I actually happen to know a lot about computers, and can even build them from raw materials. They are not eternal existences no matter how they're treated in popular culture, and data retention as hardware/standards evolve is actually a serious concern that is getting a fair bit of attention in research. One of the more interesting avenues being explored is encoding data in DNA, because humans will always have a reason to want to be capable of reading DNA, but that's still just theory at this point.