QBus termination?

From: Vintage Computer Festival <vcf_at_siconic.com>
Date: Tue Feb 8 13:01:16 2005

On Tue, 8 Feb 2005, Pete Turnbull wrote:

> > The M9400-YA does have boot PROMs. I've got one in this 11/23. The
> weird
> > thing is that the DSD-440 controller was in this system originally,
> and it
> > has its own boot PROMs. However, the terminator is in a second bus
> > segment. Does that make a difference?
> I don't know what you mean by a second bus segment. Does this system
> have two backplanes? Linked by a cable? Or are you thinking of left
> and right sides?

Qbus is "segmented", each segment having 4 quad slots. At least this is
what I've observed. So the system I'm working with now has two 4-slot
quad bus segments, for a total of 8 quad slots.

> Anyway, you should only have one set of boot ROMs. I think you can
> disable the bootstrap on an M9400, but offhand I don't know how. Such

And I didn't notice any straps on the board so I'm not sure how either. I
guess you're just supposed to use the M9400-YA with DEC controllers that
don't come with boot PROMs, or otherwise use a terminator other than the

Sellam Ismail                                        Vintage Computer Festival
International Man of Intrigue and Danger                http://www.vintage.org
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Received on Tue Feb 08 2005 - 13:01:16 GMT

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