"Graphics driver" still sounds too complex. The code was probably poking bytes to the memory segment mapped directly to the display - just like in DOS days, whe

"Graphics driver" still sounds too complex. The code was probably poking bytes to the memory segment mapped directly to the display - just like in DOS days, where each byte of the 0xA000 segment represented a pixel when using a VGA 320x200 resolution, 256 colors palette.