From owner-freebsd-hackers@FreeBSD.ORG Fri May 17 09:22:09 2013 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id E8365F81; Fri, 17 May 2013 09:22:09 +0000 (UTC) (envelope-from rb@gid.co.uk) Received: from mx0.gid.co.uk (mx0.gid.co.uk [194.32.164.250]) by mx1.freebsd.org (Postfix) with ESMTP id 7B870F30; Fri, 17 May 2013 09:22:08 +0000 (UTC) Received: from [194.32.164.26] (80-46-130-69.static.dsl.as9105.com [80.46.130.69]) by mx0.gid.co.uk (8.14.2/8.14.2) with ESMTP id r4H9M7Jl054565; Fri, 17 May 2013 10:22:07 +0100 (BST) (envelope-from rb@gid.co.uk) Subject: Re: tape (sa0) on sparc64 ? Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: Bob Bishop In-Reply-To: <20130517003058.GW77641@eureka.lemis.com> Date: Fri, 17 May 2013 10:22:03 +0100 Content-Transfer-Encoding: quoted-printable Message-Id: References: <0D672BB1-1928-4F7A-BF72-CA7EE15D0563@gid.co.uk> <20130517003058.GW77641@eureka.lemis.com> To: Zaphod Beeblebrox X-Mailer: Apple Mail (2.1283) Cc: Greg 'groggy' Lehey , FreeBSD Hackers X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 17 May 2013 09:22:10 -0000 Hi, On 17 May 2013, at 01:30, Greg 'groggy' Lehey wrote: > On Thursday, 16 May 2013 at 19:56:14 -0400, Zaphod Beeblebrox wrote: >> On Thu, May 16, 2013 at 5:08 PM, Bob Bishop wrote: >>> On 16 May 2013, at 21:51, Zaphod Beeblebrox wrote: >>>=20 >>>> I have to retrieve some very old backups. They were made on = FreeBSD and >>>> are on tape... specifically DDS4. [etc] >>>> However, attached to either controller (after a reboot of the = machine >>> and a >>>> powercycle of the drive), I get: >>>>=20 >>>> [1:25:325]root@run:/home/foo> dd if=3D/dev/sa0 of=3Dtape5 >>>> dd: /dev/sa0: Input/output error >>>> 0+0 records in >>>> 0+0 records out >>>> 0 bytes transferred in 0.002930 secs (0 bytes/sec) >>>>=20 >>>> ... which is a return code of '1' and no messages on the console... >>>>=20 >>>> I have, before you ask, tried "bs=3D10k" and 20k ... but I believe = this >>>> command should run by itself fetching the first 512 bytes of each = block >>> --- >>>> narrowing down the block size logically comes after making the tape = go. >>>=20 >>>=20 >>> Try bs=3D64k >>=20 >> Same result. Besides, as far as I understand, the proper operation >> (if the blocksize is too small) is to read the first $n bytes and >> then write them to the output.. My (dim) memory says the drive won't read at all if you get the = blocksize wrong, so may be worth trying other sizes... > The obvious question: can you write tapes and read them back? ...but certainly try that. > My > experience with DDS tapes was of extreme unreliability. The age > doesn't make things any easier. There's a lot to go wrong with settings etc. See for instance: = http://fixunix.com/setup/398541-dds-4-tape-drive-compatiblity.html > Greg > -- > Sent from my desktop computer. > Finger grog@FreeBSD.org for PGP public key. > See complete headers for address and phone numbers. > This message is digitally signed. If your Microsoft MUA reports > problems, please read http://tinyurl.com/broken-mua -- Bob Bishop rb@gid.co.uk