hello,

 this is because the Q-bus requires there to be a continuity in the grant 
lines through all devices. The end of the chain is now right before where 
your M7546 was. You have to take note that the bus is sepentine: grant passes
from the top of the  last Q/CD slot to the first Q/Q slot , thence out 
the bottom of that slot into the bottom of the next, out the top of that 
one, and thus on to the end. Rearrange boards or pop in a grant card 
(M9047) where the TQK50 used to be. A note on arrangement of boards: 

because the Qbus is an asynchronous grab-it-when-you-can bus, things with 
a high interrupt rate do well closer to the processor and memory. things 
like network interfaces and tape streamers shoudl be closest to the 
processor. Next, things like line interfaces, next, things like async 
interfaces. disk controllers shoudl be close to the last. Anything 
seriously time-sensitive, scientific i/o or analog systems, etc, shoudl 
also be close tothe processor. If you put a disk controller first, it 
will hog the bus totally, and youll see shitty network performance, etc 

all in all, though, you have a nice machine that will give you yeears of 
solid operation, 

happy hacking
isildur


On Thu, 30 Nov 2000, bart sikkes wrote:

> Hello,
> 
> Our uVax II is running so we wanted to reorganize a bit. Because we don't
> use the tape streamer and don't even have tapes we removed the Tapestreamer
> and it's controller card. After we had done this the uVax didn't want to
> boot anymore. We got an error message about the dua0.
> 
> After we put the controller card back everything worked again. Can't we
> remove the card somehow?
> 
> Further were can we read some more about this system of placing cards. If I
> rember this ok, the way you place them sets the priority. But some of the
> cards were not going to use so can we just remove those? And now we have a
> networkcontroller, a harddisk controller, memory, process and we want these
> placed the best way, can we find somehwere how to do that?
> 
> thanks,
> bart
> 
>