double buffering and page flipping question

I understand the concept of double buffering, draw stuff to a seperate buffer then blit it to the screen, but my question is, when it blits to the screen does it wait for a retrace or does it do it whenver? also, what is page flipping and is it faster/better than double buffering?

thanks

When double buffering, it is common practice to wait for a retrace so you don't get any wierd graphics glitches. This is not necessary and actually can slow down the graphics (very very little, but still...) but if you want perfect graphics, then it is worth waiting for the retrace.
Page flipping is used when you can point the graphics card to your buffer. You still have two buffers (or pages) and draw on the first while the second is displayed. When finished drawing, you just swap the addresses of the pages so you are drawing to the second and the card is displaying the first. This is much faster than double buffering (and probably easier, too) but this can usually (at least to my knowledge) only be done if you have enough memory on the video card to hold both pages at once. So it depends on what video mode you are using and the quality of your card.

cool, thanks