One of the surplus stores in my area just got in a load of 5-1/4 form factor hard drives. They look just like the ones my PDP-11/73's use (RD51 or 52, can't recall). I believe my controller is a RQDX2, not a RQDX3. My drives are 30mb. I was wondering, is there an easy way (short of looking up the model numbers) to visually determine if any of the drives are ESDI and might work with my 11/73? Thanks! Jay West