Date: Fri, 17 May 2013 10:22:03 +0100 From: Bob Bishop <rb@gid.co.uk> To: Zaphod Beeblebrox <zbeeble@gmail.com> Cc: Greg 'groggy' Lehey <grog@FreeBSD.org>, FreeBSD Hackers <freebsd-hackers@FreeBSD.org> Subject: Re: tape (sa0) on sparc64 ? Message-ID: <BC94D229-FD03-4DB9-B3E2-CB50CA78A269@gid.co.uk> In-Reply-To: <20130517003058.GW77641@eureka.lemis.com> References: <CACpH0Mcass3ONxhFw5mRrQ1K931gxaxBZgo45_%2BynLrrbm4DUw@mail.gmail.com> <0D672BB1-1928-4F7A-BF72-CA7EE15D0563@gid.co.uk> <CACpH0McOx_Kza-Ou-=ko724cehF0Kp3uhN%2B6mFy2L0GdLQ1ESg@mail.gmail.com> <20130517003058.GW77641@eureka.lemis.com>
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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 <rb@gid.co.uk> 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
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