seL4 | FStar | |
---|---|---|
60 | 42 | |
4,549 | 2,570 | |
1.2% | 0.6% | |
9.0 | 9.9 | |
3 days ago | 3 days ago | |
C | F* | |
GNU General Public License v3.0 or later | Apache License 2.0 |
Stars - the number of stars that a project has on GitHub. Growth - month over month growth in stars.
Activity is a relative number indicating how actively a project is being developed. Recent commits have higher weight than older ones.
For example, an activity of 9.0 indicates that a project is amongst the top 10% of the most actively developed projects that we are tracking.
seL4
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From L3 to seL4 what have we learnt in 20 years of L4 microkernels? [video]
> People like to snob Unix but the fact is: the world runs on Unix.
The world you are aware of runs on it.
> Can we really do that much better or is it just hubris?
Yes. Have a look at seL4[1] and Barrelfish too[2], even though that's no longer active. seL4 in particular is powering a lot of highly secure computing systems. There is a surprisingly large sphere outside of Unix/POSIX.
[1] https://sel4.systems/
[2] https://barrelfish.org/
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On the Costs of Syscalls
There are also RTOS-capable microkernels such as seL4[0], with few but extremely fast syscalls[1]. Note times are in cycles, not usec.
0. https://sel4.systems/
1. https://sel4.systems/About/Performance/
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Can the language of proof assistants be used for general purpose programming?
https://sel4.systems
Working on a number of platforms, verified on some. Multicore support is an ongoing effort afaict.
On OS built on this kernel is still subject to some assumptions (like, hardware working correctly, bootloader doing its job, etc). But mostly those assumptions are less of a problem / easier to prove than the properties of a complex software system.
As I understand it, guarantees that seL4 does provide, go well beyond anything else currently out there.
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How to write TEE/Trusted OS for ARM microcontrollers?
Take a look at this: https://sel4.systems/
- Simulation: KI-Drohne der US Air Force eliminiert Operator für Punktemaximierung
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Paragon Graphite is a Pegasus spyware clone used in the US
It's probably have to be seL4 (https://sel4.systems), running on some fully OSS hardware.
There are question marks over much of available RISC-V chips due to chinese producers, so maybe OpenPower based hardware?
Plus, the entire system (motherboard, etc) would need to be manufactured using a good supply chain.
Hmmm, this has probably all been thought through in depth before by others. :)
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Basic SAT model of x86 instructions using Z3, autogenerated from Intel docs
You can use it to (mostly) validate small snippets are the same. See Alive2 for the application of Z3/formalization of programs as SMT for that [1]. As far as I'm aware there are some problems scaling up to arbitrarily sized programs due to a lack of formalization in higher level languages in addition to computational constraints. With a lot of time and effort it can be done though [2].
1. https://github.com/AliveToolkit/alive2
2. https://sel4.systems/
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What are the current hot topics in type theory and static analysis?
Formal methods. This is not in most general-purpose programming languages and probably never will be (maybe we'll see formal methods to verify unsafe code in Rust...) because it's a ton of boilerplate (you have to help the compiler type-check your code) and also extremely complicated. However, formal methods is very important for proving code secure, such as sel4 (microkernel formally verified to not have bugs or be exploitable) which has just received the ACM Software Systems Award 3 days ago.
- Rust Now Available for Real-Time Operating System and Hypervisor PikeOS
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Amiga and AmigaOS should move to ARM.
Today we'd look at seL4.
FStar
- Lean4 helped Terence Tao discover a small bug in his recent paper
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The Deep Link Equating Math Proofs and Computer Programs
I don't think something that specific exists. There are a very large number of formal methods tools, each with different specialties / domains.
For verification with proof assistants, [Software Foundations](https://softwarefoundations.cis.upenn.edu/) and [Concrete Semantics](http://concrete-semantics.org/) are both solid.
For verification via model checking, you can check out [Learn TLA+](https://learntla.com/), and the more theoretical [Specifying Systems](https://lamport.azurewebsites.net/tla/book-02-08-08.pdf).
For more theory, check out [Formal Reasoning About Programs](http://adam.chlipala.net/frap/).
And for general projects look at [F*](https://www.fstar-lang.org/) and [Dafny](https://dafny.org/).
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If You've Got Enough Money, It's All 'Lawful'
Don't get me wrong, there are times when Microsoft got it right the first time that was technically far superior to their competitors. Windows IOCP was theoretically capable of doing C10K as far back in 1994-95 when there wasn't any hardware support yet and UNIX world was bickering over how to do asynchronous I/O. Years later POSIX came up with select which was a shoddy little shit in comparison. Linux caved in finally only as recently as 2019 and implemented io_uring. Microsoft research has contributed some very interesting things to computer science like Z3 SAT solver and in collaboration with INRIA made languages like F* and Low* for formal specification and verification. But all this dwarfs in comparison to all the harm they did.
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What are the current hot topics in type theory and static analysis?
Most of the proof assistants out there: Lean, Coq, Dafny, Isabelle, F*, Idris 2, and Agda. And the main concepts are dependent types, Homotopy Type Theory AKA HoTT, and Category Theory. Warning: HoTT and Category Theory are really dense, you're going to really need to research them.
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Why is there no simple C-like functional programming language?
F* is a dependently typed language that can be transpiled to idiomatic C via the KReMLin compiler. It’s very ML-ish to write and you can leave out some proofs. It also has the benefit of being used to write a formally verified TLS implementation that’s in wide use throughout industry.
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[Media] Genetic algorithm simulation - Smart rockets (code link in comments)
As I said, dependent types attempt to solve this problem. F* is a language where you can express complex logic as a type. The catch is, these types are checked by an SMT solver. If the solver can satisfy the type checking, then great, and you move on. If it can’t, you have no idea why, and either have to guess or manually write the proof anyway. Contrast this with Standard ML which has a proof of the soundness of its type system.
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Prop v0.42 released! Don't panic! The answer is... support for dependent types :)
So kind of like F*? https://www.fstar-lang.org/
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old languages compilers
F*
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Pegasus spyware was used to hack reporters’ phones. I’m suing its creators; When you’re infected by Pegasus, spies effectively hold a clone of your phone – we’re fighting back.
Nevermind that academia has come up with far safer ways to do a few things but social norms & inertia prevent their wider adoption (well okay, it also has a barrier to entry in the education required to use it but I don't think someone with the knowledge to meaningfully contribute to an OS kernel can be considered uneducated nor unable to learn).
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[Hobby] Amateur Generalist Programmer Seeking to Put Bugfixing Skills to Good Use
Maybe that's a little off topic here, but if you like fixing bugs, i suspect you might also enjoy showing that there are no bugs at all. Check out languages like F* https://www.fstar-lang.org/ It's a proof-oriented programming language. You can use it to write code that has no bugs at all. And you once you're done, can convert F* to C or other languages.
What are some alternatives?
l4v - seL4 specification and proofs
coq - Coq is a formal proof management system. It provides a formal language to write mathematical definitions, executable algorithms and theorems together with an environment for semi-interactive development of machine-checked proofs.
fprime - F´ - A flight software and embedded systems framework
lean - Lean Theorem Prover
nomicon - The Dark Arts of Advanced and Unsafe Rust Programming
dafny - Dafny is a verification-aware programming language
CompCert - The CompCert formally-verified C compiler
koka - Koka language compiler and interpreter
InitWare - The InitWare Suite of Middleware allows you to manage services and system resources as logical entities called units. Its main component is a service management ("init") system.
VisualFSharp - The F# compiler, F# core library, F# language service, and F# tooling integration for Visual Studio
4.4BSD-Lite2 - 4.4BSD Lite Release 2: last Unix operating system from Berkeley
stepmania - Advanced rhythm game for Windows, Linux and OS X. Designed for both home and arcade use.