disc jockeys (or djs) in clubs still frequently use vinyl records, as cueing tracks from cassette tapes is too slow and cds did not allow creative playback options until 2001. the term "dj", which had always meant a person who played various pieces of music on the radio (originally 78s, then 45s, then tape cartridges and reels; now cuts from cds or tracks on a computer) – a play on the horse-racing term "jockey" – has also come to encompass all kinds of skills in "scratching" (record playback manipulation) and mixing dance music, rapping over the music or even playing musical instruments, but the original dance club (non-radio) definition was simply somebody who played records, alternating between two turntables. the skill came in subtly matching beats or instruments from one song to the next, providing a consistent dance tempo. djs also made occasional announcements and chatted on the side with patrons while songs were playing to take requests, similar to what radio disc jockeys have been doing since the 1940s.