Your operating system license for RSX, RT11, or RSTS from Digital Equipment Corporation can be assigned to the Osprey/PC, so long as your old PDP-11 is no longer in operation. If, however, you intend to continue to use your PDP-11, you must purchase a separate operating system license from Digital -- or directly from Mentec Computer Systems in Lowell, Massachusetts in the US, or Dublin, Ireland. Please contact your Mentec or Digital Equipment Corporation sales office for price and availability.