Linux command: chroot LDD init system START process, modify startup background map

Linux system startup process

POST (This process mainly detects all hardware devices of the server hardware)-->bios (boot sequence, system boot order, from which device boot)-->mbr boot file storage space (contains Bootlocader file total size of about 446MB, Find system Boot file)-->kernel system kernel -->/INITRD--(ROOTFS)/sbin/init

Linux system operating level: 0-6

0:halt shut down the machine

1:single User mode single user, log in directly as Administrator (Maintenance mode)

2:multi user mode, no NFS multiuser, but no network file system enabled

3:multi User Mode,text Multi-user plain text mode

4:reseved schema not defined, temporary retention mode

5:multi user mode,graphic mode multiuser graphical interface

6:reboot restart

Detailed system start-up process

Bootloader (MBR)

Lilo:linux Loader

Grub:grand Unified Bootloader

STAGE1:MBR first stage, mainly to guide the second stage

Stage1_5: Phase 1.5, primarily used to identify commonly used file systems, located in the/boot/grub/directory

Stage2: The second stage is in the/boot/grub/directory

cat/etc/grub.conf the/boot/grub link file when the profile is configured:

# grub.conf generated by Anaconda

#

# Note that you don't have the to rerun grub after making changes to the This file

# notice:you has a/boot partition. This means

# all kernel and INITRD paths is relative to/boot/, eg.

# root (hd0,0)

# kernel/vmlinuz-version RO root=/dev/sda2

# initrd/initrd-[generic-]version.img

#boot =/DEV/SDA

Default=0 # Sets the title number of the default startup, starting at 0 and sorting from top to bottom.

Timeout=5 # waits for the user to select the timeout length, in seconds

Splashimage= (hd0,0)/grub/linux.xpm.gz # grub Background Image

Hiddenmenu # hidden Menu

Password--md5 $1$7yzf4/$Bo. 1rg8dzncimfomud6ed0 # makes it possible to enter single-user mode with a password

Title CentOS (2.6.32-431.el6.i686) # kernel header or operating system name, string, can be freely modified

Root (hd0,0) # kernel files are located on the device, for grub, all types of hard drives are HD;

the format is (hd#,n); hd#, #表示第几个磁盘, the last 0 indicates the partition of the corresponding disk

kernel/vmlinuz-2.6.32-431.el6.i686 ro root=uuid=47b74772-4295-493a-8aa6-8fc85ae0807d Rd_NO_LUKS KEYBOARDTYPE=pc Keytable=us rd_no_md Crashkernel=auto lang=zh_cn. UTF-8 RD_NO_LVM rd_no_dm rhgb quiet # Kernel file path/boot directory, and parameters passed to the kernel

Initrd/initramfs-2.6.32-431.el6.i686.img # RAMDisk file path in/boot directory

Kernel design style:

Redhat,suse

Core: Dynamic load kernel module

Kernel:/lib/modules/"kernel version number command directory"/

vmlinuxx-2.6.32

/lib/modules/2.6.32/

Single Core: Linux

Core: KO (Kernel object)

Micro-kernel: windows,solaris (thread)

Chroot:chroot/path/to/temproot [COMMAND ...] Switch root directory to switch root to/temproot temp directory

chroot/test/virrrot/bin/bash Switch the root directory while executing with/bin/bash

Ldd/path/to/binary_file: Shows the shared libraries on which the binaries depend

This article is from the "Learn Linux history" blog, please be sure to keep this source http://woyaoxuelinux.blog.51cto.com/5663865/1880231

Linux command: chroot LDD init system START process, modify startup background map