Developers will no longer need to first buy a Surface device to get the SDK, according to Microsoft. Coupled with a piece of table top-like hardware that has cost about US$15,000, Surface applications respond to touch, natural gestures, and physical objects. Interactivity is enabled. Objects placed on the display can be recognized and trigger digital responses.

"Our vision with Surface is that we are trying to go and create a new generation of computers and software that will unleash meaningful collaborative as well as natural experiences," using an interface that ultimately will make tables and walls come alive, said Brad Carpenter, general manager of the Microsoft Surface team.

Thus far, only those who purchased a Surface hardware unit could get the SDK; about 400 to 500 persons have participated. But that number will expand to about 1,200 people when Microsoft offers the SDK to attendees at a Surface session at the PDC on Monday and to those who come through Microsoft's hands-on lab, Carpenter said.

As part of the effort, Microsoft will offer developers a simulator to run Surface applications on a PC and leverage Windows Presentation Foundation. Developers will no longer need to buy Surface hardware, although Microsoft will offer a 10 percent discount on the hardware for a developer unit and five licenses.

"Access to the hardware, we believe, is very important," said Carpenter.