Path: utzoo!mnetor!uunet!husc6!necntc!ames!ucbcad!ucbvax!LL-VLSI.ARPA!malpass
From: malpass@LL-VLSI.ARPA (Don Malpass)
Newsgroups: comp.sys.zenith.z100
Subject: floppy controller prob
Message-ID: <8712101853.AA06460@ll-vlsi.arpa>
Date: 10 Dec 87 18:53:08 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
Lines: 19


	Last week a friend asked me to try his Z-100 floppy controller in
my system to see whether IT was what was screwing up his system.  [It
wasn't.]  After testing it for a long time I returned it to him and put
my own back in.  Since then I've been unable to WRITE floppys - of either
5" or 8" size - properly, although I can read older ones without problems.
I formatted a blank 5" one, and when I asked the Norton diskchecker program
to test it thoroughly, it did fine up to cluster 203, and then everything
went to !#@$%^& for nearly all clusters above that number.

	This week I'll drag out the prints, but does this ring a bell (or
even a decibel) with anyone?  [Yes, I DID mark the two cards before I
switched them, so that's not the problem.]  I seem to remember something
about precompensation which changes some parameter halfway "out" the
tracks on the disk because of the diameter-dependent velocity change.
I don't think it'll take forever to fix this, but since my scope weighs
about 9000 pounds, I want to go as far as I can without lugging it up
from the basement to the computer.  So any pointers will be appreciated.
	Thanks,		don	[malpass@LL-vlsi.arpa]