Software Development Methodologies

Iterative and incremental development.

We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value:

1. Individuals and interactions over processes and tools
2. Working software over comprehensive documentation
3. Customer collaboration over contract negotiation
4. Responding to change over following a plan

Source: Dilbert

Scrum is an iterative, incremental methodology for project management often seen in agile software development.

The name scrum came from rugby, where the whole team "tries to go the distance as a unit, passing the ball back and forth." Likewise, in scrum, the development phases strongly overlap and the whole process is performed by one cross-functional team across the different phases.

A key principle of Scrum is its recognition that during a project, there can be requirements churn, and that unpredicted challenges cannot be easily addressed in a traditional predictive or planned manner. As such, Scrum adopts an empirical approach accepting that the problem cannot be fully understood or defined, focusing instead on maximizing the team's ability to deliver quickly and respond to emerging requirements.

Terminology

1. Product Backlog
   Wish list for the features of final product.
2. Release Backlog
   Priotirized list of Backlog.
3. Spint Backlog
   Short duration (3-30dyas) milestones for ship-ready release.
4. Burndown Chart
   This shows remaining work in the sprint backlog.

Extreme Programming (XP) is intended to improve software quality and responsiveness to changing customer requirements. As a type of agile software development, it advocates timeboxing, which is intended to improve productivity and introduce checkpoints where new customer requirements can be adopted.

Other elements of extreme programming include: programming in pairs or doing extensive code review, unit testing of all code, avoiding programming of features until they are actually needed, a flat management structure, simplicity and clarity in code, expecting changes in the customer's requirements as time passes and the problem is better understood, and frequent communication with the customer and among programmers.

Think big, act small, fail fast; learn rapidly."

Basic principles of lean are:

1. Eliminate waste - Everything not adding value to the customer is considered to be waste
2. Amplify learning - The learning process is sped up by usage of short iteration cycles each one coupled with refactoring and integration testing.
3. Decide as late as possible- delaying decisions as much as possible until they can be made based on facts and not on uncertain assumptions and predictions.
4. Deliver as fast as possible - The sooner the end product is delivered without considerable defect, the sooner feedback can be received, and incorporated into the next iteration.
5. Empower the team
6. Build integrity in - refactoring

Test-driven development (TDD) relies on the repetition of a very short development cycle. It's a technique for designing a code. In TDD, each new feature begins with writing a test not the production code. By writing the test code first, we're focusing on the behavior of a unit or its interface.

If we deliver a project using TDD, the code tends to be more cleaner and less complicated. This is because as I'm writing the test, I'm ensuring the code testable. Testable code is clean and simple so that we can isolate it and test it easily.

The waterfall model maintains that one should move to a phase only when its preceding phase is completed and perfected.

1. Software Development Methodology

DevOps

DevOps / Sys Admin Q & A

Puppet