Using Claude Code to modernize a 25-year-old kernel driver
221 comments
·September 7, 2025theptip
bicx
This is a good takeaway. I use Claude Code as my main approach for making changes to a codebase, and I’ve been doing so every day for months. I have a solid system I follow through trial and error, and overall it’s been a massive boon to my productivity and willingness to attempt larger experiments.
One thing I love doing is developing a strong underlying data structure, schema, and internal API, then essentially having CC often one-shot a great UI for internal tools.
Being able to think at a higher level beyond grunt work and framework nuances is a game-changer for my career of 16 years.
kccqzy
This is more of a reflection of how our profession has not meaningfully advanced. OP talks about boilerplate. You talk about grunt work. We now have AI to do these things for us. But why do such things need to exist in the first place? Why hasn't there been a minimal-boilerplate language and framework and programming environment? Why haven't we collectively emphasized the creation of new tools to reduce boilerplate and grunt work?
abathologist
This is the glaring fallacy! We are turning to unreliable stochastic agents to churn out boilerplate and do toil that should just be abstracted or automated away by fully deterministic, reliably correct programs. This is, prima facie, a degenerative and wasteful way to develop software.
travisgriggs
My take: money. Years ago, when I was cutting my teeth in software, efficiency was a real concern. Not just efficiency for limited CPU, memory, and storage. But also how you could maximize the output of smaller head count of developers. There was a lot of debate over which methodologies, languages, etc, gave the biggest bang for buck.
And then… that just kind of dropped out of the discussion. Throw things at the wall as fast as possible and see what stuck, deal with the consequences later. And to be fair, there were studies showing that choice of language didn’t actually make as big of difference as found in the emotions behind the debates. And then the web… committee designed over years and years, with the neve the ability to start over. And lots of money meant that we needed lots of manager roles too. And managers elevate their status by having more people. And more people means more opportunity for specializations. It all becomes an unabated positive feedback loop.
I love that it’s meant my salary has steadily climbed over the years, but I’ve actually secretly thought it would be nice if there was bit of a collapse in the field, just so we could get back to solid basics again. But… not if I have to take a big pay cut. :)
jalk
We have been emphasizing on creating abstractions since forever. We now have several different hardware platforms, programming languages, OS's, a gazillion web frameworks, tons of databases, build tools, clustering frameworks and on and on and on. We havn't done so entirely collectively, but I don't think the amount of choice here reflects that we are stupid, but that rather that "one size doesn't fit all". Think about the endless debates and flame wars about the "best" of those abstractions. I'm sure that Skynet will end that discussion and come up with the one true and only abstraction needed ;)
lukaslalinsky
I actually prefer the world with boilerplate connecting more important pieces of code together, over opinionated frameworks, because the boilerplate can evolve, charging the opinionated frameworks is much harder, and it's probably done by full rewrite. The thing is, the boilerplate needs to be kept to minimum, that's what I consider good API design. It allows you to do custom things, so you need some glue code, but not so much that you are writing a new framework each time you use it.
mikepurvis
I feel this some days, but honestly I’m not sure it’s the whole answer. Every piece of code has some purpose or expresses a decision point in a design, and when you “abstract” away those decisions, they don’t usually go away — often they’re just hidden in a library or base class, or become a matter of convention.
Python’s subprocess for example has a lot of args and that reflects the reality that creating processes is finicky and there a lot of subtly different ways to do it. Getting an llm to understand your use case and create a subprocess call for you is much more realistic than imagining some future version of subprocess where the options are just magically gone and it knows what to do or we’ve standardized on only one way to do it and one thing that happens with the pipes and one thing for the return code and all the rest of it.
codeulike
Why haven't we collectively emphasized the creation of new tools to reduce boilerplate and grunt work?
You dont understand how things evolve.
There have been plenty of platforms that got rid of boilerplate - e.g. ruby on rails about 20 years ago
But once they become the mainstream, people can get a competitive edge by re-adding loads of complexity and boilerplate again. E.g. complex front end frameworks like react.
If you want your startup to look good you've got to use the latest trendy front end thingummy
Also to be fair, its not just fashion. Features that would have been advanced 20 years ago become taken for granted as time goes on, hence we are always working at the current limit of complexity (and thats why we're always overrun with bugs and always coming up with new platforms to solve all the problems and get rid of all thr boilerplate so that we can invent new boilerplate)
andoando
Theres a million different million environments. This includes, OS, languages, frameworks and setups within those frameworks. Spring, java or kotlin, rest or grpc, mysql or postgres or, okhhtp or ktor, etc etc.
There is no software you could possibly write that works for everything thatd be as good as "Give me an internal dashboard with these features"
IanCal
Because the set of problems we make to be solvable with code is huge and the world is messy. Many of these things really are at a very high level of abstraction and the boiler plate feels boilerplatey but is actually slightly different in a way not automatable. Or it is but the configuration for that automation becomes the new bit you look at and see as grunt work.
Now we have a way we can get computers to do it!
wer232essf
Totally agree these tools shine as amplifiers of existing skills. They take care of the boilerplate and let you focus on design and tricky logic, so productivity gains scale with expertise.
The onboarding angle is huge too: being able to “rent experience” in new frameworks drastically shortens ramp-up time, especially in environments with lots of stacks in play.
And you’re right about evaluation without real hours of use, it’s easy to underestimate what they can actually do. The “non-coders vibe coding” narrative misses that for experienced devs, they’re accelerants, not crutches.
nine_k
Yes. The author essentially asked Claude to port a driver from Linux 2.4 to Linux 6.8. Very certainly there must be sufficient amounts of training material, and web-searchable material, that describes such tasks. The author provided his own expertise where Claude could not find a good analogue in the training corpus, that is, the few actually non-trivial bits of porting.
"Use these tools as a massive force multiplier of your own skills" is a great way to formulate it. If your own skills in the area are near-zero, multiplying them by a large factor may still yield a near-zero result. (And negative productivity.)
rmoriz
You can still ask, generate a list of things to learn etc. basically generate a streamlined course based on all tutorials, readmes and source code available when the model was trained. You can call your tutor 24/7 as long as you got tokens.
theshrike79
ChatGPT even has a specific "Study mode" where it refrains from telling you the answer directly and kinda guides you to figure it out yourself.
not_that_d
For me is not so. It makes me way faster in languages that I don't know, but makes me slower on the ones I know because a lot of times, it creates code that will fail eventually.
Then I need to expend extra time following everything it did so I can "fix" the problem.
peteforde
My daily experience suggests that this happens primarily when the developer isn't as good as they assume that they are at expressing the ideas in their head into a structure that the LLM can run with. That's not intended to be a jab, just an opportunity for reflection.
skydhash
But the moment I got the idea in my head, is the moment I got the code for it. The time spent is moslty checking the library semantics, or if there’s not some function already written for a specific bit. There’s also checking if you’re not violating some contract somewhere.
A lot of people have the try and see if it works approach. That can be insanely wasteful in any moderately complex system. The scientist way is to have a model that reduce the system to a few parameters. Then you’ll see that a lot of libraries are mostly surface works and slighlty modified version of the same thing.
ZYbCRq22HbJ2y7
We have members on my team that definitely feel empowered to wade into new territory, but they make so much misdirected code with LLMs, even when we make everyone use Claude 4 thinking agents.
It seems to me that if you have been pattern matching the majority of your coding career, then you have a LLM agent pattern match on top of that, it results in a lot of headaches for people who haven't been doing that on a team.
I think LLM agents are supremely faster at pattern matching than humans, but are not as good at it in general.
baq
> they make so much misdirected code with LLMs
just points to the fact that they've no idea what they're doing and would produce different, pointless code by hand, though much slower. this is the paradigm shift - you need a much bigger sieve to filter out the many more orders of magnitude of crap that inexperienced operators of LLMs create.
matwood
It'll be interesting if tools like Claude will end up being used to highlight the people who have no clue what they are doing.
maccard
One of the things I’ve noticed is that those people are the same people who before would spend 3 weeks on something before coming out with a copy of the docs that doesn’t actually solve the problem at hand, but it spits out a result that almost matches what you asked for. They never understood the problem in the first place, they always just hammered until the nail went in - now they just have a different tool.
faangguyindia
those who use claude code, what you think are its best features which you cannot live without and makes your life so much easier? I am using claude code but I am not sure what stuff i should look into.
marcus_holmes
>> Use these tools for rapid onboarding onto new frameworks.
Also new languages - our team uses Ruby, and Ruby is easy to read, so I can skip learning the syntax and get the LLM to write the code. I have to make all the decisions, and guide it, but I don't need to learn Ruby to write acceptable-level code [0]. I get to be immediately productive in an unfamiliar environment, which is great.
[0] acceptable-level as defined by the rest of the team - they're checking my PRs.
AdieuToLogic
>>> Use these tools for rapid onboarding onto new frameworks.
> Also new languages - our team uses Ruby, and Ruby is easy to read, so I can skip learning the syntax and get the LLM to write the code.
If Ruby is "easy to read" and assuming you know a similar programming language (such as Perl or Python), how difficult is it to learn Ruby and be able to write the code yourself?
> ... but I don't need to learn Ruby to write acceptable-level code [0].
Since the team you work with uses Ruby, why do you not need to learn it?
> [0] acceptable-level as defined by the rest of the team - they're checking my PRs.
Ah. Now I get it.
Instead of learning the lingua franca and being able to verify your own work, "the rest of the team" has to make sure your PR's will not obviously fail.
Here's a thought - has it crossed your mind that team members needing to determine if your PR's are acceptable is "a bad thing", in that it may indicate a lack of trust of the changes you have been introducing?
Furthermore, does this situation qualify as "immediately productive" for the team or only yourself?
EDIT:
If you are not a software engineer by trade and instead a stakeholder wanting to formally specify desired system changes to the engineering team, an approach to consider is authoring RSpec[0] specs to define feature/integration specifications instead of PR's.
This would enable you to codify functional requirements such that their satisfaction is provable, assist the engineering team's understanding of what must be done in the context of existing behavior, identify conflicting system requirements (if any) before engineering effort is expended, provide a suite of functional regression tests, and serve as executable documentation for team members.
0 - https://rspec.info/features/6-1/rspec-rails/feature-specs/fe...
maccard
> Instead of learning the lingua franca and being able to verify your own work, "the rest of the team" has to make sure your PR's will not obviously fail.
I lead the engineering team at my org and we hire almost exclusively for c++ engineers (we make games). Our build system by happenstance is written in c#, as are all the automation scripts. Out of our control to change. Should we require every engineer to be competent and write fluent c# or should we let them just get on with their value adds?
nchmy
are you advocating for not having code reviews...? Just straight force push to main?
ponector
That is what I observe at work: people who heavily use LLM in their coding don't read, review and test their code, pushing this work to teammates and testers.
Great skill multiplier, right?
mettamage
I don’t have a lot of experience with your first point. I do I have a lot of experience with your second point. And I would say that you hit the nail on the head
jillesvangurp
I think this is illustrative of the kind of productive things you can do with an LLM if you know what you are doing. Is it perfect, no. Can they do useful things if you prompt correctly, absolutely. It helps knowing what you are doing and having enough skill to make good judgment calls yourself.
There are currently multiple posts per day on HN that escalate into debates on LLMs being useful or not. I think this is a clear example that it can be. And results count. Porting and modernizing some ancient driver is not that easy. There's all sorts of stuff that gets dropped from the kernel because it's just too old to bother maintaining it and when nobody does, deleting code becomes the only option. This is a good example. I imagine, there are enough crusty corners in the kernel that could benefit from a similar treatment.
I've had similar mixed results with agentic coding sometimes impressing me and other times disappointing me. But if you can adapt to some of these limitations it's alright. And this seems to be a bit of a moving goalpost thing as well. Things that were hard a few months ago are now more doable.
mexicocitinluez
The more you use the tools, the more you're able to recognize the situations in which they're useful.
These studies keep popping up where they randomly decide whether someone will use AI to assist in a feature or not and it's hard for me to explain just how stupid that is. And how it's a fundamental misunderstanding of when and how you'd want to use these tools.
It's like being a person who hangs up drywall with screws and your boss going "Hey, I'm gonna flip a coin and if it's heads you'll have to use the hammer instead of a screwdriver" and that being the method in which the hammer is judged.
I don't wake and go "I'm going to use AI today". I don't use it to create entire features. I use it like a dumb assistant.
> I've had similar mixed results with agentic coding sometimes impressing me and other times disappointing me. But if you can adapt to some of these limitations it's alright. And this seems to be a bit of a moving goalpost thing as well. Things that were hard a few months ago are now more doable.
Exactly my experience too.
eisa01
I've used Claude Code in the past month to do development on CoMaps [1] using the 20 USD/month plan.
I've been able to do things that I would not have the competence for otherwise, as I do not have a formal software engineering background and my main expertise is writing python data processing scripts.
E.g., yesterday I fixed a bug [2] by having Claude compare the CarPlay and iOS search implementations. It did at first suggest another code change than the one that fixed it, but that felt just like a normal part of debugging (you may need to try different things)
Most of my contributions [3] have been enabled by Claude, and it's also been critical to identify where the code for certain things are located - it's a very powerful search in the code base
And it is just amazing if you need to write a simple python script to do something, e.g., in [4]
Now this would obviously not be possible if everyone used AI tools and no one knew the existing code base, so the future for real engineers and architects is bright!
[1] https://codeberg.org/comaps/comaps [2] https://codeberg.org/comaps/comaps/pulls/1792 [3] https://codeberg.org/comaps/comaps/pulls?state=all&type=all&... [4] https://codeberg.org/comaps/comaps/pulls/1782
maelito
Thanks for your contributions to Comaps. As the main developer of cartes.app, I'm happy to see libre traction in the world of maps.
Hope to make the bridge soon with i18n of cartes.app.
I also use LLMs to work on it. Mistral, mostly.
d4rkp4ttern
> using these tools as a massive force multiplier…
Even before tools like CC it was the case that LLMs enabled venturing into projects/areas that would be intimidating otherwise. But Claude-Code (and codex-cli as of late) has made this massively more true.
For example I recently used CC to do a significant upgrade of the Langroid LLM-Agent framework from Pydantic V1 to V2, something I would not have dared to attempt before CC:
https://github.com/langroid/langroid/releases/tag/0.59.0
I also created nice collapsible html logs [2] for agent interactions and tool-calls, inspired by @badlogic/Zechner’s Claude-trace [3] (which incidentally is a fantastic tool!).
[2] https://github.com/langroid/langroid/releases/tag/0.57.0
[3] https://github.com/badlogic/lemmy/tree/main/apps/claude-trac...
And added a DSL to specify agentic task termination conditions based on event-sequence patterns:
https://langroid.github.io/langroid/notes/task-termination/
Needless to say, the docs are also made with significant CC assistance.
codedokode
LLMs are also good for writing quick experiments and benchmarks to satisfy someone's curiosity. For example, once I was wondering, how much time does it take to migrate a cache line between cores when several processes access the same variable - and after I wrote a detailed benchmark algorithm, LLM generated the code instantly. Note that I described the algorithm completely and what it did is just translated it into the code. Obviously I could write the code myself, but I might need to lookup a function (how does one measure elapsed time?), I might make mistakes in C, etc. Another time a made a benchmark to compare linear vs tree search for finding a value in a small array.
It's very useful when you get the answer in several minutes rather than half a hour.
codedokode
Also I wanted to add that LLMs (at least free ones) are pretty dumb sometimes and do not notice obvious thing. For example, when writing tests they generate lot of duplicated code and do not move it into a helper function, or do not combine tests using parametrization. I have to do it manually every time.
Maybe it is because they generate the code in one pass and cannot return back and fix the issues. LLM makers, you should allow LLMs to review and edit the generated code.
kelnos
I see that often enough too, but if I then ask it to review what it's done and look for opportunities to factor out duplicated code, it does a decent job.
nikki93
https://github.com/terryyin/lizard has been useful to track when functions get too convoluted or long, or when there's too much duplication -- in code generated by agents. Still have to see how well it works long term but it's caught things here and there, I have it in the build steps in my scripts so the agent sees its output.
jlei523
Also I wanted to add that LLMs (at least free ones) are pretty dumb sometimes and do not notice obvious thing. For example, when writing tests they generate lot of duplicated code and do not move it into a helper function, or do not combine tests using parametrization. I have to do it manually every time.
scotty79
> I have to do it manually every time.
You can tell it to move it and they'll move it and use this shared code from now on.
jabl
Blast from the past! When I was a kid we had such a floppy tape device connected to a 386 or 486 computer my parents had. I think it was a Colorado Jumbo 250. I think the actual capacity was 125MB, but the drive or the backup software had some built-in compression, hence why it was marketed as a 250MB drive. Never tried to use it with the Linux ftape driver, though.
It wouldn't surprise me if the drive and the tapes are still somewhere in my parents storage. Could be a fun weekend project to try it out, though I'm not sure I have any computer with a floppy interface anymore. And I don't think there's anything particularly interesting on those tapes either.
In any case, cool project! Kudos to the author!
meander_water
> Be as specific as possible, making sure to use the domain-specific keywords for the task.
If you don't have the technical understanding of a language or framework, there is going to be a lot of ambiguity in your prompts.
This specificity gap leads the LLM to fill in those gaps for you, which may not be what you intended. And that's usually where bugs hide.
I think this is the flip side to being a "force multiplier"
SV_BubbleTime
“I need a C class that has a constructor for a tuple”
I would hope Claude would be like “Hold on man…”
qayxc
Hm. That was interesting, so I ran it as prompt to Qwen3-Coder (which I run locally). It spat out a bunch of C functions together with a C struct and commented:
This implementation provides:
Generic Tuple Structure: A flexible tuple that can hold different types of elements (int, double, string, float)
Constructor Function: tuple_create() initializes a new tuple with specified size
Type-Safe Setters:
tuple_set_int(), tuple_set_double(), tuple_set_string(), tuple_set_float()
Type-Safe Getters:
tuple_get_int(), tuple_get_double(), tuple_get_string(), tuple_get_float()
Memory Management: Automatic memory allocation and deallocation
Utility Functions:
tuple_print() for displaying tuple contents
tuple_destroy() for cleanup
petesergeant
> I need a C class that has a constructor for a tuple
| I'll create a simple C++ class with a constructor that takes a tuple. Here's an example...
> nah C
| C doesn't have classes or constructors - those are C++ features. In C, you would use a struct and create an initialization function. Here's how you'd handle a tuple-like structure:
Brendinooo
When I read an article like this it makes me think about how the demand for work to be done was nowhere close to being fully supplied by the pre-LLM status quo.
theshrike79
LLM assisted coding can get you from an idea to MVP in an evening (within maybe 1 or 2 Claude 5 hour quota windows).
I've done _so_ many of these where I go "hmm, this might be useful", planned the project with gemini/chatgpt free versions to a markdown project file and then sic Claude on it while I catch up on my shows.
Within a few prompts I've got something workable and I can determine if it was a good idea or not.
Without an LLM I never would've even tried it, I have better and more urgent things to do than code a price-watcher for very niche Blu-ray seller =)
jason-johnson
This, for me, is the actual gain and I don't see a lot of people talking about it: it's not that I finish a project faster the LLMs. From what I've read and personally experienced, it probably takes about as long to complete a project with or without the LLMs. But the difference is, without it I spend all that time deeply engaged, unable to do anything else. With the LLMs I no longer require continuous focus. It may be the same wall-clock time but my own mental capacity is not being used at or near capacity.
matwood
This right here. It's pretty amazing tbh. I'm typing this comment while Claude churns on an idea I had...
measurablefunc
It's never about lack of work but lack of people who have the prerequisite expertise to do it. If you don't have experience w/ kernel development then no amount of prompting will get you the type of results that the author was able to achieve. More specifically, in theory it should be possible to take all the old drivers & "modernize" them to carry them forward into each new version of the kernel but the problem is that none of the LLMs are capable of doing this work w/o human supervision & the number of people who can actually supervise the LLMs is very small compared to the amount of unmaintained drivers that could be ported into newer kernels.
There is a good discussion/interview¹ between Alan Kay & Joe Armstrong about how most code is developed backwards b/c none of the code has a formal specification that can be "compiled" into different targets. If there was a specification other than the old driver code then the process of porting over the driver would be a matter of recompiling the specification for a new kernel target. In absence of such specification you have to substitute human expertise to make sure the invariants in the old code are maintained in the new one b/c the LLMs has no understanding of any of it other than pattern matching to other drivers w/ similar code.
ekidd
There is usually a specification for how hardware works. But:
1. The original hardware spec is usually proprietary, and
2. The spec is often what the hardware was supposed to do. But hardware prototype revisions are expensive. So at some point, the company accepts a bunch of hardware bugs, patches around them in software, ships the hardware, and reassigns the teams to a newer product. The hardware documentation won't always be updated.
This is obviously an awful process, but I've seen and heard of versions of it for over 20 years. The underlying factors driving this can be fixed, if you really want to, but it will make your product totally uncompetitive.
DrewADesign
AI doesn’t need to replace a specialist in their entirety for it to tank demand for a skill. If the people that currently do the work are significantly more productive, fewer people will be necessary to the same amount of work. Then, people trying to escape obsolescence in different, more popular specialties move into the niche ones. You could easily pass the threshold of having less work than people without having replaced a single specialist.
bandrami
IDK, the bottleneck really still seems to be "marketable ideas" rather than their implementation. There's only so much stuff people are willing to actually pay for.
pluto_modadic
things were on the backlog, but more important things absolutely needed to be done.
mintflow
When I was port fd.io vpp to apple platform for my App, there is code that's implement coroutine in inline ASM in a C file but not in Apple supported syntax, I have succesfully use Claude web interface to get the job done (Claude code was not yet released), though as like in this article, I have strong domain specific knowledge to provide a relevant prompt to the code.
Nowadays I heavily rely Claude Code to write code, I start a task by creating a design, then I write a bunch of prompt which cover the design details and detail requirements and interaction/interface with other compoments. So far so good, it boost the productivity much.
But I am really worrying or still not be able to believe this is the new norm of coding.
sedatk
Off-topic, but I wish Linux had a stable ABI for loadable kernel modules. Obviously the kernel would have to provide shims for internal changes because internal ABI constantly evolves, so it would be costly and the drivers would probably run slower over time. Yet, having the ability to use a driver from 15 years ago can be a huge win at times. That kind of compatibility is one of the things I love about Windows.
fruitworks
I think this would be terrible for the driver ecosystem. I don't want to run 15 year old binary blob drivers because they technicially still work.
Just get the source code published into mainline.
0xbadcafebee
I had a suspicion AI would lower the barrier to entry for kernel hacking. Glad to see it's true. We could soon see much wider support for embedded/ARM hardware. Perhaps even completely new stripped-down OSes for smart devices.
eviks
Nothing was lowered because there was no barrier:
> As a giant caveat, I should note that I have a small bit of prior experience working with kernel modules, and a good amount of experience with C in general
But yeah, the dream of new OSes is sweet...
baq
I'd bet a couple dollars that it'd take a week for someone who hasn't hacked on the kernel at all, but knows some C and two weeks for someone who doesn't even know C but is a proficient programmer. This would previously take months.
We're talking about an order of magnitude quicker onboarding. This is absolutely massive.
eviks
It's so massive that your own fantasy bet is just a couple of dollars...
giancarlostoro
If used correctly it can help you get up to speed quicker, sadly most people just want it to build the house instead of using it to help them hammer nails.
mrheosuper
>new stripped-down OSes for smart devices.
What's wrong with exist one?
csmantle
It's a good example of a developer who knows what to do with and what to expect from AI. And a healthy sprinkle of skepticism, because of which he chose to make the driver a separate module.
A good case study. I have found these two to be good categories of win:
> Use these tools as a massive force multiplier of your own skills.
Claude definitely makes me more productive in frameworks I know well, where I can scan and pattern-match quickly on the boilerplate parts.
> Use these tools for rapid onboarding onto new frameworks.
I’m also more productive here, this is an enabler to explore new areas, and is also a boon at big tech companies where there are just lots of tech stacks and frameworks in use.
I feel there is an interesting split forming in ability to gauge AI capabilities - it kinda requires you to be on top of a rapidly-changing firehose of techniques and frameworks. If you haven’t spent 100 hours with Claude Code / Claude 4.0 you likely don’t have an accurate picture of its capabilities.
“Enables non-coders to vibe code their way into trouble” might be the median scenario on X, but it’s not so relevant to what expert coders will experience if they put the time in.