Compact disc
Compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony and released in 1982. The format was originally developed to store and play only sound recordings (CD-DA) but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. The first commercially available audio CD player, the Sony CDP-101, was released October 1982 in Japan.
Mini CD
When Mini CDs were first introduced in the United States, they were initially marketed as CD3, in reference to their approximate size in inches; larger CDs were called CD5, despite the fact that both CD specifications are defined solely in terms of metric units. Now, they are known as either Mini CDs or 80 mm CDs.