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Re: Some questions
- To: Mailing List Recipients <pci-sig-request@znyx.com>
- Subject: Re: Some questions
- From: "chefren" <chefren@pi.net>
- Date: Thu, 5 Dec 1996 10:31:56 +0100
- Comments: Authenticated sender is <hagens@pop.pi.net>
- Posted-Date: Thu, 5 Dec 1996 10:30:14 +0100 (MET)
- Priority: normal
- Reply-To: chefren@pi.net
- Resent-Date: Thu, 5 Dec 1996 10:30:14 +0100 (MET)
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On 4 Dec 96 at 21:53, David Cary wrote:
> Allow me to quote from a (probably obsolete) document I found:
>
> "Because of its high clock rates PCI is currently limited to 10 loads on
> one PCI
> bus. In the desktop world each chip is a load and each connector is one load,
> thus limiting the number of PCI slots to three or four (depending on the number of
> PCI peripherals on the mother board). By using a higher grade connector and
> increasing the ground/signal ration, it is hoped to reduce the loading of the
> connector and support more slots, with six being the design goal. More slots will
> be attainable by the use of emerging bridge chips. ... CompactPCI is a new
> specification ... It builds on the proven and widely available mechanical standard
> of the Eurorack and the Telecom background of the IEC-1076 connector technology to
> create a solid basis for customers and vendors alike to design to. The final
> specification is expected to be voted on by the PICMG by June of 1995."
Because of the controlled-impedance metral (2mm grid)
connector they say a backplane with 8 connectors is no
problem. I only have seen photos of them. 10 Ohm
resistors are on the Compact-PCI cards in the signal
lines, probably to distribute the signals more evenly.
+++chefren
e È µ