At one time trag was looking at designing a CPU card for the ANS, but he never was able to get far enough with it, and I think there would be exactly two people who would buy it (he and I). I'm sure there are people still using ANSes in production environments, but very few, and I'm the only one I know of that still runs AIX.

Click to expand...

I actually built a card for it, but it didn't work. However, it gave me a bunch of ideas of things to try, which I (mostly) never did. It would be an interesting project to go back to just for interest's sake, but there are so many other projects in the queue ahead of it... It was pre-offspring.

With no components installed: http://www.io.com/~trag/PCB/ANSCPU_blank.jpg

With connectors and clock magic chips installed: http://www.io.com/~trag/PCB/ANSCPUw_parts.jpg

The bottom of the board is an edge connector that plugs into the ANS CPU socket. The brown connector is a standard x500 style CPU socket meant to take any (604(e)) CPU card that will work in a Macintosh, and possibly G3s as well. Those sockets were already mostly unobtainium when I started the project. I managed to get two samples from AMP/Tyco. But no distributor had stock, so building the upgrade in any number would have required ordering 1000+ of them at $8+ each and there might have been a market for 100 upgrades back then.

The various jumpers are there because while I had most of the 300+ pins figured out, there were some for which I was not absolutely certain of the proper connection. I suspect that many of them were actually don't cares. But I put in jumpers just in case. But then I calculated that in the worst case (i.e. every signal mattering) there were 1024 possible combinations of jumper settings.

However, I'm pretty certain that the worst case did not apply as I had some email help from one of the engineers at XLR8 and he had answered my questions about those last few questionable signals. So the jumpers were really there in case the XLR8 guy got something wrong, or just to cover the possibilities.

But it did not work. My next experiment was going to be to see whether I could clock chip the ANS bus down to 10 - 20MHz from 50MHz. If that worked with a stock CPU card, then I would retry my card, which might have noise issues at higher speeds. If that did work, then I would consider laying it out again as a four layer board. If it didn't work, I'd either invent some other experiments, or perhaps just lay it out again in four layers anyway, because the two layer layout probably is never going to work. I also needed to take an oscilloscope to the clock signals to make sure I got them in phase properly. But I didn't have an oscilloscope until near the end of the project, and I'm not sure the one I got even works (came from a coworker) and cheap PC based O'scopes weren't available back then.

I did have to create a pinout list for the x500 Mac CPU socket so at least that came out of it. The pinout for the ANS socket is in the ANS Hardware Developer Note. In the course of learning about the X500 CPU socket, I also learned some things about the Catalyst CPU socket and the PowerBase CPU socket and why those machines (from Power Computing) had the upgrade issues that they had.

But this was all back around 2001.