An accelerator contains onboard circuitry that enhances the speed of graphics operations. Such hardware can contain accelerations for specific rendering operations such as line drawing and filling, or bit block transfers. If the hardware provides support for a pointer, it is usually much faster for the driver to make use of this than to use the pointer support provided by GDI.
The S3 sample driver is a sophisticated and fairly complicated example of an accelerator that can be found in the s3 display driver source example directory. The S3 display driver is coded entirely in C so that it is portable across systems. It supports both flat and banked frame buffers. For details about banked frame buffers, see Supporting Banked Frame Buffers.