From owner-freebsd-scsi Mon Mar 30 13:38:39 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id NAA27498 for freebsd-scsi-outgoing; Mon, 30 Mar 1998 13:38:39 -0800 (PST) (envelope-from owner-freebsd-scsi@FreeBSD.ORG) Received: from uni4nn.gn.iaf.nl (osmium.gn.iaf.nl [193.67.144.12]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id NAA27491 for ; Mon, 30 Mar 1998 13:38:33 -0800 (PST) (envelope-from wilko@yedi.iaf.nl) Received: by uni4nn.gn.iaf.nl with UUCP id AA23302 (5.67b/IDA-1.5 for scsi@FreeBSD.ORG); Mon, 30 Mar 1998 23:38:22 +0200 Received: (from wilko@localhost) by yedi.iaf.nl (8.8.7/8.6.12) id WAA04292; Mon, 30 Mar 1998 22:07:35 +0200 (MET DST) From: Wilko Bulte Message-Id: <199803302007.WAA04292@yedi.iaf.nl> Subject: Re: SDT-7000 and other DDS-2 tapes In-Reply-To: <199803301820.LAA28310@narnia.plutotech.com> from "Justin T. Gibbs" at "Mar 30, 98 11:20:39 am" To: gibbs@narnia.plutotech.com (Justin T. Gibbs) Date: Mon, 30 Mar 1998 22:07:35 +0200 (MET DST) Cc: scsi@FreeBSD.ORG X-Organisation: Private FreeBSD site - Arnhem, The Netherlands X-Pgp-Info: PGP public key at 'finger wilko@freefall.freebsd.org' X-Mailer: ELM [version 2.4ME+ PL32 (25)] 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 As Justin T. Gibbs wrote... > >> I use most of my SCSI devices on a shared bus between two FreeBSD boxes. > > > > Hairy... One machine booting most likely result in a bus reset, with the > > tape loosing position. You could get lucky and find an adapter that allows > > disabling bus resets. > > I've always wondered if this is something the tape driver could recover > from. I guess if the tape driver is recording partion, FM, and block > count as it writes and the target drive allows block level repositioning > that it could recover. Do all tape drives lose their position on a > reset? How many support the soft reset alternative? I guess it's time > to do some experimentation. You are at the mercy of the device firmware. You don't want to. Some tapes rewind on a bus reset etc. I know that DEC NSR (Legato Networker rebranded) can now handle tapes on a shared bus in a Digital Unix cluster. AFAIK they indeed keep track of where they were on the tape. When a bus reset occurs a rewind follows and then a reposition to the spot they were before. NSR is picky on what devices it wants to support. Most/all (?) of them are either DLT or DLT loaders. Please note: I'm not an NSR expert by any means.. Wilko _ ______________________________________________________________________ | / o / / _ Bulte email: wilko @ yedi.iaf.nl |/|/ / / /( (_) Arnhem, The Netherlands WWW: http://www.tcja.nl -------------------------------------------------- Powered by FreeBSD ------ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message