I would like to have 3 different applications, each calling Photon drawing functions for display on both my on-board 
(i830) graphics and each of the 2 outputs on a Matrox dual-head card.

My existing system uses only the on-board graphics  and my Photon startup file consists of a simple call to io-display, 
Photon and io-graphics.

How do I modify this file for multi-head Photon use and how do I 'point' each of my applications at the correct display?