Gary Hughes,South Oakleigh College
The SDLC and the SDC: a brief introduction
For VCE Software Development ¾, 2009
Systems development life cycle (SDLC);- Analysis.- Design.- Development.- Implementation.- Evaluation.
A process by which a systems analyst analyses and designs a new information system to suit a particular purpose
SDLC overview
Lots of versions exist – the only one that matters is the one in the study design
Often drawn as a ‘circle’ however, the time between cycles is often quite long
Different ways of implementing it: Waterfall model Agile model
SDLC overview
Classic version of the SDLC In practice, not practical No feedback or iterative processes Each stage is carried out to completion
before moving to the next That is, once analysis is done, design stage
begins and so on What if the client wishes to make changes
or adjustments after the design phase has passed?
Waterfall model
Practical version, often used. Works on smaller iterations
of the SDLC. Involves more interaction with the users of the
system. Feedback gathered at the conclusion of each
stage. May result in stage being performed again
or moving up the cycle instead of down. Takes longer, but with better results.
Agile model
SDLC: Analysis; Preliminary investigation, reasons for
change. Feasibility study: is it worth fixing?; Collect data: measure, count, survey,
interview, observe, research, test, study. Processes. What is the problem?
Assumptions. Scope.
SDLC: Analysis
SDLC: Design; Logical design & physical design. Alternative solutions? Data structures, input, output, processing
required, validation rules, storage requirements.
Interfaces. Hardware, software needs. Backup, security requirements. Employee needs, requirements. Assessing alternative design solutions
SDLC: Design
SDLC: Development, Implementation, Evaluation; Development.
Components are purchased. Software is written (if necessary). System is assembled.
Implementation. Putting the new system in place. Training.
Evaluation. Solves stated problems?
SDLC: Development, Implementation and Evaluation
Software Development Cycle (SDC); Occurs within development stage of
SDLC. Stages:
Analysis. Design. Development. Testing. Documentation. Evaluation.
SDC
Software Development Cycle (SDC): Analysis Defining the problem. Requirements, scope, available resources. Project plan, time frame, programmers
assigned to particular parts of the project. Choice of programming language.
Compiled / interpreted. Low-level, high-level. Object-orientated (OO).
Hardware factors affecting software design.
SDC: Analysis
Software Development Cycle (SDC): Design; Method: Top-down, bottom-up, RAD,
prototyping, EUD. Algorithms: flowcharts, NS
diagrams, pseudo-code. Desk checks. File management. Data structures.
SDC: Design
Software Development Cycle (SDC): Development; Good programming practice / conventions. ‘Standard algorithms’.
Software Development Cycle (SDC): Testing; Testing Tables. Selecting test data. Alpha testing (or white box). Beta testing (or black box). Quality assurance: developer testing. Acceptance testing: client testing.
SDC: Development and Testing
Software Development Cycle (SDC): Documentation; Types.
User guide. Technical reference manual. Installation manual. Quick start guide. Help guide, troubleshooting. Procedures manual.
Forms. Print, On-line, Video, Poster.
SDC: Documentation