I, too, have one of these kicking around. Mine has a bad Ball Monitor inside. I believe the MDS 225 is the Development System III mentioned in Joe's documents in an earlier post. I used to play with these about 9 years ago when we bought truckloads from Intel. If you have questions contact me off list. Most info has been covered on the other posts. I think it is worth collecting. There are not many in the hands of hobbyists and collectors. I used to have CPM for this system but I am not sure I still do. If I find it I will let the list know. I bet InBus Engineering still has cards and parts for these systems, if not docs and SW. I know I sold them thousands of dollars worth of parts, especially for the 310 systems many years ago. I still have some 310 multibus systems & parts. Their contact info is : compumart(a)inbus.com 925-454-2561 voice 925-454-2501 fax InBus Engineering, 6233 Industrial Way Livermore, CA 94550 Unfortunately they realize they have almost the sole supply for these old systems and their prices used to reflect that. I haven't talked with them in years but they still advertise in Compu-Mart and the Processor. Paxton Portland, OR