Date: Tue, 12 Sep 1995 08:28:34 -0400 (EDT) From: "Jonathan M. Bresler" <jmb@kryten.Atinc.COM> To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: "Jordan K. Hubbard" <jkh@time.cdrom.com>, gibbs@freefall.freebsd.org, hackers@freebsd.org Subject: Re: Help! :-( (fwd) Message-ID: <Pine.3.89.9509120850.A8924-0100000@kryten.atinc.com> In-Reply-To: <199509120403.XAA18652@brasil.moneng.mei.com>
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On Mon, 11 Sep 1995, Joe Greco wrote:
> > Can you explain a little more about this system? What's in the thing?
> > I've never seen one of these:
> > chip2 <DEC 21050 PCI-PCI bridge> rev 2 on pci0:11
> > Before! :-)
you can get details from the book _pci_system_architecture_ by
tom shanley and don anderson, addison-wesley. look at the chapter on
"pci device configuration".
as i understand it, a pci-pci bridge connects two pci busses in a
heirarchical topology (2 host-pci bridges can be used to form a peer
relationship).
> As it's been explained to me, that is a PCI to PCI bridge ("PPB"), which
> "connects" two PCI busses together, or somesuch. It's a gateway onto a
> different bus. Apparently certain PCI peripherals, such as 4-way Ethernet
> cards, like to glue 4 PCI controllers together on a bus and then provide a
> single gateway onto the system's PCI bus. In this case, the AHA3940
> apparently puts two controllers behind a PPB. I'm mostly familiar with bus
> bridges in other contexts, so I am not sure that my description is totally
> correct, and I have no idea what the issues all are.
>
> I'll be the first to admit that PCI puzzles me. I'm not really a PC
> hardware guy - I leave that to the geniuses like Rod. Speaking of Rod, he
> was the one who sold execpc.com the motherboard and PCI Ethernet cards in
> question.
>
> Thanks,
>
> ... Joe
>
> -------------------------------------------------------------------------------
> Joe Greco - Systems Administrator jgreco@ns.sol.net
> Solaria Public Access UNIX - Milwaukee, WI 414/342-4847
>
Jonathan M. Bresler jmb@kryten.atinc.com | Analysis & Technology, Inc.
FreeBSD Postmaster jmb@FreeBSD.Org | 2341 Jeff Davis Hwy
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