A company called Norsam (norsam.com) can engrave text on a 5" nickel or gold disk using ion deposition. They get 20,000 pages per disk. Nickel will not corrode.

A company called Norsam (norsam.com) can engrave text on a 5" nickel or gold disk using ion deposition. They get 20,000 pages per disk. Nickel will not corrode. All any future civilization would need to read it back is a microscope and OCR.