From owner-freebsd-scsi Mon Aug 28 20:47:43 2000 Delivered-To: freebsd-scsi@freebsd.org Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by hub.freebsd.org (Postfix) with ESMTP id 2ED5A37B43C for ; Mon, 28 Aug 2000 20:47:39 -0700 (PDT) Received: (from grog@localhost) by wantadilla.lemis.com (8.11.0/8.9.3) id e7T3lLm16220; Tue, 29 Aug 2000 13:17:21 +0930 (CST) (envelope-from grog) Date: Tue, 29 Aug 2000 13:17:21 +0930 From: Greg Lehey To: Matthew Jacob Cc: Sam , freebsd-scsi@FreeBSD.ORG Subject: Re: "tape is now frozen" Message-ID: <20000829131721.R11422@wantadilla.lemis.com> References: <20000829130040.Q11422@wantadilla.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: ; from mjacob@feral.com on Mon, Aug 28, 2000 at 08:36:42PM -0700 Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.lemis.com/~grog X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Monday, 28 August 2000 at 20:36:42 -0700, Matt Jacob wrote: > On Tue, 29 Aug 2000, Greg Lehey wrote: >> On Tuesday, 8 August 2000 at 16:39:03 -0700, Matt Jacob wrote: >>>> >>>> Indeed, it looks like he omitted the message that we most wanted to >>>> see. >>>> >>>> Let me repeat here that I find this *very* irritating. It happens, >>>> for example, if I try to read a block which is too long. There's no >>>> way to know the length of a tape block in advance, so this is >>>> relatively easy to get, particularly with DDS-4 drives, and it >>> >>> This error should not occur if you're in variable block mode. If you >>> set the drive in fixed block mode and read a block that's too large, >>> the tape driver cannot know where the tape heads are located. It's >>> that simple. >> >> It's not that simple. If it happens in the middle of the tape, I need >> to rewind the bloody thing to recover. At least an fsf or bsf should >> be sufficient. > > So you space a filemark. Where specfically on the tape are you given you've > lost knowledge of where you are? I've lost the *exact* position. In fact, I'm not even sure I've lost the exact position, but I'm prepared to concede that. Within a block or so I know where I am. > The whole point of rewind, eom or offline is to bring the tape to a > *known* place. Spacing one filemark is not sufficient. Why not? We know we're at the beginning (or end) of a file. > I thought for awhile about allowing the use of rdhpos/sethpos to allow > for unfreezing. > > You're also, again, begging the question as to why it has occurred. Well, no, I state it above. > It has occurred because there was an I/O error, or you're not using > the tape correctly (fixed block mode and you don't issue the correct > read size). Precisely. But that's not a reason to penalize people by making them wind from one end of the tape to the other. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message