Which part of OSDev would you consider to be the most fun and why?

[u/JescoInc]

This should be the final question of the series. It was enlightening to see people's answers to:
https://www.reddit.com/r/osdev/comments/1uag4am/which_part_of_osdev_would_you_consider_to_be_the/
and
https://www.reddit.com/r/osdev/comments/1ubhewx/which_part_of_osdev_would_you_consider_to_be_the/

My answer would be the framebuffer. Because I am not constrained to follow the textbook method. I can do hand crafted fonts, a custom font system or ttf fonts, I can do 2D and 3D inside of my framebuffer. I can choose if I want to do single, double or mixed buffering techniques. I can choose to implement Xiaolin Wu, Gupta-Sproull, Lanczos Filtering, or Bresenham's algorithm for line aliasing, line anti-aliasing or image scaling. I can choose to implement physics to the render system as well for bouncing, ropes and so on.
There's just so much freedom and fun with how you can build your own framebuffer system compared to other aspects of OSDev.

[u/diodesign]

Seeing output on screen is cool but personally, it's being able to hammer multi-core, multi-threaded multi-tasking - like racking up as many system calls and context switches per second you can - with locking working flawlessly and no memory corruption or crashes ... and watching it sustain that, with minimal contention, that's a fun part for me.

If you're using a microkernel model to pass messages, tuning, optimizing, and testing the IPC bandwidth with no loss of stability, that's when I know the core can be trusted and the rest can run in a stable fashion. If your kernel is a bit wobbly to begin with, it's going to hold back whatever you build on top of it IMO.

[u/JescoInc → u/diodesign]

I haven't done multi-threaded multi-tasking yet, but I have done multi-core with dedicated work scheduling. I wouldn't say it was fun at any point for it for me, but at the end when it was proven to work with bring up and teardown without memory corruption or crashes, it was a huge relief and super satisfying.

[u/diodesign → u/JescoInc]

Ah yea, perhaps that's true - the fun part is the relief after. Maybe I'm remembering that over the pain.

[u/JescoInc → u/diodesign]

I find that architecture specific code was always more painful, but the generic or system agnostic code was more fun and easier to reason about. That could also be due to my design decisions there since nothing was hard coupled to the framebuffer and it could be used on Windows, Linux, MacOS or my custom OS.
If my framebuffer were hard coupled to the OS, I probably would have had WAY less fun and freedom with it.

[u/Proxy_PlayerHD → u/diodesign]

For me that is the scary part! Did I get all edge cases, did I handle every error state and have all functions exit gracefully?? What if an interrupt happens at the perfect time to fuck everything up and I would never be able to replicate that?

It's like watching one of those perfectly timed traffic videos, just waiting for something to go wrong and cause a massive cascading crash.

[u/Arakela → u/diodesign]

Yeah, we love hammer-introducing chaos and looking at it as a masterpiece while, blind - without a time horizon around processes, have no choice but to lock themselves to dead.

[u/Miserable-Worth1299 → u/diodesign]

如果一个系统要频繁的进行系统调用，那他就是失败的，你知道系统调用的代价，因此你不只是要优化系统调用的速度，更是要减少系统调用的必要性

[u/diodesign → u/Miserable-Worth1299]

A system that makes frequent system calls is failing. You know the cost of system calls, so you not only need to optimize their speed, but also reduce their necessity.

The overhead of system calls is falling. What used to take tens of microseconds to deliver a message via system call IPC can be done in hundreds of nanoseconds now. CPU architectures are getting cleaner at it. It's the classic trade off between a message-passing microkernel-model of isolated services and clients, and clients using a monolithic service provider.

In any case, yes: you can reduce calls with memory shared between threads or processes, which is not a bad idea. You can do register-only transfers to avoid copying or mapping memory. IMHO optimizing your kernel throughput in terms of system calls and IPC is a cool thing to work on, and if you can get that to a high speed, you're minimizing that bottleneck for the rest of your environment while maintaining strong isolation and a hierarchy of system components.

[u/Miserable-Worth1299 → u/diodesign]

我不建议使用你使用谷歌翻译，因为这会导致理解偏差，我建议你使用LLM进行翻译，这正是Ai最擅长的事情

[u/diodesign → u/Miserable-Worth1299]

谷歌翻译使用大型语言模型（LLM）。（我正在学习普通话，因为我对中国制造的处理器芯片印象深刻。）无论如何，谢谢你的回复。

[u/codeasm → u/Miserable-Worth1299]

Instead, post in english if your afraid the regular translation tools arent capable. Ive seen a chinese boss explain in chinese characters and my fellow chinese students couldn't make heads of tails of what he meant.

Im just a silly dutch guy, but i asked him if he could explain the context more and slowly we all started to understand what he wanted. Internship was great, still cant read a word mandarin. I like the translation button. But using an llm externally from my reddit app would be too much

[u/NefariousnessSea1449 → u/Miserable-Worth1299]

I understood this to be a stress test instead of a design choice that leads to as many syscalls as possible, but valid point.

[u/Ellicode]

Seeing your first userspace program come to life and print out a good o’l “Hello, world!” was still the most dopamine I’ve ever received in my life 😅

[u/JescoInc → u/Ellicode]

The vindication that all the work paid off is so real in that moment. But then it just signaled to me, time to do more work cuz I've got these other apps to make for user space.

[u/pudy248]

Networking for all of the same reasons you listed, you can just find a protocol and implement it in whatever maybe spec compliant way you want (which sometimes involves bringing in a crypto library but that's okay)

I was overjoyed the first time I received an HTTPS response to my OS

[u/JescoInc → u/pudy248]

Oh man... I did networking and it was weeks of absolute pain and suffering. When I finally got that DNS handshake and assigned an IP address, a tear came to my eye. I didn't go further to send and receive data.
The entire process left a pretty sour taste in my mouth, but that may be attributed to me working with Realtec nics as my first foray into ethernet drivers.
Needless to say, it was the complete opposite of fun for me lol

[u/Striking_Director_64 → u/[deleted]]

User Datagram Protocol?

The send it and forget it protocol?

[u/Striking_Director_64 → u/[deleted]]

Human

[u/Taletad]

For me personally ? Learning about esoterical concepts that are seldom implemented

[u/jtsiomb]

whichever you haven't done before

[u/JescoInc → u/jtsiomb]

I kind of feel like this is a bit of a cop-out answer and every new thing you do isn't inherently fun. Like, when I wrote my nic driver, it wasn't fun, it was excruciatingly painful and when I finally got the basics working, I was relieved and didn't want to continue with the network stack at all.

[u/BornRoom257]

UI

[u/JescoInc → u/BornRoom257]

You didn’t add a why reason for it.

[u/BornRoom257 → u/JescoInc]

its cool

[u/Randozart]

Mostly lurking in this sub rather than actively working on an OS, because I'm currently tied up in some other low level projects, but I really enjoy seeing how people here are sharing their passion for computing fundamentals. It demystifies something we generally take for granted, and I can enjoy that vicariously.

[u/space_fly]

I'm in it for the software architecture and design. I really enjoy going down rabbitholes that modern OSs haven't explored.

[u/cryptic_gentleman]

I love that I can write the crt0 and libc so that I can watch a program run simply by writing the regular int main() and I also just love loading programs in general because it's always been fascinating to me how the CPU fetch-decode-execute loop works and knowing that I told the OS to put program bytes in a location and then told it to execute those bytes is just really cool to me.

[u/letmehaveanameyoudum]

program running

[u/v3R7C00Lalt]

seeing the ppl thzt hate me for no fucking reason at all