Helping people with computers... one answer at a time.

Keeping digital data for a long time, say over 10 or 20 years, presents several unique problems that you'll want to plan on addressing.

A question regarding long term storage of photos, MP3's and video clips: what do you think is the best way? I have an 80GB external hard drive. I also use Delkin gold archival CD's. But they're limited for storage space. I'm curious if regular CDs such as those from Memorex, Fuji, Sony, and the like are just as good for archiving.

Long term archival is a serious issue for two reasons, one that probably won't surprise you, and one that might.

There's no single answer, but I can tell you what I do.

Long term archives, archives destined to last, say longer than 10 or 20 years, need special attention, or they're actually likely to fail for one of two reasons:

  • Media deterioration: whatever you used for your backup slowly degrades over time so that when you finally get around to needing something from the archive you can't read it any more.

  • Technology obsolescence: the equipment we might want to use to read the archives might no longer exist in any conveniently accessible way.

(There's actually a third problem, software obsolescence. Who's to say that the file formats we save as today will be readable in the future? What if there's no reader for Word documents, AVI video or MP3 audio? This too could happen, but it's not something I'll deal with in this article.)

Deterioration has gotten a lot of press in recent years. For example we've heard of old Hollywood movies stored in film canisters falling apart due to chemical reactions, and that archivists are scrambling to save as many of these historical gems as possible.

The same applies to any media you might archive your data to. Floppies, CDs, even hard disks will deteriorate over time.

The million dollar question is how long will each of those last?

And of course there's no specific answer. There are too many variables at play: the quality of the media, the environment that the media is kept in long term, the quality of the device used to create the backups, and so on.

"If there's any lesson to be learned about archiving digital data is that it's not as simple as one might believe."

I actually became concerned at some reports that CDs, for example, start to suffer serious degradation after anywhere from 1 to 5 years. I panicked and started to worry about my older archives, dating back 15 years. I began to copy them to a hard drive and not one failed. All my data was still intact.

There are mixed messages about what media types last longest, but my personal rule of thumb is that CDs last longer than floppies, and hard drives last longer than CDs. Each probably by an order of magnitude.

But that brings us to the second problem.

What do you do when the backup media you used is no longer supported by current hardware? I have had, at various times, 7-track tape (think old 1950's computers in the movies), punched cards, and small tape cartridges as my "archives". I have no way to read or use any of those today. Floppy disks are slowly disappearing. There's a lot of information out there stored on "zip drives" - though I haven't seen a reader for those in years.

Will CD's be around forever? That seems unlikely, but the question once again isn't as much if they'll become obsolete, as when.

And what they'll be replaced by.

A lot can change in 10 or 20 years.

So, what do I do?

Well, to start with, some time ago when it became clear that floppy disks were heading into history I copied all my backup floppies on to CD-ROMs.

Next, I make sure to purchase brand-name media. I'm partial to Memorex and TDK for CDs and DVDs myself, but other name brands, including the ones you mention, should do equally well. There are so called premium "archival" CD media, and I don't really have a good read on whether they're cost effective or not.

I still burn backups to CD-ROM (and occasionally DVD, though I still have less faith in the reliability thereof). However, I've also begun a process of copying my oldest CDs to hard disk. Those 15-year old CDs I mentioned? I still have them, but they've also been copied onto an external hard drive, which is itself mirrored to a second drive.

My oldest archival CD is now only 8 years old, and over time I plan to catch up and make that more like 5.

Yes, I copy to hard drives. My plan is for my "next generation" archival backup to be multi-gigabyte hard drives. These are drives that I've placed in external USB enclosures - here I'm betting that while the internal architecture is slowly changing (from IDE/PATA to SATA) external interfaces such as USB will probably be around longer, at least in a backwards-compatible way. So in 10 or 20 years even though what's inside the USB enclosure might then be considered incredibly ancient technology, there'll still be a USB socket to plug it into somewhere and have it work. (And if it still matters, I can then copy whatever I have to whatever would then be considered appropriate storage.)

I think the bets are safer there than on specific media (like CDs or perhaps even DVDs), or internal interfaces such as IDE and SATA.

And once again, I'm trying to make sure to get good quality drives for this project.

If there's any lesson to be learned about archiving digital data it's that it's not as simple as one might believe. If you truly plan to keep things for a long time, a plan to migrate digital data from older to newer media and devices (and perhaps even formats) seems the only pragmatic solution.

Article C3273 - January 21, 2008 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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10 Comments
Dave Gold
January 25, 2008 7:21 PM

If you are creating cds or dvd's for archival purposes, purchase archival quality media. They should last a good bit longer than the standard media.

For additional info, see http://adterrasperaspera.com/blog/2006/10/30/how-to-choose-cddvd-archival-media

--Dave

Eugene V
January 25, 2008 8:37 PM

I've had a recent problem with a CD that was burnt with a photo archive of mine back in 2003-4. When I went to read, extract something off the disk, guess what, it wouldn't read properly. I managed to use a retrieval program and reclaim about 80% of what was on the disk. I'm not sure if this problem was due to something during the burn process or whether the dye was deteriorating already. Either way, I've now purchased an external HD back-up as well as reburnt a few archive disks.

Linde Nobre
January 26, 2008 5:02 AM

Media are much more vulnerable in tropical climate. Here in Brazil, floppies always tended to fade away within days - sometimes hours.
CDs so far show to be more resistent. But, attention, CD Rom work fine after years, CD RW (rewrite) may deteriorate within a few months. They start to show trails like the ones of termites in wood and do not work anymore.
Harddrives only pose problems where they are constantly hooked to energy: Blackouts may destroy them. Non-hooked-up harddrives may - depending on quality - present fungal problems after a few months.

O. A. Orcan
January 28, 2008 12:19 AM

Depending on the size of the data to be stored, the best long term storage for the average user would be hard disks in terms of speed, size and the cost. I use several 500GB external drives, connected only when necessary, and have a test and re-copy schedule. However, for commercial purposes, I think optical/magneto-optical storage is much better. Reputable online storage companies could be another option and obselescence of the storage method wouldn't be a problem. For portable storage I've been using mini-HD's after I had problems with flash memories and CDRW's. Note that, although the CD/RW's and flash memories are supposed to be re-written hundreds of times, if the quality of the built in hardware programming that is supposed to prevent writing on the same location repeatedly is not good, a single data writing process may require file allocation table to be we-written many times and these areas of the media deteriorate very quickly. So I'd say go with the hard disks, at least for the time being and use other media only for temporary or short time storage.

Jim Michaels
January 28, 2008 1:49 PM

when I worked in the server room at a certain company I learned to use archival media - gold media. it really depends on how the media is made and the dyes used, etc. as to how long they will last, how much light they will stand up to shelf life, and so on.
Gold media is rated for 300 years. silver thermal media is rated for 250, and they are more expensive than regular media. some prepackaged Mitsui MAM-A gold media come diamond-coated to resist scratches.
Hard disks are warrantied for only 5 years, but I have seen then last longer.
there are several outlets that sell Mitsui MAM-A media, one of them is mediasupply.com - they come in several forms, one of them in shrink-wrap (no cakebox). They sell in bulk too. I found decent cakeboxes that lock down nicely at meritline.com
silver thermal is $51/100 and gold is $110/100 I think. but the diamond-coated packaged gold is more expensive than that and it's really heavy and it's bulky of course.

Eric Deeson
February 8, 2008 8:39 AM

"In the long run, we are all dead." (Keynes) My long run is shorter than the large majority of computer users, and I often think "why archive data?" rather than "how?".

Yes, I managed to convert my pre-PC data to modern media and file types - but it's rare that I need a file more than a couple of years old. And I can't imagine anyone looking at all those digital photos after God closes my lid.

There's supposed to be an information explosion - let's not make it worse!

Daniel
July 17, 2009 11:56 PM

I can attest to hard drives going out in blackouts; and to think I almost knew it was going to happen.

So, that's how I found this place. I'm trying to find out how to boot from my USB drive, because I have nearly a gigabyte worth of RAM combined with the flash drive. 256 mb of USB drive, 1 256 mb card of RAM, 1 512 mb carf of RAM. They're old and slow.

Dad:Hey, son, you should turn off your desktop, the lightning storm might break it.
Me:K.
*5 minutes*
*bluescreen after a light power surge, but I noticed that the reason was legit-"something failure", not unlike the regular fakes[actual blue screen, fake reason, not something I can alt+tab out of]
*real power surge*
*turns computer back on*
"HARD DRIVE 0 FAIL"
"Crap."


I didn't wanna buy an enclosure to even test for data. I took it apart and airdusted it all. I threw away the hard drive.

On second thought, I could have put it back together once and tried again before throwing it away, but that's too late now.

[At this point in time, my screen had died. Almost exactly at the 5 year/6 year mark. Weird.]

NOW onto something relevant.

I do believe that USB will be around a long time. I have noticed that the old connectors for keyboards/mouses being phased out in favor of USB connectors[on the devices themselves!].

Hm.

This computer has a backup drive, I wonder if I can use it on my old computer...

Mark Morand
April 3, 2012 11:04 AM

OK you pros, this old man is neraly 80, and trying to archive all my old LP's, tapes & 45's. After many years, I finally neared the end, only to find out that the first CDs made 7 years earlier, were already going bad (Sony, Verbatim, etc.) I bought CD-R Gold archival, just short of re-financing the house, and re-copied them all. Now I find out they should all really be put in MP3 format, on DVD-R discs. ( Adjust pacemaker). I do not find a gold "archival" DVD disk, so will these also go bad in 5 to 8 years? Anyone have a suggestion for this old man?? Thanks

Mark J
April 3, 2012 12:00 PM

@Mark Morand
The CD-R gold copies should be fine. You can save the songs to the CDs in .mp3 format. The only difference between the CDs and DVDs in this case is that you would need about 6 times as many CDs as DVDs.
I personally use a removable hard drive for of all my music. If you have the music on the CDs and the drive, you would have a backup in case one of the CDs is damaged or vice versa.

Hughie
September 11, 2012 6:32 PM

Leo, you need to know that a Hard Drive is not sealed. If stored in a humid atmosphere, that gets into the drive (slowly). If suddenly cooled, that moisture can precipitate. So store carefully! I opened an working drive when stored but now dead and saw "corrosion" at the head landing area, right under the head.

My understanding is the opposite: hard drives *are* indeed sealed. If moisture gets in that's bad for many reasons, and indicates a defective seal.
Leo
12-Sep-2012

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