System startup process

First stage hardware boot boot:

POWER---->bios---->MBR [Bootloader (Grub Program): 446bytes, partition Table partition table, 64bytes, MagicNumber: Standard verification Code

Grub File: cat/boot/grub/grub.conf

# 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

Timeout=5

Splashimage= (hd0,0)/grub/splash.xpm.gz

Hiddenmenu

Title CentOS (2.6.32-431.el6.x86_64)

the disk partition where root (hd0,0) <--grub resides

kernel/vmlinuz-2.6.32-431.el6.x86_64 <--system core ro root=uuid=65af82a4-cc0e-4361-85c0-3bec9269079a Rd_NO_L UKS RD_NO_LVM Lang=en_us. UTF-8 rd_no_md sysfont=latarcyrheb-sun16 crashkernel=auto keyboardtype=pc keytable=us Rd_NO_DM rhgb quiet

Initrd/initramfs-2.6.32-431.el6.x86_64.img <--kernel image file, unzip load driver

Second Stage grub boot boot:

Stage1 (MBR)--->stage1.5 (middleware transfer stage2, bridge function)--->stage2 (disk, core image)

Third stage kernel boot boot:

Call/sbin/init main Process---> Start level profile/etc/inittab--> Load startup script profile/etc/init/rc.conf----> Perform service etc/init/rc/and initialize/etc/ Rc.d/rc.sysinit--->./etc/fstab-> one of the run-level scripts/etc/rc3.d--->/etc/rc.d/rc.local execution configuration file

Phase IV SYS V INIT initialization phase

/sbin/mingetty Terminal--->/ETC/X11/PREFDM graphics terminal---->/etc/login Login

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System startup process