Chapter 12 : Exploring Information System Development

What is System Development?

System development is a set of activities used to build an information system. 

• A system is a set of components that interact to achieve a common goal.
•  An information system (IS) is a collection of hardware, software, data, people, and procedures that work together to produce quality information.
• System development activities are grouped into phases, collectively called the system development life cycle (SDLC)
• System development should follow three general guidelines: 
•  Group activities or tasks into phases 
• involve users 
• define standard

Project management is the process of planning, scheduling, and then controlling the activities during system development

To plan and schedule a project efficiently, the project leader identifies: 

• Project scope
• Required activities
• Order of activities.
• Time estimate for each activity 
• cost estimate for each activity
• order of activity 
• Activities that can take place at the same times

Feasibility is a measure of how suitable the development of a system will be to the organization. 

• Operational feasibility
• Schedule feasibility 
• Technical feasibility
• Economic feasibility

Documentation is the collection and summarization of data and information.

Planning Phase

The planning phase for a project begins when the steering committee receives a project request

Four major activities are performed: 

• Review and approve the project requests 
• Prioritize the project requests
• Allocate resources
• Form a project development team.

Analysis Phase

Conduct a preliminary investigation

• Determines and defines the exact nature of the problem or improvement
• Interview the user who submitted the request
• Perform detailed analysis
• Study how the current system works
• Determine the users’ wants, needs, and requirements
• Recommend a solution

Process modeling (structured analysis and design) is an analysis and design technique that describes processes that transform inputs into output

• An entity-relationship diagram (ERD) is a tool that graphically shows the connections among entities in a system
• A data flow diagram (DFD) is a tool that graphically shows the flow of data in a system
• The project dictionary contains all the documentation and deliverables of a project.

A decision table is a table that lists a variety of conditions and the actions that correspond to each condition

The data dictionary stores the data item's name, description, and other details about each data item

Object modeling combines the data with the processes that act on that data into a single unit, called an object

UML (Unified Modeling Language) has been adopted as a standard notation for object modeling and development.Two diagram include Use case diagram and Class diagram 

• A use case diagram graphically shows how actors (users) interact with the information system.
• A class diagram graphically shows classes and subclasses in a system

Design Phase

The design phase consists of two major activities 

1. Acquire hardware and software
2. Develop all of the details of the new or modified information system

A prototype (proof of concept) is a working model of the proposed system. 

Implementation Phase

The purpose of the implementation phase is to construct the new or modified system and then deliver it. 

• Develop programs > Install and test the new system > Train users > Convert to the new system.

Various tests should be performed on the new system. 

• Unit test - verifies that each individual program or object works by itself.
•  Systems test - verifies that all programs in an application work together properly. 
• Integration test - verifies that an application works with other applications. 
• Acceptance test - checks the new system to ensure that it works with actual data.

Training involves showing users exactly how they will use the new hardware and software in the system.

Operation, Support, and Security Phase

The purpose of the operation, support, and security phase is to provide ongoing assistance for an information system and its users after the system is implemented.

• Perform maintenance activities > Monitor system performance > Assess system security.

A computer security plan should do the following:

•  Identify all information assets of an organization. 
• Identify all security risks that may cause an information asset loss. 
• For each risks, identify the safeguards that exist to detect, prevent, and recover from a loss.