Slashdot Mirror
Digital Storage To Survive a 25-Year Dirt Nap?
AlHunt writes "I've been tasked with finding a way to bury digitally stored photographs in a small underground time capsule to be opened in 25 years. It looks like we'll be using a steel vessel, welded closed. I've thought of CDs, DVDs, a hard drive, or a thumb drive — but they all have drawbacks, not the least of which is outdated technology 25 years from now. Maybe I'll put a CD and a CD-ROM drive in the capsule and hope that the IDE interface is still around in 25 years? Ideas and feedback will be appreciated."
Change up IDE for SATA and you might have a chance, since SATA is relatively new and SATA2 is backwards compatible with SATA1, etc.
Seriously, just print them. Unless we somehow evolve new sensory organs in the next 25 years, I suspect that photographs won't be rendered useless through obsolescence. They can always scan them into new digital files afterwards.
How about a small digital picture frame? That way you could throw in your own flash drive, and the pictures would come with their own display medium. I'm sure they'll still have AA batteries 25 years from now.
You can't guarantee that the data will be intact when they open the capsule. Nor can you guarantee that the gear you send will survive.
Seems to me that your best bet is three separate distribution mechanism.
1. CDs AND DVDs (two copies of everything), a small portable DVD player with multiple interfaces - component/composite/s-video out
2. NAS device with at least two disks (two copies of everything) and multiple interfaces - eSATA/SCSI/USB2/FireWire/ethernet(dhcp)/etc.
3. Digital picture frame and a handful of memory modules (two copies of everything)
Ensure that whatever device you send goes complete with power adapter and user manual. In at least two languages.
All there is to do when you're done, is cross your fingers and hope that video displays still operate in two dimensions :)
If it absolutely, positively has to survive 25 years, it might be worth the expense of getting the photos professionally printed on good quality paper and, if you're worried about the box leaking, laminated. Okay, it's a smartass answer, but those are photos you're going to store, and they're known to last more than 25 years easily.
No kidding!!! What do you say at this point?
http://www.digibarn.com/collections/systems/wang2200a/
Floppy drives, $9 from Newegg.
You can still buy motherboards with serial and parallel ports, for God's sake.
25 years isn't that far in the future.
Potato chips are a by-yourself food.
Alternative title: "How many bullshit redundant replies can you fit in a Slashdot thread?"
It would be entirely possible to make a paper copy of binary data that could easily be read in with the correct software. Of course, the paper you would want to use would be acid-free.
One could simply encode the binary as forward slashes and backward slashes. Or as x's and o's.
But those would be really wasteful.
I've often thought that what would make a really good software contest would be to develop a format to back data up to a paper copy on a laser printer using the best compression possible but with enough error correction and detection to be able to read just about any paper put in that comes out in reasonable shape.
For example, one might use individual pixels on the paper. Or you might want to group several together and treat as a bit. Or use an innovative coding scheme that doesn't just map individual bits to spots on the paper.
I think that a scheme that spreads the information out over the entire paper might be interesting. In other words, the individual bits of a byte and any bits dealing with the error detection and correction would be located remotely from each other.
In such a contest, testing would be easy. Write images of several datasets to paper and then scan the images in after different stages of intentional damage to the paper. For example, you might read two data files back from the pristine paper without doing anything. Another two data sets might come from paper that has been crumpled up into a ball and then flattened. Two more might be from paper that has been moistened. Two more from paper with a tear across the middle. And, finally, make copies of two data sets on an everyday copier and then scan them in and decode.
Rank the results by the numbers of errors, possibly with factors to take in levels of difficulty based on the amount of damage to the paper, and select a winner.
Electrolytic capacitors are used in the power supply filtering of essentially all circuitry currently in use. These components will be present in a number of places on the circuit boards of both disk drives and memory sticks.
The insulating layer between the plates in electrolytic capacitors is formed by electricity-driven chemical action. It gradually degrades over a period of several years. If the capacitor is operated occasionally the operating voltage across it will rebuild the insulating layer. But if it's left unused for too long the layer will degrade to the point that, when power is finally applied, the capacitor will short and (because most of them are hooked across a power supply) fail catastrophically. Like by blowing open and jetting chemical fumes, while shorting out the supply and damaging other components in the current path.
Mechanical moving parts may lose lubrication and spot-weld with time. This also makes storing entire drives problematic.
Recordible CDs usually record on a die layer that will degrade with time.
Some types of flash memory store data as stored charges, which will leak away with time.
So IMHO degradation of the medium itself is likely to be a killer problem. Much more than readability with future devices. (After only 25 years there should still be some working players available for currently widely-deployed standards, even if no new ones are being manufactured. Once you've go the bits read you can transfer them to new media.)
Things I'd consider:
- Integrated circuit memory devices using a technology like fusible link or a crystalline/amorphous transition. (Replace any electrolytic capacitors with ceramic types - which will greatly increase the size of the assembly.)
- CD masters involving actual removal of material - a material inert enough that it will not corrode away with time.
- If you want to store drives for removable media (and convert the caps), check with the manufacturers about what the bearings are like and talk with a mechanical engineer with applicable experience (like mil-spec or space-rated). I'd avoid sealed hard drives, especially those that don't lift the heads off the platters when parked.
Also: Use a coding scheme that has industrial-grade error correction. B-)
One downside to your task is that, with only a 25-year storage time, you'll probably still be alive to be blamed for failures when they open it. B-)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Why is everyone suggest A format?
Why not store the data on a:
* DVD
* Pile of CDs
* USB drive
* SD card
* xD card
* Hard drive
And a choice few in hard copy.
Seriously... with the price of these things, and the timeframe, surely you can afford to store it on all of these things and put them all in? Plus it'll be fascinating in 25 years time to see how many are still readable... all? None? Some?
everything needs to be sealed well, however. double or triple on some water-tight somethingsomething to be safe,
Or maybe submerging it into mineral oil. Does anyone know if electronics can withstand 25 years submerged into oil ?
Everything will also need to be redundant :
- burned DVD-R/CD-R media may rot. Harddrive may refuse to spin because of chemical aging of the mechanical part, flash memory could fail, etc...
- as much spares as possible. 25 years from now, spare parts will probably be hard to find.
- a couple of SATA and USB drives/readers. Whatever the are the connection 25 years in the future, USB is currently so popular that in the future, we're bound to see adapters, just the we we currently see Serial-2-USB adapter even if serial connector have been phased out for quite some time.
---
Come to think of it, printouts of data compressed and printed out as 2D barcode may be the most durable technology.
- extensive experience shows that, under proper conditions, paper can be made survive for even longer than 25 years.
- reading and decoding a 2D barcode doesn't require any technology specific to the current generation of hardware.
- as long as the data is stored in a redundant manner and that it use open and well documented standard with source code available. It would still be accessible by computer 25 years later, even if it requires some programming and/or re-implementation of a long lost standard.
(as a bonus, include documentation of formats printed in clear on paper too)
- choose simpler standards. chance are none of the current open source library processing it will be available in 25 years. the kids will probably have to re-code a reader / decompressor using whatever will be the popular high-level language du jour ( Ruberlython#++ or something similar ). may make a fun science project for them.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
Only a handful of working systems in US including mine.
That's awesome! I have an old wang I would really like to get something from. Do you think I could take my wang out and put it in your system?
> and I know for a fact that CDRs deteriorate after about 10 years.
Some archival media is rated for 100 years. But forget that, just make a gold master and send it out to be commercially duplicated. It isn't THAT exensive, so have a small run of 100 copies made. Sell 90 of them in a fundraiser to recoup the expense of duplication and stick the other ten into a small stainless steel airtight container with an inert gas. Wrap that in some quality insulation to protect it againt the heat when the main capsule gets welded shut. I have heard lots of 25 year old audio compact discs and they sound just fine. But if there is enough bit rot to make recovering data dodgy, well you have nine more still shrinkwrapped copies to try reading any bad blocks from.
The only remaining question is whether equipment to read a Compact Disc will still be available in twenty five years. And the answer is almost certainly. It probably won't be nearly as popular as it is today but the LP is ten years in the grave and you can still buy a new turntable at Sears.
A pressed DVD might be even better because the recorded media is safely between two layers of substrate instead of only protected by the screenprinted label on the top. On the other hand we have enough history with the CD to know beyond any doubt that they survive in readable condition for the required time, even under typical consumer storage conditions.
Democrat delenda est
I don't think it will be the medium that will be the problem, it will be the message. Imagine the shock of those viewing it to learn that our generation thought that there weren't WMD in Iraq or that Han Solo shot first. I'd limit the contents of this a few MP3's and photos of the Whitehouse, otherwise your time capsule will last all of 5 minutes after being unearthed before its whisked away to the Ministry of Subversive Materials.
Actually, better forget the MP3s, or you'll be tracked down by the RIAA and sued for 25years of lost song rental income.
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.