This system looks pretty interesting, though pricey. I'm thinking it is going to be a development machine as all the switches and display would not probably have been on a production machine. I don't think National made many minicomputer format machines, in their history, someone correct me. That might make this pretty rare on that front as well. thanks Jim Beautiful-1974-NATIONAL-SEMICONDUCTOR-COMPUTER-model-imp-16p/ http://www.ebay.com/itm/252700755919