I think magnetic tape is the current standard for long term digital storage. But it sounds like you’re talking about creating a hard copy, in which case the har

I think magnetic tape is the current standard for long term digital storage. But it sounds like you’re talking about creating a hard copy, in which case the harder the object usually the longer it will last: rock, metal, hardened clay. But those mediums would hardly be reasonable given how much content is in the English Wikipedia