Thanks for the replies and apologies for the delay in response. Had a quick peruse of those sites, but due to access restrictions at this public library, I can't peek into some of the archives, at the moment, to verify their contents. What I'm really after, for a starter, I suppose, is the gengradd sample driver source code. I believe the openglddk has source for the glintgradd (or is it gligradd?) driver. My laptop has recently gone down but somehow I'll overview the resources at the links provided and see if I find the glintgradd info. Roderick, you are correct, hooking into GRADD is initially my area of interest. Thanks again for the quick responses, TJ.