CHAPTER 12: Exploring Information 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).

Ongoing Activities

• Project management
• Feasibility assessment
• Documentation
• Data/information gathering

Planning

• Review project requests
• Prioritize project requests
• Allocate resources
• Form project development team

Analysis

• Conduct preliminary investigation
• Perform detailed analysis activities:
• Study current system
• Determine user requirements
• Recommend solution

Design

• Acquire hardware and software,if necessary
• Develop details of system

Implementation

• Develop programs,if necessary
• Install and test new necessry
• Train users
• Convert to new system

Operation,Support,and Security

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

• System development should follow three general guidelines:
• Group activities or tasks into phases
• Involve users
• Define standards
• System development should representatives from each department in which the proposed system will be used.
• 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:
• Projectscope
• Required activities
• Time estimates for each activity
• Cost estimates for each activity
• Order of activities
• Activities that can take place at the same time
• 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.
• A project notebook contains all documentation for a single project.
• Users and IT professionals refer to existing documentation when working with and modifying current systems.
• During system development,members of the project team gather data and information using several techniques.
• Review documentation
• Observe
• Survey
• Interview
• JAD Sessions
• Research

Who Initiates a System Development Project

• A user may request a new or modified system
• Organizations may want to improve hardware, software, or other technology
• Situations beyond an organization's control might  require a change
• Management might mandate a change
• A user may request a new or modified information system using a request for system services or a project request.

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

• The analysis phase consists of two major activities:
• 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 requirement
• Recommend a solution
• Process modeling( structured analysis and design) is an analysis and design technique that describes processes that transform inputs into outputs
• Entity-relationship diagrams
• Data flow diagrams
• Project dictionary
• An 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.
• A data flow diagram (DFD) is a tool that graphically shows the flow of data in a system.
• Data flow
• Processes
• Data stores
• Sources
•  The project dictionary contains all the documentation and deliverables of a project.
• Structured English is a style of writing that describes the steps in a process.
• A decision table is a table that lists a variety of conditions and the actions that correspond to each condition.
• A decision tree also shows conditions and actions, but it shows them graphically.
• 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 ntation for object modelig and development
• UML includes 13 different diagrams
• Two diagrams include:
• Use case diagram
• A use case diagram graphically shows how actors (users) interact with the information system.
• Diagrams are considered easy to understand.
• Class diagram
• A class diagram graphically shows classes and subclasses in a system.
• Each class can have one or more subclasses.
• Subclasses use inheritance methods and attributes of higher levels.
• The system proposal assesses the feasibility of each alternative solution.
• The steering committee discusses the system proposal and decides which alternative to purpyse
• Packaged software
• Custom software
• Outsourcing

Design Phase

• The design phase consists of two major activities
• Acquire hardware and software
• Develop all of the details of the new or modified information system
• To acquire the necessary hardware and software:
• Identify technical specifications
• Use research techniques such as e-zines
• Solicit vendor proposals
• RFQ,RFP. or RFI is sent to potential vendors VARs
• Test and evaluate vendor proposals
• Various techniques are used to determine the best proposal
• Make a decision
• System analyst makes recommendation to steering committee
• The next step is to develop detailed design specifications
• Sometimes called a physical design
• Database design
• Input and output design
• Program design
• Systems analyst typically develop two types of designs fr each input and output.
• A prototype (proof of concept) is a working model of the proposed system 
• Prototypes have inadequate or missing documentation
• Users tend to embrace the prototype as a final system
• Should not eliminate or replace activities
• 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
• Graphically
• Prototyping
• Quality assurance
• Code generator
• Housekeeping
• Many people should review the detailed design specifications.
• An inspection is a formal review of any system development deliverable
• A team examines the deliverables to identify errors

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
• The program development life cycle follows these steps:
• Analyze the requirements
• Design the solution
• Validate the design
• Implement the design
• Test the solution
• Document the solution
• Various tests should be performed on the new system
• Unit test 
• Verifies that each individual program or object works by itself
• System test
• Verifies that all programs in an application work together properly
• Integration test
• Verifies that an application work with other applications
• Acceptance test
•  Checks the new system to ensure that it works with actual data
• Training involves showing users exactly hoe they will use the new hardware and software in the system.
• One on one sessions
• Classroom style lectures
• Web based training
•  One or more f four conversion strategies can be used to change from the old system to the new 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 risk, identify the safeguard that exist to detect, prevent, and recover from a loss