[craigmart]

>why in the heck is he going for POSIX compatibility

Because existing desktop applications can be ported to ToaruOS

>why not a safer microkernel, keeping everything in userspace?

This is a design choice, microkernels aren't necessarily better than hybrid, they're slower, harder to debug and process management can be complicated

[eggy]

Just curious how hard it would be to forego POSIX entirely if you were building an OS. I know TempleOS is entirely from scratch. I'd like to implement a small LISP like SectorLISP [1] (see yesterday's posts too on HN). I don't know much about building my own OS, so I'd like to start with something like MenuetOS (my first PL was asm), SerenityOS, TempleOS, or this one. I'd like it to be completely an 'island', i.e. POSIX not a requirement. I want to use it to hack on in isolation without any easy copy/paste shortcuts. I know Mezzano exists, and it has booted on bare metal, but I would like to start with the OS's above, implement my own LISP, and go from there.

Any other OS recommendations base on my ignorant, but wishful, reqs above? I realize there are some others in Rust too. Thanks!

[1] https://github.com/jart/sectorlisp

[adrian_b]

Someone who would make a new OS, should define a completely new system call interface, as it is likely that now it is possible to conceive a better interface than 50 years ago and anyway if it would not be different there would be no reason to make a new OS, instead of modifying an existing one.

Nevertheless, the first thing after defining a new OS interface must be writing a POSIX API translation layer, to be able to use without modifications the huge number of already existing programs.

Writing a new OS is enough work, nobody would have time to also write file systems, compilers, a shell, a text editor, an Internet browser and so on.

After having a usable environment, one can write whatever new program is desired, which would use the new native OS interface, but it would not be possible to replace everything at the same time.

Besides having a POSIX translation layer, which can be written using as a starting point one of the standard C libraries, where the system calls must be replaced with the translation layer, some method must be found for reusing device drivers made for other operating systems, e.g. either for Linux or for one of the *BSD systems.

Nobody would have time to also write all the needed device drivers. So there must exist some translation layer also for device drivers, maybe by running them in a virtual machine.

The same as for user applications, if there is special interest in a certain device driver, it should be rewritten for the new OS, but rewriting all the device drivers that could be needed would take years, so it is important to implement a way to reuse the existing device drivers.

[a-dub]

redox is one i've been following from afar. rust, not posix, microkernel, s/everything is a file/everything is a url/

it looks pretty cool, although the url thing seems yet to prove its utility. they seem to be playing around a bit with using the protocol component (net, disk, etc), but it's unclear what this adds over just using paths. although maybe if they used the protocol to describe the encoding of the data, it would add something?

[yjftsjthsd-h]

> microkernels aren't necessarily better than hybrid, they're slower, harder to debug and process management can be complicated

I was basically on board, but how are they harder to debug? I'd think being able to run components in userspace would make debugging way easier.

[mjgerm]

You are now debugging a distributed system.

[md8z]

I'm very confused by this comment. There are a ton of other things you need to implement if you want to have desktop applications. POSIX does not specify any APIs for graphical applications. You might be thinking of something else.

If you want to support the lion's share of desktop applications, it would actually be better to implement the Win32 API...

[craigmart]

Sorry, I meant software in general but wrote "desktop applications" instead. Anyway the sentence is still valid, even if you'll have to implement other things such as the graphical interface, the POSIX compliant code won't need modification

[fouc]

Isn't QNX a microkernel? I remember it being known for being quite fast?

[bregma]

No, it's more of a nanokernel. It's very fast.

Full disclosure: I maintain QNX toolchain.

[guenthert]

As a real-time OS it is known for deterministic response times. If it were exceptionally fast (and licenses cheap enough), you'd see hosts in the TOP500 using it.