Hard Disk Drives (HDDs) are a type of data storage device that use magnetic disks to read and write data. They are commonly used in computers and servers to store operating systems, applications, and files. HDDs are known for their large storage capacities and cost-effectiveness compared to other storage solutions. The technology behind HDDs involves spinning disks coated with magnetic material, which allows data to be written and retrieved by read/write heads. Despite the rise of Solid State Drives (SSDs), HDDs remain popular for their ability to store vast amounts of data at a lower price point, making them ideal for backup and archival purposes.