seL4 VS ghost

> 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 Have a look at seL4[1] and Barrelfish too[2], even though that's no longer active.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/

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/

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.

Take a look at this: https://sel4.systems/

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. :)

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/

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.

Today we'd look at seL4.

https://ghostkernel.org/about

>"Ghost is a hobby operating system for the Intel x86 platform. The project is licensed as GPLv3. It was started as a research project to learn more about low-level software programming and computer internals. The sources are available on GitHub (https://github.com/maxdev1/ghost).

Features

The kernel and the userspace applications are written from scratch in C++ and Assembly (and some C). It is not based on any existing kernel.

There is a POSIX.1 compatibility layer to simplify porting some software to the system.

o Micro-kernel

o Symmetric multi-processing

o Patched GCC (OS specific toolchain)

o IPC (pipes, signals, messages, shared memory)

o ELF executable & shared library support

o libc, self-made

o libghostapi, kernel API library

o libghostuser, simplified file I/O, creating UIs etc.

o libstdc++ port

o VESA video driver

o Window server (GUI with homemade toolkit)

o PS/2 keyboard & mouse driver

o Userspace filesystem driver support

o Serial COM1 debug interface

o Virtual 8086 for BIOS calls

o Copy-on-write implementation, fork()