tape (sa0) on sparc64 ?

[Greg 'groggy' Lehey]

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 at gid.co.uk> wrote:
>> 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 at 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
>
> 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..

The obvious question: can you write tapes and read them back?  My
experience with DDS tapes was of extreme unreliability.  The age
doesn't make things any easier.

Greg
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