Is there some actual study on the "life expectancy" of magnetic media such as cassette tapes or floppy disks?
E.g. I have a pre-recorded compact cassette that is 50 years old and works just fine (and sounds great!), and floppy disks from the early 80s that read with no problems.
Yet when I search for this topic everyone always claims "10–20 years" is what to expect from magnetic media.
@thomasfuchs there's an awful lot of variables in play for a meaningful study. Even accounting for storage conditions, different formulations degrade differently (hello, box of Scotch reel-to-reel tapes in the corner that self-destruct and leave a sticky sludge behind if I try to play them)
@thomasfuchs There are several different failure modes for magnetic media. You compare analog and digital media. Besides materials and manufacturing quality, the likelihood of problems appearing must be related to storage conditions.... I will keep an eye out for a study.
@aarbrk well both the analog and digital media I have working is 45–50 years old, which is like 3x the estimates I’ve seen
also have hard disks that work from that era
@thomasfuchs You are doing anecdotes and comparing to rough estimates. Don't bet on any of this. There is no one answer, just factors and tolerances.
@aarbrk I mean yes but I’ve seen that from many other people in the retrocomputing/vintage HiFi space
I suspect the “10–20 years” thing either originates with manufacturers that didn’t want to have to deal with lawsuits or with someone sometime just making it up and other people quoting it
@thomasfuchs Well, you can tell those figures aren't from a serious study, because they don't take into account anything like materials, manufacturer, heat, humidity, handling and usage patterns.... Also, with analog media, there may not be any ground truth against which to measure distortion.
Digitization and preservation campaigns are supposed to always focus first on the most vulnerable media in a collection: the ones that are the least shelf-stable. How do they identify these? The factors!
@thomasfuchs I'd also be interested if you run across such a study. I also have old floppies, CDs, cassettes, etc. that are still perfectly fine, and others that have lost a lot of fidelity, or can't be read. I think the quality of the media had a lot to do with it. Certain brands of floppies and blank CDs were manufactured cheaply and did flake out (in some cases, literally) after about 10 years.
