https://www.usenix.org/legacy/event/usenix05/tech/freenix/full_papers/lo/lo_html/vgabios.html "Traditionally, a VGA card is initialized by software known as the VGA BIOS, which is considered an extension of system BIOS. It is loaded by the system BIOS from an expansion ROM located on the VGA card into a specific address in system memory. Control is then transferred to the VGA BIOS, and it uses the 16-bit callback interface to communicate with the system BIOS."
