Professional C__ - Marc Gregoire [408]
We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value:
Individuals and interactions over processes and tools
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
That is, while there is value in the items on the right, we value the items on the left more.
As can be understood from this manifesto, the term Agile is only a high-level description. Basically, it tells you to make the process flexible so that customers’ changes can easily be incorporated into the project during development.
Scrum
Agile is just a high-level foundation; it does not specify exactly how this should be implemented in real life. That’s where Scrum comes into play; it’s an Agile methodology with precise descriptions on how to use it on a daily base.
Just like the Spiral Model, Scrum is an iterative process. It is becoming more and more popular as a means to manage software development projects. In Scrum, each iteration is called a sprint cycle. The sprint cycle is the central part of the Scrum process. The length of sprints, which should be decided at the beginning of the project, is typically between two and four weeks. At the end of each sprint, the goal is to have a version of the software available that is fully working and tested, and which represents a subset of the customers’ requirements. Scrum recognizes that customers will often change their minds during the development and thus allows the result of each sprint to be shipped to the customer. This gives customers the opportunity to see iterative versions of the software and allows them to give feedback to the development team about potential issues.
Roles
The Product Owner (PO) is the connection to the customer and to other people. The PO writes high-level user stories based on input from the customer, gives each user story a priority, and puts the stories in the Scrum product backlog. Actually, everyone on the team is allowed to write high-level user stories for the product backlog, but the Product Owner decides which user stories are kept and which are removed.
The Scrum Master (SM) is responsible for keeping the process running and can be part of the team, although not the team leader, because with Scrum the team leads itself. The SM is the contact person for the team so that the rest of the team members can concentrate on their tasks. The SM ensures that the Scrum process is followed correctly by the team; for example, by organizing the Daily Scrum meetings, which are discussed later. The Scrum Master and Product Owner should be two different persons.
The third and final role in the Scrum process is the Team itself. Teams, which develop the software, should be kept small, preferably fewer than 10 members.
The Process
The Scrum process enforces a daily meeting called the Daily Scrum or Standup. In this meeting, all team members sit together with the Scrum Master. According to the Scrum process, this meeting should start every day at exactly the same time and location, and should be no longer than 15 minutes. During this meeting, all team members get to answer three questions:
What did you do since the last Daily Scrum?
What are you planning to do after the current Daily Scrum?
What problems are you facing to reach your goal?
Problems faced by team members should be noted by the Scrum Master who will try to solve them after the Daily Scrum meeting.
Before the start of each sprint cycle there is a Sprint Planning meeting in which team members must decide which product features they will implement in the new sprint. This is formalized in a sprint backlog. The features are selected from a product backlog containing prioritized user stories, which are high-level requirements of new features. User stories from the product backlog are broken down into smaller tasks with an effort estimation and are put in the sprint backlog. Once a sprint is in progress, the sprint backlog is frozen and cannot be changed