Part I Overview and History

Simplicity is prerequisite for reliability.

-- Edsger W. Dijkstra, "How do we tell truths that might hurt?" (EWD498)

The rest of the book goes deep into the scheduler, the memory allocator, the garbage collector and the compiler. Before that, this part answers three more basic questions.

First, why Go looks the way it does today. Chapter 1 covers the engineering problems Go was created to solve, which ideas it inherited from Unix, C and CSP, and which it deliberately left behind. Almost every later implementation trade-off finds its motivation here.

Second, what Go code looks like at the machine level. The lowest layers of the runtime (switching goroutines, growing stacks, atomic operations) are written in assembly. Chapter 2 introduces what is needed to read that assembly: Go’s own assembly language, and where arguments and results live during a function call.

Third, which stages a program goes through from source to exit. Chapter 3 follows one program end to end: the go command orchestrates the build, the compiler and linker produce an executable, the runtime initializes before main, and finally main returns and the process ends. This thread ties together the subsystems discussed in the later parts.

After this part, the reader should be able to follow every step in the output of go build -x, read a short assembly routine in the runtime using Go assembly, and explain what happens before and after main in a Go program.