Don't Panic — Enterprise Architecture Fundamentals

Enterprise architecture is the discipline of stopping a large organization from making the same decision in seven incompatible places. It connects business direction to change across four domains — business, data, application, and technology — so separately funded projects move toward compatible outcomes rather than a portfolio of locally optimized, globally incoherent systems. That is the whole job.

Before this was framed as a discipline, the default was every team for itself: each project picked its own platform, its own data model, its own definition of the same capability, and the estate accumulated connections nobody could untangle. The cure is to scope to a bounded change, name the decision being made, and describe the baseline before proposing a target.

The idea everything else hangs off: a target without a baseline is a wish. Describe the current state in the same vocabulary as the future state, mark unknown relationships as unknown, and every gap between them has to carry the dependency that controls sequencing and the migration consequence. Skip that and you get a roadmap that falls over the first time a schedule slips.

The four domains — business, data, application, technology — exist so a change in one has somewhere to show its effect on the others. Treat any domain in isolation and a business redesign lands on applications that cannot support it, or a platform refresh breaks a data model no one mentioned.

The surprise, for people who met this as a binder-producing exercise: the method is sound, the failure is treating the method as the deliverable. Principles and standards guide repeated decisions; governance keeps them attached to implementation — and an exception with no expiry is just a control you silently retired. The architecture is not the diagrams produced at the start; it is the decisions, evidence, and exceptions that survive contact with delivery.

The Open Group's 10th Edition split into Fundamental Content and Series Guides is the standard catching up with how it was always meant to be used: universal concepts plus configurable how-to, with tailoring made first-class rather than hidden in a preface.

Read the Introduction for the four domains and the baseline-to-target flow. The Slides give you the ADM cycle at a glance, and the Cheatsheet keeps the scope discipline and governance rules to hand. Field Notes adds the operational traps. The Exercise walks through one decision pack end to end.