End HomeWelcome! The Software Development Process

End Home Development of Computer Systems  Computers are used in business to help solve problems. To increase productivity and so increase profits. "System Life Cycle" The software development process is a cyclic process. Systems grow old and have to be replaced. This is called the "System Life Cycle"  For example, a business may want a…   Payroll system   Stock control system   Customer record system  A business may need a new computer system to completely replace an existing manual system. Or they may want to upgrade their current system.

End Home The phases of the Software Development Process Software Development Life Cycle Initiation Implementation Maintenance Initiation Investigation Design Preparation Implementation Testing Documentation Maintenance Preparation Design Investigation Testing Documentation

End Home  Before designing and creating a new piece of software, it is important to fully understand the client's requirements. We need to know what their problem is and agree on how their problem can be solved. That is the purpose of this phase. 1 Problem Requirements The Requirements Should be… o o Unambiguous o o Concise o o Consistent o o Possible o o Verifiable  Discussing the client's problem  Carrying out a feasibility study  Writing up the requirements  Agreeing the requirements with the client This phase broadly involves:

End Home 2 Investigation Phase - Collect Information Collect Information This phase involves interviews with users, surveys by questionnaire, examining existing documents and observing users already on the system.  Identifying the aims of the new system  Identifying how the current system works  Identifying if the system needs to interact with other systems  Defining the scope of the system  Defining the boundaries of the system Investigating a system broadly involves: The purpose of this phase is to fully understand the existing system by collecting information and identifying the aims of the new system.

End Home 3 Design Phase  Producing design documents such as storyboards, GUI designs, psuedocode, flowcharts, data dictionaries  We often produce different designs and then choose the best solution In this phase we think about how the new system is going to work. Designing a system broadly involves: Don’t get the wrong impression. This phase does NOT involve programming. It is all paperwork

End Home 4 Preparation Phase  Ensuring members of the project team know their tasks for the next phase.  Preparing folder structures for the different project files  Ensuring backup procedures are in place  Checking anti-virus is working and up-to-date In this phase we prepare the development environment and ensure everything is ready for the implementation phase. Preparing a system broadly involves:

End Home 5 Implementation Phase  Writing the Program Code  Conversion of Data Files (incorporate existing files).  Debugging the Program Code  Installation of the new system Here we create the program code. At the end of the phase the new system is installed and becomes operational. Implementing a system broadly involves:

End Home 6 Testing Phase  Unit Testing (test individual software modules).  Integration Testing (test interfaces between software modules).  System Testing (test complete system under full load).  Acceptance Testing (the user tests the complete system). You should note that some of the testing phase will overlap with the implementation phase. Testing a system broadly involves: Which tests would have to be carried out during the implementation phase? Which tests would have to be carried out during the implementation phase?

End Home 7 Documentation Phase  Checking documentation from previous phases is up-to-date. Documents such as…  Requirement analysis documents  Design documents  Testing documents  We may produce additional documents e.g. user guides, technical help. Here we check that documentation from all the different phases has been produced and is correct and up-to-date. Documenting a system broadly involves:

End Home 8 Maintenance Phase The system is monitored; end-user interaction with the system is examined, trouble spots are identified, software modifications may be made. Even if there are no problems with the system, a time will come when it will have to be be enhanced or updated. Then the whole Software Development Process starts all over again. This phase involves two sorts of activity.  Providing end-user support (help-desk or training)  Software Maintenance (fixing problems with the code)

End Home Overview of The Phases  2 Investigation  2 Investigation – What are the aims of the new system? How does the current system work? Define scope and boundaries  5 Implementation  5 Implementation – Convert existing data (if appropriate) Write the code Install the system  7 Documentation Produce user guides Gather documentation from all phases Verify documentation is up to date  4 Preparation Prepare development environment Plan backup procedures Devise folder structures  3 Design  3 Design – Identify alternate solutions Choose hardware and software Develop design documents  6 Testing  6 Testing – Test the code Test the system under full load Carry out acceptance tests  8 Maintenance Correct errors discovered after release Train and support the end users  1 Problem Requirements Talk to the client Discuss the problem Carry out feasibility study Write up the requirements

End Home The END! Systems Analysis and Design