Hard disk  drive

Hard disk drives are the vast storehouses of information that hold all the programs and data in your computer. These devices are constructed out of platters known as disks, upon which data can be stored. As these platters spin, read-write heads access the information on the platters. Therefore, hard disks are a combination of mechanics as well as electronics. One important feature of a hard disk drive is that it does not lose information even after the system is powered down. Hard disks are identified by their interface, spindle speed and storage capacity.