From owner-freebsd-current Mon Dec 14 19:25:03 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id TAA01254 for freebsd-current-outgoing; Mon, 14 Dec 1998 19:25:03 -0800 (PST) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id TAA01246 for ; Mon, 14 Dec 1998 19:24:59 -0800 (PST) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id NAA28317; Tue, 15 Dec 1998 13:54:47 +1030 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.1/8.9.0) id NAA15850; Tue, 15 Dec 1998 13:54:48 +1030 (CST) Message-ID: <19981215135448.B15815@freebie.lemis.com> Date: Tue, 15 Dec 1998 13:54:48 +1030 From: Greg Lehey To: mjacob@feral.com Cc: freebsd-current@FreeBSD.ORG Subject: Re: Tape Driver Changes Proposed: Tape Early Warning Behaviour References: <19981215132144.H15633@freebie.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.91.1i In-Reply-To: ; from Matthew Jacob on Mon, Dec 14, 1998 at 07:15:09PM -0800 WWW-Home-Page: http://www.lemis.com/~grog Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Monday, 14 December 1998 at 19:15:09 -0800, Matthew Jacob wrote: > >>> You *can* enable/disable compression, and we could even make the change >>> persistent across tape mounts, but the issue here is whether or not you >>> also want to go and change the N different backup utilities to use the >>> appropriate ioctl to select compression or not. >> >> Precisely. That would also include any tape utilities you port, and >> any other program you may want to use to access tape. Specifying the >> function in the device name seems the easiest solution to me. >> > > The only problem with this is that the matrix of device names gets > extremely unwieldy. It's not just compression, but perhaps density. Take a > look at the Solaris tape name mess: > > /dev/rmt/U{l|m|h|c}[b][n] > > U == unit; l = low, m = med, h = high, c = compression; b = BSD semantics; > n = norewind > > and this is where you've (incorrectly, in my opinion) smooshed compression > in with density selection. > > I don't see an easy solution that makes sense (as yet- this requires a lot > of thinking). Well, you don't have to go overboard. Combine compression and density. We have BSD semantics, I suppose, so the only other thing is no rewind, which we already cater for. So for, say, an Exabyte 8505XL, you'd have: /dev/rst0l 8202 mode, no compression /dev/rst0n 8202 mode, compression /dev/rst0h 8205 mode, no compression /dev/rst0c 8205 mode, compression /dev/nrst0l 8202 mode, no compression, no rewind /dev/nrst0n 8202 mode, compression, no rewind /dev/nrst0h 8205 mode, no compression, no rewind /dev/nrst0c 8205 mode, compression, no rewind Sure, it's more than now, but it shouldn't confuse people too much. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message