Doug, it's possible that they used some kind of encryption scheme, but I expect it to be unlikely. Any such arrangement would ultimately slow down machine performance.

I hope that it's a simple situation in which all the bits of each 64 bit word are reversed or some such. I just haven't had time to look at it myself yet, and I'm not as skilled at such analysis as many of your folks. So, in my previous post, I put it out here for others to examine.

Besides, it would be good to be able to get a useful backup of our X500/X600 machines using Copyrom.