When was the hard drive first developed?
Areal density (computer storage)
Hard disk drives store data in the magnetic polarization of small patches of the surface coating on a disk. The maximum areal density is defined by the size of the magnetic particles in the surface, as well as the size of the "head" used to read and write the data. The areal density of disk storage devices has increased dramatically since IBM introduced the IBM 350 disk storage, the first hard disk drive in 1956 at an areal density of 2,000 bit/in. The growth rate has matched Moore's Law with the density reaching 1 Tbit/in in 2014. In 2015, Seagate introduced a hard drive at a density of 1.34 Tbit/in, about 600 million times that of the first disk drive. It is expected that current recording technology can be "feasibly" expected to scale to at least 5 Tbit/in in the near future. New technologies like Heat-assisted magnetic recording (HAMR) and Microwave Assisted Magnetic Recording (MAMR) are under development and are expected to continue magnetic areal density progress.
Optical disc drive
The first Blu-Ray prototype was unveiled by Sony in October 2000, and the first commercial recording device was released to market on April 10, 2003. In January 2005, TDK announced that they had developed an ultra-hard yet very thin polymer coating ("Durabis") for Blu-ray discs; this was a significant technical advance because better protection was desired for the consumer market to protect bare discs against scratching and damage compared to DVD. Technically Blu-ray Disc also required a thinner layer for the narrower beam and shorter wavelength 'blue' laser. The first BD-ROM players (Samsung BD-P1000) were shipped in mid-June 2006. The first Blu-ray Disc titles were released by Sony and MGM on June 20, 2006. The first mass-market Blu-ray Disc rewritable drive for the PC was the BWU-100A, released by Sony on July 18, 2006.