RH133 1.STEPS OF BOOT PROCESS




1. BIOS               ->Do POST ->power on self test and Check boot priority,
2. MBR                ->I stage boot loader,partition table, o/s signature
3. /etc/grub/grub.conf   ->root (hd0,0)
                           kernel /vmlinuz...... ro root=LABEL=/
                   initrd /initrd.....img
4. /etc/inittab          ->/etc/rc.d/rc.sysinit     ->Set hostname
                                  
              ->Set clock
                                      
      ->Enable selinux,quota
                                ->check filesystem
                                ->Enable root in rw mode
5. /etc/inittab          ->runlevel  ->/etc/rc.d/rcx.d (where x is num)
6. /etc/rc.d/rc          ->whenever runlevel changes
7. /etc/rc.d/rc.local    ->last script executed in boot process


GRUB FEATURES:

1. Grand unified boot loader
2. Grub indentifies upto 15 file systems
3. Grub has a pre-os enviornment use commands to load o/s
4. Grub supports LBA(Logical block addressing)


GRUB COMMANDS

1. root   (hd0,0)        ->mount the boot partition

2.find  /etc/fstab       ->find the partition  which contains label of /
3.cat (hd0,4)/etc/fstab  -> TO check label of root
OR

4.find  /etc/fstab        ->find the partition  which contains label of /
5. root (hd0,4)           ->Mount the route partiton
6. cat  / + press tab     ->shows contents of mounted partition
7. cat /etc/fstab         ->open the file to see file contents

8. kernel  /vmlinuz........ ro root=LABEL=/       ->Loads the kernel
9. initrd  /initrd...img                 
         ->provides initital ram disk
10. boot                          
                -> Helps to boot the o/s


TO  EXTRACT THE INITRD
1. mkdir initrd
2. cp /boot/initrd-2.6.18-53.el5.img initrd/
3. cd initrd/
4. ls
5. file initrd-2.6.18-53.el5.img
6. mv initrd-2.6.18-53.el5.img initrd.gz
7. ls
8. gunzip initrd.gz
9. ls
10.file initrd
11.cpio  -ivd < initrd


TO SET GRUB PASSWORD
1.grub-md5-crypt              
     ->generate the password
2.vim /etc/grub.conf               ->open file (write below line in this file)
  password --md5  <generated password> (write below hidden menu)
3.reboot
4.Try pressing e or c in grub prompt it wont let you unless you type p
   and provide password

TO EXTRACT SPLASH IMAGE
1. mkdir splash
2. cp /boot/grub/splash.xpm.gz splash
3. cd splash/
4. ls
5. gunzip splash.xpm.gz
6. ls
7. firefox splash.xpm

TO ADD MULTIPLE TEXT TERMINAL
1. vim /etc/inittab
    50:2345:respawn:/sbin/mingetty tty50  -->creates 50th terminal
2. init q                             
   -->make changes to inittab
3. chvt  50                            
  -->change to 50th terminal
Note: To allow root to login also add entries to /etc/securetty.


TO MAKE SERVICE PERMANENT

1. chkconfig --list  |grep network
2. chkconfig --list  |grep sendmail
3. chkconfig --list  |grep cups
4. chkconfig --list  |grep vsftpd
5. chkconfig vsftpd on
6. chkconfig --list  |grep vsftpd
7. chkconfig --levels 35 vsftpd on
   chkconfig --levels 35 <service> <on/off>

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