The compact disc has been around since 1978, developed by Phillips and Sony. The reason it was developed was to take over for the Laserdisc as the industry standard digital audio disc. Since its invention, we have seen many updates on the compact disc
This type of disc, also known as Blu-Ray Disc, is the next generation of optical disc. It was developed by the Blu-Ray Disc Association, a group of consumer electronic/PC/media manufacturers, including: Apple, HP, Mitsubishi, Phillips, Sony, and others. The Blu-Ray disc type was mainly developed for recording, rewriting, and playing back high-definition (HD) video. It’s also perfect for storing large amounts of data, exceeding previous DVD-R disc storage capabilities. It can hold more than 5 times the amount of information that a traditional DVD can hold, up to 25GB single layer, and up to 50GB dual layer. One of the main differences of the Blu-Ray disc is the type of laser that the disc is read with. Normal DVDs are read with a red laser, the Blu-Ray discs are read with a blue-violet laser. The main benefit of this change is the wave length of the laser types. The traditional red laser has a wider focus, so the blue-violet laser can be focused more precisely allowing more tightly packed data. This equals more data in less space on the disc, this results in the additional storage space available on the new Blu-Ray discs. These new discs are backwards compatible with regular DVDs, which they are expected to replace in the near future.
HD-DVD discs, High Definition Versatile Discs or High Definition Digital Video Discs, are very similar to the Blu-Ray discs. This disc type is being developed by a group of consumer electronics/PC companies, headed by Toshiba. They also use a blue-violet laser to read the contents of the disc, which results in an increase in storage capacity compared to normal DVD discs. The HD-DVD can store 15GB single layer and 30GB double layer, making their storage capacity 10GB per layer smaller than the Blu-Ray. But Toshiba has announced a triple layer disc that can hold 45GB of information, and the HD DVD discs can hold both HD DVD and regular DVD information on one disc.
Right now these two disc types are battling it out to become the next generation of DVD disc