In 1987, legendary computer scientist Fred Brooks published a paper titled “No Silver Bullet – Essence and Accident in Software Engineering”. In this paper he describes the characteristics of modern software systems as he saw it, and goes on to explain the reasons for their inherent and accidental complexity. Of the many challenges Brooks described, the one that stands out and still holds true is changeability.
Brooks writes about the various forces that influence and enforce change -
“the software product is embedded in a cultural matrix of applications, users, laws, and machine vehicles. These all change continually, and their changes inexorably force change upon the software product”.
These forces continue to act and are growing stronger.
In my experience, it is this challenge of changeability that most enterprises need to overcome. Systems that exist in most enterprises have been around for many years, if not decades. These systems were designed for an era when change cycles were measured in months and years. They weren’t developed to keep up with the pace of change that is the norm today. The key is to change the mindset from thinking about systems as irreplaceable, to thinking about systems that are designed to be replaceable as a whole or in parts.
The only way to try to keep up with the pace of change is to have systems with a very short half-life. Dan North, technology and organisational change specialist, defines the half-life of software as the amount of time required for half of the code to change so much that it becomes unrecognizable. Having a technology landscape where the systems have a short half-life has a number of benefits: they reflect the most up-to-date understanding of the problem and, more importantly, have a much lower cost.
In this era of constant change, your systems quickly start to hold you back, shackling you from achieving your business goals. You have to find a way to disrupt yourself before someone or something else disrupts you: at that point, it is too late to retain the upper hand. Now is the time to compare the risk of updating your core systems against the true risk of doing nothing.
[Figure 1: Taken from a poll of senior executives at ThoughtWorks Live]
At ThoughtWorks we believe in taking a holistic approach to achieving that mindset shift, tackling legacy and beginning to unlock business value.
“It is change, continuing change, inevitable change, that is the dominant factor in society today. No sensible decision can be made any longer without taking into account not only the world as it is, but the world as it will be.” - Professor Issac Asimov
This blog post is taken from the Executive Foreword of "Unlocking Business Value from Legacy Systems". Download the eBook here.