Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!caen!kuhub.cc.ukans.edu!markv
From: markv@kuhub.cc.ukans.edu
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Bridgeboard and Fast Memory?
Message-ID: <1991Apr1.111443.29387@kuhub.cc.ukans.edu>
Date: 1 Apr 91 11:14:42 CST
References: <19620015@hp-lsd.COS.HP.COM>
Organization: University of Kansas Academic Computing Services
Lines: 38

In article <19620015@hp-lsd.COS.HP.COM>, davem@hp-lsd.COS.HP.COM (Dave K. Martin) writes:
> I had posted this in c.s.a.emulations and haven't recieved any responses and 
> on reflection, it appears to be more hardware oriented, so here it is again.
> 
> Why is 6-meg of fast ram the ideal configuration for an A-2000 with a
> bridgeboard?  Does it have to do with address conflicts on the Zorro buss 
> and the shared memory on the bridgeboard?

The Bridgeboard grabs 2MB of Zorro II autoconfig space for itself.  So
if you have 8MB of fast RAM, you will have a conflict with the BB.
 
>I'm asking since my A-2000 now has 6-meg of fast, 1-meg chip and an XT bridge.
>What happens if I get another 2-megs of fast ram?  Nothing?  System slowdowns?
> Frequent visits from the Guru?

It depends I think.  Depending on which board is in which slot (which
affects the order the cards autoconfig in), you'll either get NO BB
(because the RAM board has aready taken the whole address space, so
the BB's autoconfig fails), or you get no RAM or 6MB RAM (not sure
which, I think it depends on the board but I'm not a real autoconfig
guru).

With the 3000 or GVPs new cards, you can get RAM that autoconfigs
outside the Zorro II space, so you don't have the 8MB space limit.
 
> 
> thanks.....
> 
> davem
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