On Oct 8 2004, 16:44, Gooijen H wrote: Without looking at the boards, it's impossible to tell for certain. Some 11/73s were upgraded without changing the badges on the front. *Usually* a microPDP-11/73 is in a BA23 and a microPDP-11/83 is in a BA123, but not always. The real difference is in the use of normal QBus versus PMI memory; that makes more difference to the speed than just about anything else. Originally, an 11/73 would have had a 15MHz KDJ11 and an 11/83 would have been 18MHz, so they'd have had slightly different suffixes on the M-numbers, and they'd have slightly different boot ROMs, but any of these things may have been changed. What an OS goes by is whether the memory is PMI or not. -- Pete Peter Turnbull Network Manager University of York