Microfilm
I remember that when I was younger it was always about the “microfilm.” Johnny Quest, Mission Impossible, you name it: it was the microfilm.
Whether the good guy was trying to hide it from the bad guy, or whether the dastardly villain had stolen it and the good guy was trying to get it back, the microfilm was usually center stage. It always contained the plans to the doomsday device, or some such.
Now when most of us carry virtual computers in our pockets, I guess there’s just not as much of a need for microfilm. I’ll bet if you went into a pawn shop, there would be rows and rows of microfilm available at bargain basement prices.
Used to be you needed a whole Artoo unit to shuffle the Death Star plans from one side of the galaxy to another. Now you can put ‘em on the flash drive dangling from your keychain.
I always preferred microfiche. Especially smoked. The little ones could be eaten whole.