Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!cbmvax!daveh
From: daveh@cbmvax.commodore.com (Dave Haynie)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Bridgeboard questions...
Message-ID: <18962@cbmvax.commodore.com>
Date: 14 Feb 91 18:07:52 GMT
References: <1991Feb14.034710.11646@mintaka.lcs.mit.edu>
Reply-To: daveh@cbmvax.commodore.com (Dave Haynie)
Organization: Commodore, West Chester, PA
Lines: 56

In article <1991Feb14.034710.11646@mintaka.lcs.mit.edu> blf@churchy.ai.mit.edu (Bill Frandsen) writes:

>I also have a CMI 14.28 MHZ processor accelerator installed, with a 68881
>co-processor.  (This is the board that pops in the 68000 socket, not the
>CPU expansion slot)

>My first question is:  Why can't I use the Bridgeboard with the accelerator
>on?  I have to leave it at 7.14 MHz.  Any attempts at any point running the
>toggling program will cause the bridgeboard janus software to crash.  

Offhand, it sounds like the accelerator isn't properly emulating the 7.16MHz
68000 signals when it runs at 14.3MHz and talks to the Bridge Board.  The C=
A2620 and A2630 work with fine with Bridge Boards, so I can only assume the
problem lies with the CMI board.

>Is the speed increase affecting the Bridgeboard, or is it affecting the
>Supra WordSync controller?  

The speed increase should not affect the hardware at all.  Any accelerator
card must effectively slow down when accessing Zorro II bus hardware or 
Amiga motherboard resources.  The speedups attained are only from faster
CPU clock speed (governing internal operations) and from faster CPU memory,
if any is provided.

>Since the BB seems to still work with floppies, I am now beginning to assume 
>it is the HD controller.  

That's a hard call without poking around in the system with a timing analyzer
or at least an 'scope.  All three devices are involved in a Bridge Board access
to Amiga hard disk.  But even with a DMA driven hard disk, the Bridge Board
and the hard disk controller are never involved in a single transaction; its
either CPU to BB, or CPU to HD.  I have no experience with the Supra board in
an Amiga system, so I can't say offhand whether that's a likely problem or not.

>3rd question:  How come Janus insists at looking at the A: drive all the time?
>It is very annoying to be working on the C: drive, moving files, zipping
>stuff, or running Quatto, and any time it comes to accessing C:, the light for
>A: comes on, and it sits there for about 20 seconds, unless I put in a disk
>for it to read, then it goes on its merry way.  Also, it sits there for about
>20 seconds at boot time before booting from the C: partition.  Is there a
>way to alter the time required that it hunts these drives?  It is really
>annoying.

Sounds like something is messed up in your Bridge Board setup.  You don't 
have the MS-DOS search path pointing at something on A:, do you.  I have a
setup here with a hard disk and floppy, but I only rarely use the floppy,
and have never had the floppy mysteriously accessed.  Also, it could be some
of the software you're using.  In a primitive system like MS-DOS, some programs
are hard wired to look at A:, C:, or other letters of the alphabet.  Especially
older programs.


-- 
Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests"
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	"What works for me might work for you"	-Jimmy Buffett