bobjohncat
Posts: 21
Joined: Thu Mar 05, 2015 3:41 pm

Smallest OS possible?

Thu Jul 27, 2017 12:37 pm

Hi,

I've been trying to find information on creating a very small OS for the Pi and came across info-beamer.com who suggest their entire system is 35mb in size.

I'm not sure how they've achieved this so wondered if someone would be kind enough to point me in the right direction.

Many thanks

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topguy
Posts: 5569
Joined: Tue Oct 09, 2012 11:46 am
Location: Trondheim, Norway

Re: Smallest OS possible?

Thu Jul 27, 2017 12:54 pm

Embedded Linux projects are capable of creating very small very specialized images for different hardware.
The two most known to me are:
- buildroot - https://buildroot.org/
- Yocto - https://www.yoctoproject.org/

I've only tested this example https://github.com/Metrological/buildroot myself, it uses buildroot.

bobjohncat
Posts: 21
Joined: Thu Mar 05, 2015 3:41 pm

Re: Smallest OS possible?

Thu Jul 27, 2017 7:37 pm

Many thanks for the links, I'll look into them!

drgeoff
Posts: 9366
Joined: Wed Jan 25, 2012 6:39 pm

Re: Smallest OS possible?

Thu Jul 27, 2017 8:52 pm

It isn't long since a mid-range router had a 4 Mbyte flash chip containing a Linux OS. Those gum-stick pack size pocket 3G* Wi-Fi routers you see at less than US$10 on ebay still do.

(* 3G meaning they support a separate plug-in USB dongle.)

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dividuum
Posts: 119
Joined: Sun Jun 16, 2013 1:18 pm
Location: Germany
Contact: Website

Re: Smallest OS possible?

Thu Jul 27, 2017 10:18 pm

bobjohncat wrote:
Thu Jul 27, 2017 12:37 pm
I've been trying to find information on creating a very small OS for the Pi and came across info-beamer.com who suggest their entire system is 35mb in size.
I'm the programmer behind info-beamer. The OS that drives all the digital signs is indeed only 35MB in total at the moment. The main reason that makes this possible is that the software driving the screens (info-beamer pi) doesn't have a lot of dependencies, so the OS gets away without (for example) having a complete web browser, X or any kind of widget library (e.g. gtk/qt). The biggest dependency is libav (mostly used for video demuxing and audio decoding) and all its dependencies. In total the uncompressed image is ~75MB at the moment. During the build process, everything is packaged into either an initrd file (for the very early boot process) or a squashfs that holds the main root file system that is mounted a few seconds into the boot process. Let me know if you have any further questions. I'm happy to answer them.

Another interesting project to watch if you're looking for an even more minimal system is gokrazy. It get's rid of all those nasty C based programs ( ;-) ) and replaces everything with a single Go program that is started directly after loading the kernel.
info-beamer hosted - A user and programmer friendly digital signage platform for the Pi: https://info-beamer.com/hosted

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Gavinmc42
Posts: 3168
Joined: Wed Aug 28, 2013 3:31 am

Re: Smallest OS possible?

Fri Jul 28, 2017 2:39 am

PiCore is pretty small, limited number of apps but rock solid.
Ultibo will make a kernel.bin in 2 to 3MB, so no Linux OS needed, but no video acceleration stuff yet, it can do bitmap/png images.
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