78 rpm was chosen as the standard because of the introduction of the electrically powered, synchronous turntable motor in 1925, which ran at 3600 rpm with a 46:1 gear ratio, resulting in a rotation speed of 78.26 rpm.With these factors applied to the 10-inch format, songwriters and performers increasingly tailored their output to fit the new medium.In addition, the larger surface area of the 12-inch discs allowed for wider grooves (larger amplitude) and greater separation between grooves, the latter of which results in less cross-talk.Consequently, they "wore" better, and were less susceptible to scratches.Although CBS tried to make the record more "radio friendly" by cutting the performance into halves, and separating them between the two sides of the vinyl disc, both Dylan and his fans demanded that the full six-minute take be placed on one side, and that radio stations play the song in its entirety.Singles have been issued in various formats, including 7-inch (18 cm), 10-inch (25 cm), and 12-inch (30 cm) vinyl discs (usually playing at 45 rpm); 10-inch (25-cm) shellac discs (playing at 78 rpm); cassette, 8 and 12 cm (3- and 5-inch) CD singles and 7-inch (18 cm) plastic flexi discs.In other cases a recording released as a single may not appear on an album.

The breakthrough came with Bob Dylan's "Like a Rolling Stone".The biggest digital music distributor, i Tunes, accepts as many as three tracks less than ten minutes each as a single, as does popular music player Spotify.in the late 19th century, when the gramophone record began to supersede phonograph cylinders in commercially produced musical recordings.The 7-inch 45 rpm record was released 31 March 1949 by RCA Victor as a smaller, more durable and higher-fidelity replacement for the 78 rpm shellac discs.The first 45 rpm records were monaural, with recordings on both sides of the disc.