During the startup process of the computer, the Master Boot Record (MBR, Master Boot Record) plays the role of plays a vital role. The MBR is a small program stored in the first sector of the hard disk that contains information such as the boot loader and partition table. When the computer starts, the BIOS will first load the MBR and then execute the boot loader in it to boot the loading of the operating system.
Let’s take a look at a simple Linux MBR code example:
section .text global _start _start: jmp main print_string: mov ah, 0x0E mov bh, 0x00 xor bl, bl print_loop: lodsb test al, al jz print_done int 0x10 jmp print_loop print_done: ret main: mov si, hello_message call print_string jmp $ hello_message db "Welcome to Linux MBR!", 0x0D, 0x0A, 0 times 510-($-$$) db 0 dw 0xAA55
The above is a simple assembly code example for A welcome message displays when the computer starts. This example implements the function of loading code from the MBR to printing a welcome message on the screen.
Linux’s MBR plays an indispensable role in the computer startup process and is responsible for booting the loading of the operating system. Through the above code examples, we can have a preliminary understanding of the basic functions and implementation methods of MBR. In-depth study and understanding of the principles of MBR will help us better understand the computer startup process and operating system loading process.
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