OT very long term data storage

Exactly for this reason data should be copied to an up to date format every 5 to 10 years. This requires a somewhat organized society for at least a decade or two.

While cultures and nations rise and fall, there should be at least some organized society for a century. Combined civilized societies have existed for at least for some thousand years somewhere on earth. Except for a total nuclear war, I would expect this to continue.

Regarding various formats, I have several 5.25" drives, one in a computer with NT 3.51, although I haven't booted it this year.

I assume PPT means paper tape. Who needs a reader for paper tape or punched cards, the Mark I eyeball is perfectly sufficient for that. For faster reading, put the paper tape or punched card on a flatbed scanner.

Regarding 1/2" magtapes, it is surprising how this once very popular format disappeared so quickly. I know of a single operational station in my country in a museum.

The interesting thing about 9 track magtapes is that recovery of 800 BPI and lower densities is harder, since you would have to align the reading tape drive for each writing head angle.

For densities 1600 BPI and above, each tracks are self clocking, so the read/write angle doesn't matter.

At least for me, the storage capacity increases faster that I can fill. Every time I buy a new computer, I copy the full disks of previous computers into a small segment of the new computer. There is no need to do the selection, simply copy everything.

(snip)

That was always true, even when they were new.

I used to write files on them, take them down to school, and have a real hard time reading them.

-- glen

A society that has the *resources* and *capabilities* and *motivation* to undertake that prolonged operation. If you're trying to stay alive, you are probably not too interested in preserving the contents of some book/manuscript/database that isn't directly pertinent to your own survival.

Can you spell "Dark Ages"? Plague? What about hostilities (without resorting to overt warfare) between owners of key resources and those folks *needing* those resources (e.g., semi-precious metals) to maintain their technology? It doesn't take much to represent a disruptive event in our increasingly complex societies.

I have a pair of 5.25" drives (in a Compaq 386 portable/lunchbox) that sees very little use. I imagine, sooner or later, that some piece of plastic or rubber will dry out and render the drive inoperable. E.g., the 3.5" floppies in some of my SPARCstations needed to be periodically "serviced" to keep the machines bootable (from floppies).

My 8" floppy is in storage. No idea as to its operational state (though it was put into storage "brand new"). I have one machine that is capable of talking directly to it (and understanding the associated formats encountered)

I have many different (cartridge) tape/disk media and drives, magnetic, optical, etc. A few years ago I discarded my laser video disc (e.g., 12" media) writer. Many of the tape devices have been making their way to the recycler in dribs and drabs as I am sure I've transcribed any data residing on copies of those media.

How many spare lamps do you have for your scanner? Belts? Operating system? Drivers? etc.

I discarded my last 9T a few years ago -- though I probably still have a few dozen reels of data (that I migrated to WORM at that time). Again, lots of little rubber and plastic pieces that age with disproportionate consequences wrt operability.

OTOH, you can "develop" low density tapes and read the data optically.

But we're not talking about individuals; rather, societies/cultures.

*Your* data is probably not going to be of help to someone wanting to perform a medical procedure (on you or someone you know). Your dataa probably only has value to *you*. And, as I said, above, if you're concentrating on *surviving*, that data may prove to be of considerably less interest! :>

I have many terabytes of data, here. But, if I was placed in a situation where my own personal survival was at stake (natural disaster, uprising, pandemic, etc.) there's scant little that I would even *try* to preserve.

If you are a business entity but the economic/financial system has collapsed, what value is (was) there in your preservation of your "business records"? "Bars of gold? Sorry, I can't *eat* gold..."

It's a lot harder to decide *what* to preserve if you assume you can't preserve it *all*.

I guess you were using 800 BPI or below, which suffered from the head alignment problem. Since the 8 data tracks and parity had to be read simultaneously (no self clocking between tracks), in which the bit length at 800 BPI (31 bytes/mm) was 32 um, so you had to keep the head quite well aligned.

This is how life is designed to operate. Knowledge is passed generation to generation - individual memories being of no interest to the species get just discarded. Has worked for millennia - now we are further and we discuss how to make it safer - having gathered more knowledge worth being saved... While the life based system as you suggest is the only known working solution it cannot withstand a mass extinction event - which is why we (instinctively?) think on long term data preservation without life around to maintain it.

Now how much good that knowledge - if we preserve it and it survives mass extinction and the rise of the frog civilization - will be to the frogs remains to be seen :-). Could well be at the point they can read it they will be advanced past the point where this knowledge would be any news to them.

Dimiter

There has been high cultures from Indus, Greek, Roman, Arabic/Islam and medieval Europe, not to mention the long history in China, all of which were interested in preserving the history of previous generations.

After all "Dark Ages" etc.were local things.

These days a flatbed scanner would be replaced with a smart phone with video camera.

I have seen this done with analog tapes, but I guess reading low density digital optical tapes might be usable with a microscope.

These days, storing an extra megabyte is not a big deal.

These days, you can preserve it all with very low cost. Look for some "cloud" offerings.

But they preserve what *they* think is valuable and in whatever form they consider to be "most easily supported". How valuable are "histories" ("The Great Emperor did this, that and the other thing") vs. "pure" knowledge? How much bias enters into the records/histories to serve their own needs? E.g., to perpetuate their practices/values?

Many regions have deep histories -- yet are significantly "behind" other, younger parts of the developing world. So, clearly something in the way they preserved history (i.e., culture) worked contrary to their interests, when viewed from modern day.

Stephenson's _Anathem_ is a good read (fiction), along these lines.

What do you do when you can't buy a replacement battery for your phone? (Do you have any idea how many phones are discarded each year?)

Which megabyte? My bug-out-bag has a thumb drive in it with bank records. The premise being that I will need those to access my "liquid resources" in the event of a local calamity. I make no attempt to preserve any of my "personal records". While I'd like to *have* them after the dust settles, I figure the more important issue will be avoiding whatever danger causes me to leave here expeditiously.

If the proverbial fan was "hit", even those personal records would be of little value. I'd much prefer having a First Aid book that I can read with my own two eyes (not an electronic copy) than copies of bank/investment/stock records, etc.

What happens when the service provider goes out of business? Or, when the data is (temporarily) inaccessible? If the manual for my genset is stored in the cloud and my ISP is offline, or my computer "down", or the cloud provider "has issues", then I can't repair the genset to get the lights back on, *here* (who cares about "there"!).

OTOH, if I have a copy of it stored locally and enough power to spin up that particular drive (and a laptop, etc.) then I can presumably retrieve it long enough to get the genset repaired.

The same sort of thing happens with, e.g., first aid manual. There, I don't even want to have to rely on a functioning laptop, etc. A paper copy is worth the weight and space that it requires!

The same sort of exercise applies to societies and organizations. Hence my upthread comment: "I see the problem as deciding *what* to preserve. Put your eggs in one basket -- then 'watch that basket!'"