8.1.3 software development approaches

identify the 5 stages in program development (structured approach)

identify the 5 stages in program development (structured approach)

1. defining and understanding the problem

2. planning

3. building the solution

4. checking the solution

5. modifying the solution

what does defining and understanding the problem mean (structured approach)

analyse current system, discuss nature of business, and identify requirements

what does planning mean (structured approach)

identify user needs, analyse input, output, processes and procedures, interviews, questionnaires and observation

what does it mean to build a solution (structured approach)

designers break processes down into smaller parts (modules) which are then turned into a set of steps (algorithms) that the programmer uses for coding

what does it mean to check a solution (structured approach)

conduct tests, detect errors, note performance, evaluate and implement

what does it mean to modify a solution (structured approach)

system is constantly evaluated, maintained and modified

what are the characteristics of the structured approach (structured approach)

• distinct formal stages

• long time periods

• large-scale projects

• large budgets

• development team

  • analysts

  • designers

  • programmers

  • clients (users and management)

what are the pros and cons of the structured approach (structured approach)

PROS: good planning, analysis, documentation, good control over project and maintenance

CONS: inflexible, can result in a project running over budget/time

what is the agile approach and what is it used for

iterative and incremental development that focuses on the evolution of a project

used in most projects, effective for large projects as it allows smaller teams to split as equals

what are some characteristics of the agile approach

small, self-organised groups to allow multi-skilled developers, planning/analysis and documentation done within the teams

releases working programs and the next iteration with new features is released later on

what are the pros and cons of the agile approach

PROS: supports rapid development (new features added incrementally), promotes equality within work environment, adapts well to changing situations, documentation done on-the-fly, good user involvement

CONS: minimal documentation, conflict within teams, up front design may be minimal/insufficient, change in specifications can mean changing cost/time management

what is prototyping and what is it used for

creating incomplete and unpolished iterations of a project to make sure it meets the user’s requirements before building a final product

best implemented for systems with large amounts of user-system interaction

what are the pros and cons of prototyping

PROS: flexible, possible reduction in development time and costs, results in a tested solution that meets user requirements

CONS: attachment to features, mistaken for final product, possible excessive concentration of time and resources

what are the characteristics of rapid applications development approach (RAD)

aims to produce software ASAP for lowest possible cost through:

1. short planning and project analysis

2. user feedback through interaction with prototypes

3. building alongside user feedback/design

4. cutover for data conversion, testing, implementation, etc

what are the pros and cons of RAD

PROS: flexible, promotes collaboration, extensive user-system interaction, good for small scale projects

CONS: mistaken for final product, limited time for planning/analysis, not good for large-scale projects

what are the characteristics of the end user approach

user is also the developer

• usually little to no experience meaning end user development is reliant upon packages and tools

low budget, lack of formal stages (documentation), often uses prototyping/RAD

what are the pros and cons of end user developed software

PROS: flexible, user requirements met with ease, low cost

CONS: small scope (usually only one developer), limitations of packages to develop system, security and quality concerns

what is the difference between structured and agile approach

structured is more formal, inflexible whereas agile is able to produce results with good user feedback consistently

what are some failures in software

1. baggage handling system at Denver airport destroyed bags

2. the therac-25 machine killed people with high doses of radiation

3. London’s automated ambulance transportation system left patients waiting for about half an hour

what are the characteristics of projects that lean towards specific development approaches

1. nature of the problem

2. time

3. budget

4. available resources

5. developer expertise

what are the characteristics of projects that require a combination of approaches

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