Assuming a modern SSD/Phone. If the hardware doesn’t physically change and I can’t open it and see 1’s and 0’s, then how does the device know the state before the electricity went off?
In: Technology
> Assuming a modern SSD
We need to talk about how an SSD physically works. There are billions of tiny microscopic “islands” inside surrounded by insulators. When writing data, an SSD uses a high voltage electric field to forcibly blow (suck) electrons onto (off of) the islands.
If there’s no charge it’s a 0 bit, if there’s charge it’s a 1 bit.
Once on the islands, the electrons are trapped and stay there for decades, or until you decide to write something else with another high voltage electric field.
When you want to read data, the trapped electrons have an electric field of their own. So you can use an electric field detection circuit to tell whether each island has charge or not, which gives you your the 1’s and 0’s back.
> If the hardware doesn’t physically change
It does physically change. Electrons are physically moved into different positions depending on what data you write.
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