Trash or Treasure — What’s Your Legacy?
The topic of legacy systems is something of a contentious one. In most cases, a legacy is understood to be a good thing. What makes a system “legacy”? Is it a technical or business decision?
A little over a year ago, Greger Wikstrand took a stab at clarifying the term with his post “Legacy systems, a definition”. In the post, he looked at different definitions of what constituted a legacy system, ranging from “any code that is in use” to “outdated technology” to “high technical debt”. The definition he went with, in my opinion, is the most useful:
It should be clear that legacy systems are not about technical considerations. It is about how well the existing system meets and is able to adapt to business needs.
A pair of tweets from Joanna Young that I saw yesterday brought this to mind:
Whether or not a system has crossed the line into legacy territory is not a technical decision but a business one. As Greger and Joanna both noted, it’s about fitness for purpose. Technical considerations absolutely have immense bearing on whether the system is able to meet needs. However, they are not the sole determinant.
The standard narrative is for a system to start out “clean” and then rot via neglect and/or ad hoc enhancement. This is certainly a common scenario, but it overlooks the obvious. While failure to maintain a system and its platform will certainly degrade it, keeping the technology components up to date does not ensure that the system will continue to match the needs of those who depend on it. For that matter, it’s easy enough to build a brand new system using the latest and greatest technology that is a legacy right out the gate due to its failure to meet the needs of its stakeholders.
Age of the platform is not a problem; an inability to get support or find people knowledgeable about the platform is a problem. Technical debt in and of itself is not a problem; being impeded or prevented from maintaining/enhancing the system due to technical debt is a problem. This works for any given technical issue — substitute the tangible, stakeholder-oriented result of that technical issue and the point becomes clearer to those with the ability to address them.
The key is not to focus solely on functional aspects nor quality of service and/or technical aspects, but the system as a whole. This requires the participation of the entire set of social systems involved in the creation, maintenance, and usage of the software system. Communication and collaboration across all elements of those social systems is critical to effectively maintaining the software system and the social systems that it enables.
A critically important part of promoting that communication and collaboration is maintaining the cohesion of the social systems involved in creating and maintaining the software system. Where those social systems are ad hoc and episodic, the potential for forming the relationships necessary for effective situational awareness is minimal. IT won’t know about functional gaps until too late and the stakeholders won’t know what their options are for addressing them nor will they have advance notice of impending technical issues.
Social systems create, maintain, and use software systems. Systems that are designed to work together have a better chance of doing so than those that are just thrown together and wished well.
Originally published at genehughson.wordpress.com on June 9, 2017.