Hard Disk Drives, also known as HDDs, are a type of data storage device. They are the most common method of storing information within a single computer.
Hard Disk Drives use one or more rapidly rotating disks covered with magnetic material. Changes in the direction of the magnetism represent digital bits. As the disks are spinned rapidly, information can be gathered from the disks in any particular order, meaning things don't necessarily have to be done in sequence.
HDDs can be either an internal part of a computer or attached externally. Modern gaming consoles typically have a small to medium sized internal HDD with the capability to connect to all but the very largest external ones.
Today, HDD's greatest rivals for information storage are optical discs such as DVDs, which are cheaper to produce, and Flash memory devices such as SD Cards, which are more reliable and faster. However, HDD surpasses both of these formats in terms of sheer storage capacity.
HDD storage was invented in 1956 by IBM. Within the next ten years, it became the main form of secondary memory for computers. Over half a century after its invention, the HDD remains the chief method of secondary computer memory storage.
Early HDDs were sometimes the size of refrigerators and washing machines, storing mere megabytes of data. They were also very expensive, especially for smaller computers. Over the course of the 1980's, however, HDD storage went from being included in only a few computers to being included in all but the cheapest of PC's.
HDDs have constantly gained capacity and have become smaller and less expensive at an exponential rate over the decades. However, the rate at which the data is accessed has been fairly limited in comparison.
Use in Gaming
In the 1980's, HDDs were rarely used for gaming. This was due not only to their high cost, but also due to their simply being no good method of distribution. This began to change in the 90's, as capacity went up, costs went down, and online distribution became a viable form of receiving data for games. However, it wasn't until the seventh generation of gaming consoles in 2006 when Nintendo and Sega began incorporating HDDs into their new machines: the Revolution and the Pluto.
The hard drives of the first generations of these consoles were meant primarily to contain save data. However, models with larger drives were also available to download games. As the generation went on, hundreds of games would become digital distribution exclusives, meaning that the initial round of consoles soon found themselves left behind.
By 2008, both Sega and Nintendo realized that digital distribution, both of smaller digital-only games and eventually of retail games, was the way of the future. Thus, both companies introduced new models of their systems, with the main difference being the higher capacity HDD. Whereas the Pluto and Revolution had at largest a 20 GB and 32 GB HDD in 2006, by the end of 2008 each console had a widely available 120 GB version. Even the basic models were increased to have as much as 12 GB of internal memory.