From owner-freebsd-scsi Fri Oct 3 14:37:56 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id OAA14299 for freebsd-scsi-outgoing; Fri, 3 Oct 1997 14:37:56 -0700 (PDT) Received: from alpo.whistle.com (alpo.whistle.com [207.76.204.38]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id OAA14294 for ; Fri, 3 Oct 1997 14:37:54 -0700 (PDT) Received: (from daemon@localhost) by alpo.whistle.com (8.8.5/8.8.5) id OAA12095; Fri, 3 Oct 1997 14:24:21 -0700 (PDT) Received: from current1.whistle.com(207.76.205.22) via SMTP by alpo.whistle.com, id smtpd012088; Fri Oct 3 21:24:13 1997 Message-ID: <3435623F.500F9F30@whistle.com> Date: Fri, 03 Oct 1997 14:23:11 -0700 From: Julian Elischer Organization: Whistle Communications X-Mailer: Mozilla 3.0Gold (X11; I; FreeBSD 2.2-CURRENT i386) MIME-Version: 1.0 To: "Justin T. Gibbs" CC: Andrew Reilly , freebsd-scsi@FreeBSD.ORG Subject: Re: New SCSI Framework Patches Available References: <199710031835.MAA04392@pluto.plutotech.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Justin T. Gibbs wrote: > > >On 2 Oct, Justin T. Gibbs wrote: > >> Supported peripherals: > >> > >> Direct Access driver (da): > >> 512 byte sectored disk drivers. Support for other sector sizes is > >> planned, but further investigation on the "right" approach for this > >> is needed. It probably belongs in the disk-slice code. > > > >Pardon for the unhelpful intrusion, but could someone please explain > >the issue here? > > The issue is that most of the system deals with devices in "DEV_BSIZE" > chunks (512bytes). In the past, each device driver has had to perform some > amount of conversion if the device block size doesn't match that value. > Performing the conversion to block sizes that are a power of 2 isn't hard, > but in some cases, the block size is an "odd" value (Try writing audio > tracks to a WORM for instance). I'd like to deal with this issue cleanly > and not require each and every device driver to handle this case on it's > own. Justin, I have new disk handling code that does this all cleanly. I'll send you a copy as soon as I get the last killer bugs out of it. in th emean-while don't spend too much time on this roblem as I'm working on it.. It will fit into your stuff just fine I think. > > So, the question is how to best handle the problem? NetBSD has a few PRs > in their gnats database that offer possible solutions. I just haven't had > time to really consider the problem in detail and come up with a clean > approach. > > >-- > >Andrew > > > >"The steady state of disks is full." > > -- Ken Thompson > > -- > Justin T. Gibbs > =========================================== > FreeBSD: Turning PCs into workstations > ===========================================