The man who gave us High School Musical and Hannah Montana at Disney Channel has stepped down as the head of Walt Disney Co.’s movie studio after failing to find a winning formula for film. Named to the position in 2009, Rich Ross announced his decision to resign in an email to staff on Friday. A successor was not immediately named. Ross’s departure follows the monumental fiasco that was Disney’s John Carter, a sci-fi flop approved by Ross that will likely lose the studio about $200 million. Ross got his first job at the Disney Channel in 1996, and became president of the channel in 2004.