HANDS ON GUIDE

3 - Public access programming and open source are key

ATi's GPGPU programming language is open-source software

The key to using a graphics card for processing things other than 3D graphics is making the underlying hardware open for software developers to create their own code to address it. In the same way that Intel publishes C++ compilers optimised to run on its processors, GPGPU is founded on hardware vendors opening up access to the workings of their graphics cards.

ATi’s interface for this is called Close to Metal (CTM). This allows developers to address the native instruction sets of its Stream Processor and Radeon hardware. Of course, you could simply use Direct3D or OpenGL as the API, but ATi claims direct hardware access allows code to run up to eight times faster, as it does away with the overhead of the 3D-centric software layer required by Direct3D and OpenGL.

However, CTM is not a high-level language like C++ - it’s more akin to machine code. CTM provides the API upon which compilers for languages like C++ could be built by third parties. Some are arguing this is merely ATi trying to get other companies to bear the cost of this development. But as CTM is Open Source, anyone can build their own software to take advantage of it – and the specialised applications GPGPU is aimed at are often programmed at a much lower level than C++ anyway, to provide the greatest possible speed optimisations.

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