Linux startup process

1. First load the BIOS (Basic Input Output System), self-test, read the bootable device sequence (usually hard disk).
2. Each hard drive has an MBR (Master Boot Record) area, and the MBR is the first sector of the hard disk area 446B. Set the boot order, equivalent to reading the MBR of a different hard disk.
3. Then load the MBR.
4, each operating system has its own Boot Loader,boot Loader is responsible for loading the system kernel into memory run. When the operating system is installed, the operating system installs the boot loader in its own file system.
when installing Linux, you can choose whether to copy the boot Loader to the MBR, and Windows will actively copy the boot Loader to the MBR, especially note: Only one zone in the MBR holds the boot Loader, the boot of the last copy The Loader will overwrite the boot Loader of the previous copy.
5, loading MBR, read the boot Loader, boot system. So that's the problem?
MBR only a boot Loader, after the installation of the system copy boot Loader to the MBR, overwriting the boot Loader of the previous system, this does not lead to the previous system has never been able to start?
6, this will refer to the boot Loader function, MBR only a boot Loader, but the boot Loader provides menu options, you can choose different startup options.
A. Point directly to the bootable program section and load the operating system.
B, transfer the boot load function to the other boot Loader.
7, consider the following situation, installed Windows, the file system has the boot Loader, the name W, copy W to the MBR. Install Linux again, file system has boot Loader, name L, copy l to MBR, overwrite W. When you start, load the l,l in the MBR to provide options:
A, the Linux system can be loaded directly;
B, can be forwarded to the Linux file System boot Loader, and then load Linux;
C. Can be forwarded to boot Loader in the Windows file system before loading Windows.
8, special attention is: Windows boot Loader default does not have the function of handover, and when installing Windows, will actively put boot Loader copy MBR, overwrite the previous. There is a problem with this:
Install multiple operating systems, and finally install Windows, causing the boot to boot other systems. Therefore, installing multiple operating systems, involving MBR and multi-boot, should install Windows first, install Linux, and let Linux boot Loader in the MBR cover out windows.
9, then boot loader load the system kernel into memory, the system core drive peripheral devices, take over the BIOS after the work.

Linux startup process