Ask HN: Where can I find a primer on how computers boot? • Hacker News Board

jiveturkey wrote: post #19

Plenty of good links here already. I'll just add that booting is enormously complex, and starts well before any of the dozen comments so far. I skimmed many of them (not all) and they all tell pretty much the same story whether on real hardware or virtual. But modern real hardware first boots a Management Engine (or BMC, or T2, or similar), which prepares things and starts subsystems like hardware controllers, before…

So much this. Every part of a modern computer contains unseen, non-architectural processors of various kinds. When the main architectural CPU executes the first instruction, that is the last in a sequence of miracles. The only way to be familiar with the whole process is to build a computer from scratch.

Re: Ask HN: Where can I find a primer on how computers boot?

#35

Post by vishnugupta » Mon, Mar 20, 2023, 1:35 PM UTC

Perhaps it's easier to pick an OS and understand its boot process?

And since no one's mentioned let me say that TLDP is a comprehensive, understandable, and the authoritative source on all things Linux.

That said, here's two documents from TLDP.

1. [Boot process, Init and shutdown] https://tldp.org/LDP/intro-linux/html/sect_04_02.html

2. [The boot process in closer look] https://tldp.org/LDP/sag/html/boot-process.html

Re: Ask HN: Where can I find a primer on how computers boot?

#36

Post by kfajdsl » Mon, Mar 20, 2023, 1:54 PM UTC

saidinesh5 wrote: post #6

Arch wiki is a really good place i learned this stuff from: https://wiki.archlinux.org/title/Arch_boot_process P.S I use Arch btw. ;)

2nd this, this is where I learned how computers boot up.

Re: Ask HN: Where can I find a primer on how computers boot?

#37

Post by lom » Mon, Mar 20, 2023, 2:07 PM UTC

saidinesh5 wrote: post #6

Arch wiki is a really good place i learned this stuff from: https://wiki.archlinux.org/title/Arch_boot_process P.S I use Arch btw. ;)

+1, this is also where I learned most of my knowledge

Re: Ask HN: Where can I find a primer on how computers boot?

#38

Post by mackid » Mon, Mar 20, 2023, 2:17 PM UTC

A good summary of UEFI booting:

https://depletionmode.com/uefi-boot.html

Re: Ask HN: Where can I find a primer on how computers boot?

#39

Post by photochemsyn » Mon, Mar 20, 2023, 2:34 PM UTC

This one looks pretty good, for all the terms you list. It's refreshingly free of opinionating and just covers the technicalities and the history in a straightforward manner, and has links to good wiki overviews of EFI etc, compares the BIOS vs UEFI boot processes, and so on:

https://en.wikipedia.org/wiki/GNU_GRUB

Incidentally I discovered you can learn a fair amount about the boot process by making bad edits to your /etc/fstab file on a Linux system :) e.g.

https://unix.stackexchange.com/questions/107828/how-is-etc-f...

Also this central page for different bootloaders for a variety of systems, is kind of interesting, there's many different approaches.

https://en.wikipedia.org/wiki/Comparison_of_bootloaders

Re: Ask HN: Where can I find a primer on how computers boot?

#40

Post by easterncalculus » Mon, Mar 20, 2023, 2:40 PM UTC

I honestly had a very good exchange about this exact topic with ChatGPT not too long ago. It was able to draw connections between the different stages that blog posts/wikis about each often do not. Specifically I was asking about the Linux boot process and it was able to go into enough detail for me to Google for the rest. Hope that helps.