The book was a traditional biography. Jobs co-operated and did interviews for the book expecting publication after his death.
The movie departs from the book in format. The main parts are 3 distinctive product launches in which Jobs is forced to face his responsibilities as a father, an innovator and how to deal with multiple personal and business relationships. The movie is thick on fast paced dialogue as you expect from Sorkin's writing. If you know the technology and the Apple story it helps but the movie is focussed on character.
There are obvious points where things are explained by using a character in the room to represent the audience. Suffice to say you don't need IT knowledge to follow the movie.
The 2013 movie called Jobs starring Ashton Kutchner was more conventional but both suffered from not having a dramatic element that draws in the audience, The main focus is always on the complexity of Jobs himself. Far from being a genius you learn that he had single minded visions and binary view of the world. People were in or out.
The film makes it pretty clear that the Apple world is one of a messianic leader in which a technology company moves from having commercial products to being a religion in which Jobs was content in being the focus.
Having read the book and watched both movies I certainly don't like Steve Jobs. His company was 90 days away from bankruptcy when he came back and, in part, it survived due to $150 million investment from Microsoft. Like the surfer he was able to catch the next technological waves with the iMac, iPod and iPhone better than anyone else. His Mac, back in 1984, was a little ahead of his time.
A worthwhile movie to understand Steve Jobs and Apple a little better.