Windows 7: Why do home made CDs andDVDs retain data for a short time?

I guess most of you have experienced the CD-R or DVD-R that you burned a few years ago that has no data on it now. The logic is strange; Windows says there is no data on the disc so I try to write, it then says the disk is full!!

What happens to the data does it evaporate? I mean a laser burnt the data into the metal layer if the disk, where have these indentations/grooves gone?

It doesn't exactly "burn the metal layer of the disc"; discs are made of several layers, and the coating on the layers is what's the problem here. Mass-produced cheap discs don't last long, at least not beyond a couple of years. See disc rot on wikipedia.

I use external drives now; granted, they don't last that long either, but TB-sized drives are easier to manage rather than stacks of discs, and duplicating them is less tedious. Drives get larger and cheaper all the time, and I'm hopeful that more longer lasting storage will show up given the rate of advance in this field.

Thanks Trucidation for the link it's very interesting. I also use portable USB hard disks for long term storage. I recently bought a 1TB discand I'm beginning to see 2TB HD in this country. I can't imagine what a PV disk will hold ( 1Petta = 1000x Terra)

BTW do you trust Wikipedia? Some people say it's not to be trusted as it's written by average people and not experts.

When reading any article from Wikipedia, or any other site in particular on the Internet.. check out the citations, and any other sources of the information provided at the bottom of the article.. and verify that what you read has reliable citations and sources to back it up....

Meh, I've read articles written by experts, as well as articles written by people who were either drunk, high on drugs, or pathological liars. On average though, you can trust most wikis to at least be good enough for small talk with your friends. As Solarmystic says, if you want to go further then it's time to google up and look up more sources so you can cross-check things.

I just finished checking my entire hoard of burned CDs over the past few days btw - most of the older ones were starting to be unreadable. Oh well. Got most of them saved on the external drive already. Now I just gotta worry about making sure my external drive doesn't suddenly die early on me...

I encountered the same problem, most notably with the blue dyed disks that were prominent several years ago. Apparently, these things just weren't made as well as others. But that can go for any disk, depends on the quality.

I have seen several disks that had some sort of rust looking degradation around the edges, some were compromised as far as 1/2 way into the disk. And those are disks that were kept in the house.

Though I have not had the problems some of you have I am glad you brought it up.

I at least will keep an eye on my older burned CD/DVD's occasionally to check for problems.

You never know what you will learn on the forum.