Chapter 12: Exploring Information System Development

System Development

- System development is a set of activities used to build an information system.
- System is a set of components that interact to achieve a common goal.
- Information system is a collection of hardware, software, data, people and procedures that work together to produce information.
- System development activities are grouped into phases, sometimes is called the system development life cycle (SDLC).

System development guidelines:

• Group activities into phases
• Involve users
• Define standards

Who participates in system development?

- System development should involve representatives from each department in which the proposed system will be used.

Project management

- 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 the following elements:

• Project scope (goals, objectives and expectations)
• Required activities
• Time estimates for each activities
• Cost estimates for each activities
• Order of activities
• Activities that can take place at the same time

- Gantt and PERT charts are popular tools used to plan and schedule the time relationships among project activities

Gantt chart

PERT chart

Feasibility assessment

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

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

Documentation

- Documentation is the collection and summarization of data, information and deliverables.
- A project notebook contains all documentation for a single project.

Data and information gathering techniques:

• Review documentation
• Observe
• Survey
• Interview
• Joint-application design (JAD) sessions
• Research

What circumstances initiate system development?

- A user may request a new or modified information system for a variety of reasons.
- Organisations may want to improve hardware, software or other technology to enhance an information system.
- Situations outside the control of an organisation require a modification to an information system.
- Corporate management or some other governing body may mandate a change.
- A user may request a new or modified information system verbally in phone conversation or written as an email message. In larger organisations, users write a formal request for a project request or request for system services.

Planning Phase

- 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 (money, people and equipment)
• Form a project development team

Analysis Phase

- Analysis phase consists of two major activities:

• Conduct a preliminary investigation
• Perform detailed analysis

The preliminary investigation

- The main purpose is to determine the exact nature of the problem or improvement and decide whether it is worth pursuing.
- The first task is to interview the user who submitted the project request.

Detailed analysis

- Detailed analysis involves three major activities:

• Study how the current system works
• Determine the users' wants, needs and requirements
• Recommend a solution

Process modeling

- Process modeling (structured analysis and design) is an analysis and design techique that describes processes that transform inputs into outputs.

• Entity-relationship diagrams
• Data flow diagrams
• Project dictionary

- Entity-relationship diagram (ERD) is a tool that graphically shows the connections among entities in a system.
- Entities are objects in the system that have data.

- Data flow diagram (DFD) is a tool that graphically shows the flow of data in a system.

- Project dictionary contains all the documentation and deliverables of a project.
- Decision table is a table that lists a variety of conditions and the actions that correspond to each condition

- Decision tree also shows conditions and actions, but it shows the graphically.

- Data dictionary stores the data item's name, description and other details abut each data item.
- Object modeling combines the data with the processes that act on that data into a single unit, called an object.
- Unified modeling language (UML) has been adopted as a standard notation for object modeling and development
- UML includes 13 different diagrams.
- Two diagrams include:

• Use case diagram
• Class diagram

- Use case diagram graphically shows how users interact with the information system.

- Class diagram graphically shows classes and subclasses in a system.

The system proposal

- The purpose of the system proposal is to assess the feasibility of each alternative solution and then recommend the most feasible solution for the project.
- The steering committee discusses the system proposal and decides which alternative to pursue, it consider whether to:

• Modify the existing system
• Buy retail software from an outside source
• Use web apps
• Build its own custom software
• Outsource some or all of its IT needs to an outside firm

Design Phase

- Design phase consists of two major activities:

• Acquire hardware and software
• Develop all of the details of the new or modified information system

- It consists of four major tasks:

• Identify technical specifications
• Solicit vendor proposals
• Test and evaluate vendor proposals
• Make a decision

Identify technical specifications

- Use research techniques such as e-zines.

Solicit vendor proposals

- Request for quotation (RFQ), Request for proposal (RFP) or Request for imformation (RFI) is sent to potential hardware or software vendors or value-added reseller (VAR).

Test and evaluate vendor proposals

- Various techniques are used to determine the best proposal.

Make a decision

- System analyst presents a recommendation to the steering committee.

Detailed design

- The activities to be performed include:

• Database design
• Input and output design
• Program design

- System analyst may develop a mock-up and/or a layout chart for each input and output.
- Mock-up is a sample of the input or output that contains actual data.
- Layout chart is more technical and contains programming-like notations.

Prototyping

- Prototype, aka proof of concept, is a working model of the proposed system's essential functionality.
- Computer-aided software engineering (CASE) tools are designed to support one or more activities of system development.
- CASE tools sometimes contain the following tools:

• Project repository
• Graphics
• Prototyping
• Quality assurance
• Code generator
• Housekeeping

- Inspection is a formal review of any system development deliverable.

Implementation Phase

- The purpose of implementation phase is to construct or build the new or modified system and then deliver it to the users.
- Four major activities:

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

Develop programs and apps

- Program development life cycle:

• Step 1: Analyse the requirements
• Step 2: Design the solution
• Step 3: Validate the design
• Step 4: Implement the design
• Step 5: Test the solution
• Step 6: Document the solution

Install and test the new system

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

Train users

- Training involves showing users exactly how they will use the new hardware and software in the system.
- Training takes place as one-on-one sessions,classroom-style lectures and web-based training.

Convert to the new system

- This change can take place using one or more of the following conversion strategies:

• Direct conversion
• Parallel conversion
• Phased conversion
• Pilot conversion

Support and security phase

- The purpose of the support and security phase is to provide ongoing assistance for an information system and its users after the system is implemented.
- Three major activities:

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

- Computer security plan should do the following:

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