>Modern software and hardware systems contain almost unimaginable complexity amongst many distinct layers, each building atop each other. It is common — and substantially correct — to observe that no single human understands all of the layers in, say, a modern web application, starting from the transistors and silicon up through micro-architecture, the CPU instruction set, the OS kernel, the user libraries, the compilers, the web browser, and Javascript VM, the Javascript libraries, and the application code, not even to mention all the network services invoked in loading that code.

>In the face of this complexity, it’s easy to assume that there’s just too much to learn, and to adopt the mental shorthand that the systems we work with are best treated as black boxes, not to be understood in any detail.

>I argue against that approach. You will never understand every detail of the implementation of every level on that stack; but you can understand all of them to some level of abstraction, and any specific layer to essentially any depth necessary for any purpose.