RT-11 / RX-01 issues ... "almost" boots ...

In the ongoing saga of my attempt to get RT-11 to run on my 11/34 .... (I'll spare the bandwidth by not attaching the entire chain of experiments run ...) Checked my copy of RT-11 and indeed it was SYSGEN'd. In my latest attempt, I did a SYSGEN as well, this time choosing to build a very, very basic version of RT-11SJ on RX-01. No FPU support, no timers, nothing fancy. Added device support for TT, DX, and DU devices only (the 11/34 has no installed DU device at all, I wanted to add it for future consideration). As expected, it went off for over a half-hour rebuilding RT-11. Produced the expected files and I proceeded to make the disk bootable. It boots on the LSI-11 system (an 11/73A) just fine. Put that same RX-01 disk on my 11/34 via an M7846 controller and when I tried to boot it I get the exact same result as before: it starts to boot, steps four tracks or so, then halts at "005134" on the display. If I inspect that address, it contains "140000". Sigghhhhh. Any thoughts as to what it could be? Disk controller card (M7846)? Summary: Since I've first written in with the problem I think we've eliminated as possible issues: * Memory since I had previously tried three memory cards all with the same result * Basic CPU hardware (slot C and D jumpering, Unibus termination) * RT-11 version 5 (which appears to run on other Unibus PDP 11/34s) Corrected a few small bugs along the way (like the complete lack of a terminator at one end of the Unibus). The CPU runs small programs, entered via the front panel, just fine (e.g. a ten line program to echo terminal characters). Just asking for ideas on where to go next! Anything else I should be checking? Thanks .... Mark Professor Mark Csele, P.Eng. Niagara College, Canada 300 Woodlawn Rd., L-23 Welland, ON, L3C 7L3 (905) 735-2211 x.7629 E-Mail: mcsele at niagarac.on.ca URL: http://technology.niagarac.on.ca/people/mcsele Author of "Fundamentals of Light Sources and Lasers", Wiley, 2004