A luddite writes...
I am a bear of very little brain. I'm glad there are clever people who understand all this witchcraft.
I've got a memory 'card' out of an old NCR(?) computer that is made up of proper little ferrite cores with criss-crossing wires. About 4in square, and holds 1024 bits!
I still think tying knots in string and cutting notches in sticks was a pretty reliable way of storing data.