Optical disc
Alternatively referred to as optical media and optical storage, an optical disc or optical disk is any storage media that holds content in digital format and is read using a laser assembly is considered optical media. The most common types of optical media are Blu-ray, CDs, and DVDs. Computers can read and write to CDs and DVDs using a CD Writer or DVD Writer drive and a Blu-ray is read with a Blu-ray drive. Drives such as a CD-R and DVD-R drive that not only read but write information to discs are known as magneto-optic (MO).
There are three main types of optical media: CD, DVD and Blu-ray disc. CDs can store up to 700 megabytes (MB) of data and DVDs can store up to 8.4 GB of data. Blu-ray discs, which are the newest type of optical media, can store up to 50 GB of data. This storage capacity is a clear advantage over the floppy disk storage media (a magnetic media), which only has a capacity of 1.44 MB. Another advantage that optical media has over the floppy disk is that it can last up to 7 times longer, due to its improved durability.
Also see: CD definitions, Magnetic media, Magneto-optic