From owner-freebsd-bugs Mon Mar 31 12:27:51 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id MAA08165 for bugs-outgoing; Mon, 31 Mar 1997 12:27:51 -0800 (PST) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by freefall.freebsd.org (8.8.5/8.8.5) with SMTP id MAA08029 for ; Mon, 31 Mar 1997 12:24:04 -0800 (PST) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id WAA17149; Mon, 31 Mar 1997 22:22:54 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.8.5/8.8.5) id WAA11986; Mon, 31 Mar 1997 22:06:20 +0200 (MET DST) Message-ID: <19970331220620.KM38633@uriah.heep.sax.de> 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 References: <19970331195000.TX25580@uriah.heep.sax.de> X-Mailer: Mutt 0.60_p2-3,5,8-9 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: ; from "Doug Burks" on Mar 31, 1997 10:27:28 -0800 Sender: owner-bugs@freebsd.org X-Loop: FreeBSD.org Precedence: bulk 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. ;-)