[shiroiuma]

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.

[fatihpense]

Papyrus doesn't last :) You want clay tablets, buried in the ground. Looking at Sumerian tablets that would give you 5000 years.

[shiroiuma]

I thought papyrus lasted a really long time, as long as you sealed it in huge stone tombs in the desert.

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.

[tim333]

Some lasted at least 3000 years https://www.britannica.com/topic/Ebers-papyrus