On 3/10/07, Sridhar Ayengar <ploopster at gmail.com> wrote: I think I've heard people reference this incident on the list. I didn't know it was quite as spectactular as all of that - sounds like a combination of luck and quick action on the part of all present. Hmm... I have an 8300 in the basement with a non-working DWBUA (it used to work, about 13 years ago but that was before the machine got moved). My recollection of it was that (when it was working), the DWBUA was ok in a native VAXBI environment like the 82xx/83xx, but that when you started stacking bus converter on bus converter, it didn't take much to get things to the point of violating timing maximums on certain things. We had a problem with a Qbus COMBOARD being stuck in the same Qbus as a TLZ04 controller on an early model VAX 4000 since the CPU bus _wasn't_ Qbus, and there were enough subtle changes that hardware bus timeouts came into play, especially when the TLZ04 controller "went away" for a bit - I think officially, the timeouts were too stringent, but had never been a problem up to that model of VAX. I have to seriously wonder if you could get traffic from the Qbus, over the Q/Univerter, over the DWBUA over the XMI-BI bridge (forget the model #) before something timed out somewhere. No reason not to attempt it, but if it doesn't work the first time, the chain might just be too much to handle. -ethan P.S. - the problem I'm now having with my DWBUA might be a wonky UET (Unibus Exerciser/Terminator). The UET has to work perfectly and respond correctly when the DWBUA talks to it, or the DWBUA fails self-test. Could be cables, could be bad components, or could just be the phase of the moon. Either way, I installed a DWBUA correctly once, and now it appears to have been a fluke. It hasn't worked right since I moved it. :-( I have the docs, and according to the various device status registers, it acts like the DWBUA isn't seeing the right things from the UET. *slaps forehead* I have just the thing to check it out - a not-yet-assembled bare-board UA-11. I think assembling that just moved up the priority chain to sometime in the first 1/2 of this year!