I'd like to see some solid data on this.

I used to think that DVD+/-R and DVD+/-RW had a shelf life of <10 years (this was ~10 years ago) and I can't recall anyone asserting they lasted longer.

After running a long term program where backups were written to DVD+RW discs, and seeing them last > 10 years, I was impressed.

Now I'm finding sources that say that the post-write self-life of optical media is on the order of 10s to 100s of years.

Anyhow, it just makes me wonder what the practical shelf-life is, and what the underlying media "does" over time :)

It breaks down like any material. The easiest way to sample this would be the REALLY cheap cd-r discs you could get in the late 90s. If you left one of those sitting on your dash, they would borderline melt in the sun... and for sure start peeling off the plastic if they sat on your dash for a couple hours.

Same thing with newer media - if you keep it in a climate controlled environment the sky is the limit. If you abuse it, it's not going to see anywhere near the quoted life.

On the other hand, I've never gotten writable optical media to last longer than three years, despite storing them in a cool dark closet.

Did you compare checksums on the data you wrote?

On the earliest data, nope! Very likely I had some or many flipped bits.

I did have the backups on multiple discs and comparing the two they had the same data so I guess that's almost as good.

Iirc, RWs las longer than plain Rs. Something to do with there being a second layers between the stprage surface and the environment.

any recommendation for tape recording devices these days, that will be still supported 10 years from now ?

An LTO drive is good long term since it's guaranteed to write 1 generation back and read 2 generations back. Very easy to use once you get the routine down.

As always, remember to do a restore to prove your backup is an actual backup.

Thanks. I checked the prices and a LTO drive is... expensive. I would have thought a tape recording device would be cheap by now.

Nope, but they do last a long time compared to other drives. We have stuff that got retired after 10 years (still working, we just upgraded standards). LTO-7 is out, so you might start picking up deals on older models.

I restored my 22 year old BBS off Colorado QIC tapes by jury rigging an old mini-ATX board with a floppy tape drive and installing Win98 on it. They read perfectly. Of course you can always pay someone to dump the data for you, but where's the fun in that?! I think any off the shelf modern tape will be just fine in 10 years.

Ha, just tried to read a Colorado tape backup from 98 (tape might be from 96 even, HP T1000 drive) and it ran like a charm. I didn't even realize it was an 18 yo storage until reading your comment.

Even at floppy speed, copying the 400MB wasn't that long, and it's lovely to hear the cute drive noise (for retro lovers).

LTO is the industry standard. You'll have no issues finding an LTO tape drive 10 years from now on ebay, and if for some reason you did, Kroll will still be able to recover it.

There is some evidence to suggest that these DVDs have good archival support, and I can guarantee you that DVD readers will still be abundant 10 years from now:

http://www.mdisc.com/

I had about 1000 DVDs in storage of backed up satellite data. At one point I had to restore the backup using the DVDs and it was about ~8 years into the mission so I was worried that the data would be no good on the earliest discs.

It turned out to be totally fine, as far as I could tell. None of the early data had SHA/MD5 sums (I added this later), so there's no guarantee the earlier discs weren't somewhat corrupted, but they were definitely readable.

Back then, I had assumed they wouldn't have that long of a life, but as you seem to have found, and I discovered, once written, optical media seems to have a very long shelf life.

Most Optical Media degrades almost immediately, depending on storage environment, lasting as little as two two years before they start to degrade/aren't readable (depending on the dye and substrate). The MDISC is archival format - designed to last a minimum of 100 years when stored under reasonable conditions, and up to 1000 years if stored in archival (cool, dark) environments.

They are essential carving physical holes into a stone like substrate.

The verification tests are really quite impressive: http://www.esystor.com/images/China_Lake_Full_Report.pdf

I would think you could get basic support for any device from Linux. Question is really, why not offshore the device support to someone else entirely?

Hosted backups are likely at least as reliable as anything you can do. Right?

Store both the tape and the device to read it.

PCI/IDE/SATA interfaces are so ubiquitous that even decades from now I fully expect you to be able to use them. If nothing else, via some kind of adapter.

Decades is optimistic for a tape reader or any electronics really. Caps dry out, rubber parts degrade and RoHS solder doesn't help the life expectancy. It might still work, it might not.