I've just got back from getting the disk and trying it out, your correct DMSC, not that I thought you were wrong, I just felt adamant that it would work as it was (as this is how I remembered it), I don't remember the ",16" being in the original program, obviously by the look at it it was, somewhere along the line this ",16" has been overlooked, I could see that the USR argument required some bytes on the stack but I thought the OPEN operation done that, obviously not, but thanks for making me see the correct method, otherwise there would have been an error in my book. Thanks again.