NOT CD-RWs - this much I know; I've had them rot to unreadability on timescales of 1-3 years. Among CD-Rs, there was one formulation for which the recording surface was bluish in color and those CD-Rs came from Japan as opposed to Taiwan - those were supposed to be good for a very long time. IIRC several manufacturers made the blue formulation (I can't remember what it's called; you can craft Google queries as well as I can) including Maxell and JVC. I don't know what the story is about DVD-R or Blu-Ray media. There was supposed to be some new optical media formulation as of about 3-5 years ago that was supposed to be multi-century but I've forgotten details.
When stored correctly, film lasts 100 years along with CDs (and thereabouts) that are thought to be similarly long living. However, I myself have both non-functional factory-punched DVDs as well as functional self-burned 20 year-old CDs / DVDs. I guess build quality is what dictates long term functionality.
I've also heard that damaged CDs can be resurfaced and made to work again, or alternatively have its pits and lands photographed, analysed and image-processed on a computer to recover the data. If all that is true, then the optical media may have an advantage against flash/SSDs, just like the magnetic HDDs have.
All my tapes still play correctly, at least after getting cleaned. In fact, I have seen the spools within the best compact cassette brands like Sony shatter around 40-50 years lifetime, but once again, you could just transplant the tape to another set of spools and get it working back again.
Therefore, in my opinion, the reliability would be as below, mostly because of the data being physically present on the medium.
1) Magnetic (tape / disk)
2) Optical (film / disc)
3) Flash or other electronic.
Now, if you want the ultimate, then have a look at the Voyager's golden record !!!
https://en.wikipedia.org/wiki/Voyager_Golden_Record
"The records, now traveling beyond our solar system through interstellar space, were designed to last between 1 billion and 5 billion years."
I've also heard that damaged CDs can be resurfaced and made to work again, or alternatively have its pits and lands photographed, analysed and image-processed on a computer to recover the data. If all that is true, then the optical media may have an advantage against flash/SSDs, just like the magnetic HDDs have.
All my tapes still play correctly, at least after getting cleaned. In fact, I have seen the spools within the best compact cassette brands like Sony shatter around 40-50 years lifetime, but once again, you could just transplant the tape to another set of spools and get it working back again.
Therefore, in my opinion, the reliability would be as below, mostly because of the data being physically present on the medium.
1) Magnetic (tape / disk)
2) Optical (film / disc)
3) Flash or other electronic.
Now, if you want the ultimate, then have a look at the Voyager's golden record !!!
https://en.wikipedia.org/wiki/Voyager_Golden_Record
"The records, now traveling beyond our solar system through interstellar space, were designed to last between 1 billion and 5 billion years."
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No... not unless you power them up periocally for a day or so
Also, wrap in them in a non static bag, and aluminum foil and put them in the freezer.
Heat (entropy) is their greatest enemy.
No.
HDDs are far superior, NAND is not good because it depends on the stored charge in the cell which decays over time. Magnetic storage is superior.
I have shoveled so many LTO tapes it counts as exercise. The one problem with tape is keeping a drive that will read it.
You really have to mistreat an LTO tape to get read errors. I just cannot say it is so easy to recover in 50 years in some cases. The drive needs to be in good shape too.
On the flip side it is easy to duplicate to new media.
A few years ago some were saying that LTO tape was less popular with cloud backup or remote syncing. Then online TV and movies became popular. I got to see a tape library with a few thousand tape slots sold for storing all of those TV episodes we wish to have within reach.
You really have to mistreat an LTO tape to get read errors. I just cannot say it is so easy to recover in 50 years in some cases. The drive needs to be in good shape too.
On the flip side it is easy to duplicate to new media.
A few years ago some were saying that LTO tape was less popular with cloud backup or remote syncing. Then online TV and movies became popular. I got to see a tape library with a few thousand tape slots sold for storing all of those TV episodes we wish to have within reach.