Building Information Systems lesson 26

This lesson includes the following sections: The Systems Development Life Cycle Phase 1: Needs Analysis Phase 2: Systems Design Phase 3: Development Phase 4: Implementation Phase 5: Maintenance

Needs analysis Systems design Development Implementation Maintenance The systems development life cycle (SDLC) is an organized method for building an information system. The SDLC includes five phases: The Systems Development Life Cycle

In the needs analysis phase, the development team must define the IS-related problem, analyze the current system, and select a solution. Analysts may document the current system using tools such as data flow diagrams, structured English, or decisions trees. In this phase, IS workers learn how the current system functions and how it meets (or fails to meet) the organization's informational needs. Phase 1: Needs Analysis

In this phase, designers may create working models, or prototypes, of parts of the system, to see if their designs will work. Top-down design, in which designers start with the large picture and move to the details of its function. Bottom-up design, in which designers start with the details and move to the major functions. During systems design, the team determines how the selected solution will work. To do this, designers may use two design methods: Phase 2: Systems Design

In the development phase, software components are either created or acquired. Programmers may elect to build required software from scratch, or to customize software that is purchased from another source. In this phase, documentation (such as user manuals or online help systems) is also developed. Phase 3: Development

Direct – all users stop using the old system and start using the new one. Parallel –the old system stays in use as increasing amounts of data are processed in the new one. Phased – users start using the new system, one component at a time. Pilot – users at one site use the new system while all other users keep the old system. During implementation, the new system is installed. Four conversion methods can be use to move from an old system to a new one: Phase 4: Implementation

During the maintenance phase, continuing support is provided to the new system's users. Changes and upgrades are part of the maintenance phase, as is the process of isolating and repairing problems with the system. Phase 5: Maintenance

Define the term systems development life cycle (SDLC). Identify the five phases in the SDLC. Name the IS professionals involved in each phase of the SDLC. Describe four ways an organization can convert from an old information system to a new one. lesson 26 review