On 2015-04-11 17:25, Noel Chiappa wrote: Cool. I can't remember reading that post before, but those jumpers are interesting. Good point. But there is still a question on whether the CPU just pass all signals through that you need. In a normal Qbus system, the CPU is *always* at the end, as it terminates the bus. With PMI memory, it obviously works somewhat different, since the CPU sources signals in just one direction (hence the reason the PMI memory have to be before the CPU), and as far as I understand, also interacts/intercepts with all other memory accesses to the PMI memory. Which is yet another reason why the PMI memory sits before the CPU. If you put PMI memory after the CPU, it will instead work as normal Qbus memory. So I'm still not convinced until I actually see that done. :-) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol