What's the difference between volatile and non-volatile memory?

Volatile memory, such as DRAM and SRAM, loses its contents when power is removed; DRAM stores bits in capacitor-transistor cells and requires periodic refresh, while SRAM uses multi-transistor latches for faster access and is typically employed in CPU caches. Non-volatile memory, exemplified by NAND flash in SSDs and NOR flash for firmware, retains data after power loss and includes controllers that manage error correction and wear-leveling.