From owner-freebsd-hackers@FreeBSD.ORG  Thu May 16 21:22:17 2013
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Subject: Re: tape (sa0) on sparc64 ?
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From: Bob Bishop <rb@gid.co.uk>
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Date: Thu, 16 May 2013 22:08:22 +0100
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To: Zaphod Beeblebrox <zbeeble@gmail.com>
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Hi,

On 16 May 2013, at 21:51, Zaphod Beeblebrox wrote:

> 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:
> 
> [1:25:325]root@run:/home/foo> dd if=/dev/sa0  of=tape5
> dd: /dev/sa0: Input/output error
> 0+0 records in
> 0+0 records out
> 0 bytes transferred in 0.002930 secs (0 bytes/sec)
> 
> ... which is a return code of '1' and no messages on the console...
> 
> I have, before you ask, tried "bs=10k" 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.


Try bs=64k

--
Bob Bishop
rb@gid.co.uk