A mechanical hard drive, often referred to as a HDD, is a type of data storage device that uses spinning disks coated with magnetic material to read and write information. Inside the drive, a moving arm accesses the data on these disks, allowing for the storage of large amounts of information, typically ranging from hundreds of gigabytes to several terabytes. Unlike solid-state drives (SSDs), which use flash memory and have no moving parts, mechanical hard drives are generally slower but offer a more cost-effective solution for storing large volumes of data. They are commonly used in personal computers, servers, and external storage devices.