change ⁽¹⁾

Everyone expects software to be soft. To be easily changeable. At least more easily changeable than hardware. But that is not always the case, sometimes it is easier to redesign the hardware than the software, but why and what do we mean when we say it is difficult to change software? Before the product has shipped, it should be easy to change both the hardware and the software as necessary to achieve the design. After the product has shipped, the hardware is fixed and you can only change the software. But there are often difficulties in changing software that mean it isn't as flexible as it might appear. What do we mean when we say it is difficult to change software? Let's start with what we don't mean. We don't mean that it's too much typing, or too many files, or we can't find all the source code. We don't mean that we have no ideas about how to produce the functionality required. We don't even necessarily mean that it will take a long time. Ok then, what do we mean? Often, the difficulty comes from the intertwined nature of software. Each part has some dependency on another part. In…