtime for desktop applications.
Microsoft is so keen to see Silverlight used that it will host the content for free. Silverlight streaming is a “companion service” that streams media content from Microsoft’s servers, supported by its global content delivery network. The free service allows videos up to 10 minutes long, in qualities up to a DVD-like 700 Kbps, occupying up to 4GB of total space, and serving up to one million minutes per month. Beyond that, there will a fee-based or advertising-supported service.
Silverlight cannot succeed on bribery alone, however. Its strong points are high quality video, and smooth integration between design and development tools in Expression and Visual Studio. Existing .NET developers will get an easy route to browser-hosted cross platform applications. That said, Silverlight 1.1 with CLR support is only in alpha, implying a lengthy wait before full release.