[Beowulf] PetaBytes on a budget, take 2

Gus Correa gus at ldeo.columbia.edu
Fri Jul 22 14:20:54 PDT 2011

Incidentally, we have a museum-type Data General 9-track tape reader,
which was carefully preserved and is now dedicated to recover
seismic reflection data of old research cruises from the
1970's and 80's.
(IMHO the Fujitsu readers were even better,
but nobody can find those anymore.)

Short from writting on stone (and granite also has its weathering time 
scale), one must occasionally copy over data that is still of interest
to new media, as David said.
I guess the time scale of reassessing what
is still of interest is what matters,
and it needs to be compatible with the longevity of current media.
Maybe forgetting is part of keeping sanity, and even of remembering.

The problem here, maybe in other places too,
is that funding for remembering what should be remembered,
and forgetting what should be forgotten, is often forgotten.

My two cents interjection.
Gus Correa

David Mathog wrote:
> Joe Landman wrote:
>> My biggest argument against tape is, that, while the tapes themselves 
>> may last 20 years or so ... the drives don't.  I've had numerous direct 
>> experiences with drive failures that wound up resulting in inaccessible 
>> data.  I fail to see how the longevity of the media matters in this 
>> case, if you can't read it, or cannot get replacement drives to read it. 
>>   Yeah, that happened.
> 20 years is a long, long time for digital storage media.  
> I expect that if one did have a collection of 20 year old backup disk
> drives it would be reasonably challenging to find a working computer
> with a compatible interface to plug them into.  And that assumes that
> those very old drives still work.  For all I know there are disk drive
> models whose spindle permanently freezes in place if it isn't used for
> 15 years - it's not like the drive manufacturers actually test store
> drives that long.  While it is unquestionably true that a 20 year old
> tape drive is prone to mechanical failure, it would still be easier to
> find another drive of the same type to read the tape then it would be to
> repair the equivalent mechanical failure in the storage medium itself
> (ie, in a failed disk drive.)  That is, the tape itself is not prone to
> storage related mechanical failure.
> All of which is a bit of a straw man.  The best way to maintain archival
> data over long periods of time is to periodically migrate it to newer
> storage technology, and in between migrations, to test read the archives
> periodically so as to detect unforeseen longevity issues early, while
> there is still a chance to recover the data. 
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
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