1. The Systems Development Life Cycle

2. Today What is Software Development Overview of Software Development
What is a system?
Systems Development Lifecycle (SDLC)
Iterative Development

3. What is Software Development?
Software Development implies developing some software – but it does not involve simply coding programs
Software is developed to turn manual processes into automated processes or to improve/enhance existing automated processes.

4. What does this have to do with Systems?
Software Development entails understanding the problem to be solved, understanding how a business operates and understanding that the solution to be developed will be of value to the business (First ½ of SYS366)
The Systems stream of courses provide the knowledge of the steps that need to be followed to successfully create a software solution from the inception of the idea to a working, fully operational system. This collection of steps is called the Systems Development Life Cycle.

5. What is a system?
A combination of hardware and developed software that create the software solution that meets the needs of a business.
A collection of inter-related components that collect, process, store and provide as output the information needed to complete business tasks.

6. What is a system? Characteristics of a system*
It exists in an environment
It is separated from its environment by some kind of boundary
It has inputs and outputs which come from, or are sent to the environment
It has interfaces (allows communication between two systems)
It can have sub-systems (which are also systems)
It has a control mechanism
*Object-Oriented Systems Analysis & Design using UML, 1999 pages 5-6

7. What is a system? Characteristics of a system*
It exists in an environment
It is separated from its environment by some kind of boundary
It has inputs and outputs which come from, or are sent to the environment
It has interfaces (allows communication between two systems)
It can have sub-systems (which are also systems)
It has a control mechanism
*Object-Oriented Systems Analysis & Design using UML, 1999 pages 5-6

8. What is a system? What the system does System Boundary Inputs Outputs
Control
Feedback
Feed-forward
How the system
is controlled
*Object-Oriented Systems Analysis & Design using UML, 1999 pages 5-6

9. Need for Software Development:
Environments are rapidly changing
New technologies are frequently introduced
Companies merge and need to combine their systems
Governments pass new legislation or make changes to it (example, GST & PST changed to HST)

10. Typical Software Development Solutions
Developed in-house
Turnkey
Off-the shelf
Contracted out

11. Systems Development Lifecycle (SDLC)
Software Development Projects are developed according to a definite methodology called the SDLC
organizes the activities of a project
Interactive and Incremental
followed by professionals involved in software development

12. What is a methodology?
Comprehensive guidelines to follow for completing every SDLC activity
Examples: Structured (Traditional), Object-oriented

13. Systems Development Methodologies
Structured
Worked well for centralized processing applications and procedural languages
Object Oriented
Works for GUI and web solutions
OO languages: C++, Java, C#, Pearl, etc

14. Structured Systems Development Methodology
Based on the functions that a system needs to perform
Development is rigid: does not allow for changes easily without significant impact to a project deadline
Components do not tend to be reusable: solution developed is for a specific set of functions (which usually aren’t shared)
Uses Data Flow Diagrams (the flow of data through a system) and Entity Relationship Diagrams (the data the system is going to use)

15. Object-oriented Systems Development Methodology
Fundamentally different from traditional software development
Object-oriented approach
Real world objects are modeled by corresponding programming objects. Objects have state, behaviour and identity.

16. Object Oriented Systems Development Methodology
Based on the interaction that happens between ‘objects’
Does still consider the functions the system needs to perform however
Allows for reusability or sharing of code (a dialogue box construct is the same across applications)
Reduces the development time for an application
Focuses on object technology such as multimedia systems

17. The Phases of the SDLC: Systems Development Life Cycle
The Phases of the SDLC for both the Structured and the OO methodologies are similar

18. Phases of the SDLC Project Planning Phase
Analysis Phase: understanding business needs
Design Phase: conceptualizing computer-system solutions
Implementation Phase: coding, testing and installation
Support Phase

19. How the Object-oriented SDLC is used in the Systems courses
Analysis:
Systems requirements are determined, defined and documented
Looks at functions (at a high level) and the data that will be used
Defines ‘what the system is to do’
Deliverables:

20. How the Object-oriented SDLC is used in the Systems courses
Analysis:
Deliverables:
Business Use Case Diagrams (Sys366)
Business use case specifications (Sys366)
Stakeholder Diagrams (Sys366)
Systems Use Case Diagrams (Sys366, Sys466, PRJ566
Systems Use Case Descriptions (Sys366, Sys466, PRJ566)
Project Initiation Document outlining the requirements of the system (Sys366 & PRJ566)

21. How the Object-oriented SDLC is used in the Systems courses
Design:
Architecture (what platform will the solution be developed on) (PRJ566, PRJ666)
Integrates the user interfaces with the data more clearly (PRJ566, PRJ666)
Defines ‘how the system will do it’
Follows certain design patterns (SYS466)

22. How the Object-oriented SDLC is used in the Systems courses
Design:
Deliverables:
System-Level Sequence Diagrams (Sys466, PRJ566)
Object-Level Sequence diagrams (Sys466, PRJ566)
Class diagrams (Sys466, PRJ566)
Screen Mock-ups (PRJ566)
Database Design (PRJ566)

23. How the Object-oriented SDLC is used in the Systems courses
Analysis & Design of a system for the capstone project (Sys566)
Project Management (Sys566)

24. How the Object-oriented SDLC is used in the Systems courses
Code, Test, Implement: (PRJ666)
Code and install system for capstone project
Define and create databases
Deliverables:
Program code and documentation
Tested, working system
User Documentation

25. How the Object-oriented SDLC is used in the Systems courses
Implementation: (PRJ666)
The working system is delivered
Deliverables:
Hardware
Databases
Data Converted
Software installed
Support processes implemented
This phase actually happens in varying levels of detail at the end of each cycle

26. Why the move to Object-oriented Methodology?
Software Development is too expensive
Poor Quality
Late Delivery
Poor Productivity
Too much person-power needed
Fragile systems
Legacy Systems
User Interfaces not state of the art

27. Why the move to Object-oriented Methodology?
Software Developers are being asked to
Develop more sophisticated systems
Tackle more complex systems
Produce more reliable and malleable systems
Shorten the delivery cycle
Reduce costs

28. Software Development Some common causes for Failure:
Deadlines that cannot be met
Budgets that have been exceeded
Solutions that don’t work
Systems too complex to maintain
Customer’s requirements not fully understood or captured correctly
Customers continually change their requirements
Customers are not committed to the project

29. How does the Object-oriented SDLC help to overcome these problems in Software Development?
The system under development is refined and transformed through analysis, design, code and test phases – details are added in successive iterations (changes and improvements are introduced as needed) and incremental releases of software modules are delivered.
System design – developing information systems using UML by Leszek A. Maciaszek (page 5, 2001)

30. Iterative Nature of the Software Development Life Cycle

31. SDLC Variations
Developers encounter many variations of SDLC in practice. Based on:
Phases
Iteration
Emphasis on people
Speed of development
BUT you have to understand the basic methodology before you can vary it