Chapter 12 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 should follow three general guidelines:

1.  Group activities or tasks into phases 
2.  involve users
3. define standards.

• 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.
• 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.
• Users and IT professionals refer to existing documentation when working with and modifying current systems.

Planning Phase

• The planning phase for a project begins when the steering committee receives a project request.
• Four major activities are performed for example review and approve the project requests, Prioritize the project requests, Allocate resources, Form a project development team.

Analysis Phase

• Process modeling (structured analysis and design) is an analysis and design technique that describes processes that transform inputs into outputs.
• 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.
• 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.
• 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.
• A use case diagram graphically shows how actors (users) interact with the information system.
• The system proposal assesses the feasibility of each alternative solution.
• The steering committee discusses the system proposal and decides which alternative to pursue.

Design Phase

• The design phase consists of two major activities for example Acquire hardware and software, Develop all of the details of the new or modified information system.
• Systems analysts typically develop two types of designs for each input and output.
• A prototype (proof of concept) is a working model of the proposed system. Prototypes have inadequate or missing documentation.

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.
• One or more of 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 risks, identify the safeguards that exist to detect, prevent, and recover from a loss.