Date: Fri, 12 Sep 1997 18:57:50 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: kevin_eliuk@sunshine.net (Kevin Eliuk) Cc: grog@lemis.com, questions@FreeBSD.ORG, hackers@FreeBSD.ORG Subject: Re: Do *you* have problems with floppies? Message-ID: <199709121857.LAA04034@usr05.primenet.com> In-Reply-To: <Pine.BSF.3.96.970912075116.3649A-100000@kevin.sunshine.net> from "Kevin Eliuk" at Sep 12, 97 07:59:28 am
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> Here is a problem I had and what I included in a > previous question. > > -=* > Date: Thu, 10 Jul 1997 20:06:28 -0700 (PDT) > > Heres one I can't find in the archives. > > I tried to mount a 720Kb DOS Floppy with: > > /sbin/mount -t msdos /dev/fd0 /mnt > > today which returned an input/output error, and returned to > tcsh prompt. I was interupted and while dealing with that I > turned to notice the following. > > Fatal trap 9: general protection fault while in kernel mode Anything with an invalid FS format on it that is nevertheless mounted can send the kernel off into the weeds. This is why you must be root to mount things: to prevent this from being a proble, since you only give the root password to people who only mount correct media. The fd problems you are reporting in general are either (1) incorrect media, or (2) correct media that, for whatever reason, looks incorrect to the floppy driver. In other words, it is as if you had mounted bad media, and, as expected, the machine went into the weeds. Note that you can eject floppies on a Sun machine wihout unmounting them; this is commonly used in student labs with the DOSFS, which is known to synchronously write all its data. You can eject the disk, and load another one, and it will operate correctly, without needing to sync before disk changes, etc., unlike the faster-because-it-is-cached FFS. But you can put a non-DOS formatted disk in the drive, access it, and crash the machine very easily. "Fixing" this would be prohibitively high in overhead for normal use. It's a trade-off. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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