On 2015-01-28 20:02, Noel Chiappa wrote: I can only offer one slightly related datapoint here. I used to play with an 11/34, which had an Able ENABLE product of some sort (if my memory for names are to be trusted) to expand memory. That thing brought an 11/34 up to 1M of memory, essentially working the same way an 11/24 would work. However, the was one board that went into the CPU box, and then there was a cable or two out from that to a separate memory box that held the memory. So the memory cards themself was not in the CPU box, and I actually have a hard time understanding how it would have worked in an 11/45 as well. The machines that had more than 256K of memory, and were Unibus based, and had the memory on the "unibus" actually had a special backplane for the memory cards, where otherwise unused signals were used to do the extra addressing bits. Which also means that all the memory cards had to sit in the same backplane as the CPU. They could not be put in any other Unibus backplane. The only two machines that did this was the 11/24 and 11/44. But apart from the problem of getting four more address lines, the rest is pretty simple. You will get a Unibus map, for all DMA, and you'll get a new MMU which implements all the bits in the PAR registers. And that's it. So, it also implies that the original MMU have to be removed. And that is where you put the new card in. But I don't know anything about the 11/45 extension this way. Like I said, I only played with an 11/34 that had this. Johnny

On 1/28/2015 11:02 AM, Noel Chiappa wrote: I sent a bit of this thread along to Ken Omohundro who founded Able, and his reply is below. If he sends anything else along, I'll get it to somewhere people can find out about it. /Wow!/ / / /You are talking about 30+ years ago! / / / /Let me check my archives and I'll get back to you./ / / /My memory is not as good as it once was with a long line of communication product designs since then. / / / /Our Univerter was our first product that allowed DEC to sell their first Qbus processor board in larger quantities since they released it before the developed Qbus interfaces for it. On that design we added a register to allow users to access more memory as well.,/ / / /Our Cache 45 sat on the fast bus allowing RSTS OS users to improve system performance over 50% better./ / / /SCAT 45 was a MOS memory we developed to allow us to put a full 128Kb of memory on the fast bus instead of the 32Kb bipolar offered by DEC. Mad flight simulators faster than anything else as well as many scientific and defense applications./ / / /Microverter was bidirectional and our most popular bus converter./ / / /The Enable and the Magnum was our last bus converter products trying to squeeze the last unannounced capabilities of DEC's Qbus processor boards./ /Unfortunately there was not a very big demand for those solutions. Which is why the details haven't stayed with me. I probably have data sheets archived and I will scan them as a PDF file and email them to you./ / / /Hope that will help./ / / /Ken Omohundro/ Thanks Jim