Qbus split I&D?

On 2015-03-18 19:15, Noel Chiappa wrote: Wow. This took me some time to get back to, and also find the mail thread. Anyway, I can now shed some more light here. To recap, we had multiple discussions/arguments about a memory expansion option for the 11/34, where lots of other people claimed that the Enable34 added memory, but that it was not addressable in the regular sense, and you mostly could use it in a bank switched way, and possibly DMA to it. I, on the other hand, claimed that it worked just like normal memory, and essentially expanded the 11/34 to a 22-bit addressing machine. Making it more or less the same as an 11/24. Turns out I understood/remembered it right, but was wrong about the product. The 11/34 that I played with did not have a product from Enable. So I really cannot comment on the Enable34, and I do not have any documentation on it. The product "my" 11/34 have came from Systime, and it do expand the 11/34 to 22 bit full addressing. The PAR registers are expanded to 16 bits, MMR3 gets some additional bits, and you get a Unibus map. The solution is one card in the CPU backplane. In addition, a few wires needs to be changed on the backplane, there is a cable from a CPU card to the Systime card, and a few modifications required on the 11/34 CPU itself. And then there is a separate box connected from the Systime card, which holds all the memory. Once you have installed the Systime option, you will have an 11/34 with 22-bit addressing. From a software point of view, the easiest is to tell any OS that you have an 11/24 instead, and everything just works. We still do have the manuals, even though I'm not sure where the hardware is anymore. It would take some work to scan them, and I don't have the time for that at the moment. I wonder, have anyone else but me ever seen/used this option? 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