System Life Cycle

System Life Cycle

1. Definition

   • Feasibility Study
   • Also Known as the Feasibility stage.
   • Initial look at the existing system to see how it can be improved.
     • If possible it must meet needs and requirements of the end users:
     • The analyst should also consider why a new system is required.
   • For project to continue, the new system must also be viable in terms of hardware and software choices, budget and time scale.
   • 1st

2. Investigation & Analysis

   • Feasibility Stage
   • Requirements Specification
   • 2nd
   • Follows the definition of the problem and must be fully completed before moving on to the design stage.
   • During this stages methods can be used to collect data:
     • Interviews
     • Meetings
     • Document Analysis
     • Questionnaires
     • Observation
     • Results of the investigation are analysed to gain full understanding of all the problems of the current system.
       • The user requirements are defined and agreed with the client, these are constantly referred to during the development of the new system and form the basis of the rest of the system life cycle.

3. Design

   • Requirements Specification
   • Design
   • 3rd
   • This stage cannot be started until the 'Investigation and analysis' has be completed. also the implementation stage cannot start until this stage is completed.
   • The objectives defined in the investigation and analysis stage are followed.
   • Methods and formats of data capture what are designed:
     • Input
     • Output
     • Structure of data
     • Processing and validation routines
     • Queries
     • Reports
   • Project plan is developed taking into account the client-defined deadline for the installation of the system.

4. Implementation

   • Design
   • Completed System
   • 4th
   • Also known as the 'Development Stage'
   • This stage is about taking the design forward and putting it into practice to build the system.
   • A decision about the software strategy, based on budget constraints set by the client, is made.
   • Coding, Macros and Queries are created with backup and storage of data being considered.

5. Testing

   • Completed System & Test Plans
   • Working System & Test Logs
   • Testing follows a test plan, with results being recorded.
     • Ensures that the system is free of bugs/errors and meets the defined user requirements.
       • if a test fails to provide the expected result then corrective action is taken before a retest.
   • 5th

6. Installation

   • Working System
   • Completed & Installed System
   • 6th
   • The system is installed for the client.
     • The installation strategy is chosen and training of the end users is carried out at this stage.
     • Methods of Installation:
       • Parrallel
       • Phased
       • Pilot
       • Direct

7. Doccumentation

   • 7th
   • Documents that are created and passed to the user of the system
     • Test plans
     • Data and Logs
     • User Manuals
     • Version and security details
     • Program Specifications

8. Evaluation & Maintenance

   • Evaluation
     • May form the basis on which the decision is taken to begin the system life cycle again.
       • Demonstrates the iterative nature of the system life cycle.
         • The solution should be evaluated once it has be implemented with maintenance.
   • Maintenance
     • The process of ensuring that a system continues to meet the needs of its users.
   • 8th

9. The stages that need to be completed to create a new or modified system. Referred to as a cycle as, after time, the process will have to be repeated.