On Jul 5, 2012, at 9:03 PM, Steve Davidson wrote: ... The node PLUTO:: is a PDP-11/23+ with both CIS and FPU running RSTS/E. You can run an emulated one using SimH if you do not have the physical hardware. I have both running. You would be hard pressed to know if the system running (and connected to HECnet) was the real one or not! COBOL was the reason that CIS was designed for the 11/23+. Other languages can also make use of it. One that comes to mind is DIBOL. I don't know if Dibol uses it. I do know that the RSTS kernel does for memcpy. paul