On 2014-05-22 14:22, Cory Smelosky wrote: On Thu, 22 May 2014, Johnny Billquist wrote: With parity disabled and RSTS/E: https://ghostbin.com/paste/ksd3c a bad ~50K? I can disable everything above 512kByte which is...i forget how many words. 512Kbytes is 256Kword. :-) Ahh. But it's not clear that the address are in Kwords... It's a 1M board...so it's either at the very upper end of memory or in the middle. Unfortunately it is before the halfway point, so you'd have to disable more than half the memory... (If it isn't close to the total end...) Johnny