Drives

Drives are data storage devices that retain digital information even when powered off. They are used to store operating systems, applications, and user data in computers, servers, external enclosures, and embedded systems.

There are two major families: hard disk drives (HDDs) and solid-state drives (SSDs). HDDs store data on spinning magnetic platters and are known for high capacities at a relatively low cost per gigabyte. SSDs use flash memory with no moving parts, providing faster access times, higher throughput, and greater durability in portable or compact systems. A subset, hybrid drives (SSHDs), combines a small amount of flash with spinning disks to improve responsiveness for frequently accessed data.

Drives connect to systems through various interfaces and form factors. Common interfaces include SATA, which caps at modest speeds, and NVMe over PCIe, which delivers substantially higher throughput and lower latency. Form factors range from desktop 3.5-inch and laptop 2.5-inch drives to compact M.2 and U.2 cards for PCIe-based storage.

Key performance and reliability metrics include capacity, sequential read/write speeds, random I/O performance, latency, and endurance. SSDs generally outperform HDDs across these measures. Endurance ratings (such as TBW or DWPD) indicate write durability for flash-based drives, while HDDs emphasize mechanical reliability and shock resistance. Firmware features like wear leveling, error correction, and power-loss protection influence longevity and data integrity.

Uses and considerations involve balancing capacity, speed, durability, and cost. For the operating system and frequently used programs, SSDs are common choices; for bulk storage, HDDs offer economical options. External drives provide portability, and many drives include encryption features to enhance data security. Cloud storage and RAID configurations are common in server environments to improve redundancy and availability.