Memory and Storage

Solid-state storage has no moving parts. It stores binary data as electrical charge trapped in tiny transistor cells on a flash-memory chip.

How a solid-state drive (SSD) works

1. The drive is a chip (or several chips) containing millions of tiny memory cells.
2. Each cell contains a special transistor with a floating gate: a small conductor sandwiched between insulating layers that can hold an electrical charge.
3. To write a 1, a high voltage pushes electrons through the insulator and onto the floating gate, where they stay even after the power is removed.
4. To write a 0, the voltage is reversed, drawing the trapped electrons back off the floating gate.
5. To read, the cell is checked for whether the floating gate is charged.

Because there are no moving parts, the drive can be small, silent, and resistant to shock. Reading and writing also happens entirely electronically, which is much faster than mechanically moving a head over a spinning disc.

Common solid-state devices:

• SSDs (solid-state drives) inside laptops and desktops, replacing magnetic HDDs as the primary internal drive
• USB flash drives
• SD cards in cameras and phones
• Internal storage of smartphones and tablets

Advantages and disadvantages