Harnessing the UEFI Shell

Chapter 1 Introduction

Less but better.

—Dieter Rams

To most users, a computer is represented by the operating system that they’re using and nothing more. However, unbeknownst to most basic users, there are a large number of components that must work in concert to go from where the user presses the power button, the hardware is initialized, the boot target is discovered, to where the operating system is launched.

There are two major phases of platform initialization between when a user turns a computer on and the computer has completed its initialization: the first phase is what might be called the “pre-OS” stage where the platform’s hardware is initialized and made usable, and the second phase is when the boot target is launched, which oftentimes ...