Let's say a guy wanted to construct a time capsule. I'm referring to one of those boxes or containers that you drop in the ground, and decades later you (or someone else) digs it up to learn things from that time.

And let's say you wanted to drop several Gigabytes worth of digital data in that capsule. What kind of storage media would you put it on? CD-ROM? DVD-ROM? USB stick? SATA drive? Magnetic Tape?

I would put whole computer in it because it may be hard to read sata drive 100 years latter.

Depending on conditons (low-high temperatures, etc.)

I think usb stick and sata drive are best option. Also tape can sustain long periods with little errors.

I would not say that you need whole computer. You can still read clay tables, even though nobody is producing them now.
As yooy say, it depends on conditions. If you put it in absolutely protected and hermetical capsule, then SATA drive would be best option. Othewise put book printed (embossed?) on plastic pages. 8-)

Hi,

I would say any of the suggested media presented for the time frame in a sealed conditioned container for a few decades would suffice.

@OP look at time degradation for the storage medium suggested. Tape is notorious for long term losses and dryout if not handled properly. Masked media would be the first choice. You would need the means to present the information formed on the die. Limited by density! No decay, no losses due to physical traits or handling poorly. Costly to produce but would store forever. Magnetic media does have a short live as compared to a mask prom. Fuse-able linked proms can be produced by consumers but you would be limited in storage and would need to provide the means to read at a later date.

This to would introduce potential problems, any passive or active devices may be damaged due to poor handling. Any electrolytic device would be damaged over time if used.

Someone mentioned clay tablets, these to required years to interpret. Not handily understood! You would be assuming the person who opened such a container understood your intent and able to discern the information presented if long term. Not just decades.

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Hi,

Not on topic and not constructive to the thread!

You did read the whole thread? OP wants to have a time capsule, not a backup. Whole different criteria than a backup.

/off topic
If you want long term cycled backup then look at storage drives. You would cycle and grandfather the backups. Do a Search here on LQ & Google as this has been covered many times. For your queries I suggest that you create another thread if you don't find information on your topic.
/back on topic

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My approximate times that each would last:

USB stick / flash media = maybe 5-10 years (would discharge and loose all data)
SATA / ATA / magnetic tape = maybe 20-40 years, but data would degrade over time or with elecromagnetic interference, at least make sure to put it in a sealed metal container.
CD / DVD / optical media = I would say 50-100 years if you have good media. I think they make ones specifically for backup purposes. See:
http://forums.dpreview.com/forums/re...ssage=14582362
http://www.gizmowatch.com/entry/japa...g-alternative/

I always have to laugh a little bit at those who think CD/DVD is a durable media. Many consumer articles refer to it as something which last long. Maybe it is long (10 years?) in a consumer point of vieuw, most of the magazines or web sites such an article is printed in themselves do not even exist anymore after 10 years. Besides, it is in the interest of publishers to promote anything what can be sold, not to be critical about it.

I started building my CD collection in 1984. Many of my CD's, I would say 10-20% contain so many errors they cannot be played anymore. No, that is not my CD player, when I can look through the holes there is something wrong.

In 1992 I had a CD recorded for me, at the time that was quite an enterprise at $30 for an empty disc. 10 years later while stored in a controlled environment the CD already showed defects.

First, storage media are developed to store more than the media sold 6 months ago. Data retention is nice, but it doesn't have to last longer than until the 2nd generation of media after that. Media will be replaced by the manufacturer at failure, the data is not. It is much cheaper for a manufacturer to replace a defective media than to develop something which lasts.

That having said, forget anything feasible for consumers. It won't serve. At least it should be targeted at professional use. Something which really lasts could be a golden plate with an engraved pattern of 0's and 1's. I know, data density is not much. In history something which can hold a gigabyte and lasts for a megayear has simply never been developed. You are still in the 1950's as it were.

jlinkels

Hi,

Yes, the content would be limited for certain storage media but a fused-link PROM density would store enough information for OP. Your not going to place a copy of large body of text but you could still store limited long term information.

As for long term layered media, forget it for any long term. Short life!

Why not just place it all on punched paper tape or punched mylar??

Last as long as your printed material would, if not longer.

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The statement about sticking the entire computer into the box is a good idea. Try finding a drive to read 8 inch floppy disks today. While it is possible it is difficult to find a drive and machine that can handle the disks(after roughly 30 years).

Unless you get high end disks (better than verbatim DVD/CD) do not expect much over fives years storage even in a controlled evironment without being touched. After about five years they start to degrade pretty fast.

Right on the money.

Librarians who deal with archives and now digital archives have essentially dismissed CD/DVD as an option. Having no good passive options at the moment (storage crystals anyone?), they have determined that the solution is modern day monks, also known as sysadmins -- put everything on RAID arrays and actively maintain them, copying to new systems as needed. Current thinking would be RAID 6. They have also come up with peer to peer distributed digital archives, whereby participating institutions store data for other libraries as well as their own. If a Library data center blows up, they can rebuild by collecting their data from other Libraries' archives. No more Alexandrias.

Non institutional ordinary people are flying more by the skin of their teeth, but, active archiving and backups seems to be the key (cloud storage may be a reasonable option for ordinary people). There are lots of references to be found through google, but it's a little hard to find the definitive reference I was looking for. See http://en.wikipedia.org/wiki/Digital_preservation, and check some of the links at http://www.icpsr.umich.edu/dpm/dpm-eng/resources.html.

As a side note, most of the enterprise level backup software provides media migration capability -- that old DDS/2 is no longer viable? Migrate it to current media before it's too late. When that becomes old, migrate it again -- assuming, of course, that the data is still meaningful and you want to keep it.

But, if you expect to just put something in a time capsule and have it last without degradation or loss of data, good luck. Try acid free paper, or perhaps the titanium version of a vinyl record -- something dependent on fixed physical structure rather than electronic, magnetic, moving parts or lubricant.

That's what I do at home as well.

But quite another issue. I hope I don't hijack this trhead -- the question is related.

Imagine I have my books/pictures digitized in JPG and archived it on a real non-volatile media. Civilization gets lost in 2012 as per Nostradamus' predictions. When civilization is back on the same level as it is now (what a blessing!) my JPG archives are found. But unfortunately all Wiki pages and documentation about the JPG algorithm has been lost (it was stored on DVD)

Now, without any knowledge of the current JPG algorithm, but with plenty of files, would it be possible to reverse engineer the JPG algorithm and recover my images?

jlinkels

Pressed CD's may be the best choice. Unless the safe was fully EMI/RFI resistant I doubt any magnetic media would survive a solar burst or nuke. A pressed cd is a real metal image of a master that has been fixed to a plastic disk. If protected in a vacuum and away from any light the plastic would maybe last a few hundred years. The metal may last 500 or so.


A home burned cd/dvd is by far the worst. I know that from real life and real tests. It is an organic dye and decompressed in a few years.

One of the systems I used a long time ago was supposed to last like 100 years. It was magnetic doughnut memory core in a nuclear resistant case. Oddly they failed once in a while too.

No magnetic media would be secure. It is almost impossible to protect from radiation and that could degrade the magnetic media.

The space plaque was platinum and was physically engraved. It could last for maybe a few thousand million years if protected.

I forget why the ink on old documents last but one could still use "paper and ink". I forget the name of the ink being sold but it is supposed to last as long as the stock it was penned to.

If protected in a vacuum and away from light you might be right. Otherwise the metal disintegrates from the plastic.

jlinkels

"Pressed CDs": Can you buy the equipment to make them at home? Or order them made in small quantities?

I remember there was some company that made special durable storage media, but I can't find the link anymore.