Date: Mon, 31 Mar 1997 22:06:20 +0200
From: j@uriah.heep.sax.de (J Wunsch)
To: dbx@atmos.washington.edu ("Doug Burks")
Cc: bugs@freebsd.org, toor@dyson.iquest.net (John S. Dyson)
Subject: Re: kern/3156: Floppy disk copy freezes
Message-ID: <19970331220620.KM38633@uriah.heep.sax.de>
In-Reply-To: <Pine.NEB.3.95q.970331101621.266B-100000@cargpc5.atmos.washington.edu>; from "Doug Burks" on Mar 31, 1997 10:27:28 -0800
References: <19970331195000.TX25580@uriah.heep.sax.de> <Pine.NEB.3.95q.970331101621.266B-100000@cargpc5.atmos.washington.edu>
next in thread | previous in thread | raw e-mail | index | archive | help
As "Doug Burks" wrote: > Also, you should never, _never_ use the block device for raw file > data. > > When I use the character device for the floppy copy, everything works > smoothly. Maybe my setup is the prime example of why one "should never, > _never_ use the block device for raw file data." :( There are multiple reasons for it: . you blow the buffer cache for no good reason, . you miss the possibility to get write errors reported (since the writes are cached, and the application has already got a ``good'' indication of the write), . you can never be sure when the data are being actually written; the worst i've seen so far was on Data General DG/UX where it required a shutdown to get a few KB actually written (since the OS was apparently waiting for a more data to arrive). Of course, a machine freeze shouldn't happen either. I have no idea why it happens. > As for the original problem, it still exists, but this workaround is > certainly quite easy. As for more information, I can't add much. ANY > time under ANY conditions whenever I try to copy a large file onto a raw > block floppy device, the computer completely freezes after a few > seconds. Can i convince you to compile a kernel with DDB, and see whether you can break into DDB once it freezes? This might give us a clue for what is happening. I have never been able to reproduce this kind of problem myself. Maybe it's some strange interaction between VM buffers and the floppy driver. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19970331220620.KM38633>