LogFAQs > #905265109

rogerskg1979 posted...

Zeus posted...

tbh, googled it to learn a bit more and discovered that DVDs have a projected 20-200 lifespan. I'm still a little surprised that they can wear at all, considering that they require physical contact to be read (well, other than the part being spun)

20-200 year lifespan is so laughably broad. It's like saying the human lifespan is 10-100 years.

I don't even know how they could come up with a 200 lifespan since DVDs haven't been around anywhere close to that. The oldest DVDs are like 30 years old, so how could you possibly know that they may last another 170 years? Do they have a time machine that allows them to go 200 years in the future to confirm that there will still be working DVDs 200 years from now?

Regarding the physical contact part of your post, the layers of DVDs are held together by glue. Glue is going to deteriorate over time regardless of whether or not you actually use the DVD. I really doubt there is any glue in the world that is going to hold together for 200 years. That would be some super strong glue. lol

Thinking about this in reverse, 200 years ago was the year 1818. Is there anything built in 1818 that still works today?

It's like you're scratching for excuses. Of course we haven't tested how long plastics will actually last but it's not like we're seeing them degrade so fast that 100+ years is an unreasonable guess. I mean vinyl records are maybe twice as old and they're still in use.

This isn't Elmer's glue. What's more is there's no stress on the glue to pull it apart. Optical discs don't require physical contact. The glue holds the layers together but the force from spinning is on a different plane. That's all on the spindle and the disc.

Well duh, what kind of answer do you expect? They didn't have electronics back then and there are standing structures that are centuries old.