This is a serious question 😉
I just led a workshop for a medium size company which was considering (and is now planning) to start using Scrum as the organizing principle for their SW Development efforts. And exactly this question arose.
As it was, we had a classically trained project manager in the room, so he provided much insight into what is expected of a project manager:
Explicitly not part of the Project Manager’s job is removing impediments.
How is this work distributed among the players in Scrum?
|Select Team Members||initial||once established|
|Ensure satisfactory implementations||X|
|Define and Impose Standards||X|
|Coordinate Work between Team Members||X|
|Commit to Delivery Dates||shared||shared|
|Communicate with the Customer (for realization)||X|
So a Scrum master actually has very little in common with a classically trained project manager. The most important job of the scrum master is to remove impediments, something which is explicitly not part of the project manager’s job.
The Scrum master is a ‘servant leader’ — his primary job is to ensure that his team can work and that everyone is playing by the rules. He will also be an agent if not the agent of change in his organization: identify what prevents to organization from advancing and eliminating that impediment.
If you are looking for the difference between RUP and Scrum, waterfall and Scrum, or almost anything and Scrum, look first at the roles. Here is where the fundamental differences are to be found.