In addition to the "tty" devices, KGI adds the "graph" devices. These are in a one-to-one relationship with tty devices: for every tty, there's one graph device. So the graph devices are named:
/dev/display/head0/graph1
/dev/display/head0/graph2
/dev/display/head0/...
/dev/display/head0/graph16
/dev/display/head1/graph1
/dev/display/head1/graph2
/dev/display/head1/...
/dev/display/head1/graph16
The graph device represents the same monitor as the matching tty device, except that you can use the graph device to draw graphics on the monitor. Libggi opens the graph device, and uses ioctl calls and mmap calls to control the video card. The details are described later.