Flash Memory

Flash memory is a non-volatile semiconductor memory that retains information even without a power supply. Data is stored in memory cells based on floating gate or charge trap transistors and is erased and written in blocks. A distinction is made between NAND flash for large data volumes and NOR flash for fast random access, as used for firmware. Depending on the number of bits stored per cell, types are classified as SLC, MLC, TLC and QLC, which affects speed, endurance and price. Flash memory is used in SSDs, USB drives, memory cards, network components and embedded systems. As memory cells support only a limited number of write cycles, controllers distribute access through wear levelling. Compared with hard disks, the benefits are short access times, low power consumption and mechanical robustness.