Hello,
Arno Lehmann wrote:
>
> Hi,
>
> 13.11.2008 21:58, Dan Langille wrote:
>> On Nov 13, 2008, at 11:56 AM, Heitor Medrado de Faria wrote:
>>
>>> Heitor Faria
>>>
>>> Dan Langille wrote:
>>>> On Nov 13, 2008, at 11:16 AM, Heitor Medrado de Faria wrote:
>>>>
>>>>> Guys,
>>>>>
>>>>> This is urgent.
>>>>> Is there anyway to restore data on tape after an eof?
>>>> I have no idea.
>>>>
>>>> I would guess that it would require something special to force the
>>>> tape drive to read past the EOF.
>>>>
>>>> This is not something Bacula can do AFAIK.
>>>>
>>
>>> Is there anyway of bscan ignore the eof?
>>
>>
>> Please do not reply at the top.
>>
>> I do not know. I am quite sure that you cannot force bscan to ignore
>> the EOF.
>>
>> This is not a Bacula issue. This is a tape and tape driver issue from
>> what I know.
>
> Indeed.
>
> With stupid tape technology - i.e., older ones, and only the ones
> without chip memory - you can *try* to position to *before* the EOD
> mark, then write a very short block of data, reload the tape, and see
> if that was sufficient to overwrite the EOD mark. With luck, you end
> up doing this:
>
> Broken tape layout:
> Data Block EOF Data Block EOF EOF The data you want to get at EOF
> ^^^|^^^
> tape drives/ drivers interpret this as an EOD mark
> After writing:
> Data Block EOF Data Block EOF Data unreadable data The data you want
>
> Then, ignoring read errors, you might be able to access the data you
> want to get at.
>
> Needs lots of luck (which could be less when knowing the exact tape
> technology you use, because, for example, the QIC standards specify
> how long a file mar is on tape, how long an EOD mark is, and how long
> a block of given length is), the right hardware, and afterwards you
> might have to further process you read data.
>
> If you use recent tape technology, I believe there is no way to
> achieve what you want. Those tape drives always know where the tape
> contents ends, and will not be able to overwrite the EOD mark without
> appending a new one.
>
> A commercial data recovery service might be more helpful.
>
You are right, i have got this problem some years ago, and some compagnies
have special
firmware that are able to do this kind of things. But it cost a *bit* of
money...
Bye
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