HDD is an acronym for Hard Disk Device. It is a data storage device that has rigid spinning platters that store data using magnetism. The data is written and retrieved by movable magnetic heads. The name comes from the fact that the spinning disks or platters are rigid. There where also floppy disks that used a flexible spinning disk. HDDs were the standard for years as the main storage device for PCs and laptops, but are now being replace by a much fast device known as a solid state drive. The main disadvantage with an HDD is the fact that there is a mechanical disk spinning and a head that has to move to read or write the data. All of this spinning and moving results in a delay for the head to move and then a read or write speed that is limited by how fast the disk is spinning. Also as the drive get full the data will then get written to the center part of the disk which is traveling slower which limits speed. SSDs eliminate all of the complicating and store data with no moving parts. They have lower power consumption, almost no seek time, and much higher read and write speeds.
