[comp.sys.next] Slot dependencies

carlton@ji.Berkeley.EDU (Mike Carlton) (05/02/89)

Can anyone tell me if the Next system board is hard-wired to be in slot
0 on the NuBus?  We tried moving it to another slot and the system hung
during the boot sequence.

Why do we want to put it in another slot, you ask?  Well, we got 8 megabytes
in SIMMs and thought we would plug them in our Next.  Unfortunately, these
are composed of DIPs and the SIMM modules are about 1/2" taller than those
used in the Next (which are composed of surface mount packages).  There is only
about 1/8" clearance between the system board and the central stack of power 
supply and disk drives.

No problem, we said.  We'll just move the board out one more slot.  Of course,
the disk cables will block the inner slot, but this is no loss (at least, not
until we get 3 more boards for the system :-).

Alas, the machine hangs during the boot sequence, just after announcing 
"Remote debugging enabled / Message buffer allocated at <some address>"
Evidently the ROM software knows what slot it is in (it announces "Master CPU
in slot 0" during a normal boot).  

My guess is that the slot number is used by the ROM to map memory addresses
(but I'm hoping I'm wrong).  Can anyone tell me if we can reconfigure the 
machine somehow to allow the system board to reside in a different slot?

P.S. Don't bother to volunteer to take the 8 megs worth of SIMMs off of our 
hands for us, we've got other machines to plug them into if need be :-)

thanks,

--
Mike Carlton, UC Berkeley Computer Science	  | More bits,
carlton@ji.berkeley.edu    ...!ucbvax!ji!carlton  | Give me more bits.

ali@polya.Stanford.EDU (Ali T. Ozer) (05/02/89)

In article <29010@ucbvax.BERKELEY.EDU> Mike Carlton writes:
>Can anyone tell me if the Next system board is hard-wired to be in slot
>0 on the NuBus?  We tried moving it to another slot and the system hung
>during the boot sequence.

Yes, right now that's the case and I don't think there's a way around it.

Ali Ozer, NeXT Developer Support
aozer@NeXT.com