Long Term Digital Storage....

I used the archival quality CD's for pictures, and store them in a fire safe. They say they are good for 100 years, but who knows?

I think they are probably better than a flash drive. Although, external hard drives are becoming so cheap, I wonder if those wouldn't be better yet...you would just have to keep them in a safe place after writing to them.

I'm trying to figure out how the metallic read/write layer, which is sandwiched between layers of hard and scratch-resistant plastic, could 'flake off'. I've seen DVDs destroyed by being zapped in a microwave oven, which tears and crinkles the metal layer internally. But under normal use and with reasonable care, a CD/DVD should last a very long time.

Many of the writable CD/DVD's I've encountered in the past few years are coated on the outside/labelside only and the laser writes through the plastic disc onto the bottom side of the coating. They damage easily, and flake off with unfortunate regularity both in handling and inside drives. Since I keep most of my data on multiple hard drives and flash memory now, I have not seriously looked for the archive quality disc mentioned. I will say that I have encountered some of my early commercial audio discs that used aluminum, (not the silver or gold ones) that have obvious corrosion forming in tiny spots between the layers. Seriously important info needs to be stored in multiple locations on a variety of media if possible IMHO.

FLASH memory uses quantum tunneling called Fowler-Nordheim tunneling.

It stores data via injecting electrons onto an isolated capacitor in the device. These electrons can "leak" over time, and typical life times of 10 years is shown in manufactures specs.

A CD or DVD is programmed via a laser, and changes the plastic material. But since is hydrocarbon, oxygen can long term damage this plastic. As well UV light. If its stored correctly, it will outlast FLASH.

Magnetic disks/tape has long term issues of the magnetic material (ferrite) loosing magnetic field strength, and degradation of the plastic that the ferrite material is held by.

The plastic isn't changed. The information is written to the sandwiched metal layer.

Archival CD's and DVD's typically use gold or silver, as opposed to aluminum.

As long as the 2 plastic layers are joined correctly then the information should stay for a long time, with cheap CD,DVD etcetera, there is a chance of laser rot, air coming in and causing oxidation.

My wife bought me the Zeppelin box set about 10 years ago, (CD's), for my birthday.

I just keep them in a fairly cool dark place, inside the box, and take them out only to burn new copies to replace the ones I thrashed. So far, so good.

I used to do the same with my vinyl Rory Gallagher LPs

First to 8-track ( !!! ) then to cassettes. Wore them all out!

Now CDs nearly indestructable, copying to just as indestructable laptops, flash-drives.

And to think of all the vinyl and needles I wore out!!

Vinyl's making a come back!

Not in my world though.

Commercial CDs are produced from a master by a pressing process, and as a result are much more stable than discs burned by a home user.

Granted that pressed CDs are more stable. Is there a way to use a pressing technique for our important data--family photos, industrial drawings, etc, etc.

Some new computers (and tablets and smart phones, of course) are not sold with CD/DVD drives. In 50 or 100 years, will these drives exist at all? How will we read our data? Guess I shouldn't have sold that external drive I had...

In the museum off course, when we use our data crystals and look at those antiquated systems

For important stuff I have one copy on DVD (off site) and two more copies on external drives on machines at opposite ends of the house. At any hint of failure of one of the external drives I copy it to a new one.

If the drive fails completely I immediately create a copy on a new drive from one of the other two backups.

For the really, really, really important stuff (mainly family happenings) I have another copy in the cloud.

They are also not sold with replaceable batteries - the batteries will die in the first few years of use.

After that they are only fit for the bin.

I have pix and data on 5 i/2 # 3" floppies that I'm in the process of transferring to newer media. Try to get either floppies or drives now, the current media will go the same way eventually. I'm told that thr fed gov't has several types of media in storage that no-one knows how to access. Moral? Nothing is permanent, except maybe metal pages and then???

After 50 years or less, all data will be owned by google or the government, and is mandatory to be kept in cloud at all time, and you will have to pay to look at your data.

just saying...

I'm wondering if an EMP event can damage a DVD/CD or even a USB Flash Drive. I can imagine that it would affect a Flash Drive and a HD, but a DVD/CD?

I never see any info on this potential problem. Maybe I'm performing a Google Search wrongly phrased....

Does anyone have any information about this?

Doesn't seem possible.

The information is physically burned into the CD/DVD. I don't see how an EMP could have any effect.

It appears that flash drives would be safe also.

http://www.techhive.com/article/116572/article.html

EMP (electro-magnetic pulse) would not "normally" affect CDs or DVDs. However, if the local E field is high enough there will be arc damage to the conductive metalization on pressed CDs. WARNING: May damage oven and will damage CD! Put a metalized CD in your microwave oven and watch the data disappear!

While a typical EMP may not affect the actual magnetic data on a hard drive platter, it could easily fry all the drive electronics. An EMP could also fry a typical USB FLASH drive. I can easily set up a small scale EMP generator which will create a pulsed E or B field that will damage or destroy any typical hard drive or FLASH memory device.

While a typical EMP may not affect the actual magnetic data on a hard drive platter, it could easily fry all the drive electronics. An EMP could also fry a typical USB FLASH drive. I can easily set up a small scale EMP generator which will create a pulsed E or B field that will damage or destroy any typical hard drive or FLASH memory device.

I have been concerned with an EMP. People write viruses to damage or scare people and industry. Why couldn't they also use an EMP to screw up a single system, a whole building, or maybe a city. I have read that an atomic bomb properly placed (one, high over the middle of the country) could fry all the computers in the country, including automobiles. If a person is inclined to write a virus, what prevents him/her from messing up a much larger area with an EMP?

Can we shield electronics? I have seen rooms shielded by enclosing the whole room in grounded copper screen to shield the internal electronics from outside electrical noise.

Over the long term we are more likely to lose the ability to access the format the data is stored in rather than have the media degrade.

I've got stuff archived that's over 20 years old that I no longer have the physical devices needed to access it, or don't have the device drivers that will connect the device to current operating systems and hardware.

Hooker

High volume CDs are manufactured with the data pressed onto the "label" side of the plastic disk. That side is then metalized (vapor deposition), coated with a protective film (lacquer) and printed with content information. The laser reads through the thick (clear) plastic and the metalization provides good reflective properties.

I've (accidentally) scratched the clear side with no problems. However, a tiny scratch on the label side has caused severe data loss.

Writable (one time) disks have a special dye layer just under the label side. A "write" laser alters the dye (bleaches it) so that the data is written in lighter/darker areas for the ones/zeros. A lower power laser "reads" the light/dark (bleached/unbleached) spots.

Writable disks were notorious for not being read in older CD players because of the reflective differences between a metalized layer and a dye layer. UV, excessive heat, and age will make writable disks fail long before pressed CDs.

I have some 6 year old (one time) writable data disks that were stored in near ideal conditions that are now unreadable. My nearly 30 year old audio CDs still play without audible errors.

If you truly want reliable data protection, you must use several backup methods stored at multiple locations.

Writable CDs/DVDs
Flash memory (no failures yet for my data, but <10 years old)
Spare external hard drive (cost per GB is quite reasonable)
OFF-site cloud/server archive (they use multiple & redundant archive methods for you)

Let's be realistic, most of us don't really have critical data that MUST be saved for 100 years. Everyone places a different value on their data and how much they can afford to spend to archive it. Use as many multiple storage methods you feel are necessary.


ref http://en.wikipedia.org/wiki/CD-ROM#Manufacture

While 100 years may be unrealistic to need any stored data, 10 years should be the norm, as people photograph their homes, valuables, children and now store documents on their computers which may be needed in the near future, although not necessarily tomorrow. My home burned down and the insurance company wouldn't pay without proof of existence of any items. This included business documents as well. It's amazing that old photos and negatives can survive for 100 years, but new technology can't even be processed in 20.

"It's amazing that old photos and negatives can survive for 100 years, but new technology can't even be processed in 20."

Good point! I think the ancient scrolls and the photos/negatives from the 1800s HAD to survive because they had no other way of preserving the history.

Today, with the ever-advancing, throw-away society, many really don't think more than a couple years out. Because as we've seen, things change too fast.

---> punch cards -> tape -> 8" floppy -> 5" floppy -> 3.5" floppy -> CD/DVD -> flashdrive -> ????

We've grown to not think of longevity.... just "what's next"?

I wonder if there's a way to use computers to create negatives?

http://www.wisegeek.org/what-is-microfiche.htm

Making is one thing..............

Storing - - - I am starting to worry

I think it's important that we leave a record.
We can only hope that our mistakes are not repeated, but history says otherwise.

Let's be realistic, most of us don't really have critical data that MUST be saved for 100 years. Everyone places a different value on their data and how much they can afford to spend to archive it. Use as many multiple storage methods you feel are necessary.

It is not unrealistic to want data to last for hundreds of years. People who deal with historical records want to be able to study the old info. What about family photos? In my hobby, people are quite interested in fire apparatus sketches over 200 years old, and photos as soon as they were available, and all years since then.

What about stuff we store in the cloud? Presumably the companies hosting this storage will have backups, and probably shift to newer media, but what happens when the customer dies, stops paying the fee, or the account is otherwise stopped?

Dear Mr.SidSidow,

About 2 months back - I read in Computer Magazine, that the life time for CD or DVD is just 300 years - not indifinite period, even stored in a best condition.

Let us see how other CR4 MEMBERS share their knowledge.

DHAYANANDHAN.S

I totally agree with you. CD's and DVD's get scratched and damaged too easily. And, while all these years I thought they were the answer to long term storage, I have been sadly disappointed.

There is a huge difference between 'pressed' and 'burned' optical disks and a considerable difference between CDs and DVDs.

Pressed disks are stamped somewhat like the old vinyl records were pressed except the vinyl stores analog while optical disks store digital information. Metal foil is pressed then sandwiched in plastic. Pressed disks are very stable. Even if they are severely scratched you can resurface the disk unless there is damage to the foil.

I do not think they make these anymore. They have been replaced by a very shiny dye so you might not notice that you are being gypped.

At home we burn disks with lasers to react with photosensitive dye. Depending on the dye and the manufacture process these have a half life. The burn rate also effects the length of the half life. The slower you burn the bigger the pit. CDs allow a heavier burn because the tracks are bigger and allow for bigger pits.

Faster burning dyes are more sensitive to light which can greatly speed up degradation. My kids would leave CDs and DVDs out on a desk top upside down so the read face would not get scratched. A week in direct sunlight will ruin most burned DVDs. Some DVDs such as Sony's light scribe disks degrade in the dark in 5-6 years. Even these are probably more stable that a flash memory. Flash drives do last longer than erasable CDs if you write to them from more than one computer. Most drive have a slightly different alignment. This was true with 1+ meg floppies and CDs require much more precision.

I archive on old Kodak 2x CDs.

PS an EMP event can't damage a DVD/CD even a burned one.

Excellent point. I have also seen Light Scribed discs become unplayable in a very short time. Mine were in cases in a glove box in my car. Not even a year of use. Also of note is that a well painted factory label, or an inkjet printable surface actually protects the data layer as compared to the plain unmarked discs. And burning slowly for long term storage is always a good idea whether CD/DVD or BluRay.

Two-thousand year old parchment scrolls were discovered in caves near the Dead Sea. The texts are readable with the naked eye.

We have boxes of IBM punched cards with data and FORTRAN program code that we ran thirty years ago on an IBM 360 mainframe. They're in A-1 condition and should remain that way for many years to come. However, where's there a machine to read them?!

That's the destiny of all the electronic data storage media we use today --- CD-ROM, DVD, flash memory, hard disk, etc. Remember 8" floppy disks?

The advantage of punch cards is that a human being is able to read and transcribe data from them.

Punch cards!!! I have a few stories about them.

Not exactly the most cost efficient storage medium in this day and age, though, considering you usually only store one character per card.

Hooker

Two-thousand year old parchment scrolls were discovered in caves near the Dead Sea. The texts are readable with the naked eye.

We have boxes of IBM punched cards with data and FORTRAN program code that we ran thirty years ago on an IBM 360 mainframe. They're in A-1 condition and should remain that way for many years to come. However, where's there a machine to read them?!

That's the destiny of all the electronic data storage media we use today --- CD-ROM, DVD, flash memory, hard disk, etc. Remember 8" floppy disks?

The advantage of punch cards is that a human being is able to read and transcribe data from them.

Zvi,

Good point. Still some things last. The most common Rail Road track widths comply with Roman chariot widths. Both the CD and DVD read/writers comply with the width on the obsolete 5.25" floppy drive. ASCII text is still easily read and I suspect bit map and compressed bit map jpg files will continue to be a lowest common denominator for decades to come. I would use file formats that are the lowest common denominator to put in my time capsule.

I use HDs to store my archives other than some information I highly prize. I have some old DOS utilities that I have but rarely use that are 20+ yrs old.

Spoke to a Customer of mine yesterday that kinda put this all in another perspective.....

He told me he figured ours was the LAST generation to tape anything.....

Today - no more 8-track tape, cassette tape, video tape (beta/VHS), even include magnetic media like floppy disk......

All now is completly digital

NEXT........

From the Voyager Program Wiki page:

The Flight Data Subsystem (FDS) and a single eight-track digital tape recorder (DTR) provide the data handling functions.

As V'ger leaves the solar system...

Hooker

The subject of digital conversion and storage of information has occurred often on CR4.

Reading the comments about 100 year lifetimes for writable CDs/DVDs... this concern seems to make sense in a couple of instances, the primary one being photographs. But then again, not really. If one is handing down digital photographs to children and grandchildren, it would be up to the recipients to keep the data in a form that is current and secure. Even if technology doesn't change much, it would be prudent to rewrite the data to new discs (or HDs, if they exist long into the future). And this responsibility is on the holder of the data.

The observation that photos and ancient scrolls survive beyond 100 years does incline one to view hard/paper copies as being a real "backup," in addition to magnetic/optical digitized storage. In any case, they are the originals. Paper aging has its own issues and certain precautions have to be heeded for long-term storage. (And who knows, film-based photos may become very valuable at some point in the future.) It's why many who own a substantial number of books prefer them to digital copies. If I could get digital copies of all the books I own (which I can't, and not just because of cost... too many out-of-print items), I'd still want the physical copies as the true backup. I was given a Kindle a couple of years ago and put a lot of PDF "books" I've downloaded over the years on it and the size shrunk too small to read comfortably. I prefer a physical paper copy of a book to read. Ever notice the odor in a library? There's something about it that is appealing -- at least to book enthusiasts. Maybe someday, that odor will be embedded into eReader cases.

I do use the Kindle for storing PDF versions of spreadsheet "catalogs" of books, CDs and videos that I own. For years I wanted to have portable versions of these lists when I shopped to keep from duplicating what I already owned. The Kindle serves that need now. But reading on it?... rarely.

I strongly agree that I prefer hard cover books to digital media. But, that smell at the library is mold....I had a friend who worked in a library archive and her job was to go through every book and spray the pages of museum books for bacteria...harmful to humans. She did this with the oldest books on record. It didn't damage the books in any way, but it made it safe to read them after so many years. Since there is no "perfect" media, we attempt to create new ones, while paper is still, I believe, the best media ever invented. Atmospheric changes will affect any media, no matter what it is. Flood and fire have destroyed some of my prized books, along with CD's, DVD's, tapes and you-name-it. Very little survives "forever". Unless it's carved in stone, it will have it's flaws. keep in mind that stone, too, erodes from wind and water, but it takes a heck of a long time to do it. Constantly backing up on different types of media can be mind-boggling and time wasting. I'm going with the "pick up and run" external hard drives in the case of another home disaster!

Yes, I too, know the heartache of losses due to flooding.

I wasn't suggesting becoming obsessive with backups (I'm actually pretty lame, and on the other end of that scale in that regard, knowing I'll regret it when the next HD crashes). And, yes, the external TB HDs are what I'm using for backups -- if I'd only become regular about it. I'm not sure I'd think about picking them up and running in case of a fire. When our home flooded in 1994, despite the fact that we had a couple of hours to try to get things up off the floor before the water got too high, I still overlooked the hall closet and lost manuals for electronics that I haven't been able to replace. Keeping copies of data in multiple locations (not just offline at home) is prudent. Again, I'm so so good about it.

... oh, I almost forgot the odor issue. It may be mold, but it is distinctly a library smell, and therefore, recalls that setting.

Reading through this thread, I'm reminded that I am the repository if pictures-albums, loose pix and slides of at least four of my older relatives. Alas, most of them aren't labeled, and even those that are? Who is "Cousin Johnny"? I'm the last of my line what happens to this stuff when I die? Years ago, I salvaged a case of slides that had been donated to a local library, then thrown out. They were travel mementoes and included pix taken om the 'Andrea Doria" (Anyone else remember that one?) Bottom line: A great deal of our data is ephemeral, and not just because of the storage media.

I have wondered what will happen to storage in the cloud when the person dies or quits paying the fee.

The observation that photos and ancient scrolls survive beyond 100 years does incline one to view hard/paper copies as being a real "backup," in addition to magnetic/optical digitized storage

The Dead Sea scrolls were written on sheep's skin. By the time, they were discovered they had crumbled into pieces some almost the size of confetti. Because each page was from a different animal, DNA was used to separate the pile into pages. Then the archeologists put the jig-saw puzzles (pages) together. Even though they appear whole now, I wouldn't say they really survived.

I have a page from an account book that is over 300 yrs old. That does not mean what you print out today will last that long. The paper process is completely different. Paper used to be mostly linin then cotton before paper was made from wood pulp. I have hi-acid content news clippings that are over 100 yrs old. I assure you they will not be around next century. The scrapbook they were kept in, also hi-acid is falling apart. I had to cut the clippings and photos out of it because everything was brittle. The acid even attacked the photos. All my old documents and photos have been scanned, put on CDs and distributed to family members. The originals are in archival folders to slow decomposition.

There is not much that stands up to fire; pressed CDs ought to withstand a flood. Burned ones might not since they are much more fragile. All my tapes, vinyl records have been digitized and my CDs are all ripped. It all fits on one hard disk. I DO 'constantly' back up my magnetic media. In the past I have done so every few (3-4) years. I do not find that very taxing. I use heavy-duty external boxes that I can put internal drives into. Knock on wood, I have had no failures with the heavy duty box. When I bought them external disks usually died within a year. At least that was the expectancy of whatever my friends were buying. The boxes come with an eSATA as well as a USB connection. If the USB connection is used I can turn off the drive and switch HDs any time I want. I have 2 of these boxes. I only use the eSATA connections if I am going to load or copy a disk. I have a stack of HDs in hibernation. Because they are large and still contemporary and because the disks are often dormant I will extend the time between copy sessions a few more years until those drives start to become obsolete. By them they will probably all fit on one drive.

It would be prudent to copy optical media. I do not believe any DVD will last a century. I actually read the full version of the government study. The report I read was about CDs not DVDs. The test took place years ago. The dyes allow faster burning now and are much less stable. The burner used in the test listed for $500 when my DVD burner, an excellent cheap one cost $60. I have seen a particular brand and probably version die in about 5 years even though it was kept in optimum conditions. I suspect they may still be readable by a Plextor drive. All my 10 yr old DVDs are showing signs of age. The dye is not the same hue as when it was fresh burned and some look like they have 'cracks' in the dye. I think these 'very old' DVDs are more robust because both the dye was slow and burned at 1X. Because DVDs were so expensive back then I bought only 'unbranded' blanks of dubious quality. These 2x and 4x unbranded disks age more gracefully than all but maybe the Verbatims. These brands include Fugi which I rate second best, memorix, Sony and some also rans. I intend to copy all within a few years starting with the Sony disks that are failing now. These will be stored on hard disks as images. Verbatim DVDs seem to age the slowest. That is all I use now.

I doubt that I would remember to remove the HDs in a fire. Likely we would be saving the family jewels if anything. We did have a fire and we didn't think to take anything. I concentrated on retarding the fire. Apparently, a cloths drier catching fire in the basement is a 3 alarm fire in our town. Apparently, empting even a small A/B extinguisher into the drier and the shutting all the doors was effective enough. After that it only smoked. The fire inspector told me that prevented the house from burning down.

Bluebelly

You can post a family tree with the embedded photos up on ancestry. They will last for quite some time there. They realize the value of free quality information.

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