Answer Description
HDDs or Hard Disk Drives are the older, magnetic disk storage devices that can and will become fragmented with use. SSD, NV Memory, and Flash are actually the same technology and do not become fragmented.
Wikipedia
A hard disk drive (HDD), hard disk, hard drive, or fixed disk, is an electro-mechanical data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks (platters) coated with magnetic material. The platters are paired with magnetic heads, usually arranged on a moving actuator arm, which read and write data to the platter surfaces. Data is accessed in a random-access manner, meaning that individual blocks …
Hard disk drive - Wikipedia, the free encyclopedia