Linux System Management single-machine system management-boot and shutdown

First, boot and shutdown

============== Boot =================

Boot: is the standard term for "Start computer".

Main boot sector: disk NO. 0 cylinder, a sector of number NO. 0 head, 512 bytes in size.

MBR: The operating system is written during installation, but is not part of the operating system, 446 bytes. Identify and load

Partition table: Records how many partitions and partitions of a hard disk have various properties, 64 bytes, 4 primary partitions

GRUB: is a boot loader from the GNU project. It allows users to have multiple operating systems at the same time on the computer and select the operating system that they want to run when the computer starts

Lilo

Steps for the boot process:

1, the BIOS power-on self-test

2. Read the MBR from the main boot sector and identify the active partition

3. Load and initialize the kernel

4. Detection and configuration of equipment

5. Creating kernel Processes

6, operator intervention, for manual guidance

7. Execute the System startup script

8. Multi-user mode operation

Init executes the system's startup script, Init defines 7 runlevel, and the/etc/inittab file tells Init what to do at each runlevel.

At machine boot, init runs from run level 0 to the default run level set in/etc/inittab, starting from level up.

The same process is performed in reverse order when the machine is closed.

K and S,k: Numeric order increment, S: numeric order Descending. Function: Fine-grained control of the start-up sequence of the service.

Some of the tasks performed in the startup script:

Set the computer name

Setting the time zone

Check Disk

Mount File System

Delete old files from/tmp

Configuring network Interfaces

Start the waiting process and network services

================= Restart and shutdown =================

Power off

Shutdown

Shutdown-h now

Shutdown-h 9:30 "9:30 the system will shut down, please do before the shutdown of the preparation work"

Halt

Reboot

Init n

Poweroff