Storage 37Internal Storage DevicesStorage devices that are installed inside your computer are called internalstorage devices. Generally, you cannot remove such devices when thecomputer is powered on. The data stored on internal storage devicesis generally stored till you manually delete it. Internal storage devicesinclude hard drives (HDD) and solid-state drives (SSD).Hard DrivesAn HDD contains magnetically coated platters that rotate on amotor-driven spindle, within a protective enclosure. Data is magneticallyread from and written to the platter by read/write heads that arepresent above the platters. The hard disk drive is the data center of yourcomputer.A typical HDD design consists of a spindle that holds flat circular diskscalled platters, onto which the data is recorded. The platters are madefrom a non-magnetic material, usually aluminum alloy or glass, and arecoated with a shallow layer of magnetic material, with an outer layer ofcarbon for protection.Solid-State DrivesAn SSD is a data storage device that uses solid-state (flash) memory tostore data. SSDs contain no moving parts as data is stored in electricalcircuits. Compared to HDDs, SSDs are typically less susceptible tophysical shock, are quieter, and have lower access time and latency.SSDs use the same interface to connect to the computer as HDDs,making them compatible with most existing computers.Removable Storage DevicesRemovable storage devices that you can remove from your computerwithout turning the computer off are called removable storage devices.Commonly used removable storage devices include:• Optical discs• Memory cards• Magnetic tapes