Adrian Janson,Melbourne High School

The SDLC and the SDC: a brief introduction

For VCE Software Development ¾, 2007

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