Taming Size and Complexity

The only real problem with modern software is size and complexity. If we had a bigger brain able to apprehend and reason about software as a whole without omitting details, we wouldn’t have that many issues. Unfortunately, our mental abilities are limited, and as a consequence, we need to have ways to build software whose complexity is beyond our own analytical power. The same is true for any large scale engineering initiative. Apart from discipline, which is a prerequisite to manage size and complexity, traditional ways to address size & complexity are: abstraction, automation and intuition.

Abstraction

The traditional way to address complexity is to raise the abstraction level. Get rid of details and stay focused on the essential – complexity goes away. You can then reason on different parts at various abstraction levels independently of each other. This is the ground-breaking argument about any modeling effort or methodology. The problem is that the whole is not equal to the sum of its parts. Unforeseen interactions will emerge resulting in a myriad of potential problems.  An other major problem is the traceability of the different parts.

Automation

The traditional way to address size is through automation. A lot of task that we perform are not tedious due to their very nature, but due to the effort they demand. Our concentration is also limited which implies we will make mistakes. Automation leads then not only to higher productivity but higher quality.  There are too many examples of automated task, but code formatting and refactoring fall for instance into this category.  Even though automation is extremely effective for specific task, automation is also impacted by the complexity of the software to produce. State explosion is for instance one of the main problems of a technique such as symbolic execution.

Intuition

Actually, problem solving implies not only strong analytical skills but also some form of intuition. The same goes with software and program understanding. Software exploration and visualization are powerful techniques to reason about abstract information in an intuitive way. Software is intangible and has by consequence no natural representation – this leaves the door open for new visualization metaphors. Examples of interactive visual development technologies are BPEL workflow, DSM, or polymetric views.