How can a flash drive store information without power?
In: Technology
Because we don’t let the electrons move
RAM stores charge in capacitors, but capacitors leak charge over time. Its like a big grid of leaky cups on scales, heavy cups are 1’s and light cups are 0’s. There’s a task that goes around once in a while and tops up the mostly full cups and empties the mostly empty cups. If you lose power then that task doesn’t run and the charge (water) leaks out of the cups and you no longer have clear 1’s and 0’s
Flash memory used in flash drives and SSDs don’t store charge in capacitors, they instead ram electrons through insulators and onto “floating gates” of transistors to force those transistors on/off. Its like your cups of water were instead jello shots and if you wanted a 1 you rammed a bunch of steel ball bearings into it to make it heavier. The ball bearings have no way to drift out of the jello, they’re stuck in there so you don’t need a task going around to correct each cup on a regular basis
Basically we did a better job sticking electrons into a place where they can’t easily escape from so we lose data over years rather than seconds.
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