Topics Covered Phase 1: Preliminary investigation Phase 1: Preliminary investigation Phase 2: Feasibility Study Phase 2: Feasibility Study Phase 3: System Analysis Phase 3: System Analysis Phase 4: System Design Phase 4: System Design Phase 5: System Development Phase 5: System Development Phase 6: System implementation Phase 6: System implementation Phase 7:Operations & Maintenance Phase 7:Operations & Maintenance Block designing of SDLC Block designing of SDLC ◦ Serial file organization Serial file organization Serial file organization ◦ Sequential file organization Sequential file organizationSequential file organization ◦ Direct file organization Direct file organizationDirect file organization ◦ Indexed sequential file organization Indexed sequential file organizationIndexed sequential file organization

Phase 1: Preliminary Investigation Determine if a new system is needed  Three primary tasks: ◦ Define the problem  By observation and interview, determine what information is needed by whom, when, where and why ◦ Suggest alternative solutions ◦ Prepare a short report

 Preliminary Investigation ◦ Specifies achievements of the new system over the existing system. e.g. cost reduction, better service to the customers. ◦ Specifies restrictions on cost, equipment to be used, area of business to be left unchanged etc. ◦ Decides the time limit for designing the new system. ◦ Determines the size of system. ◦ Reports or outputs needed.

Phase 2: Feasibility Study  Evaluate alternatives based upon: ◦ Economic feasibility - Do benefits justify costs? ◦ Technical feasibility - Is reliable technology and training available? ◦ Operational feasibility - Will the managers and users support it?

 Feasibility Study ◦ Tests system proposal according to its workability, impact on the organization, ability to meet user needs and effective use of resources. ◦ Technical Feasibility: Determines need of resources. ◦ Economic Feasibility: Performs cost and benefits analysis. ◦ Operational Feasibility: Determines need of job reconstruction and retraining.

Phase 3: System Analysis  In depth study of the existing system to determine what the new system should do. ◦ Expand on data gathered in Phase 1  In addition to observation and interviews, examine: ◦ Formal lines of authority ◦ Standard operating procedures ◦ How information flows ◦ Reasons for any inefficiencies

 System Analysis ◦ Analyst studies old system and identifies new requirements ◦ Understands system from user's view and thus identifies problems faced by them ◦ Information of existing system is collected. ◦ To collect information tools used in system analysis are DFD, interviews, questionnaire etc.

System Analysis: Documentation Produced  Complete description of current system and its problems  Requirements for new system including: ◦ Subject ◦ Scope ◦ Objectives ◦ Benefits  Possible development schedule

Phase 4: System Design  Uses specifications from the systems analysis to design alternative systems  Tools may be used to design the system ◦ Diagramming Tools ◦ Data Repositories ◦ Prototyping Tools ◦ Test Data Generators ◦ Documentation Tools ◦ Project Management Tools

 System Design ◦ Defines precisely the required system output. ◦ Determines the data required to produce outputs. ◦ Decides the storage media, formats of file ◦ Decides processing method ◦ Determines methods of data capture and input.

System Design: Documentation Produced  System Design Report ◦ Describe Alternatives including:  Inputs/Outputs  Processing  Storage and Backup ◦ Recommend Top Alternative based upon:  System Fit into the Organization  Flexibility for the future  Costs vs. benefits

Phase 5: System Development  Build the system to the design specifications ◦ Develop the software  Purchase off-the-shelf software OR  Write custom software ◦ Acquire the hardware ◦ Test the new system  Module (unit) test - tests each part of system  Integration testing - tests system as one unit ◦ Create manuals for users and operators

 System Development ◦ System is actually programmed. ◦ Documentation along with programmes are prepared.  System Testing ◦ Make sure that system will perform as specified at the time of analysis. ◦ Ensure incorrect input and processing will be detected.

Phase 5: System Implementation  Convert from old system to new system  Train users  Compile final documentation  Evaluate the new system

 System Implementation ◦ System installation and training ◦ Implementation can be done in three ways  New system is implemented & old system is completely dropped out.  New & old both are operated in parallel when new system is accepted old is dropped.  New system is implemented in many phases.

 User Training ◦ Ease into system, make them comfortable, and gain their support ◦ Most commonly overlooked ◦ Can be commenced before equipment delivery ◦ Outside trainers sometimes used

 Phase 7: Operations & Maintenance  Types of changes: ◦ Physical repair of the system ◦ Correction of new bugs found (corrective) ◦ System adjustments to environmental changes ◦ Adjustments for users’ changing needs (adaptive) ◦ Changes to user better techniques when they become available (perfective)

 Maintenance ◦ Periodic evaluation and updating is maintenance. It is of 3 types: ◦ Correction: means correcting errors in existing system ◦ Adaption: means customizing the s/w to run in new environment ◦ Enhancement: means adding new functionality.

 Evaluation Methods ◦ Systems audit - performance compared to original specifications ◦ Periodic evaluation - “checkups” from time to time, modifications if necessary

Recognition of Need Feasibility Study Analysis Design Implementation Maintenance Block Designing of SDLC

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