Architecture Decision Records
This directory contains Architecture Decision Records (ADRs) used throughout the OTA Reference Design.
Unlike ADRs maintained within a single commercial project, these documents are not a historical record of decisions made for one specific product.
Instead, they serve as reference architectural decisions illustrating how an experienced engineer might reason about common OTA design problems under different technical constraints.
Purpose
Each ADR documents:
- the engineering context;
- the decision being considered;
- the factors driving that decision;
- the expected consequences;
- the situations where the decision is appropriate;
- the situations where another approach may be preferable.
The goal is not to declare one solution universally correct.
The goal is to explain why a particular decision would be reasonable for a particular class of systems.
Relationship to the Documentation
The repository intentionally separates three different types of documents.
Concept Articles (docs/)
Concept articles explain the design space.
They answer questions such as:
- What approaches exist?
- How do they work?
- What problems do they solve?
- What trade-offs do they introduce?
Their purpose is education.
Architecture Decision Records (adr/)
ADRs answer a different question:
Given a particular set of engineering constraints, what decision would be made, and why?
They intentionally focus on architectural reasoning rather than implementation details.
Decision Matrix
After the individual ADRs, the series concludes with a decision matrix that compares the approaches and helps relate system constraints to architectural choices.
The matrix is not intended to automatically select a solution. Instead, it provides a structured way to evaluate trade-offs.
Educational Nature
These ADRs are examples.
A real product may reach different conclusions depending on its:
- reliability requirements;
- hardware architecture;
- network constraints;
- operational model;
- regulatory requirements;
- maintenance strategy;
- business priorities.
For that reason, every ADR should be read as:
"Given these assumptions, this is the architectural decision we would make."
rather than:
"This is the only correct solution."
Design Philosophy
Throughout this repository, architectural decisions follow the same principle:
Architecture should be driven by system constraints, not by technology preferences.
The objective is to teach the engineering process behind OTA design rather than promote a specific framework, product, or update mechanism.