SolidStateDrives

SolidStateDrives (SSDs) are non-volatile storage devices that store data on flash memory chips, rather than magnetic disks. They have no moving parts, which reduces access latency and power draw and makes them more durable against shock. SSDs gained prominence in consumer markets in the late 2000s and have since become a common form of primary storage in many computers.

Technically, SSDs use NAND flash memory organized in pages and blocks and a controller. Most employ 3D NAND with a cache, often DRAM. Data wear out as cells are rewritten, so wear leveling, garbage collection, and the TRIM command help maintain performance and longevity. Endurance is rated in TBW (terabytes written) or DWPD (drive writes per day). NAND types include SLC, MLC, TLC, and QLC, with 3D stacking increasing density.

Form factors and interfaces vary: common options include 2.5-inch SATA, M.2, and PCIe NVMe add-in cards. Interfaces include SATA 6 Gbit/s and PCIe with NVMe, delivering higher bandwidth and lower latency. Performance is described in terms of sequential and random I/O performance, as well as latency, and depends on the controller, memory type, and interface.

In practical use, SSDs provide faster boot times, quicker program launches, and improved system responsiveness, along with lower power consumption and silent operation. They are widely used in laptops, desktops, servers, and enterprise storage. However, cost per gigabyte remains higher than traditional hard drives, and endurance and data retention depend on workload, temperature, and idle time.