1. 2. 3 Software Development

Question 1

Programming Methodologies

Answer 1

• Most software development life cycles (SDLCs) have common stages
• Analysis, Design, Development, Testing, Implementation, Evaluation, Maintenance
• Waterfall lifecycle, Spiral model, Agile methodologies, RAD, and XP

Question 2

Analysis

Answer 2

• Stakeholders state what the require from finished product
• Info used to clearly define problem and system requirements
• Requirements may define following
• Strengths and weaknesses of current ways problem being solved
• Considering types of data involved (inputs, outputs) and amount of data stored

Question 3

Design

Answer 3

• Aspects of mew system designed
• Inputs, Outputs, Security features, Hardware setup, user interface (Examples below)
• Volume of Inputs and Outputs, Access levels, compatibility, menus, navigation
• Test plan may be designed at this stage

Question 4

Development

Answer 4

• Design is used to split project into individual, self-contained modules
• These modules are allocated to teams for programming

Question 5

Testing

Answer 5

• Program tested against test plan formed in design stage
• Alpha testing, carried out in-house by software development teams within company
• Bugs are pinpointed and fixed
• Beta testing, end users (after alpha testing done) test program
• Feedback from users inform next stage of development
• White box testing, testing algorithms in code, make sure function as intended
• Checks overall efficiency of code, testing all possible paths of execution through program
• Black box testing, checking every input to program has desired outputs
• Choose appropriate test data to cover a range of situations

Question 6

Implementation

Answer 6

Once testing stage used to make appropriate changes to software, its installed onto users’ systems

Question 7

Evaluation

Answer 7

• Effectiveness of software evaluated against system requirements defined at analysis stage
• Evaluate suitability in solving problem, different criteria considered
• Robustness, reliability, portability and maintainability

Question 8

Maintenance

Answer 8

• Errors, improvements that can be made, flagged up by end-users
• Programmers send out software updates, fix bugs, security issues or make needed improvements

Question 9

Waterfall Lifecycle

Answer 9

• Stages are completed in sequence from start to finish
• Analysis stage includes feasibility study, evaluate feasibility using “TELOS”
• If change needs to be made, all levels between current and stage where change needed, must be revisited
• Model is inflexible, unsuitable to projects with changing requirements
• Users have little input, only involved at beginning and end of lifecycle (analysis and evaluation stage)

Question 10

TELOS

Answer 10

• Technical, is project possible considering tech available and accessible
• Economic, can project be financed in short term and long term
• Legal, can project be solved within law
• Operational, can project be successfully implemented and maintained
• Scheduling, can project be completed given the time available

Question 11

Agile methodologies

Answer 11

• Collection of methodologies, aim to improve flexibility of software development
• Adapt to changes in user requirements faster, easier to make improvements/changes to software
• Problem broken down into sections, developed in parallel
• Design and analysis stage occur together, different sections of software can be at different stages of development
• Working prototype delivered early on, built upon, improved in iterative manner
• New prototypes delivered regularly throughout development cycle
• Less focus on documentation, more priority given to user satisfaction

Question 12

Extreme Programming (XP)

Answer 12

• Agile model, development team consists of pair of programmers and a representative end-user
• Model built on “user stories”, system requirements specified by end-user, used when designing program
• Aim of paired programming to produce high quality code (written by one, critiqued by other, improved as it is written)
• Aim is quality is not compromised, programmers work normal hours (40 hours a week)
• Each iteration generates a working version of program which could function as the final product
• Hard to produce high quality documentation (less of priority), programmers must communicate effectively

Question 13

Spiral model

Answer 13

• 4 key stages, focus on effectively managing risk-heavy projects
• Analysing system requirements
• Pinpointing risks
• Development, testing, implementation
• Evaluation to inform next iteration
• If project found to be too risky at any point it is terminated
• Hiring risk assessors to analyse risks can be expensive
• This methodology only suited for very large-scale projects

Question 14

Rapid Application Development (RAD)

Answer 14

• Iterative methodology, uses partially functioning prototypes, these are continually built upon
• User requirements gathered using focus groups, used to develop “incomplete” version of solution
• Given to user to trial, user feedback gathered, used to generate improved prototype
• Continues till prototype matches requirements of end-users (Becomes final product at this point)
• RAD commonly used where users’ requirements unclear/incomplete at start
• Changing requirements over course of project, changes made to code may be inefficient

Question 15

Writing and Following Algorithms

Answer 15

• Algorithm is a set of instructions used to solve a problem; good ones have key qualities listed below
• Inputs clearly defined (What is valid and invalid)
• Always produces valid output for any defined input
• Able to deal with invalid inputs
• Always reaches a stopping condition
• Well documented for reference
• Well-commented so that modifications can easily be made

Question 16

Merits, Drawbacks and Uses of programming methodologies

Answer 16

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