Understanding Software Develepment

Algorithms

An Algorithm is a well defined set of instructions which are deterministic.

Heuristics

A Heuristic is a mental shortcut or “rule of thumb” that gives some guidance on how to do a task, but it does not guarantee solutions consistently.

Metaphors

A Metaphor describes the software development process and act as heuristics.

• Metaphors useful as an aid to understanding.
• Map something we know well to something new and/or challenging.
• Not all metaphors are created equal.
  • Good metaphors are simple, relate to other relevant metaphors, and explain experimental evidence and observed phenomena.

Writing As A Metaphor For Software Development

• There are some parallels between the two
  • Grew out of the expression “writing code”.
  • We often talk about program readability.
• Doesn’t describe software development fully or adequately.
  • Writing is usually a one-person activity; software projects are usually teams.
  • Writing isn’t subject to constant revision once it can been published (~ 2/3 occurs after release).
  • Implies that the software process relies on expensive trial and error rather than careful planning and design.

Farming As A Metaphor For Software Development

• Sounds odd but illustrates some of the aspects of software development well.
  • Like planting seeds and growing crops you design a piece, code a piece, test a piece, add it to the system a bit at a time (incremental technique).
• Incremental technique provides a valuable lesson but farming is a bad metaphor and is hard to extend further– so much of farming has nothing to do with software development.

Accretion (Oysters) As A Metaphor For Software Development

Accretion: a growth or increase in size by a gradual external addition or inclusion.

• As opposed to growing, more accurately illustrates the incremental nature of software development.
• Oysters use accretion to make a pearl by gradually adding small amounts of calcium carbonate.
• Parallels with software development; you start with a skeleton, work towards a MVP, add dummy input, later use real input, etc.

Construction As A Metaphor For Software Development

• Image of building software is more useful than that of writing or growing it.
• Compatible with the idea of software accretion.
• Implies various stages of planning, preparation and execution.
• Involves groups and various field of expertise.
• Involves maintenance.
• Demonstrates consequences of poor design.