The Donut of Equivalence

Balisage 2024 included a short-subject “Open Microphone” session, during which conference attendees were invited give 2-10 minute presentations on any topic relevant to the conference, including specification updates, new tool announcements, and demonstrations. Joe Gollner discussed the “donut of equivalence.” The “donut of equivalence” was a solution design pattern that was introduced, along with its cheeky name, as part of a large aerospace project (2005-2010). The idea at the time was that XML, coupled with a scalable processing environment (that handled transformations and validations), could be used to usher content assets and data resources back and forth amongst a variety of different application environments. The solution was profoundly successful, and it demonstrated that portability is king if the full value of content and data investments is to be realized. Also showcased in this case study was the fact that XML played only one part in a much larger solution, and its impact was, accordingly, magnified. Two other case studies were then used to look at variations on the “donut of equivalence” — each highlighting how value was realized when XML played a specialized role in larger solutions, including in cases where it was not a welcome addition. The takeaway of this short session is hopefully a reminder that XML, and its stack of tools and techniques, is a relatively small player in the marketplace and that it can add tremendous value if it finds a way to participate in larger solutions. In many ways, this talk revisits themes from my talk of 20 years ago entitled “Making Money with XML and other Unnatural Acts.”