Optical storage

[1] Britannica notes that it "uses low-power laser beams to record and retrieve digital (binary) data.

[6] In 1961/2, they introduced the IBM 1360, which used small photographic slides that were read using a conventional incandescent lamp as a light source and a photocell as a detector.

This was followed in August 1982 by the introduction of the digital audio audio/music CD,[8] which soon led to an effort to standardize data recording on this media.

This used a laser to warm the storage media so that it became susceptible to magnetic fields and an electromagnet, similar to the one in a hard drive, to write data by realigning the material within.

It worked like a conventional optical drive during reads, with the laser operating at lower energy levels, too low to heat the disk.

Over time, this became known as CD-R.[9] In 1990, the Orange Book added magnetic-optical re-writable versions of the CD physical format, CD-MO, which differed from earlier MO systems primarily in that the disk was not enclosed in a jacket.

Continual improvements in drive and media led to the 1997 addition of the CD-RW format, which allowed disks to be written, erased and re-written.

[15] Another technical improvement during this era was the introduction of higher-frequency semiconductor lasers operating in the blue and near ultraviolet spectrum.

These shorter wavelengths, combined with improvements in the underlying media, allowed much more data to be stored on a disk.

With the widespread introduction of high-definition television in the early 2000s, the need for a medium able to store the much larger higher-resolution video files became an issue,[16] leading to two competing standards, HD DVD and Blu-ray.

Over time, Blu-ray won the resulting high-definition optical disc format war, with Toshiba announcing their withdrawal of HD DVD on February 19, 2008.

Blu-ray remains preferred to streaming services for its technical qualities, but has a tiny market share as of 2023[update].