Linux system boot and boot process

Mention the word operating system, presumably everyone is not unfamiliar, there is a computer-side operating system and mobile phone operating system. Computer-side operating system is more familiar with the Windows operating system developed by Microsoft, there is a slightly unfamiliar Linux operating system, and the mobile phone side of the operating system is the iOS operating system, Android operating system. And today's small series of people to focus on the Linux system boot and boot process.

　　Kernel boot

When the computer is powered on, it is the BIOS post that starts with the boot device (usually the hard disk) set up in the BIOS.

After the operating system takes over the hardware, it first reads the kernel file in the/boot directory.

Run Init

The init process is the starting point for all processes in the system, and you can compare it to the ancestor of all processes in the system, without which any process in the system will not start.

The INIT program first needs to read the configuration file/etc/inittab.

　　System initialization

There is a line in the init configuration file: Si::sysinit:/etc/rc.d/rc.sysinit, which invokes execution of/etc/rc.d/rc.sysinit, and Rc.sysinit is a bash shell script, It is mainly to do some system initialization work, Rc.sysinit is each run level must first run the important script.

Its main tasks are: Activating the swap partition, checking the disk, loading the hardware modules, and some other priorities that need to be performed.

　　Set up terminal

After the RC finishes executing, return to init. At this point the basic system environment has been set up, various daemons have been started.

Init then opens 6 terminals so that the user can log on to the system.

　User Login System

In general, there are three ways to log in: command line login, SSH login, GUI login

Presumably everyone knows that the journey of Linux is very long, so we learn a lot of things. Finally, if you have a better self-study ability than the students who want to learn Linux technology can also buy some books or video lessons. If the ability of self-study or poor students, you can report a training class.

Linux system boot and boot process