- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Introduction to Management Information SystemsChapter 6 System Development
What Systems to be developed
- Many different types of systems in the organization
(e.g. ERP, etc)
(B2B, SRM, etc.)
System Development Fundamentals
Constant interaction between Users (MIS, HTM 304) and IT professionals (System Analysis & Design, HTM 425)
Video – System Development
Think Big About System Development
- Many students are new to the systems development process due to working with personal computer tools.
- The scope of work is large with large-scale corporate information systems and may be global with different languages and cultures.
- Management of resources is a critical success factor.
- Comprehensive processes are required for project staff to follow and adhere to in order to successfully meet project and systems objectives.
Think Big (cont)
- Three software sources
- Off-the shelf-with adaptation
- Major IS rarely off-the-shelf due to involvement of company people and resources
System Development Is Challenging
- Systems development difficult and risky
- Many projects never finished
- Some projects finish 200-300% over budget
- Some projects finish on schedule and within budget but don’t meet the goals
System Development Challenges
- Difficulties in determining requirements
- Changes in requirements
- Scheduling and budgeting difficulties
- Changing technology
- Diseconomies of scale
Systems Development Methodologies
- There are many different system development processes
- System Development Life Cycle (SDLC)
- Rapid Application Development (RAD)
- Object-oriented System Development (OOD)
- Extreme Programming (XP)
- Information Systems Differ
- No single process works for all situations
Scales of Information Systems
The 5-Phase Version of SDLC in our book
System Definition Phase Tasks
- Define project
- Goals and objectives
- Scope – statement of work
- Assess feasibility
- Cost (budget)
- Organizational feasibility
- Form a project team
- Project manager
- In-house IT staff
- Outside consultants and staff (as needed)
- User representatives (management and staff)
SDLC Requirement Analysis Phase
Requirement Analysis Phase Tasks
Obtain User Approval Before You Move-on
- Once the requirements have been specified, the users must review and approve them before the project continues.
- The easiest and cheapest time to alter the information system is in the requirements phase.
- Changing a requirement in the implementation phase may require weeks of reworking applications components and the database.
Component Design Phase
Component Design Phase
- Each of the five components is designed in this stage.
- The team designs each of the five components by developing a list of alternatives.
- Each alternative is evaluated against the requirements.
- Typically the best alternative that meets the requirements is selected.
- Team determines specifications for hardware they want to acquire
- Team NOT designing hardware
- Typically, large company has some type of computer network infrastructure
Hardware Networking Alternatives
- PC or LANs over public Internet
- Point-to-point leased lines
- Lease time on some type of PSDN
- Create Virtual Private Network (VPN) over Internet
Slide 21 Slide 22
Database and Procedure Design
- Database design
- Convert database design to data model
- If off-the-shelf DB, little design needed
- Procedure design
- Procedures must be developed for system users and operations personnel to follow
- Procedures typically address
- Normal processing: procedures for using the system to accomplish business tasks
- Backup: user procedures for backing up data and other resources
- Failure recovery: Procedure to continue operation when system fails and procedures to convert back to the system after recovery
People Component -- Design of Job Descriptions
- Job descriptions needed for both users and operations personnel
- New IS may require new jobs
- Organizations may have to add new duties and responsibilities due to information systems changes and enhancements
Comparison of Design and Implementation
4 ways to implement system conversion
- Pilot – Implement entire system on limited portion of the business
- Phased- New system installed in pieces across organization
- Parallel – New system runs in parallel with old system for a while
- Plunge – Old system turned off and new system turned on immediately
Information System Maintenance
- Either fixing system to make it do
what is expected
- Or adapting system to changing requirement
Problems with SDLC
- The most formal procedure to develop large IS project
- Systems development seldom smooth
- Sometimes need to crawl back up waterfall
- Difficulty documenting requirements in usable way
- Scheduling and budgeting difficult, especially for large projects with large SDLC phases
Review of SDLC
- What are the five phases?
- Which phase is the most important?
- Briefly describe the five phases.
Other Developing Methods
- Rapid application development (RAD)
- Object-oriented systems development (OOD)
- Extreme programming (XP)
Basic idea - break up design and implementation phases of SDLC into smaller pieces
Use iterative process – build a piece of the system, test it and then make it better
Get user input with every iteration
- You are always involved.
RAD – Extensive Use of Prototypes
- Extensive use of prototypes
E-R modeling of the Data Form
- CASE: Computer-assisted systems engineering
Summary of RAD Characteristics
- Design / implement / fix development process
- Continuous user involvement throughout
- Extensive use of prototypes
- Joint Application Design (JAD)
- Use of CASE Tools
Object-Oriented Systems Development (OOD)
- Began after RAD – mid 1990s
- Driven by new program development method – Object-Oriented Programming (OOP)
- A series of diagramming techniques called Unified Modeling Language (UML) facilitates OOP development.
- Emerging Technique Developing Computer Programs
- Not useful for large scale development system requiring business processes & procedures (or at least not yet realized)
- There are cases where organizations have used it successfully in developing application programs.
- Three main characteristics
- Just-In-Time (JIT) Design
- Paired Programming
Compare Development Techniques