In my opinion this is a more logical way of running multiple operating systems on a host since hypervisors run the entire operating system virtually, including hardware specific code like device drivers.
It's much more logical to merely run the operating system core as a user space library enabling you to run its binaries without needing to emulate hardware. I do wonder whether you can run everything that the guest system offers, such as hardware graphics acceleration.
Another drawback is that it depends on operating system vendors making available their core OS components as a library. This is especially a problem for closed-source vendors like Microsoft who may not want to do this for strategic business reasons.
I think they will. It’s a pretty famous quote, even among people who were not old enough to see it first-hand at the time when Linus made that Usenet post.
Does this mean you still delegate to something like KVM/paravirtualzation for your device models, but your FTL guest OS can run multiple secure workloads inside a VM?
Or are you designing a custom OS from the ground up to run on native hardware? What constraints are you putting on hardware support to make this a tractable that's not re-implementing all of the stuff that linux has? I assume that's why it's advertised for the "cloud", because you know a priori the deployment machines you're gonna run on? Or is hardware support known by kernel devs to be a (relatively) trivial problem in the OS space, compared to the user-facing features (like processes, scheduling, memory management, etc)?
Or is the bet that microkernel = win = can implement everything linux has and more?
I'm curious about the eventual end goal for the project is, not just what currently exists (as otherwise the answer currently seems to be sentence 1)
Is this written in jest? Because it's very likely where the future of computing is heading. See https://www.youtube.com/watch?v=kZRE7HIO3vk; a lot of people were nagging on Casey because he implied that software was more efficient back when everyone "wrote their own kernel" and how "impossible it would be today". He even mentions how awesome it could be if every game came with it's own bootable USB. Now back then it truly was unthinkable, but today we're edging ever closer to that reality.
For instance, I have a working microkernel written in a Lisp dialect for embedded devices. Compiled to native machine code. 100% LLM generated. ~70k loc. In benchmarks it outperforms most other embedded kernel projects by a significant margin. And it only took around ~$1500 in tokens (API costs all included).
A problem with this approach is that it would put a large burden on the application developer (or development system) to support other devices (or services) than initially planned.
Of course, it would be possible to add new drivers only when necessary, but that would also allow for security problems.
So, in theory it might work, but in practice it would require quite a bit of thought.
There are/were approaches around in kernels like includeos, which promised to do as little as possible before hading control to you. So not everybody has to create their own driver's etc, but you get a bootable executable for your application.
Includeos in particular then went towards being a complete "application server" and apparently failed to gain a business as Docker became successful.
Now that we are out of the Cambrian explosion of computing hardware - are drivers such a concern anymore? Is there any chance we start consolidating on a few core interfaces?
I know nothing of hardware, but as far as I know, my keyboard and mouse work everywhere because there is a formal specification on how human interface devices are supposed to operate.
There are probably good (and anti-competitive) reasons for why hardware still needs bespoke drivers, but from the outside, it seems like something we could address. I have no interest in loading your artisanally crafted Wifi driver.
Game consoles worked a lot like this until around the PS3 era, where the disc/cartridge the game came on was shipping binaries for everything including all the hardware support.
This led to some hilarious implementation shenanigans for the Wii as a transitional console, where the Home button pause screen is not in fact a task switch to some underlying console OS but rather a piece of the SDK that is separately-delivered from each individual game.
As AI reduces the cost for writing closer to the metal, it's also reducing the cost for creating new metal to target. I suspect we'll see an explosion in new hardware as it's cheaper and easier to design custom solutions.
GPUs, wifi, power/thermal management, firmware. Especially in portable computing there is still a huge amount of hardware support surface area to contend with.
When AI proves theorems, it uses divide-and-conquer approach just as humans - it breaks a big theorem into lemmas and tackles lemmas one by one.
An alternative approach where it is just one big-ass logical expression is just not better.
Same thing with code, I think - you need some intermediate results like a calling convention, helper subroutines, etc.
A sufficiently powerful AI can do compilation "mentally" - i.e. producing machine code conforming to a specific calling convention. It can also decompile machine code. But you, obviously, don't gain anything doing it this way, if there's one-to-one correspondence between high-level code and machine code. You might as well just write high-level code.
I really hope that software becomes more efficient. But I don't think that it can only be done by generating machine code directly.
That was my first thought. I think adoption will increase if projects will have a clear FAQ about prior / related work, and not leave this to the reader (human or AI) to figure out.
I think it's a kind of like both? it runs as its own guest, but instead of implementing syscalls that are 1:1 with linux, it looks like linux runs as a library, and uses a different more pared down set to take a normal sys call path to the guest. so my guess is not cheaper at all, since instead of the gvisor syscall->vmexit for the common path, its maybe process->sys call to guest->vmexit to hypervisor.
It's a classic exokernel. Which unfortunately feels like there's some secret cabal paying those writing operating systems textbook writers to explain poorly.
Basically the point is rather than keeping the absolute minimum in the kernel, you keep the minimum needed to multiplex the hardware with the fewest abstractions possible. So stick a network driver in there, sure. But does the TCP stack need to be in there? Stick a disk driver in there, but does the VFS need to be in there?
Then you add security so that the fast path doesn't need to go to a user space abstraction service. You have something like bpf so that processes only get the packets that correspond to the ports they've opened, directly from the kernel device driver. Your FS service gives out revocable capabilities to the disk blocks corresponding to files a process was able to successfully open, etc.
This is actually interesting, since most containers don’t actually need an independent kernel at all. Of course, this moves a container a lot closer to effectively being a chroot jail (but that’s a good thing) + having some capabilities taken away.
parts of the kernel design remind me of zircon (handle oriented objects, vmo's, and so on), but then various lines are cut in different places (kernel knows of threads but not processes, maybe handles slightly higher level networking)
I fully expect formally verified C to become the standard for any reasonably critical software. It's astonishing how easy it is to crank out program equivalence proofs these days...
The real defensible reason is that with current tools available you can write perfectly safe (safer than Rust even) C++ code, while avoiding the horrid Rust compile times and without needing to pepper your code with unsafe all over the place. LLM's can help you formally verify your code and extensively fuzz/test it to the point where you can actually be sure (ie prove) that the code is safe, without really relying on Rusts compiler. Lastly, C++ lends itself more naturally to hardcore optimizations than Rust. But ultimately it really, _really_ comes down to a) Rust's horrid compile times and b) Rust's horrid metaprogramming support (this even kills it for LLM generated output because it wastes tokens).
A single BOOTX64.EFI that boots a Hyper-V VM straight into a chat prompt, streams replies from an OpenAI-compatible /v1/chat/completions endpoint (DeepSeek by default), and boots whatever the model is asked to: Omarchy, netboot.xyz, or any UEFI image at an http(s) URL. No OS, no history. Dressed up like omp, for the memes
having looked at the briefly, is really a kernel that's meant to take system calls. I think the unikernel terminology is kinda broken. it's explicitly pared down to talk to a hypervisor rather than supporting a lot of hardware drivers. is a unikernel something you link in like a library? then its not. is a unikernel something that's intended to support a single process? then sure.
In my opinion this is a more logical way of running multiple operating systems on a host since hypervisors run the entire operating system virtually, including hardware specific code like device drivers.
It's much more logical to merely run the operating system core as a user space library enabling you to run its binaries without needing to emulate hardware. I do wonder whether you can run everything that the guest system offers, such as hardware graphics acceleration.
Another drawback is that it depends on operating system vendors making available their core OS components as a library. This is especially a problem for closed-source vendors like Microsoft who may not want to do this for strategic business reasons.
Is it just a hobby, and won't be big and professional like gnu?
Only runs on 80386 since that’s all I have.
Not just a hobbyist,* an enthusiast[1[2] previously[3[4].
[1] https://x.com/seiyanuta [2] https://seiya.me/ [3] https://news.ycombinator.com/item?id=42631873 [4] https://news.ycombinator.com/item?id=28986229
* I do get the reference and releaize I'm changing the class of the referent. Anyway FTL (or the next one...) FTW, godspeed.
quick, let's find the author's shirtless beer drinking pictures before they get deleted
Plz explain context
https://www.reddit.com/r/linux/comments/15ifjt/young_linus_s...
I dont think the kids are gonna get the reference.
I think they will. It’s a pretty famous quote, even among people who were not old enough to see it first-hand at the time when Linus made that Usenet post.
thanks to your comment we all understood that you got it though, which is the point!
also, thanks to your comment, unaware folks will probably figure it out, which is the subtler point!
What does "OS" for clouds mean?
Does this mean you still delegate to something like KVM/paravirtualzation for your device models, but your FTL guest OS can run multiple secure workloads inside a VM?
Or are you designing a custom OS from the ground up to run on native hardware? What constraints are you putting on hardware support to make this a tractable that's not re-implementing all of the stuff that linux has? I assume that's why it's advertised for the "cloud", because you know a priori the deployment machines you're gonna run on? Or is hardware support known by kernel devs to be a (relatively) trivial problem in the OS space, compared to the user-facing features (like processes, scheduling, memory management, etc)?
Or is the bet that microkernel = win = can implement everything linux has and more?
I'm curious about the eventual end goal for the project is, not just what currently exists (as otherwise the answer currently seems to be sentence 1)
There’s only one OS… BIOS!
Does FTL stand for anything? “Faster than light” is the only thing that comes to mind
I just make agents generate assembly for my app and my hardware and boot directly into that.
Is this written in jest? Because it's very likely where the future of computing is heading. See https://www.youtube.com/watch?v=kZRE7HIO3vk; a lot of people were nagging on Casey because he implied that software was more efficient back when everyone "wrote their own kernel" and how "impossible it would be today". He even mentions how awesome it could be if every game came with it's own bootable USB. Now back then it truly was unthinkable, but today we're edging ever closer to that reality.
For instance, I have a working microkernel written in a Lisp dialect for embedded devices. Compiled to native machine code. 100% LLM generated. ~70k loc. In benchmarks it outperforms most other embedded kernel projects by a significant margin. And it only took around ~$1500 in tokens (API costs all included).
A problem with this approach is that it would put a large burden on the application developer (or development system) to support other devices (or services) than initially planned.
Of course, it would be possible to add new drivers only when necessary, but that would also allow for security problems.
So, in theory it might work, but in practice it would require quite a bit of thought.
There are/were approaches around in kernels like includeos, which promised to do as little as possible before hading control to you. So not everybody has to create their own driver's etc, but you get a bootable executable for your application.
Includeos in particular then went towards being a complete "application server" and apparently failed to gain a business as Docker became successful.
https://includeos.org/
Now that we are out of the Cambrian explosion of computing hardware - are drivers such a concern anymore? Is there any chance we start consolidating on a few core interfaces?
I know nothing of hardware, but as far as I know, my keyboard and mouse work everywhere because there is a formal specification on how human interface devices are supposed to operate.
There are probably good (and anti-competitive) reasons for why hardware still needs bespoke drivers, but from the outside, it seems like something we could address. I have no interest in loading your artisanally crafted Wifi driver.
Game consoles worked a lot like this until around the PS3 era, where the disc/cartridge the game came on was shipping binaries for everything including all the hardware support.
This led to some hilarious implementation shenanigans for the Wii as a transitional console, where the Home button pause screen is not in fact a task switch to some underlying console OS but rather a piece of the SDK that is separately-delivered from each individual game.
ref. https://www.copetti.org/writings/consoles/wii/
As AI reduces the cost for writing closer to the metal, it's also reducing the cost for creating new metal to target. I suspect we'll see an explosion in new hardware as it's cheaper and easier to design custom solutions.
If you're writing for VM and don't need stuff like GPUs, you can.
For actual real hardware, not really
GPUs, wifi, power/thermal management, firmware. Especially in portable computing there is still a huge amount of hardware support surface area to contend with.
You could use a library as a base.
> He even mentions how awesome it could be if every game came with it's own bootable USB. Now back then it truly was unthinkable,
Not only was it thinkable, it was common: <https://en.wikipedia.org/w/index.php?title=List_of_self-boot...>
When AI proves theorems, it uses divide-and-conquer approach just as humans - it breaks a big theorem into lemmas and tackles lemmas one by one.
An alternative approach where it is just one big-ass logical expression is just not better.
Same thing with code, I think - you need some intermediate results like a calling convention, helper subroutines, etc.
A sufficiently powerful AI can do compilation "mentally" - i.e. producing machine code conforming to a specific calling convention. It can also decompile machine code. But you, obviously, don't gain anything doing it this way, if there's one-to-one correspondence between high-level code and machine code. You might as well just write high-level code.
I really hope that software becomes more efficient. But I don't think that it can only be done by generating machine code directly.
I saw FTL and "new" and got very excited. sadly is is not the game.
It's 2026 and we've mostly ran out of good product names...
Same guy made Into the Breach which is similar and really fun.
This immediately started playing in my head, before I fully parsed the headline.
https://www.youtube.com/watch?v=QBES0jOmbCs
Here's the author: https://seiya.me -- he works at Vercel, sounds pretty legit.
Sounds kinda like gVisor more than Unikraft? With a maybe-faster intercept path?
That was my first thought. I think adoption will increase if projects will have a clear FAQ about prior / related work, and not leave this to the reader (human or AI) to figure out.
I think it's a kind of like both? it runs as its own guest, but instead of implementing syscalls that are 1:1 with linux, it looks like linux runs as a library, and uses a different more pared down set to take a normal sys call path to the guest. so my guess is not cheaper at all, since instead of the gvisor syscall->vmexit for the common path, its maybe process->sys call to guest->vmexit to hypervisor.
FTL v0.1.0 was just released, adding async Rust support (multi-thread Tokio runtime) and lots of missing pieces in the Linux compatibility layer.
(not my project)
So it's a microkernel...ish? And it runs Linux programs and supports enough features to serve its own website. Excellent; I hope it takes off.
It's a classic exokernel. Which unfortunately feels like there's some secret cabal paying those writing operating systems textbook writers to explain poorly.
Basically the point is rather than keeping the absolute minimum in the kernel, you keep the minimum needed to multiplex the hardware with the fewest abstractions possible. So stick a network driver in there, sure. But does the TCP stack need to be in there? Stick a disk driver in there, but does the VFS need to be in there?
Then you add security so that the fast path doesn't need to go to a user space abstraction service. You have something like bpf so that processes only get the packets that correspond to the ports they've opened, directly from the kernel device driver. Your FS service gives out revocable capabilities to the disk blocks corresponding to files a process was able to successfully open, etc.
I would like something Unix-y and Linux-compatible that follows the principle of least authority.
Linux namespaces and cgroups and seccomp are a mess ... but actually they are probably more functional than what OS X or Windows provides.
I wonder if we can do better. But maybe not in this project?
This is actually interesting, since most containers don’t actually need an independent kernel at all. Of course, this moves a container a lot closer to effectively being a chroot jail (but that’s a good thing) + having some capabilities taken away.
parts of the kernel design remind me of zircon (handle oriented objects, vmo's, and so on), but then various lines are cut in different places (kernel knows of threads but not processes, maybe handles slightly higher level networking)
written in rust, doesn't say written in rust on the site - i guess that phase is over
Now people just wonder why you didn't write it in rust
Especially when you can just ask for that in your prompt
I mean starting a new project in C or C++ does kinda need a defensible reason at this point, at least in any corporate environment
I fully expect formally verified C to become the standard for any reasonably critical software. It's astonishing how easy it is to crank out program equivalence proofs these days...
The real defensible reason is that with current tools available you can write perfectly safe (safer than Rust even) C++ code, while avoiding the horrid Rust compile times and without needing to pepper your code with unsafe all over the place. LLM's can help you formally verify your code and extensively fuzz/test it to the point where you can actually be sure (ie prove) that the code is safe, without really relying on Rusts compiler. Lastly, C++ lends itself more naturally to hardcore optimizations than Rust. But ultimately it really, _really_ comes down to a) Rust's horrid compile times and b) Rust's horrid metaprogramming support (this even kills it for LLM generated output because it wastes tokens).
Why is the diagram on the home page all misaligned?
Seems like it's only an issue on mobile.
MirageOS also bills itself as an OS in a library — is this similar?
https://mirage.io/
Kind of, but this still has a kernel/user seperation, unlike mirage.
This is really a classic exokernel design.
Wrong. That would be https://github.com/H4vC/oh-my-uefPi
A single BOOTX64.EFI that boots a Hyper-V VM straight into a chat prompt, streams replies from an OpenAI-compatible /v1/chat/completions endpoint (DeepSeek by default), and boots whatever the model is asked to: Omarchy, netboot.xyz, or any UEFI image at an http(s) URL. No OS, no history. Dressed up like omp, for the memes
Is this a unikernel? Your ASCII art diagram is broken.
It's an exokernel. It's kind of like if you modified a hypervisor specifically for running unikernels instead of classic VMs.
Fwiw diagram renders OKay in Brave on iOS
having looked at the briefly, is really a kernel that's meant to take system calls. I think the unikernel terminology is kinda broken. it's explicitly pared down to talk to a hypervisor rather than supporting a lot of hardware drivers. is a unikernel something you link in like a library? then its not. is a unikernel something that's intended to support a single process? then sure.
How’s this different from say openbalena?
What a nice thing!
Maybe it is time to look at other new operating systems that are more memory safe by default and don't have any legacy bloat.
Now that we have a KVM 0day + VM escape vulnerability [0] right now.
[0] https://x.com/PaulosYibelo/status/2106378929158135903