Archiving Data Permanently

[Joel Jaeggli]

This is the last thing I'm going to say on the subject...

On Thu, 18 Aug 2005, Peter Arremann wrote:

> On Thursday 18 August 2005 22:13, Claude Jones wrote:
>> On Thu August 18 2005 3:18 pm, Mike McCarty wrote:
>>> As I mentioned before, tape is very reliable. It has been shown to have
>>> 20+ year retention. One gets "wear and tear" only when the tape actually
>>> moves. For data archival purposes, this is effectively never.
>>
>> Since I've spent over thirty years in the media sector, first sound
>> engineering, and now television, I can't let this claim pass. You've
>> repeated it as gospel. I'm sure there are some studies that would make your
>> point, but, in real world conditions, I would never trust critical backups
>> to tape. Even supposing a tape's data was intact after 20 years, what would
>> be the state of the technology? What  would you retrieve your data with?
>> I've dealt with every format of tape there is. Even if it's stored
>> properly, vertically, not horizontal on the spool, in temperature and
>> climate controlled conditions, there is a wide disparity in tape longevity.
>> BetaSP tapes that cost us $60+ when purchased new, will vary widely in
>> their playability even after ten years. Older 3/4" stuff is deteriorating
>> rapidly in our archive, and we're in a rush to transfer mode lately, to get
>> the material off them and on to newer media. The machines that will play
>> this stuff are also getting harder and harder to maintain, and find parts
>> for. I've encountered many horror stories about computer tape backups as
>> well. Meticulously done, perfectly stored, and tape drives kept up to spec,
>> may succeed in the 20-year life you speak of, but those conditions are
>> almost never met in the real world. If you have the staff to maintain the
>> stuff, the equipment to be maintained, the climate controlled storage
>> environment, along with many other factors, you might get by with tape
>> backup - I personally would only recommend tape as a secondary repository.
> Agreed. I can't recommend tapes for anything longer than a few weeks if you
> really need your data. We have all kinds of tape formats where I work and
> none have ever been reliable for more than a few months.
>
> The only viable option you have for long term is MO...

There are complex set of problems that revolve around preserving data for 
long periods of time that defy simple answers. rescuing files in obsolete 
formats off media formats that were no longer supported was my bread and 
butter for a while. The best thing you can do is move all your data 
everytime you get a new storage technology, before the hardware thta 
supports it can't be connected to a modern machine, before the file format 
is not longer supported, before the media you assumed worked because they 
did the last time you tested them failed...

What computer media from 20 years ago (1985) can you still read? 51/4" 
floppies? mfm, rll sasi, or esdi hard-disks? 9-track tape? 1/4" qic tape? 
tk50? variable speed 3.5" floppies? disk pack?

how about 30 years ago? got a punch card reader? paper tape? cassette 
deck? 9 track tape? 8" floppy? ibm winchester drive?

Now? does anyone here believe a significant amount of computer media will 
actually rotate in 20 years?



> Peter.
>
>

-- 
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Joel Jaeggli  	       Unix Consulting 	       joelja at darkwing.uoregon.edu
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