We've used the term DevOps (and DevSecOps) several times within this book. This topic deserves some additional space, in our opinion. DevOps is an approach to building software products that breaks with traditional silo-based development.
In the waterfall model, teams operated on single aspects of work independently of each other. The development team would write code, QA would test and validate the code, and security and compliance would come after that. Eventually, the operations team would take care of maintenance. The teams rarely communicated, and even then, it was usually a very formal process.
Knowledge about particular fields of expertise was only available to the teams responsible for a given piece of the workflow. Developers knew very little about QA and next to nothing about operations. While this setup was very convenient, the modern landscape requires more agility than the waterfall model can provide.
That's why a new model of working was proposed, one...