From owner-freebsd-scsi@FreeBSD.ORG Mon Mar 2 17:39:17 2015 Return-Path: Delivered-To: scsi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 80281877; Mon, 2 Mar 2015 17:39:17 +0000 (UTC) Received: from mithlond.kdm.org (mithlond.kdm.org [70.56.43.85]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "A1-33714", Issuer "A1-33714" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 24E7C908; Mon, 2 Mar 2015 17:39:17 +0000 (UTC) Received: from mithlond.kdm.org (localhost [127.0.0.1]) by mithlond.kdm.org (8.14.9/8.14.9) with ESMTP id t22HdFki087288 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 2 Mar 2015 10:39:15 -0700 (MST) (envelope-from ken@mithlond.kdm.org) Received: (from ken@localhost) by mithlond.kdm.org (8.14.9/8.14.9/Submit) id t22HdFQc087287; Mon, 2 Mar 2015 10:39:15 -0700 (MST) (envelope-from ken) Date: Mon, 2 Mar 2015 10:39:15 -0700 From: "Kenneth D. Merry" To: Dan Langille Subject: Re: sa(4) driver changes available for test Message-ID: <20150302173914.GC87055@mithlond.kdm.org> References: <20150214003232.GA63990@mithlond.kdm.org> <8EFB1A84-96E6-4F63-A6D0-A87432C02B72@langille.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8EFB1A84-96E6-4F63-A6D0-A87432C02B72@langille.org> User-Agent: Mutt/1.5.23 (2014-03-12) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (mithlond.kdm.org [127.0.0.1]); Mon, 02 Mar 2015 10:39:15 -0700 (MST) X-Spam-Status: No, score=-2.9 required=5.0 tests=ALL_TRUSTED,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on mithlond.kdm.org Cc: current@freebsd.org, scsi@freebsd.org X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Mar 2015 17:39:17 -0000 On Mon, Mar 02, 2015 at 11:45:59 -0500, Dan Langille wrote: > > > On Feb 13, 2015, at 7:32 PM, Kenneth D. Merry wrote: > > > > > > I have a fairly large set of changes to the sa(4) driver and mt(1) driver > > that I'm planning to commit in the near future. > > > > A description of the changes is here and below in this message. > > > > If you have tape hardware and the inclination, I'd appreciate testing and > > feedback. > > This came to me today via the Bacula mailing lists. > > http://marc.info/?l=bacula-users&m=142531236722693&w=2 > > > As far as I can tell ltfs support on linux sits on top of the standard mt-st stuff \ > > as a userspace (fuse) filesystem > > I'd hope it's much the same with BSD. Removing the standard interface would be \ > > counterproductive overall > > Can you answer that and I'll relay please? Sure. In short, the current interface will stay in place. I have added additional ioctls that provide more features and information, but I don't see any issue with leaving the current ioctls in place. The MTIOCGET ioctl even gets an improvement in behavior when the tape drive supports long position information -- it will report the file number after a 'mt eod'. IBM's LTFS sits on top of their own Linux tape driver, and operates with a combination of tape driver ioctls (e.g. the standard MTIOTCOP ioctls) and SCSI passthrough. When I ported it to FreeBSD, I ran into several areas where we needed more information out of the tape driver. So that was the primary motivation behind adding the additional features. (Other features I implemented using SCSI passthrough.) He is correct that it runs with FUSE, although it can be linked into an application as a library as well. Ken -- Kenneth Merry ken@FreeBSD.ORG