Arch Linux

medicineman25

Member

Registered: 2014-12-03

Posts: 110

Anatomy of the installation ISO

Hi,

I am very interested in what is inside the installation ISO from a live USB. (And I don't mean Archiso, the tool used to create live USB's). What's inside? How does it detect my local hardware? Does it matter what BIOS is running? How much of it is in the USB vs on the mirrors? Is that why it needs an Internet connection? I have been rather successful in installing Arch on several varying machines with few hiccups with regards to specific drivers (except NVIDIA, which was still a simple pacman) and it only just occurred to me today that there is no part of the process which requires me to compile the C kernel for my specific chipset, so it has me baffled as to how Arch works its magic.

I have been doing some research into Archiso, but if someone could spell out what is happening or point me in the direction of some learning material, I would be eternally grateful. Thank you.

Awebb

Member

Registered: 2010-05-06

Posts: 6,298

Re: Anatomy of the installation ISO

You could extract the iso and look at the files. There will be obvious file names of stuff you can look up. Also extract all the images inside the image (whatever squashfs and initramfs you find there) and look at these.

The reason why it needs an internet connection, is that there are no packages in the ISO, you will fetch them from the mirror in the process. The image could be smaller, it could be about half the size, but it supports both i686 as well as x86_64, so there are basically two live operating systems in the ISO.

Why does it recognize all your hardware? Hardware support in Linux mostly happens directly in the Kernel. Arch uses a more or less unmodified Linux kernel, that means if it's in the Kernel, Arch can do it. Your chipset probably wasn't supported until recently. The reason Arch recognizes it and other distros probably don't (as I assume from your question), is that Arch more or less always uses the latest stable Kernel, while other distros often only release once a year (or similar) and only backport security patches to their old kernel versions, but not features.

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: Anatomy of the installation ISO

The reason why it needs an internet connection, is that there are no packages in the ISO

What does take up the space on the iso then? :-)
https://projects.archlinux.org/archiso. … igs/releng -> e.g. https://projects.archlinux.org/archiso. … kages.both

medicineman25

Member

Registered: 2014-12-03

Posts: 110

Re: Anatomy of the installation ISO

ok cool, thanks guys. super helpful ... I will delve into more specific research about the kernel itself and definitely gonna open that image up and have a look. Thanks again!

Awebb

Member

Registered: 2010-05-06

Posts: 6,298

Re: Anatomy of the installation ISO

The reason why it needs an internet connection, is that there are no packages in the ISO

What does take up the space on the iso then? :-)
https://projects.archlinux.org/archiso. … igs/releng -> e.g. https://projects.archlinux.org/archiso. … kages.both

If you find any packages pacman can install, write me an email ;-)

Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 29,548

Website

Re: Anatomy of the installation ISO

So are we just quibbling over semantics here.  Of course many packages are installed on the iso, but there are no pkg.tar.gz files.

---

"UNIX is simple and coherent..." - Dennis Ritchie, "GNU's Not UNIX" -  Richard Stallman

karol

Archivist

Registered: 2009-05-06

Posts: 25,440

Re: Anatomy of the installation ISO

Wouldn't https://wiki.archlinux.org/index.php/Pa … _USB_stick work?
Ah, I get it. As Trilby said, it's semantics.

Last edited by karol (2015-08-08 13:46:47)

Awebb

Member

Registered: 2010-05-06

Posts: 6,298

Re: Anatomy of the installation ISO

Trilby, can you split this to a new thread, probably to offtopic, so we can discuss in length, if a package is still a package once it is installed. Maybe we could have a closer look at the unwrapping analogy.