> And again the question why not simply write something new.

The world isn't black or white. Some people write Rust programs with the intent to be drop-in compatible programs of some other program. (And, by the way, that "some other program" might itself be a rewrite of an even older program.)

Yet others, such as myself, write Rust programs that may be similar to older programs (or not at all), but definitely not drop-in compatible programs. For example, ripgrep, xsv, fd, bat, hyperfine and more.

I don't know why you insist on a word in which Rust programs are only drop-in compatible rewrites. Embrace the grey and nuanced complexity of the real world.

> And again the question why not simply write something new.

There is a ton of new stuff getting written in Rust. But we don't have threads like this on HN when someone announces a new piece of infra written in Rust, only when there's a full or partial rewrite.

Re automotive and other legacy industries, there's heavy process around both safety and security. Performing HARAs and TARAs, assigning threat or safety levels to specific components and functions, deep system analysis, adding redundancy for safety, coding standards like MISRA, etc. You don't get a lot of assurances for "free" based on time-proven code. But in defense there's already a massive push towards memory safe languages to reduce the attack surface.

> why not simply write something new.

Because of backwards compatibility. You don’t rewrite Linux from scratch to fix old mistakes, that’s making a new system altogether. And I’m pretty sure there are some people doing just that. But still, there’s value in rewriting the things we have now in a future-proof language, so we have a better but working system until the new one is ready.

Sorry. I will answer on this because I feel people got a bit hung up on the “new” thing. Might be a language barrier. I really understand the reasons why with backwards compatibility etc. The point I tried to make is that we really spend tons of time either to maintain software that where written or “born” 50 or so years ago or rewrite things in the same spirit. I mixed my comments wit the the security aspect which might muddled a lot what I tried to say with the “new” part. One sees this also on HN. I love the UNIX philosophy and also the idea of POSIX. But it’s treated as if it is the holy grail of OS design and in case of POSIX the only true cross platform schema. Look also at the boot steps a CPU has to run through to boot up. By pretending to be 40 year old variant and then piece by piece startup features. Well I hope I cleared my point :)

Writing tools that are POSIX compatible doesn't mean one puts it on the pedestal of the "holy grail of OS design." I've certainly used POSIX to guide design aspects of things I build. Not because I think POSIX is the best. In fact, I think it's fucking awful and I very much dislike how some people use it as a hammer to whinge about portability. But POSIX is ubiquitous. So if you want your users to have less friction, you can't really ignore it.

And by the way, Rust didn't invent this "rewrite old software" idea. GNU did it long before Rust programmers did.

Yes but GNU to put them under GPL. Or that was my understanding.

So then your original comment should be amended to say, "and this is actually all fine when the authors use a license I personally like." So it's not actually the rewriting you don't like, but the licensing choices. Which you completely left out of your commentary.

You also didn't respond to my other rebuttal, which points out a number of counter-examples to your claim.

From my view, your argument seems very weak. You're leaving out critical details and ignoring counterpoints that don't confirm your bias.

Sorry I didn’t response by intention. The thing with the license I actually didn’t bring up because I totally forgot about this part of the discussion. I saw comments a few weeks back going into the fact that it’s not just a rust rewrite but also a relicense with maybe shady intend. I don’t know. I don’t know much about this. To your comment. I don’t know when I actually did any claims? Nor did I claim that a rewrite is fine when it’s changing to a license I like. Just stated that the reason back then was not to rewrite in a more modern language with better security. I wasn’t around when this happened and have no real thought if at the time I would have like or dislike the move. As it’s stands the net positive was obviously great otherwise a Linux as we know it might have been longer in the making. Or never. And yes my argument is weak because I’m actually not an expert on core utility development. I voiced just my feelings about the fact that we seem to move slowly forward or stand still in development rather than progressing to something else. And it seems that others see it differently and or have a better perspective on that.

> And yes my argument is weak because I’m actually not an expert on core utility development.

Yes, and I'm trying to point out why your argument is weak. You said things like this:

> But I wonder if the core utils which have been rewritten got rewritten by the original maintainers? And again the question why not simply write something new. With a modern architecture etc rather than drop in replacements.

And it honestly just comes across as rather rude. People do write things that are new. People also write things that re-implement older interfaces. Sometimes those people are even the same people.

Like, why are you even questioning this? What does it matter to you? People have been re-implementing older tools for decades. This isn't a new thing.

> Nor did I claim that a rewrite is fine when it’s changing to a license I like.

When I pointed it out, your response was, "oh yeah but they did this other thing that made it all okay."

Damn I wanted to write “not with intention”.