Diskdrive

Disk drive is a data storage device that uses rotating disks to read and write data. The most common form is the hard disk drive (HDD), storing information magnetically on spinning platters. Optical drives, such as CD, DVD, and Blu-ray, use lasers to read and write on plastic discs. Floppy drives are largely obsolete. In modern systems, HDDs handle bulk storage while optical drives are used less frequently.

HDDs consist of one or more magnetic platters attached to a spindle. Data is stored in tracks and sectors and accessed by read/write heads on an actuator as the platters spin. A controller interface connects the drive to the computer, typically via SATA or SAS; some enterprise models use more advanced interfaces. Modern drives include a small cache to smooth data transfers and speed up access.

Performance depends on rotational speed (RPM), data density, and seek times. Common consumer HDDs run at 5400 or 7200 RPM; higher-performance and enterprise models use higher speeds. Sequential transfers are faster than random reads, and larger caches improve throughput.

History and market: Disk drives emerged in the 1950s and evolved from large mainframe devices to compact desktops. With solid-state drives providing faster random access, HDDs are increasingly used for bulk storage and archival because of their lower cost per gigabyte.

Reliability and maintenance: HDDs are mechanical devices subject to wear, with failure modes such as bearing or head crashes. Modern drives report self-monitoring data (SMART) to predict failures. They require stable cooling, protection from shock, and regular backups; redundancy through RAID can improve data availability.