a) Flip has the effect of *interchanging* the contents of back and front
b) Flip has the effect of copying back to front
b) Flip has the effect of copying back to front
FYI - Flip does neither (Unless I've missed something somewhere). It only changes the REFERENCE to the drawing buffer. On each screen refresh of the monitor the video card will transfer information to the monitor STARTING at the memory location referenced in either FrontBuffer() or BackBuffer(). No information is ever copied from one buffer to the other.
This way, ABSOLUTELY no time is lost transferring any data anywhere. This is the fastest possible screen update available.
This phenomenon you are talking about where any data is being moved around doesn't sound correct. If it is a video card 'feature', it sounds like a stupid one. Two buffers have to co-exist anyways (to allow you to draw to one while displaying the other) so why bother transferring any data?