Compact disc

The compact disc (CD) is a <a href="/facts/Digital_media/QLXzDrhL">digital</a> <a href="/facts/Optical_disc/vjVDB1GH">optical disc</a> <a href="/facts/Data_storage/uCvJ6nrq">data storage</a> format co-developed by <a href="/facts/Philips/Xp4uczGg">Philips</a> and <a href="/facts/Sony/7x4tCtBd">Sony</a> to store and play <a href="/facts/Digital_audio/PgugcLAI">digital audio</a> recordings. It employs the <a href="/facts/Compact_Disc_Digital_Audio/FDMqNLw5">Compact Disc Digital Audio</a> (CD-DA) standard and was capable of holding of uncompressed <a href="/facts/Stereo/mFp93LMe">stereo</a> audio. First released in <a href="/facts/Japan/U5mz0SRT">Japan</a> in October 1982, the CD was the second optical disc format to reach the market, following the larger <a href="/facts/LaserDisc/nU4WJhDM">LaserDisc</a> (LD). In later years, the technology was adapted for computer data storage as <a href="/facts/CD-ROM/JwuaYLJv">CD-ROM</a> and subsequently expanded into various writable and multimedia formats. As of 2007, over 200 billion CDs (including audio CDs, CD-ROMs, and <a href="/facts/CD-R/yjBjpaIM">CD-Rs</a>) had been sold worldwide.
Standard CDs have a diameter of 120 millimetres (4.7 inches) and typically hold up to 74 minutes of audio or approximately 650 <a href="/facts/Mebibyte/BNHUp9Qq">MiB</a> (681,574,400 bytes) of data. This was later regularly extended to 80 minutes or 700 MiB (734,003,200 bytes) by reducing the spacing between data tracks, with some discs unofficially reaching up to 99 minutes or 870 MiB (912,261,120 bytes) which falls outside established specifications. Smaller variants, such as the <a href="/facts/Mini_CD/BxSG8aP5">Mini CD</a>, range from 60 to 80 millimetres (2.4 to 3.1 in) in diameter and have been used for <a href="/facts/CD_single/gnlnYqx7">CD singles</a> or distributing <a href="/facts/Device_driver/rDYnHU1G">device drivers</a> and software.
The CD gained widespread popularity in the late 1980s and early 1990s. By 1991, it had surpassed the <a href="/facts/Phonograph_record/ccuFV9Af">phonograph record</a> and the <a href="/facts/Compact_cassette/w8I5uyfs">cassette tape</a> in sales in the <a href="/facts/United_States/P0sCdLe5">United States</a>, becoming the dominant physical audio format. By 2000, CDs accounted for 92.3% of the U.S. music market share. The CD is widely regarded as the final dominant format of the <a href="/facts/Album_era/xlYNf8FV">album era</a>, before the rise of <a href="/facts/MP3/yrBpxUSD">MP3</a>, <a href="/facts/Music_download/96QbSLNp">digital downloads</a>, and <a href="/facts/Music_streaming_service/x7gDWdEG">streaming platforms</a> in the mid-2000s led to its decline.
Beyond audio playback, the compact disc was adapted for general-purpose data storage under the <a href="/facts/CD-ROM/JwuaYLJv">CD-ROM</a> format, which initially offered more capacity than contemporary personal computer <a href="/facts/Hard_disk_drive/kekLSGSE">hard disk drives</a>. Additional derived formats include write-once discs (<a href="/facts/CD-R/yjBjpaIM">CD-R</a>), rewritable media (<a href="/facts/CD-RW/W7THUREl">CD-RW</a>), and multimedia applications such as <a href="/facts/Video_CD/87gb1XJ5">Video CD</a> (VCD), <a href="/facts/Super_Video_CD/KHNsG689">Super Video CD</a> (SVCD), <a href="/facts/Photo_CD/Y4Klg0hA">Photo CD</a>, <a href="/facts/Picture_CD/BDpE0ouQ">Picture CD</a>, <a href="/facts/CD-i/SrDmhr1K">Compact Disc Interactive</a> (CD-i), <a href="/facts/Enhanced_Music_CD/BQYtCBSx">Enhanced Music CD</a>, and <a href="/facts/Super_Audio_CD/f4a7Gu0V">Super Audio CD</a> (SACD), the latter of which can include a standard CD-DA layer for <a href="/facts/Backward_compatibility/FbHFBu5y">backward compatibility</a>.

Compact disc open-in-new

Compact disc