From owner-freebsd-chat Thu May 22 17:29:29 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id RAA19035 for chat-outgoing; Thu, 22 May 1997 17:29:29 -0700 (PDT) Received: from freefall.freebsd.org (freefall.cdrom.com [204.216.27.21]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id RAA19025 for ; Thu, 22 May 1997 17:29:26 -0700 (PDT) From: Greg Lehey Received: from diablo.ppp.de (diablo.ppp.de [193.141.101.34]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id RAA03977 for ; Thu, 22 May 1997 17:29:23 -0700 (PDT) Received: from papillon.lemis.com by diablo.ppp.de with smtp (Smail3.1.28.1 #1) id m0wUhkx-000QcaC; Fri, 23 May 97 01:58 MET DST Received: (grog@localhost) by papillon.lemis.com (8.8.4/8.6.12) id LAA00601; Wed, 21 May 1997 11:44:01 +0800 (CST) Message-Id: <199705210344.LAA00601@papillon.lemis.com> Subject: Re: floppy flaky In-Reply-To: <19970520132403.10028.qmail@squirrel.tgsoft.com> from mark thompson at "May 20, 97 01:24:03 pm" To: thompson@squirrel.tgsoft.com (mark thompson) Date: Wed, 21 May 1997 11:44:00 +0800 (CST) Cc: joerg_wunsch@uriah.heep.sax.de, freebsd-chat@freebsd.com Organisation: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8250 Fax: +61-8-8388-8250 Mobile: +61-41-739-7062 Reply-to: grog@FreeBSD.ORG (Greg Lehey) WWW-Home-Page: http://www.FreeBSD.org/~grog X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-chat@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk mark thompson writes: > Date: Tue, 20 May 1997 08:50:19 +0200 > From: j@uriah.heep.sax.de (J Wunsch) > > As mark thompson wrote: > >> Pretty strange, that no errors are reported, huh? Floppy drive, cable, >> controller, software? > > Writing a floppy can only detect catastrophic errors (sector marks not > found). Data-field only errors remain undetected. > > Reformat your floppy. > > True. But the read should detect a bad checksum, not just return bad > bits, nicht wahr? And besides, i DID reformat the floppies, it still > failed pretty much the same. > > I'm flummoxed. I seem to recall things like this happening in the "good old days". We frequently had two different 5 1/4" floppy drives (360 kb and 1.2 MB) on our machines to get around the problem, which was related to different track widths for the two formats. Here's a scenario: somehow (not difficult), your floppy drive has got out of alignment. As a result, you're accessing it slightly off-track. Formatting it writes new tracks, slightly off the old tracks, but reading still "sees" the old tracks as well. So why don't you get CRC errors? Good question. My guess is that something is ignoring them. Greg