First things first. How long are things going to remain in your impervious time-capsule? Microsd cards are just flash memory. Over time, the information will

First things first. How long are things going to remain in your impervious time-capsule? Microsd cards are just flash memory. Over time, the information will leak away. How long that will take is hard to guess, but if you are aiming for a century or more, microsd is likely to not be a good choice. Furthermore, what is going to be used to read the data you preserve on the microsd? Do you think there will be microsd readers a few decades into the future, much less a century. Assuming that you do use the microsd, I would use two different physical cards, incorporate multiple copies of whatever I choose to include on each of the microsd cards, and add in some heavy duty error correction codes so degraded content can be recovered. Oh, one more thing, it might be a good idea to use a card that has write protection so that revisionist history is difficult.