The secret to immortality is knowing how to keep your memories

If your data are important enough to be worth to survive you and many generations ahead, let´s say up to a billion years this is the answer:

"Dr Zettl and his colleagues constructed their memory cell by taking a particle of iron just a few billionths of a metre (nanometres) across and placing it inside a hollow carbon nanotube. They attached electrodes to either end of the tube. By applying a current, they were able to shuttle the particle back and forth. This provides a mechanism to create the “1” and “0” required for digital representation: if the particle is at one end it counts as a “1”, and at the other end it is a “0”.

The next challenge will be to create an electronic memory that has millions of cells instead of just one. If Dr Zettl succeeds in commercialising this technology, digital decay itself may become a thing of the past."

More...