 The VBI is particularly useful if the display hardware includes some sort of page flipping support, in which case the hardware can be set up to draw a new frame during the period where there is no drawing taking place.A VBI was implemented on the Atari 8-bit family, whose ANTIC display chip included a register pointing to the start of the display memory.The main program could draw a complete new frame into a back buffer and the VBI service routine would change the ANTIC register.