I'm looking over some data retention strategy documents for a company, I noticed that they want to keep some data "forever". Now, beyond the quibble of determining how to store something for eternity, how permanent can data really be? There are atomic (n, not ACID, atomic) ways of storing binary representations, but will the interpretation of those 0's and 1's really be there for more than a few decades? Think about the data stored on punch cards - where is that now?
The answer is that it morphed into other storage along the way. If something really needs to be permanent, you need to think more about it's migration than the actual media it's stored on. That's what I'm recommending in this document - tag data sets to be migrated first, or at least considered in the migration planning. It's a simple pivot on storage versus programming, but an important one.