Preserving your digital data requires high- and low-tech solutions

Let me start this week by say­ing that what I’m about to tell you is based in part on the­o­ry and con­jec­ture. Opinions abound, many dis­guised as fact. Your mileage may vary. Some set­tling of con­tents may occur.

That said, let’s talk about keep­ing your dig­i­tal data safe.

In case you haven’t noticed, more and more ‘stuff’ is going dig­i­tal. Digital images, dig­i­tal music, dig­i­tal video. Unfortunately, most of that con­tent is only a disk crash away from oblivion.

When we lived in a paper world, the con­cept of “back­ing up” did­n’t exist. Papers were put in a file draw­er. If you were ner­vous about such things, you made a pho­to­copy and put it in a fire­proof file cab­i­net. But with more and more of our stuff being con­vert­ed to those not-so-prover­bial ones and zeros, keep­ing your stuff safe isn’t so easy.

‘What?’ I hear you say, ‘It’s easy to make copies of dig­i­tal infor­ma­tion. I just click “Copy”.’

Yes, it’s eas­i­er to make copies. No argu­ment. But it’s not eas­i­er to make long-last­ing copies.

Digital media breaks. Hard dri­ves crash. CDs get scratched. DVDs rot . That’s the down­side of dig­i­tal: You can either access it or not, peri­od. A stained and fad­ed book may still be read­able, at least par­tial­ly. But a rot­ted DVD is gone.

If you’re not care­ful, your dig­i­tal data will dis­ap­pear. And that’s some­thing to keep in mind next time you’re look­ing at the dig­i­tal pho­tos you took on your son’s first birthday .

Only a few years ago, peo­ple backed up to flop­py dri­ves, big flop­py dri­ves (e.g., Zip or Jaz), or mag­net­ic tape. (A few rebels used mag­ne­to-opti­cal dri­ves.) All of these were based on mag­net­ism: They record­ed data on some kind of flex­i­ble plas­tic that had a mag­net­ic coating.

But mag­nets lose their mag­net­ism. Common things like heat or oth­er mag­net­ic fields (say, from a stereo speak­er) dam­age flop­py disks and tapes. They were great for short-term back­up, but that’s about it. (Not to men­tion hav­ing oth­er prob­lems, like lim­it­ed stor­age space, slow access times, and obso­lete hardware.)

Today the media of choice is opti­cal: CDs and, increas­ing­ly, DVDs. Instead of being based on mag­net­ic mate­r­i­al on flim­sy plas­tic, they’re based on micro­scop­ic spots burned into a chem­i­cal dye with a laser. They’re tougher, they hold more data, and they’re faster than flop­pies, Zip disks, or tape. In fact, there are peo­ple who say that CDs and DVDs can last 100 years — when they’ll be some­one else’s problem.

Would that it were true. It’s prob­a­bly not. At best, it depends on the disk; some will last longer than oth­ers. There are still Yugos around, after all.

First off, for­get about rewritable disks (the kind that end with an “RW”). Trust me, you don’t want to use those for long-term back­up of your data. We’re talk­ing a 10-year lifes­pan, tops. Instead, let’s look at your typ­i­cal CD‑R or DVD±R.

Without get­ting into dis­turb­ing detail, the disks you buy at Office Max have two lay­ers encased in clear plas­tic: a reflec­tive lay­er and a trans­par­ent dye lay­er. When you “burn” a disk, your CD or DVD writer fires a laser at that dye to cre­ate dark spots that don’t let the reflec­tive coat­ing shine through. (We’re talk­ing tiny spots: 1/100th the width of a human hair for a CD, small­er for a DVD.) Your com­put­er reads the dark and reflec­tive spots as the ones and zeros of your data.

But some dyes are bet­ter than oth­ers. After a while those burned-in opaque spots start to get less opaque. The disk fails. El Cheapo disks use a dye called cyanine—the disks look bluish green, and they’ve got a life expectan­cy of about 10 years. (But remem­ber what I said above: Your mileage may vary.)

El Super Cheapo disks are poor­ly con­struct­ed as well, so air (and ozone and var­i­ous pol­lu­tants) can get into the disk and make the dye go bad faster. Even well-made disks are affect­ed by their envi­ron­ment: light, heat, and humid­i­ty. Depending on how you store them, they could last six months or 60 years. Don’t bet on the latter.

There are bet­ter disks: Some use a gold reflec­tive lay­er and a mate­r­i­al called phthalo­cya­nine as the dye. (Don’t ask me to pro­nounce it.) They look gold on both sides. Others use a dye called azo and are sil­ver on one side and dark blue on the oth­er. Both of these have pro­ject­ed lifes­pans of more than 100 years. Just keep them out of the light—those UV rays are CD and DVD killers.

Still, even the high­est-qual­i­ty disk is sus­cep­ti­ble to fail­ure. Which means you might want to think of oth­er ways to pre­serve your data for the ages.

There are, of course, printouts.

A dis­cus­sion came up at my com­pa­ny about how to archive the thou­sands of doc­u­ments we have. What was the best media — mag­net­ic tape? CD-ROM? DVD?

Smartass that I am, I said, “paper.” Smartass, yes. But correct.

Books from the 15th and 16th cen­tu­ry and ear­li­er are still around. (Although some, like the Dead Sea Scrolls from the 2nd or 3rd cen­tu­ry C.E., are on vel­lum. You won’t find that at your local Office Max.)

For long-term stor­age of doc­u­ments, you can’t beat paper. It needs to be high qual­i­ty stuff — acid-free rag made from linen (as opposed to wood pulp). And print using good ink in a large, easy-to-read type­face. If it becomes your last remain­ing copy, you’ll be able to scan it and use OCR — opti­cal char­ac­ter recog­ni­tion, in which your com­put­er reads the print­ed word — to cre­ate a new dig­i­tal document.

Printing is a viable option for pho­tos, too. Consider that the image in the world’s first pho­to­graph, dat­ing from 1826, is still vis­i­ble . Not to men­tion the thou­sands of pic­tures from the Civil War, and in your par­ents’ pho­to albums.

Your typ­i­cal col­or print — the kind you get from your local one-hour lab — begins to notice­ably fade after only 15 or 20 years. Those made with a high­er end dig­i­tal print kiosks, like one using a Fuji Frontier print­er, make prints that can last three times as long.

But the lifes­pan of an inkjet print can be longer. That’s right: You can make longer-last­ing pho­tos at home than you can get from your stan­dard pho­to print­er. You just can’t skimp on the ink and the paper.

For exam­ple, Epson claims a lifes­pan of more than 100 years with its Archival Ink (and, of course, Epson paper). Hewlett-Packard claims a 73-year fade-free life for prints made with its ink and its pre­mi­um paper. Both count on the pho­tos being under glass, which fil­ters out UV rays. (It’s not all mar­ket­ing hype. The folks at Wilhelm Imaging Research tend to agree with those numbers.)

We’ve looked at both ends of the spec­trum here: from high-tech DVDs to good old print­outs. What’s the best way to pre­serve your data? Archive to CD or DVD and you risk los­ing it after only a hand­ful of years. But rely­ing on print­outs seems so, well, low-tech — and it does­n’t work with data­bas­es, anyway.

The answer is a com­bi­na­tion. Take advan­tage of iden­ti­cal dig­i­tal copies and store them in lots of places — on oth­er hard dri­ves, CD or DVD, or even Internet-based back­up ser­vices. But also keep good-qual­i­ty print­outs of your doc­u­ments and pho­tos, stored in a dry, dark cor­ner. Just in case.