SSD

A solid-state drive (SSD) is a non-volatile storage device that uses NAND flash memory to store data. Unlike hard disk drives, SSDs have no moving parts, which yields faster data access, lower latency, quieter operation, and greater durability. They are used in desktops, laptops, servers, and embedded systems to hold the operating system, applications, and user data.

An SSD comprises a controller, NAND flash, and often DRAM cache. The controller handles wear leveling, garbage collection, parity and error correction, and, in some designs, caching. NAND flash types include SLC, MLC, TLC, and QLC, with 3D stacking becoming common. Drives connect via interfaces such as SATA and PCIe, with NVMe over PCIe providing higher performance. Common form factors include 2.5-inch, M.2, and U.2.

Performance and endurance depend on interface and NAND technology. SATA SSDs are typically limited to around 550–600 MB/s, while PCIe/NVMe drives can reach multiple GB/s. Endurance is described by metrics such as TBW (total bytes written) or DWPD, and is affected by workload, temperature, and drive quality. Features like TRIM and advanced wear leveling help extend lifespan.

History and impact: SSDs emerged in the early 2000s and became mainstream in the 2010s, progressively replacing HDDs as boot drives and for performance-sensitive storage. The shift to NVMe and 3D NAND has driven large gains in speed and capacity, while prices have fallen, expanding use cases from consumer PCs to data centers and enterprise environments.