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Vinyl records

Vinyl LP records have two sides, each comprising one-half of the album. If a pop or rock album contained tracks released separately as commercial singles, they were conventionally placed in particular positions on the album. During the sixties, particularly in the UK, singles were generally released separately from albums. Today, many commercial albums of music tracks feature one or more singles, which are released separately to radio, TV or the Internet as a way of promoting the album. Albums have been issued that are compilations of older tracks not originally released together, such as singles not originally found on albums, b-sides of singles, or unfinished " demo " recordings.

Double albums during the seventies were sometimes sequenced for record changers. In the case of a two-record set, for example, sides 1 and 4 would be stamped on one record, and sides 2 and 3 on the other. The user would stack the two records onto the spindle of an automatic record changer, with side 1 on the bottom and side 2 (on the other record) on top. Side 1 would automatically drop onto the turntable and be played. When finished, the tone arm's position would trigger a mechanism which moved the arm out of the way, dropped the record with side 2, and played it. When both records had been played, the user would pick up the stack, turn it over, and put them back on the spindle—sides 3 and 4 would then play in sequence. Record changers were used for many years of the LP era, but eventually fell out of use.