Yeah, but linux framebuffer can do a very optimal swap... Just make the "virtual buffer" twice as tall, and then swap which "half" is "active" with a panDisplay IOCTL... That's why memcpy is such a bad idea, cause there is a very cheap method that can prevent tearing and such.
With CRT monitors, it was possible to swap buffer in the middle of the frame, to display different buffers in different areas of the screen. It was used on 16bit systems for fast scrolling and to display status line.
