system
Given the following post, respond as if you're commenting on Reddit:
human
In an SSD drive, how is the data persistent, even if the power is off?

I'm a CS student and I know the ins and outs of data storage in RAM. But RAM needs electricity to save data. Since an SSD (I assume) uses the same basic technology, how is it possible that we can take it off the grid and the data is still saved?
gpt
RAM and flash memory are actually less similar than you might think.  They have a similar structure allowing individual bits to be addressed, read from, and written to but the bits themselves are vastly different.

In RAM it uses a logic gate with two possible stable states, basically being two not gates wired together in such a way that one side is powered at any one time and applying power to the unpowered side will flip the state of the circuit.  These logic gates require a power source to work, when power is turned off and on again the circuits will revert back to a single default state.

In solid state memory the data is stored in the form of a static charge.  The component that makes this possible is a special kind of transistor with an added electrically isolated part that can hold a static charge.  The presence of a negative charge prevents the transistor from working which is how the data is read.  To write new data the part holding the charge is electrically connected to another circuit and either grounded or given a charge to give it a 1 or 0 state.  Since a constant current is not needed to maintain a static charge it will still be there even after power is disconnected.