System Development Life Cycle

System Development Life Cycle

What is SDLC?

The formal process by which organizations build systems is known as SDLC.

Also referred to as Application Development Life Cycle orStructured Development Life Cycle

TQM/RE

TQM-Total Quality ManagementSet of business practices which improve profit and productivity

RE- Reengineering/Process InnovationChanging fundamental proceduresreexamining/repositioning corporateStrategies.

TQM/RE Goals

•Improve quality of all company activities•Reduce costs•Improve timelines•Other business goals

Why systems fail?

•Lack of communication between people•Continuing the old system•Failure of parts of system not fitting•Lack of management Support•Technological Incompetence•Changes in technology in the middle•Lack of user involvement/training/support(missing JAD-Joint Application Development)

Why systems fail?(Not following steps of SDLC)

•System does not meet users’ needs•Unnecessary/insufficient hardware is acquired•Software inadequately tested

Six Phases of SDLC

1. Preliminary Investigation2. Systems Analysis3. Systems Design4. Systems Development/Acquision5. Systems Implementation6. Systems Maintenance

Person in charge: Project LeaderSystem Analyst/Engineer

1. Preliminary Investigation (feasibility study)

Determine the organization’s objectiveRead internal/external documentsInterview users/executives

Nature and scope of problemsPropose alternative solutions

leave the system as is modify the existing systemdevelop a new system

Describe costs/benefits of each solutionSubmit a preliminary plan with recommendation

1. Preliminary Investigation

BenefitsTangible Cost savings

Profitability/ProductivityIntangible

Employer satisfaction

BPR (Business Process reengineering)independent of ITProcesses are identified for bottlenecks,removed, then IT is applied.

2. System AnalysisGather data

documents, interviews, questionnaires,observations, sampling

Analyze dataCASE tools, DFDs, Data Dictionary,System Flowcharts, Connectivity Diagrams, Grid Charts, Decision Tables

Write a reportWritten report

Approval from the Manager next phase

3. System DesignPreliminary Design

describes the functional capabilitiesof the systemCASE tools, PM Software

Detailed DesignOutput RequirementsInput RequirementsStorage RequirementsProcessing/Network RequirementsSystem Backup

4. System Development

Substantial expenditures of money/timeAcquire softwareAcquire hardwareTest the System

Unit TestingIntegrated testing

Workable system ready to be implemented

5. System Implementation

Objective:To make system not just workable but successful1. Software Conversion/Data conversion

4 Major strategiesDirect ImplementationParallel ImplementationPhased ImplementationPilot Implementation

2. Documentation3. Training

4. System Maintenance

Never ending phaseAdjustments/improvementssystem monitoring

Auditing- independent auditor’s reviewEvaluation- outside system analyst

Once the system is old enough SDLC is started all over again.