Lesson 4 - Extensions to the Main Bootstrap (Part 1)
1. Limitations of the main bootloader
As mentioned in the previous lesson, the code size of the main boot program cannot exceed 512 bytes! !
Can these 512 bytes complete the function of the operating system? The answer is obviously impossible, so how to break through this limitation?
2. The idea of breaking the limit
The main bootloader performs the following functions:
(1) Complete the most basic initialization work
(2) Load the program from the storage medium into the memory
(3) Give control to the newly loaded program for execution
（4）......
It is represented by a diagram, as shown in the following figure: