Software Development

Software Development

1. Aspects of software development

   • Analysis
     • defining the problem and establishing the requirements of the project
   • Design
     • considering which algorithms, data structures, user interfaces etc. should be used
   • Testing
     • Black box/functional
       • looking at the program spec. and a creating set of data that covers all inputs and outputs and program func..
         • doesn't look at the code
     • White box / structural
       • SOFTWARE DEV. TEAMS -> program code is studied -> tests are devised which test each possible path at least once.
     • Alpha
       • IN-HOUSE SOFTWARE DEV. TEAMS reveals both errors and omissions in the system requirements definition
     • Beta
       • giving a newly developed software package to a number of potential users who agree to use the system and report any problems to the developers
   • Implementation
     • After testing stage has been used to make the appropriate changes to the software, it is installed onto the users’ systems
   • Evaluation
     • effectiveness of software is evaluated against the system req. defined during analysis stage to evaluate its suitability in solving the problem. Different criteria are considered -> robustness, reliability, portability and maintainability.
   • Maintenance
   • Development

2. Methodologies

   • • iterative, regularly develops prototypes
     • collection of methodologies
     • aim to improve the flexibility of software development
     • adapt to changes in user requirements faster.
     • builds software incrementally from the start of the project, instead of trying to deliver all at once.
     • Small - medium projects + unclear initial requirements
     • Agile
   • Waterfall lifecycle
     • large complex projects
     • req. well understood
     • stages carried out sequentially
   • • focus of effectively managing risk-heavy projects
     • Analysing system requirements
       • Pinpointing and mitigating risks
         • Development, testing and implementation
           • • Evaluating to inform the next iteration
     • Large, risk-intensive projects with a high budget
     • Spiral
   • XP
     • pair of programmers alongside a representative end-user
       • built on ‘user stories’:
         • system reqs. are specified by end-user + used when designing the program.
     • XP
     • high quality code
   • • user requirements made in focus groups
       • prototype made and developed along with the reqs.
         • continuously until the final product is reached
     • Small - medium, low-budget projects with short time-frames.
     • RAD
   • Comparisons
     • System Development methods comparisons

3. Writing and following algorithms

   • ALGORITHM
     • sequence of instructions that result in a desired outcome

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