But instead of trying to pry him away from his machine or coaxing him outside to get some fresh air, his mother, Barbara Ackerman, had another solution: she suggested that he drop out of high school to be home-schooled. “I saw him at school all day and absorbed all night into his computer,” said Ms. Ackerman, reached by phone Monday afternoon. “It became very clear that David needed the space to live his passion. Which was computers. All things computers.”