A couple of days ago I was playing a CD I had made at FYE’s Mix and Burn. Wonderful company. They will burn any song that you want on CD, as they have a large collection of songs. Anyways, I noticed the CD had lumps on the back. That would be odd if it was damaged, because I had just played it moments before.
Anyway that got me to thinking. How long do CD’s and DVD’s last? They are made of plastic. And plastic lasts for thousands of years. This is an important question. Because this might be the way information is passed onto the future. And as you know, books just don’t last. Now, they are made of wood pulp. And the acid they use to break down the fiber ultimately eats away at the book. (Ironically books used to be made of cloth fiber, which lasts forever.)
And as long as we’re talking about it, what about the internet? I have heard that lasts forever too. Will what we write on the internet be here a hundred years from now? What about a hundred? I surely can’t be the first person to wonder this.
The internet is by definition a network, not just a set of files. There is a shitload of redundancy and a lot of cached information. (Go spend a day in the Wayback Machine, for example). It is likely that as the cost of storage continues to shrink and the digital storage capacity of the species continues to grow that most of what you think of as the internet will be preserved in some fashion. Not guaranteed. Do you have all the files you had on your first computer? Many people don’t. I do, or at least I do for the most part. They don’t take up much space, so why not?
CDs and DVDs aren’t forever, or even as long as their plastic. They deteriorate. But they probably last at least as long as hard disks and floppies.
As long as whomever has your data that you are worried about is functional and competent, indefinitely. Backups and maintenance are an ongoing thing. It was a major part of my job as a datacenter tech to replace hard drives as they failed, do backups, and restore from backups after catastrophic failure. Not to mention we had multiple mirror sites across the country to hedge against a major disaster that could wipe us (or them) out entirely.
There isn’t. Almost everything that has ever been put on the Internet is already lost forever. Once your company decides it doesn’t want to host www.yyy.zzz and pulls it down, it’s gone. Maybe some parts of whatever static html and jpg files are still being used in 2021 are at the Wayback Machine, but most likely they’re not, and anything actually functional isn’t captured there even if they do crawl the website in question.
There’s absolutely no comparison between issuing a million or even a few thousand DVDs of something, which all but guarantees a working copy will survive somewhere [especially since there are multiple professional libraries archiving them], and a file on a central web server that is gone once it’s gone. All the redundancy designed to keep the website working while it’s actively being maintained is irrelevant once that point is passed.
Among the manufacturers that have done testing, there is consensus that, under recommended storage conditions, CD-R, DVD-R, and DVD+R discs should have a life expectancy of 100 to 200 years or more; CD-RW, DVD-RW, DVD+RW, and DVD-RAM discs should have a life expectancy of 25 years or more. Little information is available for CD-ROM and DVD-ROM discs (including audio and video), resulting in an increased level of uncertainty for their life expectancy. Expectations vary from 20 to 100 years for these discs.
Note that these are when stored in the recommended conditions. Disk rot, as mentioned above is definitely a thing. And discs can wind up damaged beyond repair–though often you can fix scratches, especially if you then just copy the data on the disc.
As for hard drives and stuff: both tend to be warranted around 10 years. But it’s expected you’ll keep copying the data.
Personally, I recommend online backup. I use Backblaze, as it’s cheap and unlimited on a per-computer basis. But you can look into other options, too. I pay extra to make sure they keep my data for at least a year if anything happens to my data.
(If you wonder how they keep it safe: they use mirroring and stuff to store the data in more than one place at any given time. It’s also encrypted, so they can’t actually read said data.)
I have some CDs I bought from Columbia House in the early 90s that still play just fine.
Also, I have a bunched of ripped CDs that I made nearly 20 years ago that for the most part still play fine as well (at the time I was a broke college student, so my primary method of acquiring new music was ripping my friends’ CD collections). The only ones I’ve had any real issues with are generic or off-brand discs, which tended to skip or become unplayable after only 2 or 3 years. But the more well-known brands, like Sony, Memorex, Verbatim, etc., have held up really well.
Not all CD/DVDs age the same, due to the different chemical composition, I suppose. Same is true of recording tape. Leave a CD/DVD out in the sun (or even room light) for long enough, and it will change color and become unreadable. I know; I tried it.
While this is true of the ones you burn, it is not true of commercial disks, since they are not altered by light, but pressed.
The moral of the story is – to best preserve your precious memories, store your disks in a dark place that doesn’t get too hot. The enemies (as of so many things) are heat, light, and air.
There are factors that can probably vastly accelerate the degradation of optical media. I bought a DIY CNC kit a couple of years back; it included a couple of small mini CDRs - I remember checking them and one had some installers on it, the other had some gcode files.
I put them back in the box and forgot all about the kit for a couple of years. When I came to assemble the kit after that time, the discs were unreadable - you could still see the area where data had been written, but they would not read at all (using the same drive).
My guess is that volatiles outgassing from new plastic components and packaging in the kit affected the media.
The “internet”, by which you presumably mean some form of networked global digital communication will presumably last as long as some form of advanced civilization lasts. The internet is different from a specific media like CDs or DVDs in that it is not just one thing that can break or be turned off. It’s a bit of a “ship of Theseus” in that its components are constantly being replaced, backed up, upgraded, etc.
CD/DVDs created by a disk burner/writer use various forms of dyes to hold the information. These don’t last long, and as noted, leave one in the sun and the dyes are swiftly bleached. Disks that are manufactured by commercial pressing plants to be distributed in their thousands are made with a very different process. These encode the information as physical pits in a plastic substrate. These are aluminised and covered with a layer of lacquer. Degradation there comes about because the aluminium layer degrades. Entry of water from the edge of the disk is one issue. The earliest disks pressed the pits into the thick later of the disk in a manner similar to pressing a vinyl recording. This was expensive. Later a process whereby a thin sheet fed from a roll was pressed and then laminated became the standard. This process is less robust than the initial process, possibly because the lamination goes right to the edge and there is a join where water can creep in over time. In principle, if you really wanted too, you could probably recover the data on a very old CD by stripping off the lacquer and re-applying the aluminium layer. The pits won’t degrade even if the aluminium corrodes.
I have CDs from the early 80’s that play perfectly. The expected lifetime when the CD was first introduced was much less.
The principle for data archive is to simply keep copying your data to new media. This has proven easy as the density of storage has continued to improve so fast that archiving your ten year old data in its entirety only takes up a small corner of your current storage. This will obviously eventually cease to work, but for now it still does.
The problem with the internet is as described above. Almost all of the data you see is dynamically served. Back in the early days of the WWW everything was static pages of html. It was worthwhile running web caches in any large organisation. These made a huge dent in what was then often quite costly network charges. Nowadays it is a waste of time. So much is dynamically served that caches get no traction. Which means a lot of the data on the WWW is very volatile. If you don’t preserve it, nobody else can or will.
" Among the manufacturers that have done testing, there is consensus that, under recommended storage conditions , CD -R, DVD-R, and DVD+R discs should have a life expectancy of 100 to 200 years or more; CD -RW, DVD-RW, DVD+RW, and DVD-RAM discs should have a life expectancy of 25 years or more."
That’s a long time, and the shit only needs to hit the fan once to negate that.
I guess it’s “True Confessions” time because I do keep hard disc copies of everything I have. I only update them every six months, but I have them just in case something really, REALLY bad happens.
There have been several mentions of plastic degradation, scuffing and such; also I heard early on about CDs that no medium can provide a perfect airtight seal forever-- everything is slightly porous to some degree, including the plastic that contains the aluminum encoded part. So, the theory went, no matter how carefully you handle your CDs and store them in climate-controlled environments, eventually oxygen will work its way into the encoded layer, oxidize it, and render the CD unusable. So it’s not a way to archive recordings for hundreds of years, however careful you are. I should look for my first CDs I ever bought and see if they still work.
Incidentally when I saw the post title I assumed it meant “How long will CDs and DVDs last as a commercial medium?” In that sense, I’ve been subscribed to a music service for probably a couple years now, and can’t remember the last time I handled a CD. As for DVDs, we used to check out free movie or TV series DVDs from the local library until the lockdown; now we get our audiovisual entertainment strictly through streaming services.
I still play CDs I bought in the 80s. They’re pretty resilient.
But the recordable CDs weren’t. None of those lasted much more than a decade for me. Far less if stored in a car.
Yes. I have some beautiful, professionally-made CDs from the early 1990s or maybe even the late 80’s. By “beautiful” I mean they look good and have smooth, polished edges, unlike most CDs that have come out since then. The CDs work fine.
The packaging they came in, not so great. There used to be foam inserts to keep the CDs from rubbing against each other in shipping, this being a multi-pack of CDs in one plastic enclosure, e.g. for an opera. Being the perfectionist I am, I kept those inserts…and years later they deteriorated. Gross, crumbly yuck. But the CDs were fine.
I’m embarrassed to say I can’t find a description of the laminated CD production. I certainly didn’t imagine it, but I read about it quite some time ago when CDs were at their peak. Makes me wonder if flaws in the design did not subsequently kill it off again. CDs are now manufactured in smaller numbers and maybe improvements in pressing has made that process the default again.
Video of the original process. Pits are etched into the glass master, used to press the main body of the CD.
