The “Requirements” category in systems engineering serves as a critical guide to defining, documenting, and maintaining system necessities. It begins with gathering inputs from stakeholders, which may include customer needs, legal obligations, or technical constraints.
Most requirements tools were built for a world of giant documents and specialist administrators — powerful, expensive, and miserable to actually use. Reqi is a modern requirements management tool built to make capturing, organising, and tracing requirements fast enough that engineers will actually do it. This guide walks through what Reqi does, who it is…
You have a system-level requirement: “the aircraft shall stop within 1,500 metres.” But no single part stops the aircraft — the brakes, the spoilers, the reverse thrust, and the tyres all share the job. Requirement allocation is the work of taking a high-level requirement and dividing it among the subsystems and components that will actually…
There is a myth that good requirements do not change. They always change — the world moves, stakeholders learn, budgets shift. The question is never whether requirements change, but whether you control the change or it controls you. Requirements change management is the disciplined process of handling changes to requirements — assessing each one’s impact,…
A stakeholder says “I want it to be fast.” An engineer cannot build “fast.” Somewhere between those two sentences is the work that makes or breaks a project. Transforming stakeholder needs into requirements is the process of turning vague, human expressions of what people want into precise, testable statements engineers can actually build to. Do…
In a contract, one wrong word can cost millions. Write “the system should encrypt patient data” when you meant shall, and you have just made a legal obligation optional — and the supplier who skipped it to save money was, technically, within their rights. In requirements, “shall”, “should”, “will”, and “must” are not interchangeable —…
IBM DOORS is the requirements tool everyone in systems engineering has heard of, half of them are quietly scared of, and a surprising number have never been properly shown how to use. This guide closes that gap. DOORS — Dynamic Object-Oriented Requirements System — is a requirements management tool for capturing, linking, tracing, and analysing…
People throw “requirement” and “specification” around as if they are the same word. They are not, and the confusion causes real damage. A requirement states what the system must do and why; a specification states how it will do it. Blur the line and you either handcuff your engineers before they have explored the options,…
Every system is ultimately built for someone — and that someone rarely knows, or can articulate, exactly what they need. Bridging that gap is the whole job. User requirements describe what the people who will actually use a system need it to do, in their own terms — the foundation every technical requirement is later…
A great product idea dies the moment two people picture it differently and both start building. A Product Design Specification (PDS) is the document that prevents that — a complete statement of everything a new product must be and do, from performance and cost to materials and regulations, agreed before design begins. It is the…
Picture the demo that goes wrong. The developer proudly shows the finished feature; the product owner frowns and says “but that is not what I meant by done.” Both are right, because nobody agreed what “done” meant before the work started. Acceptance criteria are the conditions a user story must satisfy to be accepted as…
