From owner-cvs-all Tue Dec 7 0:29:24 1999 Delivered-To: cvs-all@freebsd.org Received: from apollo.backplane.com (apollo.backplane.com [216.240.41.2]) by hub.freebsd.org (Postfix) with ESMTP id 3C90914C49; Tue, 7 Dec 1999 00:29:13 -0800 (PST) (envelope-from dillon@apollo.backplane.com) Received: (from dillon@localhost) by apollo.backplane.com (8.9.3/8.9.1) id AAA75674; Tue, 7 Dec 1999 00:29:12 -0800 (PST) (envelope-from dillon) Date: Tue, 7 Dec 1999 00:29:12 -0800 (PST) From: Matthew Dillon Message-Id: <199912070829.AAA75674@apollo.backplane.com> To: Julian Elischer Cc: Mike Smith , cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/kern kern_shutdown.c References: Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk :Softupdates is pointless without this because Soft Updates cannot :guarantee the state of the filesystem to be sane unless the disk does not :lie about whether it has written to the disk. Soft updates also makes all :the writes async, so who cares.. :-) : :More precisely, the order of the writes must be absolutly maintained :and disks that buffer writes usually reserve the right to re-order :adjacent writes. : :This is basically what we decided was needed in discussion with Kirk to :make Soft Updates safe. (The whole point). : :Julian The disk can lie about whether it has written data to the disk without messing softupdates up, but it cannot reorder writes that the system has told it must be ordered. SCSI has a tag to guarentee ordering (or not), but I don't know if IDE has the same sort of feature. -Matt To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message