Date: Fri, 5 Dec 1997 01:54:07 -0800 (PST) From: gram@cdsec.com To: freebsd-gnats-submit@FreeBSD.ORG Subject: kern/5231: Mounted MS-DOS floppy disk writes unreliable/reads can crash system Message-ID: <199712050954.BAA08616@hub.freebsd.org> Resent-Message-ID: <199712051000.CAA09268@hub.freebsd.org>
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>Number: 5231 >Category: kern >Synopsis: Mounted MS-DOS floppy disk writes unreliable/reads can crash system >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-bugs >State: open >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Fri Dec 5 02:00:03 PST 1997 >Last-Modified: >Originator: Graham Wheeler >Organization: Citadel Data Security >Release: 2.2.2 >Environment: FreeBSD gram.cdsec.com 2.2.2-RELEASE FreeBSD 2.2.2-RELEASE #0: Mon Sep 29 12:34:17 SAT 1997 root@gram.cdsec.com:/home/src/sys/compile/GRAM i386 >Description: I find that writing files to a mounted MS-DOS floppy disk almost always results in the file being written with data errors. If I unmount the diskette, remount it, and copy the file back, the hard-drive light goes on and the system freezes. This is with an Adaptec 1542B, although I also have problems with my home PC which uses a motherboard-based FDC. I haven't tried reading a corrupt diskette on the IDE machine as yet, but I suspect the behaviour will be similar. I suspect that the corruption on write is due to the PC services other interrupts while the write is in progress; i.e. is timing related. The freeze on read is probably a bug in the MS-DOS filesystem support. Reading a non-corrupt floppy (written while DOS is booted) is fine. I've long known about the write corruption; the freeze I only noticed yesterday when I tried to write a small file, hoping that the fact that it was small would let me be successful for a change. >How-To-Repeat: Easy in my case - just do it again... >Fix: The only workaround I know is to copy files to my DOS HDD partition, boot DOS, and then copy them to the floppy - which is rather tedious. >Audit-Trail: >Unformatted:
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