Re: The Infamous Bad Data Problem

[Chris Albertson <chrisalbertson90278@yahoo.com>]

Pure guess but I notice you picked an I/O space location
for your register that is commonly used on network cards.
I forgot the address (hex three hundred and something?)

It's not random.
Windows will poke around and try to find hardware by stuffing
bytes into registers and reading them back out.  This could
be the cause and it could also be why I don't see it on
my card.   But I only used either Linux or just plain DOS,
never Windows.  What you need is a fool proof reset function
built into the card.  Either that or give up on using
Windows :)
 
Tom Droege wrote:
> 
> As you all know, I have been plagued with a "bad data" problem.  It is most
> likely caused by the data from the memory card being one byte off.  That is
> what it looks like.
> 
> Whenever it happens I take care to note what might have happened.  This
> evening while testing TOM2, the bad data appeared suddenly.  It happened
> just after I interrupted the program while it was in the middle of running
> Rob's Download program.  After that, it read consistently bad data.
> 
> I then shut down windows properly.  It shut down as if it was doing it
> properly.  I turned off power, and when I turned it back on, it said that I
> had not turned off the computer properly and did the memory scan
> thing.  Now it read out the memory card properly.
> 
> OK, it looks to me like Windows is stashing an odd byte
> somewhere.  Possibly it is a random thing on turn on and it thinks that
> there is an odd byte to read and does so.  The result is that sometimes
> when I turn on the system reads out the bytes in correct sequence and
> sometimes it is one byte off.
> 
> OK, I accuse my hardware first.  But I have tried everything.  It is
> beginning to really look like there is something in Windows that gets one
> byte off on the I/O port, and then often remembers that on turn
> on.  Barf!  This may be hard to believe.
> 
> Now that several of you are trying to run Mark IVs and with different
> operating systems, it will be interesting if you see this problem.  The
> symptom is an image with -32k to +32k range and a sigma of large.  The data
> looks like big time noise.  It suddenly comes and is hard to get rid
> of.  Usually a few restarts of Windows will do it.  Sometimes it takes all
> night.
> 
> Tom Droege

-- 

--
   Chris Albertson             
   Redondo Beach, California
   home:   310-376-1029   chrisalbertson90278@yahoo.com
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   office: 310-336-5189   Christopher.J.Albertson@aero.org