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Re: DECStation update...

To: linux-mips@guadalquivir.fnet.fr
Subject: Re: DECStation update...
From: Stu Allen <allens@vivanet.com>
Date: Thu, 8 May 1997 13:28:50 -0400 (EDT)
In-reply-to: <199705072315.XAA19808@suede.sw.oz.au> from "Paul Antoine" at May 8, 97 09:15:14 am
>
> Paul Antoine wrote:
>
> 
> <image of a machine sitting in a corner all by itself, plugged in but
>  not turned on!>
> 

That is _amazling_ accurate ... it's sitting under the table in the corner
of my "computer lab" at home.  It's probably for the best though - if it
were up on top it could see all the other machines that get to actually do
something! :-)

> Hmmm... I'm feeling better about the possibility of getting your
> machine going, at least to the point of making something print on the

Cool!

> console!  In peering at the Mach 3.0 code, and the header files in the
> standard RISC/OS kernel binary release, it became apparent that early
> DEC MIPS designs were based *very* heavily on the workstations from
> MIPS themselves.  The DS3100's prom calls are near identical to those
> of the MIPS 3230's...
> 
> So it would strike me as entirely possible that the 5100 is very
> similar to a 3100.
> 

That would make a lot of sense, since as I remember DEC positioned this beast
as the replacement for the 3100, or at least to _us_ they did!  I'm actually
the one who bought the thing in the first place, and had originally gotten
quotes on a 3100 and was all set to order one when the 5100 came out, so I
ended up with this instead.

>  (snip)

> Thinking about your problem some more: it's entirely possible that in
> the boot PROM of your machine is a jump table of useful functions, but
> that jump table may be a little different from the 3100's (albeit
> modelled on the MIPS machines).  We should probably write a small
> program to disassemble the PROM...

Based on what's been on the list, and my experiece with the previous 
kernels, I've suspected all along that a PROM call was probably the 
culprit.  Of course, the lack of any output is also a clue!

I _do_ have a working Ultrix 4.5 system on this box, complete with GCC and
friends, so I would be more than happy to try compiling and running a 
"PROM finder" program.

> 
> Another thing you could do is describe the hardware of your machine a
> bit.  Have you taken the lid off your machines?  Can you describe how
> the boards are arranged?  Does it have a motherboard with the CPU,
> ether etc., and optional QBUS slots, or are devices like SCSI and
> ether on QBUS cards??

OK this is from my memory of when I last opened the beast, and that was 
over a year ago.  One thing for certain - there is no QBUS (or any other
bus) in the box.  (I think the web page is wrong on this point BTW.)  The
only slot it has is for a serial interface card, which I believe was 
specific to this one system.  It added like 4 async and 1 sync interface
I believe (it already has 4 async ports).  Everything else is on the
motherboard - Ethernet (10Base2 & AUI), SCSI, etc.

I'll try and open it up again tonight if I get a chance.

> 
> > KN230 V1.4
> > 08-00-2b-1d-3a-20
> > 0x800000
> > >>
> 
> Do you have a list of the commands that the boot prom accepts?  What
> does it print when you type '?' or 'help'?
> 

I'll have to get you this ....

Oh - one other clue - the command to boot using TFTP follows the 2100/3100
convention, which perhaps suggests that the PROM is similar to the 3100's.

> > Linux kernel-hacker-wannabee!
> 
> Resistance is useless... :-)
> 

It's funny really.  This box only has 8 (!) meg of RAM (I think - can't 
remeber!) and 2 207 meg hard disks, so chances are it will never really do
anything "useful".  But it sure will be cool to see it running Linux!

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