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Mark

@offlinemark.bsky.social

257 followers 187 following 68 posts

trying hard. streaming kernel dev - youtube.com/@offlinemark blogging about life, art & systems programming. non-expert work: @ableton, prev @trailofbits home: offlinemark.com/about berlin, de

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Mark @offlinemark.bsky.social · 25/08/2026

week 134, streaming kernel dev (c++) topic: Local APIC timer started on the timer interrupt using the LAPIC. located it in phys mem using IA32_APIC_BASE MSR, mapped it into an uncacheable MMIO page and got some basic MMIO accesses working link + recap ↓

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Mark @offlinemark.bsky.social · 16/08/2026

week 133, streaming kernel dev (c++) topic: task creation API kernel tasks get passed a Kernel& ref, but there was no other argument to pass more data. this introduced some ugly global variables in a few places. so I extended the API to pass a void* arg link + recap ↓

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Mark @offlinemark.bsky.social · 10/08/2026

week 132, streaming kernel dev (c++) topic: kernel rflags test testing out the integration testing framework by writing a test that rflags are saved and restored currently during context switch (was a real bug I encountered during dev). looking pretty good link + recap ↓

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Mark @offlinemark.bsky.social · 01/08/2026

week 131, streaming kernel dev (c++) topic: kernel integration tests got the snitch C++ testing framework integrated into kernel mode, and ported some of my ad hoc test kernel tasks into it. looking pretty good! link + recap ↓

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Mark @offlinemark.bsky.social · 26/07/2026

week 130, streaming kernel dev (c++) topic: kernel integration tests continued on the integration test framework, and wrote a basic test that guard pages fault. it worked but i'm not 100% happy with the design. tips appreciated from anyone who has done this b4 link + recap ↓

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Mark @offlinemark.bsky.social · 19/07/2026

week 129, streaming kernel dev (c++) topic: kernel integration test framework worked on adding integration test infra which will let me write tests for behavior that would be difficult to test with unit tests (e.g. that guard page writes fault) link + recap ↓

Mark @offlinemark.bsky.social · 14/06/2026

week 124, streaming kernel dev right now discovered a dead end with my stack guard pages approach last stream, will regroup and decide on a final strategy for handling them this stream see ya 👋 youtube.com/live/AWEvMS...

building my own OS in c++ (week 124, more stack guard pages...)

#livecoding #operatingsystem #coding welcome: https://offlinemark...

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Mark @offlinemark.bsky.social · 07/06/2026

week 123, streaming kernel dev right now topic: stack guards + smart pointers testing the stack guard support we developed last week, and also improving and iterating on the pool smart pointers see ya 👋 youtube.com/live/NPe-uA...

building my own OS in c++ (week 122, stack guard pages)

#livecoding #operatingsystem #coding welcome: https://offlinemark...

Mark @offlinemark.bsky.social · 31/05/2026

week 122, streaming kernel dev right now topic: stack guard pages continuing with the custom allocator for task stacks, plus some smart pointer refactors youtube.com/live/YBYhzW...

building my own OS in c++ (week 121, stack guard pages)

#livecoding #operatingsystem #coding welcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’m an aspiring systems programmer...

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Mark @offlinemark.bsky.social · 24/05/2026

week 121, streaming kernel dev right now continuing with various scheduling/task related development, eg stack guard pages, refining the context switch implementation, etc youtube.com/live/E3dllU...

building my own OS in c++ (week 121, stack guard pages)

#livecoding #operatingsystem #coding welcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’m an aspiring systems programmer...

Mark @offlinemark.bsky.social · 17/05/2026

week 120, streaming kernel dev right now topic: scheduling / task stacks will continue with either: 1. changing the task register state to be stored on the stack, instead of in the task struct, or 2. continuing with task stacks see ya 👋 youtube.com/live/05EpiL...

building my own OS in c++ (week 116, kernel thread boot loop)

#livecoding #operatingsystem #coding welcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’m an aspiring systems programmer...

Mark @offlinemark.bsky.social · 12/04/2026

week 115, streaming kernel dev right now topic: kernel threads continue with properly cleaning up task stacks at the end of a task lifetime, probably implementing some kind of deferred task cleanup see ya 👋 youtube.com/live/eFS0hb...

building my own OS in c++ (week 115, kernel threads)

#livecoding #operatingsystem #coding 👉Get Rust training from Let’s Get Rusty: https://letsgetrusty.com/start-with-markwelcome: https://offlinemark.com/welco...

Mark @offlinemark.bsky.social · 05/04/2026

week 114, streaming kernel dev right now topic: scheduling working more on scheduler stuff -> idle task, scheduling policies, mapping the stack, etc see ya 👋 youtube.com/live/ap76Lb...

building my own OS in c++ (week 113, kernel threads)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 29/03/2026

week 113, streaming kernel dev right now topic: kernel threads continuing with scheduling/kernel threads, working on thread exit, an idle task, and properly mapping stacks instead of using the physmap see ya 👋 youtube.com/live/DM13pq...

building my own operating system in c++ (week 112, kernel threads)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

Mark @offlinemark.bsky.social · 22/03/2026

week 112, streaming kernel dev right now topic: scheduling continue on scheduling, refactoring the yield path with an idea to remove the global scratch buffer. and then creating an api to allow tasks to exit see ya 👋 youtube.com/live/Jtw6fD...

building my own operating system in c++ (week 111, kernel threads)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 15/03/2026

week 111, streaming kernel dev right now topic: kernel threads (cooperative) continuing with scheduler work today, will fix some interrupt-safety topics and generally continue this line of work see ya 👋 youtube.com/live/VRukq7...

building my own operating system in c++ (week 110, kernel threads)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

Mark @offlinemark.bsky.social · 01/03/2026

week 109, streaming kernel dev right now topic: kernel threads (cooperative) last week, we started a basic scheduler/thread implementation and got a single kernel thread running. going to work on switching between threads today see ya 👋 youtube.com/live/wWDHk4...

building my own operating system in c++ (week 108, kernel threads)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 25/01/2026

week 104, streaming kernel dev right now topic: x86_64 interrupts last week we started interrupts and got the most basic divide by zero exception handler working. will continue and flesh it out with a trap frame and handling it in c++ see ya 👋 youtube.com/live/h6HwJD...

building my own operating system in c++ (week 103, x86_64 interrupts)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

Mark @offlinemark.bsky.social · 18/01/2026

week 103, streaming kernel dev right now topic: x86_64 interrupts i'm moving on to setting up interrupts. i already did this before on JOS, but now will revisit it on 64 bit to learn how that differs, including new concepts like the IST see ya 👋 youtube.com/live/vVzgOE...

building my own operating system in c++ (week 102, virtual memory)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 11/01/2026

week 102, streaming kernel dev right now topic: virtual memory last week we got the kernel running on its own page tables for the first time. will continue with fleshing out the kernel's virtual address space see ya 👋 youtube.com/live/iJMQcC...

building my own operating system in c++ (week 101, virtual memory)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 04/01/2026

week 101, streaming kernel dev right now topic: virtual memory last week we got vm unmap started. might continue with this, but also might sanity check that basic mappings work within qemu. haven't done that yet, we have only used the unit tests so far see ya 👋 youtube.com/live/_PH6kF...

building my own operating system in c++ (week 101, virtual memory)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 28/12/2025

week 100! streaming kernel dev topic: virtual memory unmap continuing with virtual memory, i start working on a function to unmap pages from an address space. tried using a TDD approach which worked well! prerecorded since I'm at #39c3! see ya 👋 www.youtube.com/watch?v=rqp...

building my own operating system in c++ (week 100!, virtual memory)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 21/12/2025

week 99, streaming kernel dev right now topic: virtual memory last week we started implementing support for mapping memory using page tables, along with a basic unit test. will continue with this this week! see ya 👋 youtube.com/live/J63PmB...

building my own operating system in c++ (week 98, virtual memory)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

Mark @offlinemark.bsky.social · 14/12/2025

week 98, streaming kernel dev right now topic: virtual memory last week, we got the page table code harnessed and runnable in a unit test. still not sure that's a good idea, but will continue with implementing virtual memory see ya 👋 youtube.com/live/3sWoM-...

building my own operating system in c++ (week 97, page tables)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

Mark @offlinemark.bsky.social · 06/12/2025

week 97, streaming kernel dev right now topic: virt mem/page tables continuing with virtual memory/page tables. i'm interested to see to what extent I can make my page table code unit testable, will give this a try see ya 👋 youtube.com/live/xJAo_p...

building my own operating system in c++ (week 93, page tables)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/P6zQBsD2ngWelcome!I’...

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Mark @offlinemark.bsky.social · 04/12/2025

I was interviewed by @Raspberry_Pi for my dayjob embedded systems work at @Ableton! It's about Ableton Move, which is our portable device for making music. It's powered by a Raspberry Pi Compute Module, which has been great to work with :) Check it out: www.youtube.com/watch?v=G85...

Raspberry Pi Compute Module is the brain of Ableton Move

Raspberry Pi Compute Module is the brain of Ableton Move, allowing anyone to make and perform musicFind out more about Ableton Move at https://www.ableton.co...

Mark @offlinemark.bsky.social · 30/11/2025

week 96, streaming kernel dev topic: page tables got started on a simple virt address class that makes it easier to extract the bits needed for page table indexing. will be useful for doing page table walks (prerecorded since I'm away) see ya 👋 youtu.be/LRZ40QCKUno...

building my own operating system in c++ (week 96, page tables)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/XsgpqpVxNuWelcome!I’...

Mark @offlinemark.bsky.social · 18/11/2025

Long shot, but does anyone have an extra CCC ticket I could buy? Wasn’t able to get one in the open sales :/ I’d love to organize another hobby OS dev meetup and maybe do a small kernel dev workshop for anyone interested. Could also bring some merch to sell from shop.offlinemark.com ! 🙏

shop.offlinemark.com

Mark @offlinemark.bsky.social · 16/11/2025

week 94, streaming kernel dev topic: physmap Working on some unit tests for the physmap physToVirt() and virtToPhys() functions today. Testing out LLM assisted unit test generation (Prerecorded since I'm away) see ya 👋 youtu.be/oXY1ylrW6GM

building my own operating system in c++ (week 94, physmap)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/XsgpqpVxNuWelcome!I’...

Mark @offlinemark.bsky.social · 09/11/2025

week 93, streaming kernel dev right now topic: virtual memory last week we finished the bitmap allocator, complete with unit tests. will continue on whatever's next, probably using that to allocate page tables and set up virtual memory see ya 👋 youtube.com/live/SO7x0Z...

building my own operating system in c++ (week 93, page tables)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/XsgpqpVxNuWelcome!I’...

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Mark @offlinemark.bsky.social · 24/08/2025

week 82, streaming kernel dev right now topic: c++ STL last week we got c++ working in the cmake build. now that we have that working, continuing today with trying out some embedded/freestanding STL options see ya 👋 youtube.com/live/-ukB4U...

building my own operating system (week 82, c++ stl)

(detailed timestamps in comments)#livecoding #operatingsystem #codingwelcome: https://offlinemark.com/welcomediscord: https://discord.gg/XsgpqpVxNuWelcome!I’...

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Mark @offlinemark.bsky.social · 17/08/2025

week 81, streaming kernel dev right now topic: lldb, c++, STL last week we got all the clang/llvm work ported over to cmake. will continue with using lldb instead of gdb, then moving on to c++ support (hopefully including some kind of STL to use) see ya 👋 youtube.com/live/lJRi_h...

building my own operating system (week 81)

(detailed timestamps in comments)#livecoding #operatingsystem #codingNew here? Welcome info here: https://offlinemark.com/welcomediscord: https://discord.gg/...

Mark @offlinemark.bsky.social · 10/08/2025

week 80, streaming kernel dev right now topic: clang/c++ cmake last week we got limine integrated into cmake, will continue with porting the clang/c++ support I previously worked on, into cmake see ya 👋 youtube.com/live/jwvHrq...

chill OS/kernel hacking // code with me (week 80, clang cmake)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

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Mark @offlinemark.bsky.social · 04/05/2025

week 66, streaming kernel dev right now topic: networking last week we finally got RX working and received network data into userspace. continuing with networking today and likely finish the networking lab see ya 👋 youtube.com/live/7X8WKy...

chill OS/kernel hacking in C // code with me (week 66)

#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating Systems development "gardening" p...

Mark @offlinemark.bsky.social · 16/03/2025

week 59, streaming kernel dev right now topic: network driver continuing with last week's work to get the nic initialized! see ya 👋 youtube.com/live/Gf6Y_Q...

chill kernel hacking in C // code with me (PCI network driver, DMA)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

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Mark @offlinemark.bsky.social · 02/03/2025

week 57, streaming kernel dev right now topic: network/NIC driver after learning last week about qemu networking, today we're going to work on initializing the network card via PCI and accessing it via mmio see ya 👋 youtube.com/live/cFfENG...

chill kernel hacking in C // code with me

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

Mark @offlinemark.bsky.social · 23/02/2025

week 56, streaming kernel dev right now topic: network driver starting the network driver, which is the final lab of the coursework I'm following (also, multi-streaming to twitch today for the first time) see ya 👋 youtube.com/live/j4o7Km...

chill kernel hacking in C // code with me (week 55)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

Mark @offlinemark.bsky.social · 16/02/2025

week 54, streaming kernel dev topic: filesystem / process spawn streaming some filesystem dev and debugging, then moving onto start process spawning (prerecorded since i'm away today, back live next week - see ya 👋) www.youtube.com/watch?v=E0K...

chill kernel hacking in C // code with me (week 54)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

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Mark @offlinemark.bsky.social · 09/02/2025

week 55, streaming kernel dev right now topic: exec / spawn syscall now that we have a filesystem, we can try to exec programs from disk :) working on this today see ya 👋 youtube.com/live/-FeYOM...

chill kernel hacking in C // code with me

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

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Mark @offlinemark.bsky.social · 02/02/2025

week 53, streaming kernel dev right now topic: filesystem working on the core fs routines for walking the filesystem to find disk blocks see ya 👋 youtube.com/live/zTUK5f...

chill kernel hacking in C // code with me

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

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Mark @offlinemark.bsky.social · 26/01/2025

week 52! streaming kernel dev right now topic: continue hacking on the filesystem see ya 👋 youtube.com/live/3o-CYb...

chill kernel hacking EVERY week (week 52!!! filesystem)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

Mark @offlinemark.bsky.social · 19/01/2025

week 51, streaming kernel dev right now topic: filesystem needed to debug some boot issues last week after merging in the new lab code; will actually start the filesystem work today see ya 👋 youtube.com/live/bNg7oQ...

chill kernel hacking every week (week 50, debug boot virt mem)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

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Mark @offlinemark.bsky.social · 12/01/2025

week 50! streaming kernel dev right now topic: begin filesystem finished the multicore/fork/IPC labs last week, beginning filesystem work this week 🤠 see ya 👋 youtube.com/live/kVPJ95o...

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Mark @offlinemark.bsky.social · 05/01/2025

week 49, streaming kernel dev right now topic: basic IPC working on a basic IPC system so processes can send messages between each other see ya 👋 youtube.com/live/35QuRw...

chill kernel hacking every week

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...

Mark @offlinemark.bsky.social · 29/12/2024

week 48, streaming kernel dev topic: debug final bugs with COW fork syscall debugging a subtle bug in my COW fork support: I didn't realize that the child will immediately fault in its stack when it gets execution after the fork (prerecorded since I'm at CCC!) youtu.be/ohT3ZHI4kRc

Mark @offlinemark.bsky.social · 22/12/2024

week 47, streaming kernel dev right now topic: preemptive multitasking very exciting! we've only had cooperative multitasking with explicit yields so far — now it's time to implement preemption with a timer interrupt see ya 👋 youtube.com/live/CfEJOB...

Mark @offlinemark.bsky.social · 15/12/2024

week 46, streaming kernel dev right now topic: copy on write fork() in userspace continuing with this now that I finally understand this "UVPT" recursive page table mechanism for mapping the page tables so they're accessible from userspace see ya 👋 youtube.com/live/ura43M...

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Mark @offlinemark.bsky.social · 08/12/2024

week 45, streaming kernel dev right now topic: copy on write fork() in userspace now that we have userspace page fault handling working, we can proceed to the lab where we implement copy on write fork, entirely in userspace see ya 👋 youtube.com/live/PjsXpSu...

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Mark @offlinemark.bsky.social · 03/12/2024

hit a milestone, 5000 subs on youtube 🤯 a heartfelt thank you to anyone who has joined, watched, commented, or supported my streams in any way 🙏 it's really wild how much you can learn by just practicing something for 2 hours a week, every week. next stop: 52 weeks of kernel dev 🌽 🤓

Mark @offlinemark.bsky.social · 01/12/2024

week 44, streaming kernel dev topic: userspace page fault handling prequel to week 43, worked on the kernel-mode syscall support behind userspace PF handling (incl. recursive page fault support) (pre-recorded since I'm away this week ✌️) www.youtube.com/watch?v=5fv6Pjx3in8

chill kernel hacking for fun (week 44, user page fault + assembly)

(detailed timestamps in comments)#livecoding #softwareengineering #operatingsystem discord: https://discord.gg/XsgpqpVxNuWelcome! This is my chill Operating ...