Been there. Seen it. It seems paper or tyvek is the way to store these things. But the question is in 2023 why are you still committing data to optical media? I dumped all my cds and dvds on to magnetic storage years ago. I got burned waiting as long as I did even. Some of the old spinning cd cleaner/restorers used an abrasive slurry. The last one I bought (Onn) only has a cleaner afaik. You'll want to clean the disks thoroughly. Then try a "cleaning" solution that's more aggressive. My old cd cleaner would leave circular scratches on the disk. But it was readable after that. In 1 instance (then I lost it). Such an approach should be a last resort though. Don't just rely on Mac/Windoze facilities for reading stubborn disks. There are programs that work better if you search.

Don't know, don't care. If we're being attacked by nuclear bombs of any stripe, I have far more humongous things to worry about then what's on my hard drives. I suppose if you were wring a book and wanted to back that up to an optical disk, go for it. On Monday, January 16, 2023, 09:04:48 PM EST, Ryan de Laplante via cctalk <cctalk(a)classiccmp.org> wrote: What about M-DISC DVDs and BluRays?  Archival grade, not susceptible to magnetism or EMP.  I think BluRay discs are made of a harder material than DVDs and don’t scratch as easily.

The only answer that anyone can provide is redundancy. Keep 2 or 3 copies of everything on seperate external drives. Every 3 to 5 years buy new drives and transfer the data to them. Or just run checkdisk twice a year and wait for 1 drive to start popping errors. Replace it. Wait for other to fail. Then replace it. No one can tell you how long a single media will last as you pointed out. You can only rely on making periodic reliable backups. There's also the issue of practicality. Burning disks is laborious. If they're big disks, it's not as laborious (I guess). Much maintenance and replacement of hard drives can be done unattended. But be careful with that as Windows gets lazy and will quit if you try to transfer too much data at a single time. Cost wise I don't think magnetic backups is much different from any other. On Monday, January 16, 2023, 09:48:17 PM EST, Fred Cisin via cctalk <cctalk(a)classiccmp.org> wrote: to magnetism or EMP.  I think BluRay discs are made of a harder material than DVDs and don’t scratch as easily. On Tue, 17 Jan 2023, Chris via cctalk wrote: I care, and would like to know more. Even without nuclear bombs, which I stopped worrying about 60 years ago, I have occasionally had to deal with damaged data, from causes much more mundane than EMPs. I have had magnetic, AND optical media that have "gone bad". I am interested in whatever media are more likely to still be readable in a few decades. M-Disc claims 100 year life, but, obviously, no M-Disc has lasted that long, and they are making promises based on what they THINK will happen. M-Disc BDXL is currently available in 100GB per platter. -- Grumpy Ol' Fred            cisin(a)xenosoft.com

You have to make the best of what you have to work with needless to say. Are you making arguments im favor of long term optical storage? It doesn't seem so, but if you were, you lost me. On Tuesday, January 17, 2023, 05:32:33 AM EST, Peter Corlett via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: On Tue, Jan 17, 2023 at 05:42:55AM +0000, Chris via cctalk wrote: [...] If you mean CHKDSK.EXE, it's broadly equivalent to Unix fsck plus a surface scan, and all fsck does is check and repair filesystem _metadata_. If the metadata is corrupt then that's a good sign that the data itself is also toast, but a successful verification of the metadata does not tell you anything useful about the data itself. The surface scan asks the drive to read each sector, and relies on the disk correctly identifying sectors which have changed from when they were written. This is almost always the case, but that "< 1 in 10¹⁴" in the datasheet is still not zero. And that's before we consider dodgy SATA cables and buggy disk controllers. (SAS won't save you either: what it gives in increased quality, it takes away in extra complexity.) On typical Windows desktop computers, the probability that something else will go wrong and destroy the system is way higher than the raw error rate of the disk, but on non-toy systems with many tens or hundreds of terabytes of data, the probability of a disk lying rises uncomfortably-close to 1. A good filesystem needs to defend against disks which do that. FAT and NTFS are not good filesystems by that measure.

On Mon, Jan 16, 2023 at 06:48:11PM -0800, Fred Cisin via cctalk wrote: ... Acid free paper. -- db(a)FreeBSD.org db(a)db.net http://www.db.net/~db @Dianora@Octodon.social

In the early days of this list (think back 25 years), I believe it was Tim Shoppa that was recommending either Gold CD-R blanks, or Verbatim DataLifePlus. If I remember correctly, he’d done some aging tests on them, and they were the two that held up well. As a result, I standardized on Verbatim DataLifePlus for any CD’s I expected to be reading after a year. I’ve read ones from 1997 without problem. In fact I think I’ve only had a couple minor issues. One of the disks I read had to be washed before I could even attempt it as it has been sitting out bare. What has surprised me is the results from the floppies, mostly stored in the garage for the last 15 years, and before that, I don’t remember. Granted I tended to go with higher quality floppies, but still, I’ve expected a lot more issues than I’ve had. Some of the 3.5” floppies I’ve read date back to 1987 or 88. Mind you I’ve not tried to recover data from 5.25” floppies yet, I’m still trying to find those, and a big drawer/box of 3.5” floppies. Zane

Not SSD, that's for sure. The fact those are becoming the predominant storage medium is a bit of a concern for long term storage, because SSD is entirely unfit for that job. Apparently they are ok when powered because the firmware will refresh the bits from time to time, but you can't put an SSD on the shelf and still expect its data to be good a decade later, as you can with hard drives. With hard drives you have to worry about mechanical faults, of course. I wonder if there are any long term storage issues with the bearings. Most likely, the biggest issue with old storage devices is the loss of the device to connect them to, and/or the loss of the code that reads them. To pick one example, I have an 1990s era Dell laptop that no longer passes POST (it gives a "beep code" failure that I haven't been able to cure). I would like to get whatever is on its hard disk, but that has a proprietary interface as far as I can tell and I have nothing to plug it into. I have an RM03 pack somewhere. There probably are a few places left that could read it. If it were an RA60 pack it would be a whole lot more problematic, I suspect. Without an old drive, how would you recover the data? Spin table? Perhaps, if you can find, or reverse engineer, the format. The Long Now foundation has done work on the question of storing data in a way that can still be deciphered a millennium from now. It's not a simple question. Some SF writers have wrapped stories around the question (James P. Hogan did it several times -- Echoes of an Alien Sky, Inherit the Stars, and much earlier (1957) there was H. Beam Piper "Omnilingual"). Early storage devices are less problematic than newer ones, given the more and more complex coding used. Never mind intentional encryption; just the high density codes with interleaving and ECC and all that would be somewhat akin to encryption when examined with a future archeologist. Imagine, for example, an archeologist 5 centures from now trying to make sense out of a box full of SATA interface hard drives, full of documents in PDF, JPG, or MP4 format. paul

On 1/17/2023 7:54 AM, Paul Koning via cctalk wrote: My understanding is that it is a good idea to plug the hard drives in once in a while just to get them rotating for a moment to keep the bearings lubricated or whatever. So far, so good on all my backups but I am a bit bad about doing that.  I use 2 backups at least but some of the more important stuff I use 3. There used to be a program that would read the disk and write the bits back to freshen up their magnetic domains. That might have been "Spinwriter" ? boB

Yes, and the higher density, and the fact that the on-disk format is more complex and unlikely to be documented in any open documentation. paul

On Mon, Jan 16, 2023 at 9:48 PM Fred Cisin via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: LTO tape, properly stored, is advertised as having a 30 year lifetime. Of course tape isn't particularly convenient for ad-hoc access so my archival strategy is to dump things to a file server with a *lot* of disk space (RAID1 or RAID10, not RAID0 or RAID4/RAID5), then regularly back up that server to LTO tape. The current generation (LTO8) is very expensive so I use LTO4 and LTO6 tapes which are comparatively very affordable. The data doesn't tend to change but taking repeated backups anyway helps to ensure that silent bit-rot on the hard disks is detected early enough to be correctible. Having backups on tape also has the advantage that the tapes are easily moved off-site, so a fire or other such disaster won't take out my server and my backups both at once. There is another significant advantage to focusing on a backup strategy as opposed to an archival strategy -- I don't need to worry about tapes I made today being readable decades in the future (i.e. I don't need to worry about keeping legacy tape drives running). The file server is the "archive" and I only *need* to be able to read the tapes I made last year or last month. If a tape drive fails I can just get another one, and if they become hard to get there's nothing stopping me from upgrading to something newer with better availability (i.e. I don't have a library of old media that I need to be able to read forever). The disadvantage of course is that a file server isn't something you can reasonably put in storage for future generations to access. This strategy really only works if the file server is accessed frequently so that accessibility/compatibility issues can be fixed incrementally as they happen (while they are still easily addressed using current/recent technology). -ken

But then you're dealing with stored media, and their shelf life. USB hard drives may be ok so long as USB interfaces are available; if they are USB SSDs that's a different matter entirely. Those would not be good for a decade on the shelf. One advantage of setting up a server is that it's more obvious that something has failed. If a disk on the shelf goes bad, you may not discover it for years, and by then the recovery may be quite hard. paul

A take (mine) on the backup/archiving problem is that any medium that is used for this purpose will eventually be rendered obsolete and possibly unusable without going to extreme measures. My solution is to use whatever (economical) hard disk device has the most capacity and store stuff there along with some metadata where possible for about 6 years and then upgrade to something new. In this case, because hard disk capacity is still growing, replacing 1 TB disks with 4 Tb in a triple mirror raid. I use a synology 4 disk bay with 4 tb disks that is configured as 4 mirrors. In 6 years or so i’ll upgrade to something like that that’s newer with bigger drives like 8 - 12 TB (might be bigger, but depends upon cost) . This is the best solution, both affordable and redundant that i currently can come up with. I think computers will continue to use disks( and thus be supported) for the rest of my lifetime so I’m reasonably happy. Sent from my iPhone

Yeah, but can you read them? Sent from my iPhone

And the Rosetta Disk is a new construct along the same lines. However, neither is a computer storage device. Creating something that can be used as a computer storage device and still be good a century ago is a harder problem than designing a storage device that can be accessed by human eyeballs. paul

Old stuff being preserved is often a matter of chance or luck rather than planning. Consider the Linear B clay tablets; those were preserved because they were accidentally baked, in the fires that were set when the city was sacked. Papyrus documents were preserved in Egypt because it's desert, but not in other places that aren't quite so dry. As some civil engineer put it, it's not that the old timers built so much better allowing us to see the buildings they put up centuries ago -- rather, the buildings that are still there for us to see are the ones that happened to be strong enough. Sometimes just barely so, like the cathedral in Utrecht (the Netherlands) -- part of it blew down in a storm centures ago, but about 3/4 of it didn't and is still good today. paul

Nice idea and a very good point. You have to deal with a number of compatibility issues but they are all short range. The backups is one aspect. Another is the file server protocol. If your server uses NFS V2, some hosts can use it but others may not. And the hardware on which it runs might fail. For these last two cases you'd have to stand up a newer file server, and in the case of server failure you'd have to be able to load the new server with the old data. Depending on the backup media that might be problematic. I suppose for both of those issues the answer is to bring up newer file servers ahead of time, as they become available. You still have to deal with the question of how old format documents would be read. If the formats are proprietary and no longer supported that's a problem. For example, I have some old Eagle CAD files that are no longer readable. And some old CorelDraw files that are also difficult, though I think I can still get there via intermediate old versions of the software on a VM. And I have an old CPLD designed in Abel HDL; if that ever needs modification I'm going to be in trouble. paul

On Jan 16, 2023, at 5:11 PM, Chris via cctalk &lt;cctalk(a)classiccmp.org&gt; wrote: Thankfully most of the disks that I’ve imaged that don’t have jewel cases, are in paper sleeves. Or even worse, a few have been loose. It looks like this may be the main CD impacted. It looks like most of I used these accursed sleeves for are DVD-R’s from nearly 20 years ago, that I don’t care about. I’m recovering CD’s and Floppies at this point, not burning, though I will probably see about burning these onto an M-Disc. Zane