iterative incremental development

Iterative vs Incremental Oliver Schreck, 2012

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Rough overview of picture

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Iterative DevelopmentDevelop, then evaluate, then change, …

Never expected it to be right.

Iterate to find the right solution.

Given some good candidate solution, we might then iterate to improve a candidate solution.

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Iterative DevelopmentWikipedia:

Iteration means the act of repeating a process usually with the aim of approaching a desired goal or target or result. Each repetition of the process is also called an “iteration”, and the results of one iteration are used as the starting point for the next iteration.

The whole product is iterated all the time. (This of course is in the purest iterative, non-incremental case)

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1st Iteration

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2nd Iteration

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3rd Iteration

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4th Iteration

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Incremental developmentIncrementally add software a time

Build up functionality gradually

Release incrementally so that we actually get that business value we're chasing.

We don't really get return on investment till people begin to use the software we've built.

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Incremental developmentWikipedia:

Incrementalism is a method of working by adding to a project using many small, incremental changes instead of a few (extensively planned) large jumps.

It means you develop one part of the system and when it’s ready you develop the next part

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1st Increment

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2nd Increment

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3rd Increment

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4th Increment

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Putting both togetherIncremental development goes through all the phases

of development (analysis, testing, development, design, integration, production) it is a perfect tool to expose all problems in the process.Incrementalism improves the process and adds new topics.

Iterative process means rework on the existing product.Iterativity improves the product

Both can be used without each other but they can be used together as well.

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1st Increment and 1st Iteration

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1st Increment and 4th Iteration

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2nd Increment and Xth Iteration

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3rd Increment

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4th Increment

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The different flavorsWaterfall is non-

iterative, non-incremental process

Staged delivery is incremental but not iterative

Spiral model is highly iterative but not at all incremental

Agile process has many different flavors, amount of iterative and incremental can vary

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Document levelRequirement

Specification (Customer req.)

System Specification (System req.)

Feature Specification (Feature req.)

Design Specification (Design req.)

What to do rough?

How to do rough?

What to do in detail?

How to do in detail?

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Requirement Specification – What to do rough?

ViewerFilmin

gServic

e

Customer ViewCR CR CR

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System Specification – How to do rough?

ViewerFilmin

gServic

e

Services

Back End

Front End

System Architecture View

CR CR CR

System req.

System req.

System req.

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Viewer

Feature Specification – What to do in detail?

Filming

Service

Services

Back End

Front End

Zoom

Load

Imag

es

Customer ViewCR CR CR

System req.

System req.

System req.

Featu

re re

q.

Featu

re re

q.

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Viewer

Design Specification – How to do in detail?

Services

Back End

Front End

Zoom

Load

Imag

es

DesignArchitecture View

System req.

Design req.

System req.

Customer req.

Featu

re re

q.

Featu

re re

q.

System req.

Design req.

Design req.

Design req.

Design req.

Design req.

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Viewer

After Multiple Iterations

Services

Back End

Front End

Customer req.

System req.

System req.

System req.

Design req.

Design req.

Design req.

Design req.

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Questions?

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