5 ms·
This is all well-and-good, but how do we read all that data in 500 years time, or even 20 years time? People were busily archiving data to CDs and DVDs two dec
by mattowen_uk 5y ago
This is all well-and-good, but how do we read all that data in 500 years time, or even 20 years time?
People were busily archiving data to CDs and DVDs two decades ago, thinking 'yeah this digital storage media will last for centuries!'... Loads of bit-rot combined with complete lack of DVD drives still in common [computer] usage, has totally shown that the more complex the storage media the shorter it's useful lifetime is. Compare this to books, which can still be read a millennium later.
- 0des 5y agoLet's not forget actual rot too. I peered into a stack of CD's not long ago to find that a lot of them have quite literally rotted while sitting in a dark and dry closet. No dust, no humidity, no smoking, no abuse, just a spindle of CD's recognizable only by their sharpie'd identifiers covered in pits of rotted foil.
- throwaway946513 5y agoTemperature? I've yet to experience rot on decades old discs at home. Most sit in a basement that doesn't exceed 68*F
- 0des 5y agoA constant 72F, this is an indoor closet, top shelf, no moisture incidents.
- MivLives 5y agoIt's a well known problem: https://en.wikipedia.org/wiki/Disc_rot https://en.wikipedia.org/wiki/Disc_rot
- TacticalCoder 5y agoYup it's a well-known problem, but several of us still have CDs decades old that still do read totally fine. That doesn't mean we rely on them as backups: mine have long since been copied to DVDs, then more recent DVDs but also backup'ed on harddrive / servers etc.
- rbanffy 5y agoCDs and DVDs are pressed. Recordable media is not and, with the wrong conditions, will rot. DVD-RWs will get corrupted if you look funny at them.
- mixmastamyk 5y agoI still have music CDs from 1985 and CD-R from 1995 in perfect condition. None of them have gone bad.
- throwaway946513 5y agoThe linked article also explains: > DVDs are more resistant to rot > DVDs and CDs use aluminum layers for the reflective 'data encoded' layer > Discs using a gold layer are extremely resistant to corrosion and thus disc rot > Blu-ray discs use a silver-alloy for their reflective layer. Though not linked, or stated, it is quite likely that the BR discs are significantly less likely to be damaged due to disc rot for similar reasons as gold-layered discs are, though not necessarily as resistant as gold. Disc rot though appears to stem due to the damage of the lacquer or plastic layer on discs, which if the disc then remains undamaged, it should not be as susceptible to rot.
- cogman10 5y agoWe are mostly talking about burnt discs which achieve their burning via chemical reactions with light. Those disks rot. Any standard Blu-ray/DVD/CD you have has no rotting as it's simply pressed.
- adrian_b 5y agoWhile the pressed discs should have a longer life, there are some where the metallic mirror oxidizes in time and it becomes partially transparent, which results in reading errors. The oxidation speed depends on the quality of the lacquer that protects the mirror (on the label side), so it varies greatly between manufacturers. As an end-user, you cannot predict the lifetime, you can just hope for the best. There have been archival CDs, with gold used for the mirror instead of aluminum. Those were immune to oxidation, but they have been discontinued, due to high cost.
- Sosh101 5y agoSame - maybe something oxidised.
- vel0city 5y agoRegular CD's and DVD's have an organic layer that will rot away. There are alternative styles of discs which use a ceramic layer instead of organic which are rated to last a thousand years. These discs can still be burned and read in most standard burners and readers. https://www.mdisc.com/ https://www.mdisc.com/
- MisterTea 5y ago> This is all well-and-good, but how do we read all that data in 500 years time, or even 20 years time? If the data is important enough, we'll find a way. Perhaps by then camera phones will have sensors with quantum resolution that can capture the optical pits in one snap and use AI or whatever to reconstruct the bits from the image on whatever magical storage exists.
- bufferoverflow 5y agoThere's no lack of DVD drives, they are widely available on Amazon, BestBuy, eBay.
- kipchak 5y agoI think right now the most permanent way to store digital data is have enough redundant copies on enough impermanent media one is likely to survive. For example my CD copy of 1998's HARDWAR might be lost due to disk rot, but there's enough copies of copies of copies floating around on various places it's still easily accessible.
- TacticalCoder 5y ago> This is all well-and-good, but how do we read all that data in 500 years time, or even 20 years time? I know it won't last due to bit-rot but all my CDs burned in the nineties are still readable. > Loads of bit-rot combined with complete lack of DVD drives still in common [computer] usage... They are still very common: both in desktop and as USB-connected readers/burners. You can find countless models on Amazon. I don't think they're going away anytime soon. > People were busily archiving data to CDs and DVDs two decades ago, ... That's precisely why they're not going away anytime soon. There are even companies like FB would, at some point, were burning insane amount of data to Blu-Ray discs. > Compare this to books, which can still be read a millennium later. Having a book from 1575 here I do agree (not quite a millenium but still). However the solution to disc bit-rot is simple: once every ten years or so, read your discs and burn them on the new fancy tech of the day (say CDs to DVDs, DVDs to Blu-Ray, now Blu-Ray to these 5D thinggies, rinse and repeat). It's not as if new mediums had less capacity than older ones.
- nomel 5y ago> I know it won't last due to bit-rot but all my CDs burned in the nineties are still readable. Were these the more expensive archival disks? I lost all ~50 of my old CDs and DVDs to rot, within 10 years. They were middle range Memorex.
- GhettoComputers 5y agoWhat kind of data is even worth storing? If it’s text based it’s not hard and it’s not very large. If it’s media it’s probably some uncompressed videos and pictures that are overly large, phones that take 16mb photos that aren’t going to have more useful information over compressing it to 400kb. I am sick of my phone taking large photos that don’t have any clear benefit to me aside from clogging my phone with unreasonably large files that don’t look better, Apple wants to sell me iCloud by not allowing me to take lower resolution images.
- vel0city 5y agoOptical drives aren't common in most consumer devices but that isn't really a hurdle if you're trying to recover archived data on optical media. If you're only worried about DVDs a USB DVD drive can easily be had for ~$20. Blu-Ray drives aren't very expensive, I included one in my last desktop build for the purpose of data archival. Many consumers figured optical disks would last a long time but many knew about disc rot from the get go. I picked optical media that marketed itself as archive quality. My oldest discs are reaching 20 years old now and I've lost less than 10% of the discs I've burned that were burned on good discs. These days I burn data to M-DISCs which use a ceramic layer instead of organic. They're rated to 1000 years and the Blu-Rays are quite durable. I've had one bouncing around my desk and outside for several years. The one on my desk has zero errors while the one outside has a few bit errors.
- wazoox 5y agoSome guys I know propose a storage on 35mm-film solution that looks pretty foolproof for a couple of centuries at least. https://digifilm-corp.com/preserve-your-works-for-eternity https://digifilm-corp.com/preserve-your-works-for-eternity To read back the data, you need something to digitize the film (a flatbed scanner would work, I've tried, or probably even a smartphone with a a DIY magnifier), then something to decode the data (the necessary source code is provided in clear on the first images of each roll).
- nomel 5y agoI'm having trouble finding the data density. How many lbs of film/GB?
- wazoox 5y agoIt's not very dense at the moment, around 600KB per frame IIRC, with lots of redundancy and while staying really easy to read even with DIY hardware. They think they should be able to cram about 2MB per frame without compromising durability and without any compression (but lots of in-picture redundancy). That should give about 200 GB per roll of film (the large ones).
- rbanffy 5y agoIt all depends on how technology changes. We can still read floppies written in the 70s with essentially a motor, something magnetic and a wire going around it (and a computer reading the currents). I’m pretty sure we’ll know how to cobble together an optical microscope and camera device to read at least one bit out of every volume cell. Let’s just hope the data format is simple enough.
- louwrentius 5y agoArchiving data is a process, not a one-time effort. You can't just store data on a medium and hope if that medium will last. You have to periodically check for defects and from time to time, transfer data to fresh media. At some point, you may even need to convert the data to keep it readable...