"Maciej W. Rozycki" wrote:

> On Fri, 19 Nov 2004, Dennis Grevenstein wrote:
> 
> > >  Yeah.  Don't forget to jumper the motherboard for the 5000 mode.
> >  
> > What jumper do you mean and why is that necessary?
> 
>  It's located in the TC slot 0 area, beneath the option board, if you have
> one installed.  It should be open for the 5900 and closed for the 5000.  
> Originally it was apparently meant to be a diagnostic jumper, but when the
> 5900 was engineered, it got redefined.  Its state is visible as bit 15 in
> the I/O ASIC's SIR register.
> 
>  I know it's used by Ultrix to differentiate between the two systems; it's
> quite possible it's used by the firmware as well, but I can't tell for
> sure.  It won't hurt to set it correctly anyway.  Barring this setting,
> there is actually no way to differ the two systems by software means.

NetBSD checks the same bit, and it's only used to determine the board
name (see sys/arch/pmax/dec_3maxplus.c, around line 210).

Unfortunately my 5900 has a fried power supply.  Anyone know if you can
somehow transfer the innards of a 5000-style PSU in to a 5900?

Simon.
--
Simon Burge                            <simonb@wasabisystems.com>
NetBSD Support and Service:         http://www.wasabisystems.com/