There is some information (last updated in 2003) on Markus Kuhn's pages at Cambridge University.
Some more recent work (2009) from LeoNerd(?)
[Neither of the following liks work anymore - December 2014]
Some detailed info from the 2005 Sun Systems Handbook http://sunsolve.filibeto.org/Systems/SunRay1/SunRay1.html (An alternative site is http://www.sunshack.org/data/sh/2.1.8/infoserver.central/data/syshbk/Systems/SunRay1/SunRay1.html )
Any comments? email me. Last update June 2012