Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!apple!oliveb!amiga!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga
Subject: Re: Wish I had an Amiga 1500
Message-ID: <7253@cbmvax.UUCP>
Date: 10 Jul 89 15:15:12 GMT
References: <8823@vdsvax.crd.ge.com>
Organization: Commodore Technology, West Chester, PA
Lines: 33

in article <8823@vdsvax.crd.ge.com>, perley@vdsvax.crd.ge.com (Perley Donald P) says:

>>The IBM compatibility consists of four 64-pin sockets, two 36-pin sockets, a
>>set of termination resistors/capacitors, and traces on the printed circuit
>>board connecting all this together.  That's all there is!  Redesigning the
>>motherboard without those IBM slots won't bring down the price much.

> The point isn't just the cost.  As it is now there are less amiga
> slots than there could be. 

Nope.  Even without the PC slots, you'd still have the same number of Amiga
slots; there's no wasted Amiga space due to the PC bus.  Unless you attach
a bridge card, but if you're of the mind that a bridge card is wasted space
instead of a utility, you won't add one.

> .. but is there any reason not to extend this theme so the bridge could go 
> in the last slot if desired?  Then if you skip the bridge altogether, all 
> the slots could be used for amiga cards.

The bridge card can go in the last Amiga slot.  Obviously it needs an Amiga
slot and a PC slot, or it wouldn't be "bridging".  The space to the left of
the last Amiga slot is used by bus termination logic, and that has to be there,
so even with a 6 slot Buster chip (the current 8721 only supports 5 slots)
you couldn't run a slot all the way to the end of the board.  You can do that
with the PC bus, since there's nothing actually going from the motherboard to
the PC bus, so it doesn't matter all that much which side of the PC bus gets
the termination logic.

> -don perley
-- 
Dave Haynie Commodore-Amiga (Systems Engineering) "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
           Be careful what you wish for -- you just might get it