The wardens before Norten didn't really do anything special. There was an older man named Sherwood Bolton in the book. The same character was in the movie, but he had a different name. His name in the movie was Brooks. Brooks contrast prison life and life outside the walls.
In my opinion there were two protagonists in the movie and book, Red and Andy. Andy fought against the "sisters" and Red helped everyone out with his connections. When I first read the book, I pictured Red as a white male, with red hair. In the book it says that Red got his name from his hair, which was red. In the movie, he was a black male with black hair. I was surprised when I found out that he was actually black, because I don't see why they made the change from white to black. The fact that he was black in the movie really didn't really change anything at all. .
There was a young kid Tommy who came in about halfway through the movie. He was a young thief. He had some important information regarding Andy and how he was framed for his murder. The warden didn't want any of this getting out, so in the book, Tommy was transferred to another prison, but in the movie the warden has Tommy shot.
In the book they do not really mention any of the side characters that were in the movie. Andy was alone when he first entered Shawshank, but once he started to become friends with Red, it seemed like he was part of a gang. In the book King didn't mention anything about any of Andy's other friends in Shawshank. .
Red is the one telling the story in the book, and he's also the one telling the story in the movie. In the book it is more Red talking then anyone else. In the movie Red narrates most of it, but there are also many times where there are other characters talking. In the book Red states that most of what he says is hearsay. He talks about how Andy is more of a legend then a man. "You may also have gotten the idea that I"m describing someone who's more legend than man, and I would have to agree that there's some truth to that.