Either papyrus or clay tablets if you want it to last.
More seriously, perhaps the "2 different media" means don't use, for instance, the same brand and/or model of hard drive for your multiple backups.
More seriously, perhaps the "2 different media" means don't use, for instance, the same brand and/or model of hard drive for your multiple backups.
I think we should build a big library in a lava tube on the Moon to store all the most important data humanity has generated (important works of art and literature, Wikipedia, etc.). That's probably our best hope of really preserving so much knowledge.