Memory is not stored, it is powered: the archive remembers exactly as far as the wire reaches.
An artistic imagining, rendered procedurally, of an archive vault at the Earth-Sun L4 point spending its collected sunlight on the computation that keeps a stored archive readable: one unbroken wire carries the power through the slabs in series, each slab filling with light as its contents are refreshed, and the waste heat leaves through the fins at the foot of the mast. Earth-Sun L4 is a real Lagrange point, held data really does cost continuous power to refresh, scrub and error-correct, and any computer in vacuum must radiate its waste heat away; the vault itself is speculation, and the largest slab in the frame stays blank because the wire has not reached it.Image: poweringspace.com. Artistic imagining.