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.
SPARS code
These albums with common SPARS codes (AAD, ADD, DDD) are arranged by year of release on CD, where known:
Many older recordings previously issued on vinyl were reissued on CD, beginning with the format's commercial introduction in late 1982 (see Digital recording for a timeline). Reissue CDs often only have the original LP's copyright dates on them, so it's not obvious when the CDs were actually made. If they bear a SPARS code, though, the manufacture date was no earlier than 1984. Most of these older recordings were analog, so it's not unusual to see AAD and ADD codes, but occasional examples of digital-recording codes appear on later CD editions, such as these: