The art of Linux kernel design--the first step in system startup

The computer in the end is how to run it, in my study of the computer has not been very clear, but recently borrowed this "the Art of Linux kernel design" is to know what the computer from the boot to start the operating system between what exactly do.

This book has just started to introduce not Linux startup, but a step before the Linux boot, that is, after you press the power button to enter the system before booting into the computer to do things, this time to do is every computer running the operating system needs to do, the approximate steps are similar, OK, into the topic.

Its really when we press the power button, the hardware circuit will be the CPU CS set to 0xf000,ip set to 0XFFF0, so the program starts from 0XFFFF0, and the 0XFFFF0 command is exactly the first command of the BIOS, so the BIOS began to execute instructions, (Where does the BIOS program come from?) , the BIOS is hardware manufacturers in the production of hardware has been written to the motherboard of RAM, of course, now is not write RAM, because the current BIOS program can be modified, so the BIOS began through a series of instructions for hardware inspection work, And in the 0x00000 with 1KB space to build the interrupt vector table, in the immediately following 256 bytes loaded the BIOS data area, in the area around 57KB load the terminal vector table corresponding interrupt service program, after these operations, the BIOS program will perform a 0x19 interrupt, The Interrupt Service program loads the 512B (first sector) of the floppy disk into the 0x07c00 of the memory, so the system starts executing the boot of the disk, and the boot program does the work of loading the operating system's boot program into memory. The following article details the process of loading the Linux operating system into memory.

The general flowchart is almost like this: