A local disk drive is a data storage device inside a computer that holds the operating system; software; and files, such as images, music, movies and documents. Hard disk drives store data as bits, zeros and ones, on a stack of plates coated with magnetic material. As the plates spin, a magnetic head detects or changes the orientations in this material to read or write data.
The maximum transfer speed of the drive is dependent on its interface. For example, a drive using a SATA interface is capable of transferring data at a faster rate than a drive using a USB interface. However, a device may never utilize the full capability of an interface, potentially rending the interface irrelevant.
The speed of a disk drive is measured in revolutions per minute, which means a disk drives that spins at 7200 rpm is faster than a drive spinning at 5400 rpm. However, the use of spinning parts requires the drive move to the correct position before data can be accessed. This issue causes access time to suffer as a result.
Solid-state drives solve this issue. Solid-state drives do not have moving parts, but instead use flash memory technology, which electronically stores data using specialized transistors to trap electrons. The state of each of these transistors determine whether bits are ones or zeros.