VAX 6400 booting saga: A scary story with a happy ending.

Hi, let me share a frightening story with you that I lived through while my family had naptime. I decided to try out Isildur's idea of booting Ultrix using a KA62A processor in the hope that that would be supported right off the 4.5 boot tape. And I just happened to have one such T2011 board in a box (taken off a lonely 6310 in a barn full of bird-poop.) So, I took all 6 KA64As out and stacked them on some papers that I use to pack most of my boards (with papers between the boards so they would not stick together :-). Put the KA62A in and fired up. A lonely light lit and no real function was to be observed. I moved all 4 MS65A-DA boards out too, because I figured that may be a KA62A doesn't know how to deal with MS65A-DA. I swapped in some of those T2014 that seem to multiply while stored in the box. Anyway, it still wouldn't work. The self test progress report shows that the CPU detects no memory and then it reports that problem explicitly and stops. The CPU error status lights say hexadecimal C0. I could not find any table explaining what C0 status code is. It could be boring (like "no memory found", which I know) or it could indicate some condition that I could fix, like "backplane wiring error" :-). I stuffed the whole XMI bus full with those 32 MB cards in the hopes that one would work, but to no avail. So, perhaps the memory access path in that CPU board is broken? Is there any rewiring to be done when converting a 6400 down to a 6200? Anyway, my daughter came downstairs indicating naptime was over and so it was time to finish up. KA62A and all MS62A back in the box and all 6 KA64As and 4 MS65A-DA back into the bus fired up and all processors were indicating they were somehow not agreeing who would get to be the primary CPU. Hit reset and they figured it out. But now they were bitching about memory and the CPUs showed minuses in the selftest monitor. Rearranged the CPUs and the memory, still no good luck. Everything was screwed up! I was afraid I had killed all my boards by careless handling (I did this before, may be not with that polyester pullover that might have sent static sparks, like they do.) Took all but one CPU out and that did do the self test OK. But one MS65A board seemed broken. It failed regardless which slot I put it. Finally I took it all out. Then the CPUs back in and again it didn't work. I then put CPUs back one by one powering up each time to see progress. Slowly, one by one, the number of board which I thought I had killed reduced down to 1, the memory board. The order in which I put in the CPUs and the restarting every time seemed to be important. Then, finally I even found one configuration of the memory boards where all 4 were detected and tested fine. Hey I was so scared I had killed half of my VAX through carelessness. But I didn't. I am quite confused why it is all so finnicky about the order of installing the hardware. I won't mess with this machine's XMI configuration any time soon. regards -Gunther -- Gunther Schadow, M.D., Ph.D. gschadow(a)regenstrief.org Medical Information Scientist Regenstrief Institute for Health Care Adjunct Assistant Professor Indiana University School of Medicine tel:1(317)630-7960 http://aurora.regenstrief.org