Randall Poster was nine years old when he bought his first 45 rpm record. It was “Laughing,” the Guess Who’s 1969 hit. His first album purchase came a couple of years later: Rod Stewart’s Every Picture Tells a Story. As the 1970s progressed, many of Poster’s musical purchases ended up being cassettes, a medium he grew to love via membership in the Columbia House mail-order music club. When he wasn’t Hoovering music, the young Poster, who grew up in the Riverdale section of the Bronx and attended the Horace Mann School, was making the rounds of New York’s cinemas. It was a great era to be a fledgling movie hog: The French Connection, The Godfather, Shampoo.