Understand the Linux Master Boot Record (MBR) and its functions

Linux MBR Introduction and Function

MBR, the Master Boot Record, is the first sector (i.e. No. 0) stored in the computer hard disk. sector) is a small program, usually occupying 512 bytes. It is an important part of computer boot and plays a key role in connecting the previous and the next. In the Linux system, MBR also plays an important role. Next, the structure, functions and related code examples of Linux MBR will be introduced in detail.

1. Linux MBR structure

Linux MBR generally consists of three parts:

1. Main boot program (Boot Loader): responsible for loading the operating system, such as GRUB ( GRand Unified Bootloader);
2. Partition Table: records hard disk partition information, including partition type, starting location, size, etc.;
3. MBR Signature: indicates that the MBR is valid The sexual symbol is 0x55AA.

2. The functions of Linux MBR

The functions of Linux MBR mainly include the following points:

1. Boot the operating system: The main boot program in MBR will Initialize the boot program chain, load the operating system core files, and start the operating system;
2. Partition management: The partition table records the information of each partition on the hard disk, such as logical address, size, etc., to help the operating system correctly identify the hard disk partition;
3. Data protection: MBR signature is used to verify the validity of MBR, prevent malicious tampering or damage, and ensure system safety and reliability.

3. Linux MBR code example

The following is a simple Linux MBR code example, which demonstrates the role of MBR by emphasizing the GRUB loading process:

; mbr.S
; Simple MBR program to load GRUB

    .code16
    .section .text

    .org 0x7C00

start:
    jmp 0x00, end_of_program   ; 跳转到GRUB加载点
    nop

end_of_program:
    cli
    hlt

In the above example, use jmp 0x00 to jump to the GRUB load point to load the GRUB boot operating system.

Summary: As a key component of computer booting, Linux MBR plays a vital role in Linux systems. Through the structure, functions and code examples introduced above, I hope readers will have a deeper understanding of Linux MBR.

The above is the detailed content of Understand the Linux Master Boot Record (MBR) and its functions. For more information, please follow other related articles on the PHP Chinese website!