Linux-系统启动时会自动运行哪些进程

Question

I have a somewhat noob-ish question regarding the system startup in linux (Scientific Linux).

What processes run automatically at the system startup?

As far as i have researched, Linux has 7 init Run Levels(counted from 0 to 6) and on the 3rd level(Full multiuser mode) it initializes all the scripts(system startup scripts) located in the /etc/rc.d/rc3.d/ folder.

Am i right, wrong? Please explain

Answer 1

1. The BIOS performs hardware-platform specific startup tasks
2. Once the hardware is recognized and started correctly, the BIOS loads and executes the partition boot code from the designated boot device, which contains phase 1 of a Linux boot loader. Phase 1 loads phase 2 (the bulk of the boot loader code). Some loaders may use an intermediate phase (known as phase 1.5) to achieve this since modern large disks may not be fully readable without further code.
3. The boot loader often presents the user with a menu of possible boot options. It then loads the operating system, which decompresses into memory, and sets up system functions such as essential hardware and memory paging, before calling start_kernel().
4. start_kernel() then performs the majority of system setup (interrupts, the rest of memory management, device initialization, drivers, etc.) before spawning separately, the idle process and scheduler, and the Init process (which is executed in user space).
5. The Init process executes scripts as needed that set up all non-operating system services and structures in order to allow a user environment to be created, and then presents the user with a login screen.