Linux Booting Process Sequence

  1. When the computer is switched on, it automatically invokes BIOS [a ROM chip embedded in the motherboard].
  2. The BIOS will start the processor and perform a POST [power on self test] to check whether the connected device are ready to use and are working properly.
  3. Once the POST is completes BIOS will jump to a specified location in the RAM and check for the booting device. The boot sector is always the first sector of the hard disk and BIOS will load the MBR into the memory.
  4. Here the boot loader takes the control of the booting process.
  5. LILO or GRUB is the boot loaders commonly available. It will help the user to select various boot options.
  6. Depending on the boot option selected the kernel is loaded.
  7. After kernel is loaded the kernel will take the control of the booting process
  8. initrd will be loaded which contains drivers to detect hardware (Initialization of RAM Disk)
  9. Then it will initialize all the hardware including I/O processors etc.
  10. Kernel then mounts the root partition as read-only
  11. INIT is loaded.
  12. INIT will mount the root partition and other partitions as read/write and checks for file system errors.
  13. Sets the System Clock, hostname etc..
  14. Based on the Runlevel, it will load the services and runs the startup scripts (Network, cups, nfs, etc.)
  15. Finally it runs the rc.local script.
  16. Now the login prompt will appear.
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Anonymous
December 2, 2010 at 6:25 PM delete

Very easy to follow up

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August 1, 2011 at 1:02 PM delete

thanks buddy... very easy to follow.. I am looking for a change .. i am sure your post will help me :)

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August 1, 2011 at 7:04 PM delete

Hi Sumit,

Thanks for visit and comment...

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Anonymous
January 31, 2012 at 4:24 AM delete

Thank You for posting such information



Shekhar

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Anonymous
August 28, 2012 at 10:49 PM delete

This really very good site for all the technical things

Thanks
Vinayak

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Anonymous
September 21, 2012 at 2:03 PM delete

Nice ...... But in point number 3 , instead of CMOS wrongly you mentioned RAM .

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February 27, 2013 at 10:01 PM delete

For indepth understanding of boot process:
http://www.ibm.com/developerworks/library/l-linuxboot/

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