Everything you ever wanted to know about how your PC boots up

PC LoadingHave you ever wondered just what is it, exactly, that happens when you press that simple “power” button on your PC? How does your computer go from electricity reaching the power supply to the BIOS power-up sequence on your screen, how the computer checks attached disks and devices, and how it decides which to load from?

Or perhaps you’ve wondered what happens next, after your computer’s BIOS has chosen a drive and wants to pass control of your PC on to the target disk? What role does the MBR play in this process, and how does the core bootloader – a simple, single file sitting, forlorn, all on its lonesome in a plain-jane directory on your PC – wind up being executed and put in control of the madness that is the boot process?

Part one of our “everything you ever wanted to know about how your boots up” series covers these questions and much, much more; delving into the depths of the boot process, and exploring the intricate connections between the worlds of hardware and software, and the various conventions and standards that hold everything together. It’s a bit of a lengthy read, but there’s a lot to learn!

Read now: The BIOS/MBR Boot Process

Future parts in this series will, insha’Allah, include an article on the similarities and differences in the  BIOS vs the EFI and the MBR vs the GPT, and another article on the opposite-but-eerily-similar boot process involved in the completely-new UEFI/GPT specification.

Have questions or comments? Feel free to ask any questions below, and we’ll do our best to answer or address them.

Image credit: yng from The Noun Project

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  • 4 thoughts on “Everything you ever wanted to know about how your PC boots up

    1. 28 jun 2015 3 a.m. I have a question, since I changed the motherboard (to MSI G41M-P33 combo soc 775/GIGABYTE Intel 4 series Utilities), I moved; then was without ISP connect for two months.
      When I boot up, neither “del” nor “F9” allow me to enter the boot or bios menus. What am I doing wrong?
      Thank you for helping this old lady find her way.
      Jesus loves you. a.

    2. This is very informative article but it seems that the UEFI article can longer be found.

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