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Comment by roqetman | Hacker News Reader

I guess this would be useful in the case of an apocalypse scenario involving mass EM pulses (assuming anyone is still around to build new computers with OCR to reload the code). Better use good acid-fee paper stored at near-vacuum though.

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If I can find a computer survived the EM pulses to scan the paper, then most likely I don't need this paper back up anyway. On the other hand if all my data is dead upon the EM pulses attack, I won't put too much faith on the chance of getting hold of any surviving computer.

Well, you could house your precious scanner in a Faraday cage along with a RepRap and other "reboot the world" tech.

Please elaborate; I'm intrigued...

A Faraday cage will protect against an EM pulse? http://en.wikipedia.org/wiki/Faraday_cage

RepRap is a self-reproducible 3D printer? http://reprap.org/wiki/RepRap

And so with the RepRap (and some power source/converter) inside a faraday cage (with other physical protections as well), you're saying that this is the ultimate backup system for worst case scenarios? Do you have any links to provide more information about such a setup?

You seem to have answered your own questions.

Yes, the Faraday cage protects against EM interference. But so does turning your computer off. Your main computer is fried? Pull out your old laptop and dust it off...

Would turning your computer off, help? I can see it helping for normal EM interference, but in an apocalyptic EM pulses scenario I thought the induced current would be enough to damage components.

EM would not erase optical media like CD's either.

No, instead those degrade naturally on their own.

"CD-Rs are expected to have an average life expectancy of 10 years" -- http://en.wikipedia.org/wiki/CD-R#Expected_lifespan

CD/DVD experiential life expectancy is 2 to 5 years even though published life expectancies are often cited as 10 years, 25 years, or longer -- http://www.archives.gov/records-mgmt/initiatives/temp-opmedi...

Regarding degradation: CD-Rs degrade because you write them by using a laser to effect chemical changes, and the chemicals can break down. Commercially-produced CDs, on the other hand, are pressed; they are physically molded by being pressed against a "glass master", and the physical pits are much more durable. Making the glass master is expensive, but the incremental cost of pressing is tiny compared to burning CDs.

So, if you could figure out a way to etch CDs instead of burning them, or make the pressing process cheap enough, you could make very durable CDs. Or if you want to make lots of durable copies of one CD, you can do that now with a glass master.

It sounds like it is possible to make longer lasting CDs using a glass master, but it is only practical if I am making lots of copies. So, for purely archival purposes, optical media doesn't really have a process for extending longevity.

That's why I write all my crucial data onto stone tablets.

The write speed and data density are terrible, the drive, media and storage space cost a fortune, but dang if the data won't last a couple thousand years.

Discussions like these always bring me back to the "10,000 year clock" ... http://en.wikipedia.org/wiki/Clock_of_the_Long_Now

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