+The TGI driver is implemented as a dual buffering device. To use it as a
+single-buffer device set draw page and view page to the same value 0 or 1;
+
+The TGI driver has a few Lynx-specific extensions.
+
+Calling tgi_ioctl(0, spr) will display a standard Lynx sprite on screen.
+
+Calling tgi_ioctl(1, 0) will do a flip screen. If you decide to flip the
+screen then it may be a good idea to call the install-routine for the
+joystick to get that flipped too.
+
+Calling tgi_ioctl(2, bgindex) will set the text background color to the index
+defined by bgindex. If bgindex is 0 then the background color is transparent.