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Re: Tandem 4440/A ??

To: "R.Charles Sweeten" <alpha@rasgroup.rasgroup.com>
Subject: Re: Tandem 4440/A ??
From: Eric Jorgensen <alhaz@xmission.com>
Date: Mon, 05 Jul 1999 12:09:25 -0600
Cc: linux-mips@fnet.fr
References: <Pine.LNX.3.93.990705084553.17554A-100000@rasgroup.rasgroup.com>
Sender: alhaz@fnet.fr
"R.Charles Sweeten" wrote:
> 
> Eric,
> 
> You'd be correct on the video.  The connector is not in line with the rest
> of the EISA bus.  I suspected that it may not be actually EISA, but I'd
> thought that I'd seen other EISA boards with an offset slot like that.

        Yup, that sounds like it's probably one of the many systems that were
based heavily on the Jazz motherboard. Few companies varied from the
design until NEC started manufacturing multiprocessor ARC systems. 

        There were two video cards available for the proprietary 128-bit frame
buffer interface in the Jazz motherboard. The low end one I believe was
just refered to as "Jazz" and was a more or less brainless 8 bit
non-accelerated Brooktree frame buffer. This is probably what you have.
There should be a prominant Bt chip near the back of the case on the
card. This frame buffer is fixed at 1024x768x8bpp. Probably at 60 or 72
hz. So nearly any good VGA monitor these days is compatible with it's
signals. 

        The high end one, I could have sworn they named it after some large
jungle cat but Cheetah doesn't sound right. I believe it was
manufactured by Carrera. It was accelerated and I believe was usually
shipped with either both the 13W3 and an HD15, or just an HD15. This
board was multi-frequency like PC video cards so it could do several
resolutions. You probably don't have this one, since they were awful
expensive, and you have just the one 13W3 connector anyway. 

        There are companies that manufacture 13W3 to VGA adapters intended to
let people attach PC monitors to SGI computers. They charge from $40 to
$65 for the finished product. 

        Alternately, on Sparc mailing lists, I've heard reports that ViewSonic
will sell you a Sun 13W3 to SVGA adapter for $23 if you call them and
tell them about how you'd just love to use a bright, crisp ViewSonic
monitor instead of a fuzzy old Trinitron on your Sparc. If you're up for
a little social engineering you might be able to swing the same deal
saying how much more you like ViewSonic monitors than the monitor on
your ageing Onyx. 

        If you want to build your own, somebody on this list maintains a faq
that includes SGI 13W3 to SVGA pinouts that I gave them. I still haven't
personally tested them. What I have here is a fully wired cable hacked
off the back of a dead Sun 21" monitor. It's quite fortunate that every
pin is wired because Sun and Mips/SGI use different pins on the
connector. My plan here is to stick an SVGA connector on the other end
and plug it into a keyboard/monitor/mouse switchbox I bought about a
month ago. One of these days when I get some of that "free time" I've
heard about. 

        Anyway, the 13W3 connector is available from Mouser for $11,
preassembled. You want the preassembled one, since it's no fun to crimp
the mini-coaxial bits into the housing without the proper tools.
www.mouser.com. 
 
> As for the memory, there's no guarantee, of course, that the memory that I
> found in the system is the memory that worked in it.  It looked
> authentic/orginal, but oh well.  It has 8 chips on the stick and would
> be seen in my PS/1{requires parity} and came up in a generic 486 I was
> playing with.

        Hmm, well, it might work anyway. I mean, it's not like they couldn't
have adjusted that part of the design. Have you tried booting it up at
all? The original Magnum hardware has a small one-digit LED readout on
the motherboard that serves more or less as a POST code display. 

        As long as you have a keyboard plugged into the keyboard port (Should
be PS/2 style), if all is well it should go completely blank as soon as
the bootprom console loads - signifying that it didn't have any problems
with the hardware. 
 
> So, is there no reference point for these machines?  No web page with docs
> or anything?  Or is this a "you want it, then do it" kind of thing?

        I believe there is a web page with docs on this somewhere. I'm sitting
here with my own server on a T1 colocated at a company i work for, so I
should go ahead and start a "Linux/Mips on Jazz/ARC Hardware" home page,
if nobody else has one in the works already. Of course, it'd be cooler
if i were running it on a Magnum, instead of a Sparc 2. Or if i had
Linux running on my Magnum at all . . . . . 

        Anyway, I'm sure you've noticed that, while pretty, the fnet.fr page is
a couple years out of date. You can indeed run Linux mostly without
problems at all on Jazz hardware. X and everything, so I hear it. Here
are some more links on the issue: 

http://www.linux.sgi.com/
http://decstation.unix-ag.org/
http://www.xs4all.nl/~vhouten/mipsel/
http://www.inter.nl.net/users/schnecke/mips/

        Jazz platform machines are bi-endian, being able to boot into either NT
or RISCos. If yours is in big-endian mode and boots to an SRM console
once you've got it hooked up to some video and a keyboard, you will need
to switch the system into little-endian mode. on the Magnum this
involves using a disk to load the ARC console into the boot prom, and
the Magnum disk may or may not work in your system. You'll know SRM by
the sinking feeling of futility generally associated with it. It's
designed to mount a BSD filesystem and launch the OS, and I don't know
if anybody has managed to get Linux/Mips to boot from SRM. It may well
be possible, since Linux/Alpha is now booting correctly from the similar
SRM console on AXP systems. 

        To make things more confusing, Alpha and Mips both have both SRM and
ARC consoles available, and both call their boot loader MiLo. 

        If it boots up into something bearing a striking resemblance to the old
Windows 3.0 setup program, that's the ARC console, and you're in
business. 

 - Eric

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