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From: greg@isrnix.UUCP
Newsgroups: comp.sys.amiga
Subject: Amiga Disk & HAM problems
Message-ID: <867@isrnix.UUCP>
Date: Tue, 5-May-87 14:12:54 EDT
Article-I.D.: isrnix.867
Posted: Tue May  5 14:12:54 1987
Date-Received: Thu, 7-May-87 04:16:59 EDT
Organization: Inst. for Social Research (Indiana University, 47405)
Lines: 51
Keywords: flicker io errors

My Amiga tends to trash disks fairly regularly.  Enough to be very
frustrating.  I can usually (but NOT always) trash a disk with the following
scenario:  emacs a file, start a subcli, emacs another file within it,
write the file - BANG - disk I/O error.
Other times I can be just working along (doing 'dir's, 'info's whatever and
not changing disks at all)
and out of the blue - disk I/O error.  Most of the time it's just track 40
that gets munged and I can 'disksalv' everything.  Yesterday it seemed to
trash the whole thing though.  The disks always re-format fine.  It
usually (but, again,  not always) happens on my external floppy.
My disks are not physically mistreated, nor exposed to magnetic
fields (i.e. I keep them well away from the monitor).  Note that disks which
I never write to do not get trashed.

I've read the articles about disks going bad, etc, but my problem is bad
enough that I feel that if others were experiencing the same frequency
of trashed disks there would be a general uprising.  As it is it's
nearly impossible to do serious development.

Now, my Amiga also has another problem.  When I display the 'brick.img'
ray-traced DBW picture a section of a line (about 1 inch long) half way down
the screen will flicker from what it should be to a solid line of
another color.  The 1 inch section usually has a bit of blue and some
red/white for part of a brick but when it flickers the whole section turns
(momentarily) the same color.  The same thing >JUST< started happening (i.e.
the picture used to be fine)
on another line higher on the monitor when displaying 'marble.img', except
that now there are TWO flickering segments only about 1 mm long.  So far
I've only seen the problem when displaying HAM images.

The 'flicker' problem does not seem to be a memory error, as it always
happens in the same position of the picture regardless of where the
program is loaded.  Also memory diagnostics don't point anything
obvious out.  If I pull the screen down with the mouse the flickering
section moves down in step with the picture.

I recently added a TechniSoft 2m expansion to my Amiga and upgraded
the PAL's.  The problem has not changed in any way since I added/upgraded
them.

Is it possible that the two problems are related?  Do Floppy I/O and
video generation ever hang out together on any of the custom
chips?

Thanks for any help on either of these VERY annoying problems.

-- 
    Gregory R. Travis
    Institute for Social Research - Indiana University - Bloomington, In
    ihnp4!inuxc!isrnix!greg
    {pur-ee,allegra,qusavx}!isrnix!greg