Odd Magnetic Media question

OK, I've got a wierd question now. What is the lifespan of Magnetic Media? In this case, I'm concerned about 4mm DAT, but since I'm more familiar with 8mm it as an example. Let's say I've got a stack of 8mm tapes with data on them. They're supposed to be good for archival purposes, when stored in the proper conditions for 2 years. Now let's say I've got a brand new box of 8mm tapes that have been sitting around still sealed for 8 years. Again, they've been stored in the proper conditions more or less. So are they still good? Is the 2 year number for their ability to hold data, or the actual physical lifespan. Anyone have any ideas? The real reason for the question is finding some 4mm tapes that are still sealed, and I'd estimate about 8 years old. Zane | Zane H. Healy | UNIX Systems Adminstrator | | healyzh(a)aracnet.com (primary) | Linux Enthusiast | | healyzh(a)holonet.net (alternate) | Classic Computer Collector | +----------------------------------+----------------------------+ | Empire of the Petal Throne and Traveller Role Playing, | | and Zane's Computer Museum. | | http://www.aracnet.com/~healyzh/ |