Back to Home11/18/2025, 2:46:50 AM

Unofficial "Tier 4" Rust Target for older Windows versions

130 points
92 comments

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excited

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positive

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tech

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Rust

Legacy Systems

Retro Computing

Debate intensity40/100

The Rust community is exploring ways to run Rust code on older Windows versions, with an unofficial 'Tier 4' target, sparking discussions on supporting legacy systems and retro computing.

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  1. 01Story posted

    11/18/2025, 2:46:50 AM

    1d ago

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  2. 02First comment

    11/18/2025, 5:32:42 AM

    3h after posting

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  3. 03Peak activity

    11 comments in Hour 4

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  4. 04Latest activity

    11/19/2025, 1:19:19 AM

    18h ago

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Discussion (92 comments)
Showing 84 comments of 92
umanwizard
1d ago
2 replies
The idea of running Rust code on Windows 95 is very funny to me. Two completely different universes colliding.
sedatk
1d ago
3 replies
IIRC, somebody ran .NET on Windows 3.1.
userbinator
1d ago
1 reply
https://news.ycombinator.com/item?id=22010159

3.11, Win32s (so still using 32-bit, not 16-bit code.)

sedatk
1d ago
Yes, that one!
haunter
1d ago
The reverse of that is running 16bit Windows 1.x/2.x/3.x apps on 64bit Windows 10/11 https://github.com/otya128/winevdm
lifthrasiir
1d ago
wongarsu
1d ago
1 reply
In my mind the most common cases of people running ancient operating systems are computers in control of hardware. Plenty of hardware lasts much longer than 30 years, consequently there's still stuff out there that shipped with Windows 95 and never got new drivers. If you want new software for that environment Rust sounds like a great choice
rkagerer
1d ago
Indeed. Though these days, some prefer older Windows as the new ones are abjectly worse, along all the axes they care about.
vbezhenar
1d ago
11 replies
I wish more languages support old platforms. I'm working in a company and a lot of our customers are running Windows 7 and 8, few of them running Vista. I have to use ancient versions of development tools to target those. For example stuck on Java 8 for eternity. It's PITA.
userbinator
1d ago
1 reply
It's not hard to do either, especially on Windows where backwards-compatibility is almost completely guaranteed.

Of course those in the planned obsolescence mindset would fight hard against it, because then it would be harder for us to take the good without the bad.

carstenhag
1d ago
2 replies
I really hate my bakery, the buns are only edible for some days, after that, they grow mold!

Without sarcasm, it is entirely reasonable that when the OS is EOL by the 1st party, software support for it by 3rd party also ends soon after that.

duskdozer
1d ago
1 reply
I think it's more like your gen1 wi-fi enabled Philips screwdriver stops working because it's EOL as opposed to because nobody uses Philps screws anymore. Sometimes it's the latter, but not always.
dwattttt
1d ago
A more direct analogy is right there; your Phillips head screws cam out more easily than Torx. Everyone who wants screws that don't shred as easily moves to that weird 6 pointed star pattern, and your Phillips head screwdrivers are suddenly EOL'd.
tcfhgj
1d ago
1 reply
Unlike buns, software doesn't deteriorate
purkka
1d ago
1 reply
It does, especially at the scale of operating systems.

Bugs and vulnerabilities are always being found, with fewer and fewer people in the pool that might even theoretically want to pay for fixing them.

Also, hardware does deteriorate, and the story is the same for adding software support for whatever is currently available in hardware.

tcfhgj
1d ago
> Bugs and vulnerabilities are always being found

none which haven't been there from the beginning

vips7L
1d ago
1 reply
I’m a huge Java fan, modern versions are amazing, but being stuck on 8 is the only time I’d recommend just using Kotlin or Scala and compiling to v8 byte code. 8 is just a miserable experience.
tapete2
1d ago
1 reply
Do you happen to know some good learning resources (books, etc.) for modern Java versions?

My last job used Java 8 exclusively and it was indeed a miserable experience, but I am contemplating using modern java for my next project.

vips7L
1d ago
This is unpublished still but is worth checking out: https://www.manning.com/books/data-oriented-programming-in-j...

Other than that, I think we’re all waiting for Josh Bloch to put out Effective Java 4th edition.

The main benefits of the post-8 world that I would look into learning are: pattern matching and destructuring, sealed (sum) types, records, and switch expressions.

asimovDev
1d ago
2 replies
seeing Windows 8 called old really did some psychic damage to me. If it's not a secret, what kind of customers do you have? Is it some industrial stuff as usual?
vbezhenar
1d ago
2 replies
Medicine. I'm living in third world country and probably they don't have enough money to upgrade often, they just install something and work with it for many years. Works for them, I guess, I often see computers with 2-4 GB RAM and some ancient Celeron.
dijit
1d ago
1 reply
Not to be glib, but medical equipment in the first world is the same.
inferiorhuman
1d ago
1 reply
Surely it uses MSVCRT though.
amiga386
1d ago
1 reply
I can't speak for medical equipment, but lab equipment in testing labs (including the ones in hospitals) needs to be calibrated correctly and run exactly to the vendor's specifications. They will continue to sign off on old hardware they continue to support, even if it's actually a Pentium 3 running Windows 95 with the expensive lab device attached via the parallel port.

If you try and switch out the host computer to something newer, the software may or may not work, but you will definitely fail your audits for changing software without the vendor's approval.

For their part, the vendor supports you buying the new version of their device for a few million quid and it now runs via USB attached to a Windows 10 computer running their proprietary software.

dwattttt
1d ago
Since it took me a minute to realise... glib vs MSVCRT are the keywords to the joke.
trollbridge
1d ago
My dentist had a system running Windows XP for X-rays until 2 years ago.

The vendor stopped supporting it (they technically still did, but would dodge replacing parts, etc.) so I eventually fixed some minor issues for her which turned out to just be software related.

A key thing is that the machine was not network attached.

1718627440
1d ago
Isn't Windows 8 even the same major version/generation of the OS, as the current versions?
grishka
1d ago
2 replies
The way some language runtimes have dropped support for Windows 7 feels outright malicious.
Ygg2
1d ago
2 replies
Malicious? It's almost 20 years old (it will be in 2029).
eimrine
1d ago
2 replies
So why the 20 years has no outcomed anything better than 7? The result is malicious.
Yossarrian22
1d ago
1 reply
Define better? I’d prefer modern Debian or Ubuntu over Windows 7 any day
eimrine
1d ago
Modern Ubuntu is a laughable example with a lot of untested Rust components added just for the sake of some big corporations.

Defining better OS is almost as complicated as defining better philosophy. Somebody is leftist, somebody is rightist you know what I mean. When you see what's better usually you can not unseen it.

For me Woedows 7 can give:

1. years of uptime (still with regular browsing! and with using S-states!);

2. native support of god-like NTFS, all my personal backups has it;

3. better support on laptops, for example just try to ditch the UnneededD (Devuan) and you are going to say buy-buy to predictabrle S-states, stable USB performance when using multiple devices and who knows what else;

4. the best battery time among all the market;

5. some old hardware like ATI videocard can not be run on modern kernell, also some old hardware like my digital oscilloscope, my friend's digital syntheiser - all of that makes me not just use but love he Bill Gate's crap. You don't even tied to any version of your appreciated Debian.

6. A lot of industry-best software at least requires me to have Wine. Foobar as the best audio player, STDU as the best book reader, Viktoria as the best HDD tester etc. I have a terabyte of music, hundreds gigs of books and dozens of external disk drives, consuming all of that is my typical non-work activity.

7. I also still use it for my daily job which involves using Internets. No viruces gotten, no unexpected behaviour observed, just working.

Ygg2
1d ago
I meant it's not malicious compared to similar offerings. If anything, Microsoft has been extremely generous when it comes to support. Albeit not so much today (more on that later). It's a half-joke that the only stable ABI on Linux is Win32.

You can have Linux and waste your time, and then stuff updates and Linux breaks. You can have MacOS and lock yourself into a padded Mac themed cell, for five years, then you have to upgrade or stuff will stop working (I'm on Intel Mac, less and less stuff works each day).

---

As for your question.

Short: Blame capitalism and its current setup.

Long: MSFT needs to beat the inflation; otherwise, it's falling behind. And because Windows is no longer growing, you can't really do anything other than rent extraction. It's reached saturation point, which means that money needs to be extracted in some other ways - via ads, via upselling (buy an Xbox 365 subscription), via selling data, etc.

grishka
1d ago
And? There are barely any API differences between 7 and 10.
krior
1d ago
Malicious? Thats a heavy accusation.
archargelod
1d ago
1 reply
Languages that compile to C (e.g. Nim) are great on older systems. If a system has a working C compiler (or cross-compiler), there’s a good chance that it’ll just work.

I’ve myself compiled Nim on Windows 7, Windows XP, and Haiku, and have run simple Nim programs on the C64 and GameBoy Advance.

self_awareness
1d ago
1 reply
Tried to use Nim with VBCC to cross-compile to Amiga, but I failed. I think Nim does some pretty heavy assumptions about the C compiler that is used to compile the generated code.
actionfromafar
1d ago
1 reply
Just in case you aren't in the loop, but there are gcc and llvm based Amiga cross compilers.
amiga386
1d ago
GCC cross-compiling for the Amiga is available from https://franke.ms/git/bebbo/amiga-gcc for a standalone toolchain, and https://github.com/BartmanAbyss/vscode-amiga-debug for one that requires VSCode.

I'm not aware of any working LLVM solution? All I know is that LLVM supports MC680x0 as a backend, can spit out 68k-but-non-amiga-objects and some brave souls have trying to use vlink or mold to produce Amiga executables. Have you seen any working LLVM-based Amiga (680x0 in hunk format) cross-compilers in the wild?

Fulgen
1d ago
1 reply
The problem is, as usual, that some people want that support, but nobody is actually interested in helping out with that support - and that doesn't only include people willing to help out with the code, it includes things like CI. Just how the riscv targets won't be able to reach tier 1 without GH or someone else offering CI support.

Rust's target tiers, while historically not as enforced as they are today, have requirements attached to them that each target has to fulfill; demoting a target or removing support isn't done for fun, but because of what the reality reflects. In Windows 7's case, support from the Tier 1 Windows target was not so much removed as it was acknowledged that the support guaranteees just didn't exist - host tools had long been dead with LLVM having removed support for running on Windows 7, and tier 1 support wasn't guaranteed without any CI to test it on. Thus support was removed, and very soon contributors popped up to maintain the win7 target which is tier 3 and accurately reflects the support gurantees of that target.

(Not a jab at your situation btw, and I wish I could offer you a solution beyond the win7 target - but as it's essentially the preexisting Windows 7 support extracted into a target that matched its reality, it works quite well in practice)

duskdozer
1d ago
3 replies
I do wonder how much support is removed because of genuine maintenance or compatibility burden, because I've encountered enough examples where it was done solely because some target was deemed "too old" arbitrarily, even if it would still work without any modifications.
TylerE
1d ago
3 replies
Perhaps the best example I can think of is the whole situation

InstallShield is....massive crapware and actually generated 16 bit installers way way after anyone was using 16bit PCs. Nobody notices until, I think it was W8 or W10 dropped support for running 16bit executables (something about dropping the subsystem that supported them.

dtech
1d ago
3 replies
It was 64-bit Windows versions, 16 bit was never supported not even on XP 64-bit. I think W8 was the first 64-bit only Windows.
Wowfunhappy
18h ago
> I think W8 was the first 64-bit only Windows.

Nope, that would be Windows 11! There is a 32-bit version of Windows 10.

fredoralive
1d ago
Windows 11 drops IA32, and thus (first party) MS-DOS and Windows 3.x support.

Windows actually has some special cased support for (at least some of) the problematic 16 bit InstallShield installers to run a 32 bit version instead on AMD64.

EvanAnderson
1d ago
Windows 11 was the first 64-bit only build of the NT-based Windows tree. There are 32-bit x86 builds of all previous versions.
Wowfunhappy
18h ago
From InstallShield’s perspective, why would they replace working 16-bit code which is still natively compatible with Windows and x86? Because Windows and/or Intel might (or might not) drop support a decade later?
Fulgen
1d ago
Nobody noticed because Windows special cased InstallShield.

https://devblogs.microsoft.com/oldnewthing/20131031-00/?p=27...

Fulgen
1d ago
In Rust or in general? Because an arbitrary "too old" moniker is not something I've seen happening, and the only target that was removed instead of demoted in recent times was i586-pc-windows-msvc, aka Windows 10 without SSE, which was...utterly pointless since Windows 10 requires SSE.

If anything, I quite like the way Rust handles it with target tiers and easy switching between targets, because it's an honest approach about how well a target is supported. Having a win7 target that is tier 3 is a reflection of the support it has, and much better than stringing it along in the main Windows target that promises tested support when there isn't even a Windows 7 CI to test on.

s1mplicissimus
1d ago
> even if it would still work without any modifications

even in this case, maintenance burden is still real. supporting the old target often prevents you from using features/tools that make maintenance easier

BiteCode_dev
1d ago
1 reply
The question is how much are people willing to pay for this trouble. Usually industries that stick to very old system did so because they didn't want to invest resources in the migration.
thewebguyd
1d ago
> Usually industries that stick to very old system did so because they didn't want to invest resources in the migration.

That can be the case, but there's also a lot of instance where it's not a matter of not wanting to invest, but that being stuck on an older system is the only option until a larger component also goes EOL or dies and cannot be repaired.

I see this all the time in manufacturing. User control interfaces that run on Windows XP or 2k. Machine is still great, can still get parts & repair it, but the software has long ago since stopped being supported. The manufacturer isn't going to spend 6 figures to replace a machine that hasn't fully depreciated yet.

In these instances, you just air gap it off and you're fine.

jonkoops
1d ago
2 replies
What kind of business are you in that you need to be able to support these platforms that have been end-of-life for quite some time? Genuine question.
eimrine
1d ago
1 reply
In my country the Government requires any salesman to have some computer for the sake of sending the info about any sell preferably immediately. I don't know why does they need this, maybe it is making easier for them buying the gold toilets. For example we still have corona-style limitations like no paying with card if the country is bombed somewhere or the businessman risks to be fined. The thing is that nobody wants to buy something more expensive than Pentium 4 or Core2duo especially because most of accounting software still does not support multithreading. So we the businessmen use to mass-buy that cheap hardware, then we install W7 as a good enough OS with no irrigating/pesky/unneeded nanny notifications. The used motherboard if dies it makes no problem, it costs $10. Believe me, the 7 is a perfect OS for self-spying to our Governments and if you want to lobby Rust into this business you have to support W7 somehow.
iSnow
1d ago
1 reply
In my country the Government requires any salesman to have some computer for the sake of sending the info about any sell preferably immediately. I don't know why does they need this, maybe it is making easier for them buying the gold toilets.

If that country happens to be Germany, it's to combat tax fraud.

indigo945
1d ago
Germany still does not generally require this. It's required if you use an electronic cash register (and only since recently), but if you don't, it's perfectly legal to just tally the money with pen and paper at the end of the business day. It's how all the small fast food restaurants do tax evasion: just scribble half of what you actually sold on the back of a napkin, and that's enough "proof" for the tax authorities.

The current governing coalition has come to an agreement that electronic cash registers will be mandatory starting in 2027, but that law hasn't been passed yet.

loeg
1d ago
1 reply
And how do you get paid when your users that are so broke they're still needlessly on 7/8?
spikej
1d ago
1 reply
Big assumption there... chances are they would rather keep the money or spend it elsewhere, instead of "unnecessarily" upgrading when things still work
loeg
22h ago
1 reply
Win10 has got to cost less than a single ransomware attack.
officeplant
21h ago
If its medical industry those machines are offline. Same thing with CNC machines still running windows 98 in some workshop. Hell we still use some windows XP laptops here with the networking disabled because places are still running fire alarm panels from the 80s/90s and using serial comms via Virtual Machine is finicky as fuck on a modern laptop.
GardenLetter27
1d ago
3 replies
Why? That effort is far better spent on developing new things and taking advantage of modern hardware.

People need to upgrade. I'm surprised any machine running Vista could even use the modern web.

officeplant
21h ago
Upgrade all you want, some modern machines just can't run the software needed to talk to and control old industrial, fire, medical, etc equipment.

Somewhere out there is a Windows 98 machine controlling an industrial machine that will out live early posters on HN.

voidUpdate
1d ago
The only things really driving upgrades are gaming and web browsing. If you dont need to do either of those, you could probably get by with windows 9x
cwillu
1d ago
People do not, in fact, need to upgrade.
david_wpg
1d ago
Use Temurin Java 8 JDK/JRE. It's designed to be 1:1 compatible with Oracle Java.
giancarlostoro
1d ago
I thought the entire point of Kotlin was to allow you to write in a more modern language, and then compile to older versions of Java no? I've not kept up with Kotlin much, but I would expect it to help a little.

I know uh FreePascal targets everything including the Gameboy. But then Pascal isn't super modern or sexy unfortunately.

NooneAtAll3
1d ago
3 replies
considering the all-insistence of rust on using internet for all the libraries, this doesn't seem like a good idea...
josephg
1d ago
What do you mean? Cargo downloads packages from the internet by default programs do exactly what they’re programmed to do. No more and no less.

Just because you’re targeting windows xp doesn’t mean you need to run windows xp to do development.

gspr
1d ago
What insistence? I do 99% of my Rust development with this ~/.cargo/config.toml:

  [net]
  offline = true
  
  [source]
  
  [source.crates-io]
  replace-with = "debian"
  
  [source.debian]
  directory = "/usr/share/cargo/registry"
Works great.
sanxiyn
1d ago
With cargo --offline, Rust has better than average support for offline build.
arka2147483647
1d ago
3 replies
For someone who is not a rust programmer, but would like to keep up to date, can somebody tell me what "Tier 4" is. And why must it be quoted?
chiffaa
1d ago
Rust has 3 "platform support" tiers (effectively - guaranteed to work, guaranteed to build, supposed to work). However, these are (obviously) defined only for some of the target triples. This project defines "Tier-4" (which is normally not a thing) unstable support for Windows Vista-and-prior
the8472
1d ago
tiers 1-3 are policies[0] for in-tree targets, so by saying tier 4 they mean one implemented in a fork. Though that kind of skips over targets that can get away with just a custom target spec[1] and not modifying the source.

[0] https://doc.rust-lang.org/beta/rustc/target-tier-policy.html [1] https://doc.rust-lang.org/rustc/targets/custom.html

rwaksmunski
1d ago
Tier 3 is max official
binaryturtle
1d ago
1 reply
And here I'm still trying to get an up-to.date Rust running on my outdated OS X (10.10). No luck (though I may not try hard enough).
estebank
1d ago
I knew I'd seen something along those lines:

https://nitter.net/turbolent/status/1617231570573873152

fithisux
1d ago
I think this is valueable for efforts like Reactos.
pwdisswordfishy
1d ago
Can it manage Win32s?
ptspts
1d ago
Shameless plug: Some of my hobby projects written in C (e.g. https://github.com/pts/bakefat) can be built reproducibly for Linux >=1.0 (1994), FreeBSD (same ELF executable program file as for Linux) and Win32 working on all versions of Windows (Windows NT 3.1 (1993)--Windows 11). The C compiler (running on Linux i386 and amd64 host) used for the release build is self-contained and included in the project, along with the libc.

Doing such backward compatibility is definitiely possible for command-line tools. Once set up, it's automatic, and it needs extra testing after major changes.

anthk
1d ago
MinC for XP and up: (MinC is not Cygwin, you get cc, ncurses, ksh, git and some goodies).

https://minc.commandlinerevolution.nl/english/home.html

IronTCL for XP and up

https://minc.commandlinerevolution.nl/english/home.html

Updated SSL/TLS certs, again for XP and beyond:

https://legacyupdate.net/

Tiny Pascal-like language targetting DOS, CP/M and Unix:

https://t3x.org/t3x/0/index.html It's no Free Pascal but it can do good stuff with very little:

https://t3x.org/t3x/0/programs.html

JimTCL, a tiny TCL with bundled TLS, JSON, Sqlite3 and, optionally, some SDL2 support:

https://github.com/msteveb/jimtcl https://jim.tcl-lang.org/home/doc/www/www/index.html

You can compile JimTCL with MinC under XP, and maybe T3X0 too. With JimTCL you can build a quick TCL expect clone, some netcat clone too with TLS can be done in minutes too, really good for debugging or to create a simple IRC/Email/Gopher/Gemini client in text mode.

sanxiyn
1d ago
An interesting bit of history: for a long time Rust maintained first party support for Windows XP, after other parts of ecosystem generally gave up. This was because Firefox needed it.

https://github.com/rust-lang/compiler-team/issues/378 (major change proposal to drop Windows XP support) notes this history and links to other relevant pages.

zozbot234
1d ago
This target might become more viable in the future as Stable Rust adds options to rebuild libstd with custom features as part of building a project.
self_awareness
1d ago
And unofficial "Tier 5" Rust Target is... for Commodore-64:

https://github.com/mrk-its/rust-mos

It works, and builds binaries that are ready to be executed by Vice emulator.

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