Build your own OS: Pre-emptive Multitasking

08 February 2020

One of my recent long-running projects has been building my own operating system. It’s called SOS, for Stephen’s OS (real creative, I know). And beyond all odds, this project has progressed really well! Recently, SOS got the ability to do pre-emptive multitasking — and it only took me 116 commits and 1.5 years of on-and-off effort to get there! Throughout that time, I haven’t really posted about SOS because it felt too complicated to write about. But I don’t want to let that prevent me from trying, so going forward, I’m going to try to post about different features and achievements with SOS. To start, this post will describe how I got pre-emptive multitasking working.

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Network Booting Raspberry Pi 4B with Upstream Kernel

04 December 2019

This is a guide and personal documentation for how I got my Raspberry Pi 4B booted with an upstream Linux kernel. I use this setup for quickly booting custom kernels as I do development. As a result, I had the following goals:

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Site Update

17 February 2019

Today I made a few changes to my site’s design which hopefully makes things a bit more user-friendly for anyone using this site.

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Creating an Alien Themed Linux Greeting Card

14 June 2017

My (former) roommate is a big fan of the Alien series, especially the classic first movie, and the really awesome video game, Alien: Isolation (I guess you could say I’m a fan too!). As a goodbye gift, I thought I’d create a really odd e-card: a bootable Linux flash drive with the same boot splash as computers from the movie, sound effects from the movie and game, and programs that look like the ones in the game. Everything turned out much better than I hoped, and so I thought I’d share the method and the result in a blog post!

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Public Mistakes are Cool

24 April 2017

Confession time: I’m vain. While I write a blog because I like to write and share things, I’d be lying if I said that I didn’t enjoy the occasional publicity resulting from a successful post on Hacker News or Reddit. I get to open up a Google Analytics tab and watch visitors enter my site. How cool is that?

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Linked Lists are Still Hard

21 April 2017

Kernel development offers a set of challenges that are very different than the ones you would encounter in other types of programming. When you’re new to kernel dev, you hear from lots of sources that you’re gonna have a hard time. But for me, after some initial culture shock, I didn’t feel that uncomfortable. It still felt like user-space C programming. But a few days ago, I finally encountered that bug that made me realize, we’re not in Kansas anymore, Toto.

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Wireshark Tricks

12 April 2017

This is mostly for my own reference, but maybe others will find it interesting as well.

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Development of a Developer

14 March 2017

I was a curious child. I spent hours on the family computer, exploring every menu in Windows 95, and later XP. My exploration sometimes ended badly, like the time when I changed our computer’s language to Portuguese, or the time I set the foreground and background colors of the menus to lime green[^1]. Exploring and learning about computers has never failed to put that elated, soaring feeling in my chest.

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How to Get the Network Namespace Associated With a Socket

08 March 2017

For the past week I’ve been struggling with a very particular issue in the Linux kernel. I seriously doubt that anyone else will have this issue, but if they do, perhaps a bit of luck and SEO will bring them to this page.

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Kernel Development Made Easier

08 March 2017

A little while ago I wrote a post about creating a Linux system call. In it, I explained how to create a virtual machine, get the Linux source, modify it, build it, and boot your custom kernel. This is a totally valid way to do kernel development, but it can be a bit inconvenient. For one, the code was stored within the VM, so all editing and compiling was done in a VM too. For another, there was a pretty complex process to build an “initrd” in order for Arch Linux to boot properly. And finally, the kernel configuration we used was pretty massive, resulting in longer build times for extra features and device support to be compiled into the kernel.

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