As mentioned previously, the bootloader is the component that is first run after initializing the system, and prepares the entire ecosystem for the operating system boot process. This process differs from one architecture to the other. For example, for the x86 architecture, the processor has access to BIOS, a piece of software available in a nonvolatile memory, which is usually a ROM. Its role starts out after resetting the system when it is executed and initializes the hardware components that will later be used by the first stage bootloader. It also executes the first stage of the bootloader.

The first stage bootloader is very small in terms of dimensions - in general, it is only 512 bytes and resides on a volatile memory. It performs the initialization for the full bootloader during the second stage. The second stage bootloaders usually reside next to the first stage ones, they contain the most number of features and do most of the work. They also know...