Coding: The difference between readability and understandability

For many people the readability of a program is an important thing. While code is written to be executed by machines the readability has become more and more important over the years. For many applications processing power and memory has become cheap and is available as easy as moving a slider with a mouse. At the same time developers have become sparse and hiring them has become expensive measured both in time and money. This includes the time to find any and the hiring process. At the same time software development has become much more complex over the last decades. And while abstraction has brought us much more readable code, the complexity is now under the sheets. Hidden in sometime dozens of layers between the developer and the executions of the program at machine level.

<picture about layers now vs. 20 years ago in web development>

It is much too easy to confound the readabilty of a program with the actual understandabilty and there for the ability of the developer to work with existing code.