Released in April 1977, the Apple II started the boom in personal computer sales. President Jimmy Carter warned of the need to conserve energy. Americans gathered around their televisions for the miniseries Roots, a dramatic portrayal of slavery, which was watched by more than 100 million people. The space probe Voyager sent "Sounds of Earth" into space with an eclectic 90-minute musical program including Chuck Berry’s "Johnny B. Goode" and Mozart’s "Magic Flute." The Disco era took off with the release of the film Saturday Night Fever. Star Wars: A New Hope became a pop phenomenon while kids took to the streets with their new skateboards.