Major Software Development Methods

Question 1

Major Software Development Methods and Strategies

(Covered in this course)

Answer 1

• Test Driven Development
• Model Driven Development
• Prototyping
• Incremental Delivery

Question 2

Model Driven Development:

Basic Description

Answer 2

Models of the software are created at different levels of abstraction

Greater emphasis on architectural models,

with a separation between abstract implementation, independent models, and implementation-specific models

Question 3

Common Development Issues:

Types of Change

and the problems that they can introduce

Answer 3

• Business Changes
  
  • Can alter System Requirements
• New Technologies
  
  • New possibilities to improve implementation
• Changing Platforms
  
  • May require major application changes

All types of change lead to rework, including reanalyzing requirements.

Rework adds extra time and cost to implement new functionality

Question 4

Common Development Issues:

Reducing the Cost of Rework:

Two Approaches

Answer 4

Change Avoidance(or Anticipation)

Software process includes activities that can anticipate possible changes BEFORE significant rework is required.

Example: Identifying problems early with prototyping

Change Tolerance

Process is designed to be able to change at low cost. Normally involves incremental development.

Question 5

Prototyping:

What is a Prototype?

Answer 5

Prototype

An initial version of a system, used to demonstrate concepts and try out design options.

Can be used in:

• Requirements Engineering process
  
  • Helps with requirements elicitation and validation
• Design Processes
  
  • Explore options and develop a UI design

Question 6

Prototyping:

Two Types of Prototyping

Answer 6

Evolutionary Prototyping

Throw-Away Prototyping

Question 7

Prototyping:

Evolutionary Prototyping

(summary)

Answer 7

Evolutionary Prototyping

An initial prototype is produced and refined through a number of stages to the final system

Question 8

Prototyping:

Throw-Away Prototyping

(summary)

Answer 8

Throw-Away Prototyping

A prototype is produced to help discover requirements problems, then discarded.

The actual system is developed using another process.

Question 9

Prototyping:

Benefits

Answer 9

• Improved system usability
• Closer match to user’s real needs
• Improved design quality
• Improved maintainability
• Reduced Development Effort

Question 10

Prototyping:

Prototype Development Process

Steps and Deliverables

Answer 10

• Establish Prototype Objectives
  
  • Prototyping Plan
• Define Prototype Functionality
  
  • Outline Definition
• Develop Prototype
  
  • Executable Prototype
• Evaluate Prototype
  
  • Evaluation Report

Question 11

Incremental Delivery:

Pipeline Steps (9)

Answer 11

Initial Steps

• Define Outline Requirements
• Assign Requirements to Increments
• Design System Architecture

Increment Steps (Repeat for each increment)

• Develop System Increment
• Validate Increment
• Integrate Increment
• Validate System
• Deploy Increment

Deploy Final System

Question 12

Incremental Delivery:

Advantages

Answer 12

• Customers can use early versions to gain experience that informs requirements for later system increments
• Customers do not have to wait for the “full” system to gain value
• Incorporates incremental development, so retains the benefit of easily incorporating changes
• Highest priority services are delivered first, and increments then integrated.
  
  • Most important services recieve the most testing

Question 13

Incremental Delivery:

Problems/Disadvantages

Answer 13

• Can be hard to know what shared basic facilities will be needed by future increments
• User expectations “locked in”
  
  • Users want all functionality of previous releases
  • Can be difficult to develop a replacement system
  • Users do not want to experiment with a new system
  • Hard to get customer feedback
• Requires different system development contracts, since there isn’t a “Final” version to deliver