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]