Music-Album Evolution

FILE – In this Sept. 9, 2014 file photo, Apple CEO Tim Cook, left, greets Bono from the band U2 after they preformed at the end of the Apple event on Tuesday, Sept. 9, 2014, in Cupertino, Calif. Apple unveiled a new Apple Watch, the iPhone 6 and Apple Pay and U2 offered iTunes customers a free download of their latest album, “Songs of Innocence.” (AP Photo/Marcio Jose Sanchez)