Long term back up options

[airborne_artist]

I'm starting to scan a collection of old family photos, letters etc, and I already have a large stash of photos on the HD. After a narrow miss a year ago, I'm looking into the best solution for long term back-up. I have a CD writer and a DVD writer.

So the questions are:

Is CD/DVD media safe for the long term - say 10 years?

If not the above, what else? I was interested by BT's Digital Vault Basic service - 2Gb of online free storage. OK, so it's free, which means they can mess you around if they choose, but it's an interesting idea.

[Saab Dastard]

Write once (NOT Re-writable) CDs are your best bet for longevity, apparently. They should last several decades. Stored correctly, of course!

Worst would be re-writable DVDs.

For serious long-term archiving of important data, the professional approach is to keep copying from existing media to next generation media - that way the data is constantly being checked and refreshed, and the storage medium is keeping pace with technological change.

SD

[Dark Star]

Agree with Saab - CD non rewritable stored properly

Also - Get good quality branded CDs and make 2 copies, 1 each on CDs from different sources and brands (you don't want to find you had a bad batch!). Before storing check that your files pictures etc are all readable on a different computer than the one you made them on. Keep one copy and store the other in a remote location (fire/burglary). Periodically check they will both still read properly.

And as Saab said keep up to date with new media/formats

Finally if you are scanning photos, index file and keep the negatives, they are known to last for decades and better quality scans may be available in the future.


That may seem a bit over the top but if your data is worth keeping 10 years or more it ought to be worth the effort.

DS

[Willows]

I think you can buy specific archival DVDs/CDs that are supposed to last longer than standard ones. First link from Google. (http://www.spaphoto.co.uk/store/acatalog/Archival_Gold_DVD-R.html) I've never bought them myself but would consider them in the future.

It is also a good idea to use a pen or marker that won't affect the integrity of data on the disk. "They" say the proper way to store them is in a jewel case, in a cool dark place, standing vertically. Not lying flat. Don't know why.

I have pretty much everything backed up to DVDs. Music, pictures, all my important documents, log book scans, scanned certificates (birth, drivers license), etc...

I also have 2 external hard drives, which get updated regularly. I learnt a very important lesson after falling victim to a hard drive failure last year. Luckily, I didn't lose too much, but it put it all in perspective.

Backup, backup, backup!

[IO540]

Is CD/DVD media safe for the long term - say 10 years?

I don't think anybody knows, yet. The very first CDs came out c. 1985. These were music disks and they still work today - if not exposed to much humidity or heat.

The first writeable CDs came out c. 1993 (the Yamaha writers then cost £5000!). These are still readable, if stored properly. But that's only 13 years' data we have.

The only storage proven over longer is, believe it or not, good old mag tape. You can get 20GB on a DDS4 cartridge. DLT will do much more, and there are other formats. Most serious businesses use tape even today. Even then, one would recommend rewriting it to new media after 20 years or so.

The problem with CDs is that they are very easily damaged. One little scratch and it's gone. I never use them for serious backups. Digital photos are stored on two separate hard disks, and a DDS3 or DDS4 tape. The DDS tape drives are about £300 now (HP).

Soon, blue-ray DVD writers (30GB?) will compete with tape, for the first time, on capacity. That will change the backup market a bit. but it will be a long time before anybody will trust it for retention life. And you still need just one scratch...

[Saab Dastard]

IO,

I had occasion to research this for a client not long ago - the manufacturers' accelerated testing programs did indicate that WORM CDs have the best chance of retaining data reliably for up to 100 years.

Yes, accepted that's best on testing, not 100 years elapsed time.

The problem with magnetic tape is / was delamination - vast amounts of data (mainly sound archives) on magnetic tape from the 60s and 70s is largely useless now, as the ferric oxide layer has simply come off the backing.

I haven't investigated whether or not this is likely to be a problem with modern tapes, but it scares the crap out of me!

SD

[IO540]

By "WORM" do you mean a normal writeable CD, or the special WORM drives which were "about to take over the world" about 10 years ago and are now long obsolete except in very special applications requiring evidence to be preserved?

I reckon writeable CDs should last a very long time but they do suffer from humidity and temperature, especially both together. Environmental control (achieving something like a normal summer office atmosphere) appears essential.

Everybody loathes mag tape, but it has always been way ahead of any other removable medium when it comes to capacity. I haven't heard of pro grade data tapes (DDS or DLT) delaminating. Maybe you mean normal audio tape? I would expect audio recordings to be useless after say 20 years anyway, due to loss of magnetisation (making the S/N ratio poor) and things like print-through.