The Microsoft Surface SDK has been released to the general public. Previously the SDK was restricted to PDC attendees and other special invitees. The Surface SDK is designed to run only on 32-bit versions of Windows Vista. Windows 7 and 64-bit versions of either OS are officially not supported. Developers will also need C# Express 2008 or Visual Studio 2008 and the XNA Framework.
The hardware requirements are listed in terms of Windows performance ratings. CPU, RAM, and Disk should be rated at 4.0 or higher, while both graphics numbers should be at 5.0. You will also need “a monitor that is capable of 1280 × 960 screen resolution or a widescreen monitor that is capable of 1440 × 900 screen resolution.” Support for touch screens isn’t mentioned as a requirement in any of the documentation and the mouse can be used to simulate gestures.
The wide-spread release of the Surface SDK comes with a Service Pack that adds some API enhancements. The classes getting new functionality include ScatterView, Contact, TagVisualizer, and SurfaceSlider. New classes include a playback mechanism for recorded simulator scripts and the base classes SurfaceSelector and SurfaceHeaderedItemsControl.
Amongst the development tools is a stress generator. This tool can send randomly generated input, optionally “parameterized by types, sizes, velocities of contacts, regions where the contacts should appear, the rate of appearance, the contact density, and whether the simulated contacts can touch the Surface Shell access points.” For reproducibility, the randomization can be based on a seed value.
Support for “Service Applications” has been added. These are like Windows Services in that they don’t have user interfaces and persist across user sessions. Service Applications can be automatically restarted if they fail and initiate other Surface applications.
The Surface Shell, which hosts all Surface applications, can now use tags on objects to start the application associated with the tag.
In addition to the SDK download itself, there is a lot of useful information in the release notes and getting started documents. You will need an XPS reader if you wish to view these documents on a non-Vista OS.