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Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

2653.0. "2090A & DMA problem?" by FSCORE::KAYE (He who dies with the most toys is dead) Sat Jun 17 1989 23:46

Current configuration:
A2000 (Rev 4.4 motherboard + 3.3K resistor on U605 which is Signetics)
2090A + 2 Seagate 412's in external box (~3' cables)
MEGABoard 2000 (2M - 120ns Hitachi devices)
A2300 (genlock)
Internal 3 1/2" floppy (DF1)
1.3 roms
WB 1.3 

Problem:
Using Quarterback (either 1.3 or 2.2) i never get past the 1st floppy.
It randomly fails with a 'bad floppy' requestor and asks for another.
At the time of failure the screen does something, ie jumps, flickers
or a few pixels change color (screen memory being changed by mistake?)
I don't have any other symptoms or strange happenings running any other
software.

Things i have tried:
 o DF0 and DF1 act the same
 o different floppies (formatted & unformatted SONY 2DD)
 o tried either hard disk - similar failures
 o removed MEGABoard 2000 - no change
 o reseated 2090A and A2300 - no change
 o bypassed SETFASTMEM - no change
 o booted WB 1.3 from floppy - no change (mounted HD's by hand)
 o MRBackup works fine (altho about 1/3 of the background color
    changed at 1 point and remained changed)

I'm familiar with the 3.3K resistor fix (had to install it myself),
but am wondering if a better fix is to replace U605 and U602 with
non-Signetics chips (they are the only LS245's which are Signetics). I
can't get my hands on another A2000 for another week to sort it out by
swapping, so i'm open for suggestions.

 mark

T.RTitleUserPersonal
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2653.1an updateFSCORE::KAYEHe who dies with the most toys is deadSat Jul 29 1989 01:1614
I got my hands on another 2000 with an internal Miniscribe. I hooked
my 2 Seagates up to his 2090A and tried again. It worked
a little better than mine, but gave me the same 'bad floppy' stuff at
#4, instead of the first floppy. I tried swapping his 2090A into mine,
but nothing changed. I called Commodore (Canada) and they sent me a
new ROM for the 20290A (cus the new 2090A's were different than the 1
i had). It came today, but didn't change the problem (hopefully it
will fix the problem of not booting accasionaly). In the USENET in 1
of the notes about NOCLICK was a reference to a problem with
TRACKDISK.DEVICE and raw reads and writes. I assume that Quarterback
uses raw reads and writes cus it bypasses AmigaDos and writes it's own
format. Anyone know what the problem with TRACKDISK is?

 mark
2653.2An OS bug...FRAMBO::BALZERChristian Balzer DTN:785-1029Mon Jul 31 1989 07:298
    Re: .1
    
    The RawRead/RawWrite problem is an OS bug to be fixed in 1.4 or
    an intermediant SetPatch release. See the various PC-Patch, PC-Copy
    topics for some more details.
    
    <CB> (slightly feverish, but still at work)
    
2653.3DPIII/2090...AaaarghhGIDDAY::LAWSONThu Aug 02 1990 22:3318
    I dont know wheter or not this is going in the right topic but here
    goes... (also, let me preface this by saying that I'm not sure my
    investment in an A2500 was all that good an idea, given the general
    flakiness of various bits of software....)
    
    	However, when using DPIII in hires overscan AND reading/writing to
    hard disk, I get the disk access led on and depending on how frustrated
    I get (by clicking mouse buttons etc) I get various symptoms, non of
    which do much for my state of mind. I need this facility because Im
    trying to drive a polaroid palette. ) or at least I think I do.
    
    I tried 2090patch.zoo. Did it as per instructions and then spent the
    remainder of the night rebuilding my hard disk (Not a Dos device!!!)
    
    Maybe I got a bad copy. Any suggestions?
    
    Glenn
    
2653.4Swapping ScreensTLE::RMEYERSRandy MeyersFri Aug 03 1990 00:3421
Re: .3

>    	However, when using DPIII in hires overscan AND reading/writing to
>    hard disk, [problems occur with the 2090 disk controller]

Sigh!  The guy who invented the FlixerFixer use to do what you are
doing as a test of Commodore's 2090 patches.  The FlixerFixer folks
use to (maybe still do) encourage people to use overscan screens
since the FlixerFixer can handle it.  However, they started getting
complaints that the FlixerFixer broke disk I/O.  Of course, the
FlixerFixer was causing no problems: the overscan screen was just
revealing the DMA bug in the A2090.  Anyway, every time Commodore
would patch the 2090 driver code, the FlixerFixer inventor would
fire up dpaint in overscanned mode and try and load or save
a file.  Usually, the experiment would show that the 2090 still
had problems.

There is a workaround you might try.  When you need to do disk I/O,
use the Amiga-M and Amiga-N keys to swap the overscanned screen for
the Workbench screen as soon as the disk I/O starts.  This will allow
the 2090 a clear shot at memory.
2653.5WHat is Commodore doing about this?GIDDAY::LAWSONSun Aug 05 1990 22:2012
    Thanx Randy..I'll give it a try....
    
    BTW, Does anyone out there know what the official  C= attitude is WRT  this
    problem? This is still under warranty and I feel that they might want to 
    fix this somehow, like maybe swapping the 2090a for a 2091??? 
    
    I phoned the local C= tech support people and got a "uhhh?" I
    interpreted this as either a) ignorance or, b) toeing the party line
    (nothing wrong with OUR kit!)....not encouraging.
    
    Cheers,
    Glenn