From owner-freebsd-scsi Mon Oct 19 10:51:30 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA28970 for freebsd-scsi-outgoing; Mon, 19 Oct 1998 10:51:30 -0700 (PDT) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from smtp01.primenet.com (smtp01.primenet.com [206.165.6.131]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA28952; Mon, 19 Oct 1998 10:51:27 -0700 (PDT) (envelope-from tlambert@usr02.primenet.com) Received: (from daemon@localhost) by smtp01.primenet.com (8.8.8/8.8.8) id KAA22386; Mon, 19 Oct 1998 10:51:02 -0700 (MST) Received: from usr02.primenet.com(206.165.6.202) via SMTP by smtp01.primenet.com, id smtpd022349; Mon Oct 19 10:50:55 1998 Received: (from tlambert@localhost) by usr02.primenet.com (8.8.5/8.8.5) id KAA28209; Mon, 19 Oct 1998 10:50:55 -0700 (MST) From: Terry Lambert Message-Id: <199810191750.KAA28209@usr02.primenet.com> Subject: Re: filesystem safety and SCSI disk write caching To: gibbs@plutotech.com (Justin T. Gibbs) Date: Mon, 19 Oct 1998 17:50:55 +0000 (GMT) Cc: tlambert@primenet.com, gibbs@plutotech.com, dkelly@hiwaay.net, freebsd-fs@FreeBSD.ORG, freebsd-scsi@FreeBSD.ORG In-Reply-To: <199810182316.RAA21632@pluto.plutotech.com> from "Justin T. Gibbs" at Oct 18, 98 05:09:52 pm X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > >I suppose we should test by making a loadable system call that directly > >calls the reset code, so as to put the "reset causes a reset reliably, > >but even though no hardware other than the disk write cache is > >affected, we believe it's because no one debounced the switch" theory > >to rest. > > Who needs a system call? The user can easily cause a bus reset to occur > by opening the XPT device and sending a ccb with the XPT_RESET_BUS > function code in it. The alternative is to put the drive on a separate > power supply. You were claiming it was the machine reset. I was suggesting a software method of machine reset to take the undebounced reset switch out of the equation. I'm *not* claiming it *is* the SCSI reset, I'm merely claiming that I don't believe that an undebounced reset switch is any more likely than a SCSI reset, and that there's a method we can use to verify or impugn the undebounced reset switch theory. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message