[HN Gopher] The Lions Operating System
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       The Lions Operating System
        
       Author : plunderer
       Score  : 197 points
       Date   : 2025-11-20 18:19 UTC (1 days ago)
        
 (HTM) web link (lionsos.org)
 (TXT) w3m dump (lionsos.org)
        
       | cjs_ac wrote:
       | Presumably named after Associate Professor John Lions[0], of _A
       | Commentary on the UNIX Operating System_ [1] fame.
       | 
       | [0] https://en.wikipedia.org/wiki/John_Lions
       | 
       | [1]
       | https://en.wikipedia.org/wiki/A_Commentary_on_the_UNIX_Opera...
        
         | santoshalper wrote:
         | It's developed by UNSW Sydney, whose mascot is a Lion.
         | (Specifically, "Clancy the Lion"), so I am guessing it's
         | probably that.
        
           | kragen wrote:
           | That's also where John Lions taught.
        
             | skavi wrote:
             | John Lions is not Lions OS            is not        is not
             | Clancy the Lion
        
           | imvetri wrote:
           | What does mascot mean
        
             | saithound wrote:
             | A mascot is an animal figure that represents a product or
             | sports team. For example, the penguin named Tux is the
             | mascot of Linux, and the mascot for the Brisbane Broncos
             | rugby team is the horse named Buck the Bronco.
             | 
             | Mascot is, unrelatedly, also a suburb of Sydney.
        
         | mlinksva wrote:
         | It is https://www.youtube.com/watch?v=W8Ka_8kHTj4&t=903s
        
         | woolion wrote:
         | The mascot it super cute lion too. How can a project do
         | everything so right? I was browsing some popular python
         | libraries and they just slapped on the first image they got out
         | of ChatGPT. It's nice to see care in the craft.
        
         | mzs wrote:
         | aka the Lions book
        
         | snvzz wrote:
         | Not presumably, but explicitly. Both in documentation and
         | presentations by seL4 they consistently make a point to mention
         | so.
        
       | spencerflem wrote:
       | Very cool! I'm a huge fan of Genode, another OS that runs on
       | SeL4. Does anyone here know how they compare?
        
         | Y_Y wrote:
         | Unequal
        
         | panick21_ wrote:
         | Genode is a framework that can run on many places and on higher
         | level has its own abstractions. Lion OS is based on Microkit
         | the framework developed by the seL4 people that will also be
         | verified. So Lion OS/Microkit is basically the outgrowth of the
         | original seL4 research.
        
         | lproven wrote:
         | > Genode, another OS that runs on SeL4.
         | 
         | Hang on, what? Genode can run on seL4 but seL4 is not part of
         | it. Genode can also run on Linux and a bunch of other things.
         | It has its own native kernel and it's not based on seL4 in any
         | way, AFAIK.
        
           | spencerflem wrote:
           | No, you're totally right I phrased it badly
        
       | hulitu wrote:
       | > To be successful, many more components are needed.
       | 
       | What is the purpose of this OS ? Can it mint Bitcoin ? Can it do
       | fluid dynamics simulation ? Can it act as an interface to a
       | database ? Can it host a database ? Is it interactive ? What kind
       | of interface it presents to the user ?
        
         | qubex wrote:
         | That's a rather luridly practical view that's entirely out of
         | sync with academia and basic research that provides tangible
         | benefits much further down the line.
        
           | lukan wrote:
           | Yes, but basic reseach in IT is still not random, but usually
           | has a clear goal, or at least some scope. Like indeed, focus
           | on security? Focus on speed? Focus on reliability? Focus on
           | energy efficency (because it is supposed to run on a tiny
           | embedded device for long).
           | 
           | And the gimmick here seems to be in fact, that it is supposed
           | to be flexibel
           | 
           | "is not a conventional operating system, but contains
           | composable components for creating custom operating systems
           | that are specific to a particular task. Components are joined
           | together using the Microkit tool"
        
         | charlycst wrote:
         | There is an example of interface in the docs:
         | https://lionsos.org/docs/examples/kitty/
        
         | kragen wrote:
         | Those are applications, not operating systems. With occasional
         | exceptions, you can run any application on any operating
         | system.
        
           | mmooss wrote:
           | That begs the point: Each application will often run better
           | on some OSes than on others. For example, high traffic
           | websites usually aren't run on Windows 11.
        
         | fortyseven wrote:
         | Yeah, Linus, what's the point?
        
           | lmm wrote:
           | Hardly a fair comparison. Linus wanted an OS that would run
           | on his own PC and let him do his Unix homework assignments.
        
             | johnisgood wrote:
             | What makes the comparison not fair? We do not know the
             | author's story!
        
         | kjs3 wrote:
         | Could have been done for fun. You wouldn't understand.
        
         | oytis wrote:
         | One application would be safety and security critical real-time
         | systems that also need significant amount of processing power
        
         | vrighter wrote:
         | no operating system does. That's application software you're
         | thinking of. So no, it can't. But neither can windows, linux,
         | macos, solaris, templeOS or any others
        
         | lproven wrote:
         | > What is the purpose of this OS ?
         | 
         | What is the purpose of any OS?
         | 
         | As all the modern ones slowly converge on similar attributes of
         | being incomprehensibly vast codebases unreadable by any human,
         | typically implemented in C or something closely related to it,
         | using a similar underlying register-machine model, there is
         | value in simply being small, simple, readable, able to do
         | useful work, and being different. If something is also
         | _provably correct_ that 's just the icing on the cake.
        
       | snvzz wrote:
       | On recent news, LionsOS, as of about a week ago (I got notified
       | via their announcement maillist), includes a router/firewall
       | scenario[0].
       | 
       | Do not miss Gernot Heiser's recent talk[1] at the seL4 Summit,
       | where among other things he shows seL4 massively outperforming
       | Linux in a web server scenario.
       | 
       | 0. https://lionsos.org/docs/examples/firewall/
       | 
       | 1. https://youtu.be/wP48V34lDhk
        
       | gethly wrote:
       | Oh no, it's written in C and not Rust. The blasphemy!
        
         | snvzz wrote:
         | Rust, an immature language with fluidly evolving specification
         | / reference implementation, is not suitable for high assurance
         | nor formal verification.
        
           | steveklabnik wrote:
           | ... except that Rust's compiler has been qualified for
           | several safety critical standards, with more to come, and has
           | several formal verification tools as well. Amazon even has
           | placed bounties (and paid some) for proving things about the
           | standard library.
           | 
           | Rust is not as immature or evolving in the ways you imply.
        
             | fooker wrote:
             | > Amazon even has placed bounties (and paid some) for
             | proving things about the standard library.
             | 
             | Can you provide some links? Thanks.
        
               | steveklabnik wrote:
               | https://aws.amazon.com/blogs/opensource/verify-the-
               | safety-of...
        
               | fooker wrote:
               | This is awesome.
               | 
               | Are these reasonably current?
        
               | steveklabnik wrote:
               | That announcement was a year ago, I haven't kept up with
               | the repo.
        
             | johnisgood wrote:
             | Why would Rust need formal verification tools like
             | https://github.com/rust-lang/miri if the programming
             | language is so safe that it prevents them[1]?!
             | 
             | [1] Undefined Behaviors.
        
               | steveklabnik wrote:
               | Miri is not really a formal verification tool. It is more
               | of a runtime sanitizer.
               | 
               | And it's because Rust's "no undefined behavior" is for
               | safe Rust. Miri is used dynamically at runtime to catch
               | undefined behavior in the unsafe superset.
               | 
               | Finally, Rust's safety guarantees relate to memory safety
               | only. There's a lot more properties you'd want to prove
               | about programs, some safety related in a broader sense,
               | some totally unrelated to safety concerns.
        
               | johnisgood wrote:
               | Is it possible to find UB in "unsafe" at compile time?
        
               | steveklabnik wrote:
               | By using some proof tools, you can find some of it.
               | 
               | It is technically impossible to find 100% of it at
               | compile time because some of the finer details about what
               | is UB are not nailed down 100% yet. But those are
               | generally pretty fine corner cases, and one of the goals
               | of those definitions is to not invalidate code as
               | written.
               | 
               | Formal verification is _very_ hard.
        
         | aloha2436 wrote:
         | I'm trying to picture in my mind a person who is a fan of Rust
         | and somehow against an OS with a formally-verified kernel no
         | matter the language. I'm not having much success.
        
           | fooker wrote:
           | I see you have not met a lot of Rust activists.
        
             | aloha2436 wrote:
             | Certainly I don't seem to run into as many of them as I'm
             | led to believe exists.
        
             | pppppiiiiiuuuuu wrote:
             | It's funny how people always allude to fanatical Rust
             | developers in the most tangential threads, but they never
             | actually turn up and demand we rewrite the entire Kernel in
             | Rust or whatever terrible takes they're alleged to have.
        
               | fooker wrote:
               | https://discuss.haiku-os.org/t/replace-c-code-with-
               | rust/6753
               | 
               | https://github.com/seL4/seL4/issues/487
        
               | aduty wrote:
               | Love that discussion on the Haiku board.
        
               | johnisgood wrote:
               | Oh man, these are great.
               | 
               | Check out https://github.com/ansuz/RIIR/issues/ for more.
               | 
               | Gosh... and people on HN tell us that they have yet to
               | meet a Rust fanatic. Just look around the GitHub Issues I
               | linked.
               | 
               | ---
               | 
               | BTW I stumbled upon https://github.com/r9os/r9 as well.
               | Reading the source code, it is mainly unsafe blocks and
               | assembly. :| Who would have thought?
        
             | adastra22 wrote:
             | I am a "Rust activist" any day of the week. seL4 is awesome
             | and amazing.
        
               | johnisgood wrote:
               | Thoughts on Ada / SPARK? Why are you not using Ada /
               | SPARK considering it has such a neat type system, pre-
               | and post-conditions, formal verification, and so forth.
               | It has built-in concurrency constructs as well and it
               | helps you avoid deadlocks and race conditions.
        
         | kjs3 wrote:
         | At least someone hasn't complained about it being 'unix like',
         | always without defining what the non-unix-like OS they want
         | would look like, or where the software to run on it would come
         | from.
        
           | pjmlp wrote:
           | First, we could start by what UNIX authors did after they
           | considered UNIX done, looking at Plan 9 and Inferno.
           | 
           | Then there are the OSes already done during the 1960 and 1970
           | outside Bell Labs, as possible ideas.
           | 
           | As from where the software would come from, if we keep
           | recicling UNIX, we will keep getting UNIX regardless of
           | whatever cool features the OS might offer, as most developers
           | are lazy.
           | 
           | Hence why it is great that while Apple and Google OSes have
           | some UNIX there, bare bones POSIX apps will hardly make it
           | into the store.
        
           | snvzz wrote:
           | Because it is not UNIX like.
           | 
           | It does provide some degree of POSIX compatibility, but it
           | does not dictate architecture.
        
         | lovidico wrote:
         | Rust is supported by the [seL4
         | Microkit](https://docs.sel4.systems/projects/rust/), which is
         | the core framework enabling LionsOS. LionsOS can currently run
         | components written in Rust, and there are some WIP drivers
         | written in Rust in the seL4 Device Development framework
         | (judging from pull requests).
        
       | amelius wrote:
       | Mountain Lion is calling and wants its name back.
        
         | CursedSilicon wrote:
         | You mean OS X 10.7 Lion?
        
           | lproven wrote:
           | 10.8 was Mountain Lion.
           | 
           | But before OS X was OS 9, and OS 9 was not the same thing as
           | OS-9.
           | 
           | https://apple.fandom.com/wiki/Mac_OS_9
           | 
           | https://microware.com/
           | 
           | Before OS 9 was OS 8, which was unrelated to OS/8.
           | 
           | https://apple.fandom.com/wiki/Mac_OS_8
           | 
           | https://gunkies.org/wiki/OS/8
           | 
           | Names overlap. The hommage in this one is fairly clear, I
           | think.
        
       | fithisux wrote:
       | Aussies were supposed to progress with Darbat.
       | 
       | It never happened.
        
       | fifticon wrote:
       | if you rearrange the letters, you get the Linos OS.
        
       | pjmlp wrote:
       | While folks keep discussing C vs Rust, what got my attention was
       | MicroPython and Pancake
       | (https://trustworthy.systems/projects/pancake).
        
         | mhd wrote:
         | When I read about Pancake, for a very short moment I was hoping
         | for some Elan[1] influences...
         | 
         | 1: https://os.inf.tu-dresden.de/L4/l3elan.html
        
           | pjmlp wrote:
           | Cool, thanks for the link.
        
           | bolangi wrote:
           | For a short while, I ran the Eumel operating system and wrote
           | an application in Elan. Among other interesting properties,
           | files weren't saved, but were checkpointed by the OS. I
           | enjoyed this exercise, although Eumel remained a very small
           | niche.
        
         | johnisgood wrote:
         | I have not heard of Pancake, seems interesting. It led me to
         | https://cakeml.org. Looking at https://github.com/CakeML/cakeml
         | /blob/3194e00b69ce817cf47751..., I feel quite dumb. :P
        
       | fithisux wrote:
       | "but contains composable components for creating custom operating
       | systems that are specific to a particular task"
       | 
       | like reviving OSfree aka 64bit OS/2
        
         | Propelloni wrote:
         | It's an OS built around a verified and formally proofed L4
         | kernel, ie. a microkernel like QNX or MACH. The L4 is a
         | venerable design reaching back at least 25 years, if not
         | longer. It has seen commercial and research uses, e.g. the
         | SIMKO3 mobile phones or the Fiasco distribution. The term
         | "task" is specific here. Running Linux as a custom operating
         | system is a task in microkernel lingo.
        
       | dctoedt wrote:
       | My first thought was to wonder whether it was a Linux offshoot.
        
       | peterisza wrote:
       | Finally an OS that is really an OS and not a linux distro
        
       | mikewarot wrote:
       | >It is not a conventional operating system, but contains
       | composable components for creating custom operating systems that
       | are specific to a particular task. Components are joined together
       | using the Microkit tool.
       | 
       | Unfortunately, like Genode, this approach yields something that
       | is interesting, but can't be a daily driver for me. 8(
       | 
       | Meanwhile, the US national security continues its downhill slide
       | because we've chosen operating systems based on ambient
       | authority.
        
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       (page generated 2025-11-21 23:02 UTC)