A frame buffer is dedicated memory on a video adapter. Simple frame buffer video adapter hardware contains a frame buffer but no accelerator. If the hardware is linearly addressable and it can support standard format bitmaps (DIB format), GDI can handle the rendering operations and write directly to the frame buffer. This can reduce the size of the display driver because the driver can let GDI do all or most of the drawing. Most frame buffers today are linearly addressable, or "flat".
Among the sample display drivers is a frame buffer driver in the directory named framebuf. Because this driver supports linearly addressable frame buffer hardware, it allows GDI to do most of the work, and so is quite small and relatively simple.