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Interest Survey: Bracket to expand to full ISA Size




Please respond if an ISA retainer enabling the pci card
to be 0.75" longer and 0.3" higher might be of interest
to you. If you have any idea as to potential quantities
and probabilities of use, please include that information.
My intent is to show market potential to interest a
vendor in producing such a bracket.

The net effect would be to add 6.8 usable square inches
to a PCI card.  Details and motivations below.


Technical Details:

Cases are designed to accomodate ISA cards which are
0.3 higher (4.2") and longer.  Given the need for a
retainer eating a little length, 0.75" longer is
feasible.  

Proposed changes:

* Spread feet from 3.9" to 4.2"
* Lengthen card 0.75"
* No obstructions to a daughter card mounted 9mm above
  base PCI card.  Daughter card same dimensions as base
  (4.2" high, square end).  Component free area in top
  and bottom corners on bottom of daughter card 0.4"
  by 0.4" max.
* Potentially, ears? squeeze-posts? to go through holes
  on daughter board supporting it 9mm above the base 
  board.
* Retainer to leave as much open space at end of card
  stack as possible for air flow between cards and above
  daughter card.

Motivation:

PCI bus and platform performance make it suitable for
high bandwidth applications which used to require a
custom solution.  Gate array densities and the level
of integration of support chips available off the 
shelf enable what used to be subsystems packaged in
boxes to be crammed onto a PCI board.

In my case, the present PCI board area will result in
compromises in planned.  The current specification
was written to enable PCI cards to be used in
microchannel chassis, which are a thing of the past.
It makes no sense to artificially constrain and limit
the functionality of systems to maintain compatability
with a packaging scheme which was never a large part
of the market and has been abandoned by everyone, 
including its creator.  This serves only to limit
progress with no pay back.

Flame Catcher:

I realize that this violates the PCI specification.
My reasoning is above; when backed into a corner you
have to make tradeoffs.  Comments both in support of
and opposing my plans are welcome.

-------------------------------------
Name: Raymond J. Clark, Xerox Corp
E-mail: Raymond J. Clark <clark@scan.mc.xerox.com>
Date: 9/18/96
Time: 8:49:10 AM
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