 Another important part of the SDK, the Compute Abstraction Layer (CAL), is a software development layer aimed for low-level access, through the CTM hardware interface, to the GPU architecture for performance tuning software written in various high-level programming languages.In August 2011, AMD released version 2.5 of the ATI APP Software Development Kit, which includes support for OpenCL 1.1, a parallel computing language developed by the Khronos Group.The concept of compute shaders, officially called DirectCompute, in Microsoft's next generation API called DirectX 11 is already included in graphics drivers with DirectX 11 support.