"""POSIXLY_CORRECT (originally proposed as POSIX_ME_HARDER) is a historical environment variable used in GNU utilities to force strict compliance with the POSIX standard."""
the netbsd gallery (https://netbsd.org/gallery/) had a picture of somebody using that on windows xp (iirc) in order to compile pkgsrc packages in a "posix compliant" environment. the picture seem to be gone now :(
The whole UNIX certified thing is a bit odd to start with, but those addendums are really just saying that because the UNIX compliance tests are thoroughly stuck in the past, a bunch of security measures (that users expect to exist on modern systems) have to be disabled to run the test suite.
SIP is not some irrelevant detail, nor is it an obviously good "modern security practice". A system that the hardware owner cannot modify is not really on the same wavelength as traditional UNIX.
The hardware owner can modify it all they want, disable SIP. For a large swath of average and non-average users that will not be modifying the closed-source OS they're running, it is obviously good.
Traditional UNIX is does not mean having an open source core you're intended to tinker with. Traditional UNIX was entirely proprietary, connected with well-defined text-based interfaces. This is entirely orthogonal to user control and manipulation of the OS.
Traditional UNIX was entirely proprietary, with source you're intended to tinker with.
AT&T was forbidden by its consent decree from productizing Unix. Licensees received the source code, on an as-is basis, with no official support from AT&T.
Sure, but that just means UNIX vendors had access to the source code.
It doesn't mean end users had access to the source code.
In fact, vendors would have been prohibited from distributing AT&T source code to customers who weren't themselves AT&T licensees, just as CSRG was prohibited from distributing BSD to customers who weren't licensees before 4.4BSD-Lite.
The same goes for most other proprietary source-available products. For example, game developers can't open source Unreal Engine projects even though Unreal Engine source licenses are available to end users for free.
You would absolutely normally get source to the vast majority of the unix components with a unix install.
At a bare minimum, you would almost have to have source to the vast majority of the kernel because there was no kernel modules. Sysgenning for a particular system involved compiling the kernel for that set of hardware.
I'm literally working on an early sun system emulator right now, heavily assisted by the standard sec tape that came with the standard software distribution of sunos, which has plenty of AT&T code.
Sure, if by “you” you mean universities, Sun, DEC, IBM, etc.
As a non corporation end user with a sublicense from one of the above licensees (which is the apt analogy for an individual user in my opinion) you most certainly did not receive the source or have the rights to it.
This is fine and I hope it's permanent. Unix certification never really captured what once made "OS X is a Unix" attractive or exciting to many.
What I care about, at least, are experiences of ease, convenience, compatibility, control, order, and freedom around a programmable system that invites the blurring of the lines between user and developer, between quotidian use and automation, and between decoration and reshaping. Such experiences still involve many of the same elements as they did two decades ago: a composable language of commands, commonly observed conventions, well-organized hierarchies of files, formal software freedom, powerful package management systems, great in-band/offline documentation, etc. But Unix certification isn't the center of gravity around which such experiences revolve, if it ever was. And for that matter, neither is macOS.
If this is an intentional move, Apple is just acknowledging reality. UNIX(tm) is no longer so relevant compared to the early days of OS X, when Linux was still in its infancy and the Unix certification gave Apple street cred among developers. Most developers these days target Linux for production. That's why Microsoft developed WSL, not WSU.
SFU 1.0 and 2.0 relied on the MKS Toolkit by MKS/PTC, and SFU 3.0 later adopted the Interix (OpenNT) subsystem, which Microsoft acquired from Softway Systems in 1999.
The original POSIX Subsystem (psxss.exe) was Cutler's team who implemented a minimal POSIX.1 subsystem server alongside Win32 and OS/2. This was done primarily to satisfy US Federal Government procurement requirements (FIPS 151-2).
True, though to Microsoft's credit, the existence of the POSIX subsystem, even as a proof-of-concept, ensured the underlying kernel design supported the development of products like Interix, just as Windows on Alpha et al. ensured NT remained reasonably portable to future platforms like ARM, unlike say OS/2 where the only non-Intel release (for PowerPC) was basically a prerelease lacking core OS features like networking.
Linux has been effectively Unix™ for me ever since the days when Dennis Ritchie indicated that he used Linux for everything on his web page. Late 2000s at the latest, maybe early 2000s. Unix enough for Dennis should be Unix enough for anyone.
Well he and others moved away from UNIX, created Plan 9 and Inferno.
In these efforts they also tried to create successor languages to C, Alef and Limbo (for userspace), and never cared that much about anything past C89.
He has settled with Linux because that is the winner of UNIX wars, which predated Linux wars on Distrowatch.
As for the original UNIX,
"Using Unix is the computing equivalent of listening only to music by David Cassidy"
Yes, Unix = Linux for all intents and purposes in 2026. When I started in the early 90s, there was a galaxy of Unices - SunOS/Solaris, HP-UX, AIX, and many others people people don't even remember (ConvexOS anyone?). Heck, back then if you wanted to run a particular software for your industry, you might have to buy and install a specific proprietary Unix.
Today? It's all Linux or Windows (of course, now also Web/SaaS). All these different Unices have fallen by the wayside in favor of Linux. Yes, some are still around but the mindshare has been in Linux for the last 20 years.
I suspect you could rip out a ton of autoconf rules and no one would notice.
I've been using Linux for 30+ years now and have always considered it free (as in speech) Unix. For my purposes, the difference was always more legal and philosophical than practical. Of course, I was a student back then and didn't need to run the commercial software of the time.
I swear I've seen these "[Latest macOS release] does not appear in UNIX certification site" threads every year since the release of Big Sur in 2020.
It takes several months for the certification to appear on the site. What would be newsworthy is if we see a release next year without this release getting certification.
Apple originally certified Mac OS X as a UNIX because they used the word UNIX all over their website and the Open Group came knocking; they decided it was cheaper/better for goodwill to do the conformance and pay the license fee than to fight the case in court.
Looking now, I see almost no uses of the word UNIX on the website except the docs archive, so I guess they’ve decided to abandon both the certification and the use of the UNIX trademark in macOS.
Maybe. But I don't remember seeing them use the word for the last decade, and the last-but-one release was certified. My first guess would be that it's too new, and hasn't passed certification yet.
Indeed. And, weirdly, there are items that show up by that 03 standard alongside macOS 26 (e.g. "HP-UX 11i V3 Release B.11.31") that also show on the front page. Is it a latest version kind of thing?
Yea — said as much in another comment. That looks like it could be the rule — for example your HP-UX version there appears to be the latest, final HP-UX.
While it may simply acknowledge reality, I’ve already moved my main development off macOS to a NixOS workstation months ago. Too much friction in an OS that is clearly trying to be more “consumer” than “creative” at this point.
Which is a damn shame, because AI dev is going to result in a massive influx of new software right when Apple makes it ever more difficult to do so on its platform.
I still make Mac builds, but it is more of an afterthought on a secondary Mac build machine now.
You know something has peaked when they become less open and more “clawbacky”; that is basically collecting interest on an investment (marketshare) instead of remaining more open (at the cost of some things). “Increased security” is always the rationale.
Well Unix as a standard is completely dead. macOS as a Unix is completely dead. I expect another branch in the already complicated as hell tree of Unixes.
macOS as Unix is not dead – the compatibility with developer and unix infrastructure it has is an important reason why the company I work for uses MacBooks (at least I believe so).
I would guess that your company isn’t actually interested in the UNIX compatibility specifically, more that they’re interested in laptops that can run a similar toolset.
They probably also buy MacBooks since they’re reliable, performant, high-endurance (battery life) general purpose business laptops that employees like using and see good productivity with.
I think he means macOS as official, certified Unix is dead.
macOS as a more Linuxy-friendly place to work on Linuxy-type software, sure. Definitely true compared to Windows. But no one cares if macOS is blessed as Official UNIX.
How many people are writing software that they need to be able to run on Linux, Solaris, AIX, and HP-UX in 2026?
We've found it to be a much worse experience than windows for dev stuff. It's a different OS and architecture to the target env (Linux). Aligning with that makes life considerably easier.
If you're using a language compiled to bytecode or interpreted, then the OS and arch don't matter a whole lot (so long as you don't have to deal with Window's weird filename conventions or other oddnesses). If you're using compiled-to-bytecode languages, there's a huge advantage in forcing your code to be cross-arch safe from day one, lest ye accidentally end up with something that can only build on the exact CPU in your devs' laptops or can only run on the flavor of WSL you're using that year.
Writing on Mx Mac and deploying on Intel Debian is a little harder in the beginning, but spares you oh, so many footguns down the road. Eventually you might want to deploy to a different OS or arch for cost or convenience reasons. That's a really bad time to find out that your project can't be made to work there without heroics.
Your production is not going to be the same as everyone else's. It's also not going to be the ideal for everyone else's, or even possible for everyone else's.
The differences between ARM and x86 are probably less relevant for the majority of server-side development than API and admin interface differences.
In practice, anyone seriously developing Linux software on either macOS or Windows is using VMs or containers running the actual Linux kernel, at least for testing, and the difference is that Microsoft has put far more effort into integrating specific support for these things into the OS.
I've been a software engineer for 25 years, doing Linux stuff at startups and big companies (the biggest even). In all my time as a software engineer, I've seen maybe 3 people who didn't use a MacBook Pro for work. Apple makes the bulk of its money from tech companies and schools and they cater very well to both. If it stops being Unix-like, they lose the thing they make the most money from. They are smarter than that.
I don't think apple makes the bulk from professionals at all, the iphone is their flagship product and their laptop line has been expanding towards casual markets with budget models.
They don't make any money on macOS anymore. You get it preinstalled on their computers, you can't buy it separately, you can't install it on other computers, and major upgrades are free.
It is a part of the computer that people pay for. This is like saying they don't get any money from Apple Silicon because its already installed on the motherboard.
The money they make from MacOS is a footnote compared to the money they make from phone hardware, the app store transaction tax, and ads. To a first approximation, the only reason that Apple cares about MacOS is so that people can make iOS apps.
This is a poor approximation, as there would be no need for such an extensive Mac product lineup if this were true. The Mac mini and one laptop product line with two or three sizes would be more than sufficient, and continuing development of first-party Mac applications like Logic and FCP would serve little purpose.
And so are developers on Linux. 99.5% of your backend stuff will run just fine on macOS without any modification, but it's been a good practice for a long time now to run stuff in containers (Docker/OrbStack/podman/etc.) in order to have a reproducible environment free of contamination. My development process in macOS is basically no different than it was on Linux.
You still end up in uncanny valley often enough, with commands that are missing, or working unexpectedly differently. It often feels like macOS could be made so much better for developers, but Apple just doesn't care because people buy their devices anyway.
It’s not that. It’s that their lawyers won’t let the engineering side distribute gnu tools. Period.
At Apple, if you even use GPL tools in your workflow you have to seek approval, and most often there’s pushback of “why won’t this (alternative that isn’t GPL) work ?”
Their lawyers aren’t stupid, they understand the GPL and its limits, but they’re simply doing a risk assessment- which one is less risky, the GPL variant or the BSD. For a corporation, that’s generally BSD.
It’s a computer. I can make a computer go beep if I want, that is not the issue.
The fact that someone who didn’t grow up at the time when open source was an idealistic concept instead of free support to corporations needs to learn about the gnutils and how to install them with homebrew is what makes me sad.
Why do we seriously not have a command-line package manager on macOS yet? Windows has one by now. It’s just sad to me that you need a manual checklist of post-setup steps to turn a Mac into a useful machine for software development.
The point I was making was that knowing what GNU means in the first place probably requires some cultural background that many people lack, especially younger ones.
Right, and the point I'm making is that you can learn this from Google once you notice there is a difference from how common commands work on Linux and MacOS. You don't need to know about GNU, you just have to wonder why its different.
It already feels a bit like it's two separate operating systems on one machine. It's still usable, but I am starting to notice odd behaviours. Files created in the terminal not showing up in the UI, there seems to be no notification from the filesystem to Finder, informing it that the terminal has created a file.
Developers and operations people are already starting to move to Linux. More and more I see colleague either switching to Linux, or have a mac laptop for administrative tasks and then a Linux workstation, or VMs, where they do their actual work.
> Developers and operations people are already starting to move to Linux.
I’ve been in this industry for a long time now. Linux always had more credibility among devs and ops folk. This “starting to move” view is weird.
My view is that OS X was acceptable by these teams because it was close enough to Linux and corporate could deal with it.
When I worked in corporate IT Linux was simply not an option for a primary workstation because there was no standard configuration or management tooling that made everyone happy. Macs were an easy compromise.
I personally don’t see macos anyhow competing with Linux or to be anyhow comparable to Linux in each others sweat points. linux dominated server side, so be its fair victory but it’s continually shit kind of clone of many things done in MacOs desktop experience. It just kept cloning Apple since forever to repeat a glimpse of that experience even during Next times with WindowMaker and then with many incarnations of modern desktop systems to compare with OSX and MacOs continually and in that direction. Linux is open, it’s different, that comes with value but still a little handicapped brother to MacOS desktop experience with continually f*up fundamentals even if you include wayland as the base. So is MacOs in servers but there Apple just resigned last year and stopped pretending they have servers. Both have only one thing in common, shell with base posix tools. Nothing else. And none are as open as original idea for Unix as this idea is long dead and linux tries to make Stallman’s wet dream about GNU system come true as his own kernel implementation did not move forward much it at all since mid 80s.. that’s the only UNIX reality that matters.. rest is bureaucracy and 5000 pages of POSIX standard nobody cares about as this is more about C libraries than kernel’s internals.
> Files created in the terminal not showing up in the UI
You might wanna look into that because that’s not how it works at all. I frequently switch between terminal and GUI apps and have not once noticed Finder failing to catch up with whatever it is I’m doing in the terminal.
Strange, because I have the same issue on two different machines. It doesn't happen all the time, but frequently enough that I assumed that Finder does some re-scan every now and then (or when you open a new Finder window).
Microsoft just shipped a full-fledged first class Linux container runtime as part of Windows[1]. I don’t think it even made front page of HN, which shows how far windows has fallen as a developer environment, but it is absolutely something Apple should be offering as a first class capability on OS X. The compatibility of the host OS file system with being mounted into docker images makes it a better environment for running such things.
Has it really, though? Because outside the HN bubble, Windows still seems to be the most common developer environment for most things that don't specifically target Linux or Apple platforms, and a popular option even then (e.g., in game dev).
In some alternative dimension Ternus decides to realize the full potential of the Mach kernel by embracing Hurd in place of XNU. Users are discouraged because the new system is not enough like GNU/Linux.
I'm suspecting some forces at Apple would be perfectly content with ripping most of the BSD core and the assorted CLI out and just have Linux containers spawned in VMs, WSL2-style.
I haven't tried it. colima also simplifies linux VMs which is more of an analog to WSL2 than just running containers. It has really nice integration with Incus as well, if you like persistent system containers.
yeah I guess there isn't really much to move to... a new custom Kernel and Userspace? extremely unlikely - I guess it's here to stay, despite not being formally Unix.
It's distinctly problematic there unfortunately. Particularly the moment you add any UI toolkits to it. I've had so many problems with stuff that uses Qt because Qt takes a while to catch up with things Apple broke inside their Cocoa internals. Very irritating platform to work on.
Edit: love how I get downvoted for facts?! They literally broke Cocoa so it was throwing hopeless useless exceptions at the bottom of the stack when they changed the native file open boxes to run in another process. Two bits of software I use couldn't raise an open file dialog window any more.
I see macOS 26 listed under the Unix 03 standard. Was macOS 27 listed and then removed? The submission title + site contents combined do not give enough info to assess what exactly was silently removed.
The this is much ado about nothing. Every single entry on the page you linked goes to its product page with the exact Unix standard it is certified as. Once you select a filter, you cannot get back to unfiltered list without the back button on the browser.
This is just a site rendering issue. Rather than silently removed, it's more like some bug was introduced. macOS 26 is still Unix 03 certified.
Apparently it was for legal reasons. Apple was sued by the Open Group for describing Mac OS X as Unix® so they decided it was cheaper to bring it up to spec rather than to fight the lawsuit.
Enterpise espeically banking need standard and certification for reliability thats why , also certain Linux distro had certified before from China based on RHEL.
This is UNIX 03 certified OS with OSS alternatives from I gathered on internet :
- Apple OS X 10.7 - Apple macOS 26 , provide OSS Darwin 9 - Darwin 26
- Oracle Solaris 10 / 11 , provide OSS OpenSolais , then Illumos
- EulerOS 2.0 , based on RedHat Enterprise Linux / RHEL 7 and 8
- Inspur K-UX 2.0 , based on RedHat Enterprise Linux / RHEL 5
- Inspur K-UX 3.0 , based on RedHat Enterprise Linux / RHEL 7
Linux can’t be listed, because Linux is not an operating system. It’s just a kernel. Unix specifies a whole operating system, which includes things like libc, cat, sh etc.
At best a distro could be certified. But that certification would not automatically extend to other distros.
From that Wayback page, it looks like only one version of macOS is certified at any one time: the latest version. Since macOS Golden Gate was only recently released, perhaps it's a process blip and we'll see Golden Gate listed soon.
I won't be surprised if you will have to boot into recovery, disable SIP, come back to user-space and run those unsafe 'ls' and 'cat' commands you were trying to live dangerously with on '~/Library', and then go back to recovery again to renable SIP to stay safe. You may also have to do that to install every software you want to install and use on your (is it?) mac other than the ones that are from companies that had tied up with and signed Apple's USA certificaiton (i.e User Safety Alliance™; involving non-publicly disclosed deals), or from the smaller devs who were not small enough and could pay a few thousand dollars annually and sent Apple 3 kidneys annually to publish softwares with very reduced scope and access on the device/OS. The data transfer between your mac and those app endpoints will be so protected that even your own self-destructive hands and insufficient intellect won't be able to gather what is happening beneath the Apple's hardware hardcoded encryption. All for safety beyond the UNIX way. So not all surprising.
When you're small, you need the certificates and badges others give you to be seen and be validated. I really don't think anyone needs to become familiar with Apple or macOS and that any of these certificates now matter a tiny amount to a multi trillion dollar corporation.
Given the amount and volume of software that mac has, the fact that almost all new interesting stuff are released for mac first or even mac alone, I also don't think it needs to attach itself to bigger names for platforms.
I think the financial burden of Ubuntu Mobile, Unity 8, and Mir; and the immediate rise of docker and WSL made canonical fully shift to server, so much so that their website no longer is about a better os for people, but what can it do for your cloud. Other distros also followed its path and Linus became all in on servers and IoT. I see windows as the biggest pile of trash in the world. Infinitely inconsistent, buggy, patched worked, visionless and rotting. Honestly that is one piece of software that is worse that AI slop.
And so what is there for Apple to compete with honestly? Haiku? Solaris?
And if you're honest, macOS has sadly dropped in quality too...
But the reason why I wrote my comment was just that you gave off the feeling that you consider macOS to be the only relevant desktop operating system, which seemed like a very strange view to have given the reality of it's userbase.
This doesn't mean anything. The official Unix registry is completely irrelevant to the modern world. Nobody uses OSX pretending it's compatible with Solaris. Like Microsoft, Apple only cared about this certification because it used to be a checkbox on certain government procurement tenders.
It'd matter if this certification came with an extensive test suite guaranteeing some degree of compliance. Instead, you have macOS defaulting to an antediluvian bash as /bin/sh full of ridiculous bugs like this:
In many ways, macOS is kind of driving towards irrelevance.
Apple wants it to be more like iOS (so they can control what you do on it) while users want a normal computer they can do computer things on without it spewing ads or applying political pressure when someone tries to hold Apple accountable (e.g. the EU trying to make Apple stop abusing their market position).
> In many ways, macOS is kind of driving towards irrelevance.
You mean the second most used desktop OS with about 15% of the global consumer OS market? About 30% of consumer desktops in the US alone? That “irrelevant” macOS?
Indeed it is one in the same. The middle layer of MacOS has been rotting for years, the introduction of gatekeeper and SIP has made downloading and running programs or observing your system a pain. Software developers are being pushed toward App models and many other examples exist. For people who simply need a computer that works MacOS is moving futher away from that goal with every release.
The certification was always a bit odd, applying only to a configuration nobody would run in practice: https://www.osnews.com/story/141633/apples-macos-unix-certif...
If you'd try to certify any modern Linux distribution, you'd end up with a very similar list.
- The Linux kernel also has timer coalescing
- Linux also has lazy atime ('relatime') by default
- No Linux distro installs uucp by default, and certainly not suid
- Desktop distros will also run a file indexer of some sort
etc.
Isn’t the difference here that Linux was never trying to claim UNIX certification?
The certification documents read like the world's most abstruse bar trivia quiz...
"1.12 Threads
1.12.1 Cancellation Points
Question 31: Which C stdio functions have cancellation points that occur when a thread is executing?"
https://www.opengroup.org/csq/repository/noreferences=1&RID=...
The certification also was kind of bad at actually checking that the standard interfaces behaved as they should.
Reminds me of (technically) POSIX compatible Windows.
"""POSIXLY_CORRECT (originally proposed as POSIX_ME_HARDER) is a historical environment variable used in GNU utilities to force strict compliance with the POSIX standard."""
ah, yes! https://en.wikipedia.org/wiki/Microsoft_POSIX_subsystem
the netbsd gallery (https://netbsd.org/gallery/) had a picture of somebody using that on windows xp (iirc) in order to compile pkgsrc packages in a "posix compliant" environment. the picture seem to be gone now :(
The whole UNIX certified thing is a bit odd to start with, but those addendums are really just saying that because the UNIX compliance tests are thoroughly stuck in the past, a bunch of security measures (that users expect to exist on modern systems) have to be disabled to run the test suite.
SIP is not some irrelevant detail, nor is it an obviously good "modern security practice". A system that the hardware owner cannot modify is not really on the same wavelength as traditional UNIX.
The hardware owner can modify it all they want, disable SIP. For a large swath of average and non-average users that will not be modifying the closed-source OS they're running, it is obviously good.
Traditional UNIX is does not mean having an open source core you're intended to tinker with. Traditional UNIX was entirely proprietary, connected with well-defined text-based interfaces. This is entirely orthogonal to user control and manipulation of the OS.
Traditional UNIX was entirely proprietary, with source you're intended to tinker with.
AT&T was forbidden by its consent decree from productizing Unix. Licensees received the source code, on an as-is basis, with no official support from AT&T.
Sure, but that just means UNIX vendors had access to the source code.
It doesn't mean end users had access to the source code.
In fact, vendors would have been prohibited from distributing AT&T source code to customers who weren't themselves AT&T licensees, just as CSRG was prohibited from distributing BSD to customers who weren't licensees before 4.4BSD-Lite.
The same goes for most other proprietary source-available products. For example, game developers can't open source Unreal Engine projects even though Unreal Engine source licenses are available to end users for free.
You would absolutely normally get source to the vast majority of the unix components with a unix install.
At a bare minimum, you would almost have to have source to the vast majority of the kernel because there was no kernel modules. Sysgenning for a particular system involved compiling the kernel for that set of hardware.
I'm literally working on an early sun system emulator right now, heavily assisted by the standard sec tape that came with the standard software distribution of sunos, which has plenty of AT&T code.
Sure, if by “you” you mean universities, Sun, DEC, IBM, etc.
As a non corporation end user with a sublicense from one of the above licensees (which is the apt analogy for an individual user in my opinion) you most certainly did not receive the source or have the rights to it.
This is fine and I hope it's permanent. Unix certification never really captured what once made "OS X is a Unix" attractive or exciting to many.
What I care about, at least, are experiences of ease, convenience, compatibility, control, order, and freedom around a programmable system that invites the blurring of the lines between user and developer, between quotidian use and automation, and between decoration and reshaping. Such experiences still involve many of the same elements as they did two decades ago: a composable language of commands, commonly observed conventions, well-organized hierarchies of files, formal software freedom, powerful package management systems, great in-band/offline documentation, etc. But Unix certification isn't the center of gravity around which such experiences revolve, if it ever was. And for that matter, neither is macOS.
If this is an intentional move, Apple is just acknowledging reality. UNIX(tm) is no longer so relevant compared to the early days of OS X, when Linux was still in its infancy and the Unix certification gave Apple street cred among developers. Most developers these days target Linux for production. That's why Microsoft developed WSL, not WSU.
> That's why Microsoft developed WSL, not WSU.
Developed WSL and discontinued SFU (Windows Services for UNIX), which they had since NT 4 days.
SFU 1.0 and 2.0 relied on the MKS Toolkit by MKS/PTC, and SFU 3.0 later adopted the Interix (OpenNT) subsystem, which Microsoft acquired from Softway Systems in 1999.
The original POSIX Subsystem (psxss.exe) was Cutler's team who implemented a minimal POSIX.1 subsystem server alongside Win32 and OS/2. This was done primarily to satisfy US Federal Government procurement requirements (FIPS 151-2).
True, though to Microsoft's credit, the existence of the POSIX subsystem, even as a proof-of-concept, ensured the underlying kernel design supported the development of products like Interix, just as Windows on Alpha et al. ensured NT remained reasonably portable to future platforms like ARM, unlike say OS/2 where the only non-Intel release (for PowerPC) was basically a prerelease lacking core OS features like networking.
SFU ended in XP/2003. Vista/2008 had SUA
Linux has been effectively Unix™ for me ever since the days when Dennis Ritchie indicated that he used Linux for everything on his web page. Late 2000s at the latest, maybe early 2000s. Unix enough for Dennis should be Unix enough for anyone.
Well he and others moved away from UNIX, created Plan 9 and Inferno.
In these efforts they also tried to create successor languages to C, Alef and Limbo (for userspace), and never cared that much about anything past C89.
He has settled with Linux because that is the winner of UNIX wars, which predated Linux wars on Distrowatch.
As for the original UNIX,
"Using Unix is the computing equivalent of listening only to music by David Cassidy"
-- Rob Pike
Yes, Unix = Linux for all intents and purposes in 2026. When I started in the early 90s, there was a galaxy of Unices - SunOS/Solaris, HP-UX, AIX, and many others people people don't even remember (ConvexOS anyone?). Heck, back then if you wanted to run a particular software for your industry, you might have to buy and install a specific proprietary Unix.
Today? It's all Linux or Windows (of course, now also Web/SaaS). All these different Unices have fallen by the wayside in favor of Linux. Yes, some are still around but the mindshare has been in Linux for the last 20 years.
I suspect you could rip out a ton of autoconf rules and no one would notice.
Caring about which systems are branded UNIX is like caring about which NBA player was paid to endorse a particular brand of athletic footwear.
I've been using Linux for 30+ years now and have always considered it free (as in speech) Unix. For my purposes, the difference was always more legal and philosophical than practical. Of course, I was a student back then and didn't need to run the commercial software of the time.
I’m pretty sure Federal procurement is the big driver of relevance for this certification. They have always had a huge Fed business.
If they are in fact dropping it, that’s why. But… Apple often “finishes” the enterprise features with a point release.
Sure, I just hope macOS doesn't end up doing some custom thing rather than staying Unix/Linux like, which we've had with macOS/OS X till now.
If true, a better title would be "macOS is no longer UNIX certified".
Tahoe was Unix 03 certified, and is still listed on that page if you filter by standard and choose Unix 03.
Perhaps Golden Gate simply hasn't yet passed certification.
I swear I've seen these "[Latest macOS release] does not appear in UNIX certification site" threads every year since the release of Big Sur in 2020.
It takes several months for the certification to appear on the site. What would be newsworthy is if we see a release next year without this release getting certification.
Apple originally certified Mac OS X as a UNIX because they used the word UNIX all over their website and the Open Group came knocking; they decided it was cheaper/better for goodwill to do the conformance and pay the license fee than to fight the case in court.
Looking now, I see almost no uses of the word UNIX on the website except the docs archive, so I guess they’ve decided to abandon both the certification and the use of the UNIX trademark in macOS.
Maybe. But I don't remember seeing them use the word for the last decade, and the last-but-one release was certified. My first guess would be that it's too new, and hasn't passed certification yet.
Indeed. And, weirdly, there are items that show up by that 03 standard alongside macOS 26 (e.g. "HP-UX 11i V3 Release B.11.31") that also show on the front page. Is it a latest version kind of thing?
Yea — said as much in another comment. That looks like it could be the rule — for example your HP-UX version there appears to be the latest, final HP-UX.
Yep linked page is active certification rather than historical.
"silently" doesn't occur in the title, so is clickbait drama editorializing.
LLMs love "silent" and "quiet."
Also the suggestion Apple was entirely removed is false; see https://www.opengroup.org/openbrand/register/apple.htm
it's "silently" never left. :)
indeed, some may even call it a quiet load bearing footgun haha
While it may simply acknowledge reality, I’ve already moved my main development off macOS to a NixOS workstation months ago. Too much friction in an OS that is clearly trying to be more “consumer” than “creative” at this point.
Which is a damn shame, because AI dev is going to result in a massive influx of new software right when Apple makes it ever more difficult to do so on its platform.
I still make Mac builds, but it is more of an afterthought on a secondary Mac build machine now.
You know something has peaked when they become less open and more “clawbacky”; that is basically collecting interest on an investment (marketshare) instead of remaining more open (at the cost of some things). “Increased security” is always the rationale.
> but it is more of an afterthought
If the platform I use is an afterthought for you then your software becomes afterthought for me as well.
It is still there.
For those that don't know how to use a filter drop down, check UNIX 03 version.
That’s historical. The linked page is active. Zzz
Well Unix as a standard is completely dead. macOS as a Unix is completely dead. I expect another branch in the already complicated as hell tree of Unixes.
macOS as Unix is not dead – the compatibility with developer and unix infrastructure it has is an important reason why the company I work for uses MacBooks (at least I believe so).
The relevance of Open Group and the UNIX brand has been a walking corpse for decades.
I would guess that your company isn’t actually interested in the UNIX compatibility specifically, more that they’re interested in laptops that can run a similar toolset.
They probably also buy MacBooks since they’re reliable, performant, high-endurance (battery life) general purpose business laptops that employees like using and see good productivity with.
I think he means macOS as official, certified Unix is dead.
macOS as a more Linuxy-friendly place to work on Linuxy-type software, sure. Definitely true compared to Windows. But no one cares if macOS is blessed as Official UNIX.
How many people are writing software that they need to be able to run on Linux, Solaris, AIX, and HP-UX in 2026?
We've found it to be a much worse experience than windows for dev stuff. It's a different OS and architecture to the target env (Linux). Aligning with that makes life considerably easier.
If you're using a language compiled to bytecode or interpreted, then the OS and arch don't matter a whole lot (so long as you don't have to deal with Window's weird filename conventions or other oddnesses). If you're using compiled-to-bytecode languages, there's a huge advantage in forcing your code to be cross-arch safe from day one, lest ye accidentally end up with something that can only build on the exact CPU in your devs' laptops or can only run on the flavor of WSL you're using that year.
Writing on Mx Mac and deploying on Intel Debian is a little harder in the beginning, but spares you oh, so many footguns down the road. Eventually you might want to deploy to a different OS or arch for cost or convenience reasons. That's a really bad time to find out that your project can't be made to work there without heroics.
Linux doesn't have an "architecture".
You know what I mean. ARM vs x86-64 -and- macOS API vs Linux API.
And yes, they are different even at the user end on the shell.
All of our production Linux systems are running on Graviton these days, i.e. they’re arm64.
Your production is not going to be the same as everyone else's. It's also not going to be the ideal for everyone else's, or even possible for everyone else's.
The differences between ARM and x86 are probably less relevant for the majority of server-side development than API and admin interface differences.
In practice, anyone seriously developing Linux software on either macOS or Windows is using VMs or containers running the actual Linux kernel, at least for testing, and the difference is that Microsoft has put far more effort into integrating specific support for these things into the OS.
Indeed.
I just wonder if macOS will stop being UNIX like.
That is, whilst it still has home brew and a BSD core it’s great. If that goes away it’s no longer a viable alternative to Linux.
I've been a software engineer for 25 years, doing Linux stuff at startups and big companies (the biggest even). In all my time as a software engineer, I've seen maybe 3 people who didn't use a MacBook Pro for work. Apple makes the bulk of its money from tech companies and schools and they cater very well to both. If it stops being Unix-like, they lose the thing they make the most money from. They are smarter than that.
I don't think apple makes the bulk from professionals at all, the iphone is their flagship product and their laptop line has been expanding towards casual markets with budget models.
Right but in this thread it is pretty clear we are talking about the money they make from MacOS.
They don't make any money on macOS anymore. You get it preinstalled on their computers, you can't buy it separately, you can't install it on other computers, and major upgrades are free.
It is a part of the computer that people pay for. This is like saying they don't get any money from Apple Silicon because its already installed on the motherboard.
The money they make from MacOS is a footnote compared to the money they make from phone hardware, the app store transaction tax, and ads. To a first approximation, the only reason that Apple cares about MacOS is so that people can make iOS apps.
This is a poor approximation, as there would be no need for such an extensive Mac product lineup if this were true. The Mac mini and one laptop product line with two or three sizes would be more than sufficient, and continuing development of first-party Mac applications like Logic and FCP would serve little purpose.
Backend developers are already conditioned to use Linux VMs when developing in Mac OS.
And so are developers on Linux. 99.5% of your backend stuff will run just fine on macOS without any modification, but it's been a good practice for a long time now to run stuff in containers (Docker/OrbStack/podman/etc.) in order to have a reproducible environment free of contamination. My development process in macOS is basically no different than it was on Linux.
I bet you are located in US.
You’re in a bubble. Windows is still huge, especially in middling companies that dictate it and standard HP/Dell/Lenovo hardware for all 3k staff.
It’s insanely common.
His point isn’t that it’s common, it’s that a unix-like environment is a key selling point.
Given that Windows made WSL in an attempt to capture developer mindshare, that tends to support his comment
You still end up in uncanny valley often enough, with commands that are missing, or working unexpectedly differently. It often feels like macOS could be made so much better for developers, but Apple just doesn't care because people buy their devices anyway.
It’s not that. It’s that their lawyers won’t let the engineering side distribute gnu tools. Period.
At Apple, if you even use GPL tools in your workflow you have to seek approval, and most often there’s pushback of “why won’t this (alternative that isn’t GPL) work ?”
Their lawyers aren’t stupid, they understand the GPL and its limits, but they’re simply doing a risk assessment- which one is less risky, the GPL variant or the BSD. For a corporation, that’s generally BSD.
The problem is that being a developer is not a synonymous with UNIX.
In deeply saddens me to think that there is a developer who has not installed gnutils and put them earlier in the PATH.
The remaining differences are related more to systems stuff - managing daemons with launchd for example. These aren't really a distraction day-to-day.
It really is that simple. No different from a BSD or even a non-GNU (busybox, etc.) Linux distribution. If you like GNU tools, use them.
It’s a computer. I can make a computer go beep if I want, that is not the issue.
The fact that someone who didn’t grow up at the time when open source was an idealistic concept instead of free support to corporations needs to learn about the gnutils and how to install them with homebrew is what makes me sad.
Why do we seriously not have a command-line package manager on macOS yet? Windows has one by now. It’s just sad to me that you need a manual checklist of post-setup steps to turn a Mac into a useful machine for software development.
I don't think you have to grow up in some idyllic era that never existed. Its more like you type 'ls', notice that its total crap, and google it.
The point I was making was that knowing what GNU means in the first place probably requires some cultural background that many people lack, especially younger ones.
Right, and the point I'm making is that you can learn this from Google once you notice there is a difference from how common commands work on Linux and MacOS. You don't need to know about GNU, you just have to wonder why its different.
It already feels a bit like it's two separate operating systems on one machine. It's still usable, but I am starting to notice odd behaviours. Files created in the terminal not showing up in the UI, there seems to be no notification from the filesystem to Finder, informing it that the terminal has created a file.
Developers and operations people are already starting to move to Linux. More and more I see colleague either switching to Linux, or have a mac laptop for administrative tasks and then a Linux workstation, or VMs, where they do their actual work.
> Developers and operations people are already starting to move to Linux.
I’ve been in this industry for a long time now. Linux always had more credibility among devs and ops folk. This “starting to move” view is weird.
My view is that OS X was acceptable by these teams because it was close enough to Linux and corporate could deal with it.
When I worked in corporate IT Linux was simply not an option for a primary workstation because there was no standard configuration or management tooling that made everyone happy. Macs were an easy compromise.
I personally don’t see macos anyhow competing with Linux or to be anyhow comparable to Linux in each others sweat points. linux dominated server side, so be its fair victory but it’s continually shit kind of clone of many things done in MacOs desktop experience. It just kept cloning Apple since forever to repeat a glimpse of that experience even during Next times with WindowMaker and then with many incarnations of modern desktop systems to compare with OSX and MacOs continually and in that direction. Linux is open, it’s different, that comes with value but still a little handicapped brother to MacOS desktop experience with continually f*up fundamentals even if you include wayland as the base. So is MacOs in servers but there Apple just resigned last year and stopped pretending they have servers. Both have only one thing in common, shell with base posix tools. Nothing else. And none are as open as original idea for Unix as this idea is long dead and linux tries to make Stallman’s wet dream about GNU system come true as his own kernel implementation did not move forward much it at all since mid 80s.. that’s the only UNIX reality that matters.. rest is bureaucracy and 5000 pages of POSIX standard nobody cares about as this is more about C libraries than kernel’s internals.
> Files created in the terminal not showing up in the UI
You might wanna look into that because that’s not how it works at all. I frequently switch between terminal and GUI apps and have not once noticed Finder failing to catch up with whatever it is I’m doing in the terminal.
Strange, because I have the same issue on two different machines. It doesn't happen all the time, but frequently enough that I assumed that Finder does some re-scan every now and then (or when you open a new Finder window).
Microsoft just shipped a full-fledged first class Linux container runtime as part of Windows[1]. I don’t think it even made front page of HN, which shows how far windows has fallen as a developer environment, but it is absolutely something Apple should be offering as a first class capability on OS X. The compatibility of the host OS file system with being mounted into docker images makes it a better environment for running such things.
[1] https://blogs.windows.com/windowsdeveloper/2026/09/29/wsl-co...
https://github.com/apple/container
Well… that’s handy.
Has it really, though? Because outside the HN bubble, Windows still seems to be the most common developer environment for most things that don't specifically target Linux or Apple platforms, and a popular option even then (e.g., in game dev).
Game and app developers certainly not.
In some alternative dimension Ternus decides to realize the full potential of the Mach kernel by embracing Hurd in place of XNU. Users are discouraged because the new system is not enough like GNU/Linux.
I'm suspecting some forces at Apple would be perfectly content with ripping most of the BSD core and the assorted CLI out and just have Linux containers spawned in VMs, WSL2-style.
Of course they were, even NeXTSTEP was designed to be compatible with UNIX only to compete with UNIX workstations like those from Sun.
Neither Apple nor NeXT had a UNIX culture, and efforts like A/UX and mkLinux were never that much serious.
Had they acquired Be, BeOS was even less UNIXy than NeXTSTEP.
Its called colima and its excellent.
https://colima.run/
and they have a first-party one now as well
https://github.com/apple/container
I haven't tried it. colima also simplifies linux VMs which is more of an analog to WSL2 than just running containers. It has really nice integration with Incus as well, if you like persistent system containers.
I also use colima mostly, it‘s great! (the Apple container thing de facto requires macos 26+)
would be awesome
What would that going away look like?
Swift on Mach
yeah I guess there isn't really much to move to... a new custom Kernel and Userspace? extremely unlikely - I guess it's here to stay, despite not being formally Unix.
It's distinctly problematic there unfortunately. Particularly the moment you add any UI toolkits to it. I've had so many problems with stuff that uses Qt because Qt takes a while to catch up with things Apple broke inside their Cocoa internals. Very irritating platform to work on.
Edit: love how I get downvoted for facts?! They literally broke Cocoa so it was throwing hopeless useless exceptions at the bottom of the stack when they changed the native file open boxes to run in another process. Two bits of software I use couldn't raise an open file dialog window any more.
MacOS 26 is still listed: https://www.opengroup.org//openbrand/register/xy.htm
Was it delisted from a different “product standard”, or is this submission about macOS 27 not being listed?
I see macOS 26 listed under the Unix 03 standard. Was macOS 27 listed and then removed? The submission title + site contents combined do not give enough info to assess what exactly was silently removed.
macOS was listed on the main register (the link in this submission).
It was Tahoe, it’s since been removed.
The UNIX03 page still lists it, but I believe that’s a mistake.
macOS has been removed from the main register/list.
macOS is still very much registered: https://www.opengroup.org/openbrand/register/apple.htm
The index page seems to only list the status of current OS versions.
Perhaps Golden Gate simply hasn't passed certification yet? It's less than a month old.
macOS Tahoe was certified on launch (September 14th 2025)
https://news.ycombinator.com/item?id=45238930
Yes, that is interesting and certainly lends credence to the OP’s interpretation.
The this is much ado about nothing. Every single entry on the page you linked goes to its product page with the exact Unix standard it is certified as. Once you select a filter, you cannot get back to unfiltered list without the back button on the browser.
This is just a site rendering issue. Rather than silently removed, it's more like some bug was introduced. macOS 26 is still Unix 03 certified.
The registry of remaining products is a list of irrelevant operating systems hardly anyone uses anymore.
Why would anyone care about what the Open Group has to say in this day and age? Is anyone actually still using SCO or AIX any more?
I never quite understood what the point of this was beyond marketing. Linux is also not listed probably because no one ever paid to have it listed
Apparently it was for legal reasons. Apple was sued by the Open Group for describing Mac OS X as Unix® so they decided it was cheaper to bring it up to spec rather than to fight the lawsuit.
https://retrocomputing.stackexchange.com/questions/27095/why...
https://www.quora.com/What-goes-into-making-an-OS-to-be-Unix...
It is specific Linux distributions that would be Unix-certified. Huawei had one; not sure if it has ever been on this page.
Enterpise espeically banking need standard and certification for reliability thats why , also certain Linux distro had certified before from China based on RHEL.
This is UNIX 03 certified OS with OSS alternatives from I gathered on internet :
- Apple OS X 10.7 - Apple macOS 26 , provide OSS Darwin 9 - Darwin 26
- Oracle Solaris 10 / 11 , provide OSS OpenSolais , then Illumos
- EulerOS 2.0 , based on RedHat Enterprise Linux / RHEL 7 and 8
- Inspur K-UX 2.0 , based on RedHat Enterprise Linux / RHEL 5
- Inspur K-UX 3.0 , based on RedHat Enterprise Linux / RHEL 7
Enterprise. Checklists.
Linux can’t be listed, because Linux is not an operating system. It’s just a kernel. Unix specifies a whole operating system, which includes things like libc, cat, sh etc.
At best a distro could be certified. But that certification would not automatically extend to other distros.
It was a legal problem, and an interesting story: https://www.quora.com/What-goes-into-making-an-OS-to-be-Unix...
And Gnu’s Not UNIX.
It would be marvelous to see GNU/Linux certified as a UNIX specifically with rms’s preferred GNU/Linux as the name.
They could even just call it GNU is now UNIX.
It was Stallman who came up with the name POSIX by the way.
IIRC there were some UNIX Linux distributions in the past but the certification wasn’t renewed
It appears here https://www.opengroup.org//openbrand/register/xy.htm
Maybe it’s time to come out with a new standard that supersedes POSIX and Unix cert?
Standards are useful and the fact that these have lasted this long is IMHO evidence of that
HN thread, 150+ comments:
The story behind macOS UNIX certification.
https://news.ycombinator.com/item?id=29984016
It saddens me to think of all the CPU cycles spent on hosting online discussions that mention the fact that MacOS officially licenses the UNIX brand.
Perhaps Apple decided to get out of the way and let IBM and SCO duke it out on that page ;-)
It could be that macOS 27 never got Unix certified. Wayback Machine on Oct 7th only shows macOS 26 being Unix certified.
https://web.archive.org/web/20261007103902/https://www.openg...
27 wasn’t certified and 26 was listed but is now removed.
From that Wayback page, it looks like only one version of macOS is certified at any one time: the latest version. Since macOS Golden Gate was only recently released, perhaps it's a process blip and we'll see Golden Gate listed soon.
Nope, Sequoia and Tahoe both remain registered: https://www.opengroup.org/openbrand/register/apple.htm
26 is in UNIX 03, if you use the pulldown
I won't be surprised if you will have to boot into recovery, disable SIP, come back to user-space and run those unsafe 'ls' and 'cat' commands you were trying to live dangerously with on '~/Library', and then go back to recovery again to renable SIP to stay safe. You may also have to do that to install every software you want to install and use on your (is it?) mac other than the ones that are from companies that had tied up with and signed Apple's USA certificaiton (i.e User Safety Alliance™; involving non-publicly disclosed deals), or from the smaller devs who were not small enough and could pay a few thousand dollars annually and sent Apple 3 kidneys annually to publish softwares with very reduced scope and access on the device/OS. The data transfer between your mac and those app endpoints will be so protected that even your own self-destructive hands and insufficient intellect won't be able to gather what is happening beneath the Apple's hardware hardcoded encryption. All for safety beyond the UNIX way. So not all surprising.
Except you don't.
Is this “make shit up” day, or something ?
> make shit up
When it's about the fruit company, is there a difference? Unless it's for the eyes of the beholden i.e., le iFans.
oh no! security measures! scary!
They are, when used against the user.
"Silently removed" meaning Apple probably did not bother going for certification of macOS 27.
And I'm not sure why it would be non-silently/loudly removed: is there an expectation of a press release or weblog post about non-certification?
I could see this being corporate incompetence or a genuine deviation. I wonder which one it is.
Better for both sides. They clearly have different visions for what an OS should do.
What? The Open Group has no vision for what an OS should do, it simply writes standards describing what implementations are already doing.
And does this have any actual impact on either the OS itself or its users?
well not specifically, but directionally could mean less adherence to a UNIX like environment.
When you're small, you need the certificates and badges others give you to be seen and be validated. I really don't think anyone needs to become familiar with Apple or macOS and that any of these certificates now matter a tiny amount to a multi trillion dollar corporation.
Given the amount and volume of software that mac has, the fact that almost all new interesting stuff are released for mac first or even mac alone, I also don't think it needs to attach itself to bigger names for platforms.
I think the financial burden of Ubuntu Mobile, Unity 8, and Mir; and the immediate rise of docker and WSL made canonical fully shift to server, so much so that their website no longer is about a better os for people, but what can it do for your cloud. Other distros also followed its path and Linus became all in on servers and IoT. I see windows as the biggest pile of trash in the world. Infinitely inconsistent, buggy, patched worked, visionless and rotting. Honestly that is one piece of software that is worse that AI slop.
And so what is there for Apple to compete with honestly? Haiku? Solaris?
> I see windows as the biggest pile of trash in the world.
I mean I don't disagree with that, but you're in dire need of a reality check wrt Apple's dominance
It's not even the most used OS. It's userbase has certainly grown over the last 20 years, but it's still at <30% on desktop...
There are however some demographics in which it's more represented, and that's probably just such a bubble where you're coming from
Usage and quality are not particularly correlated, though.
I never said they were?
And if you're honest, macOS has sadly dropped in quality too...
But the reason why I wrote my comment was just that you gave off the feeling that you consider macOS to be the only relevant desktop operating system, which seemed like a very strange view to have given the reality of it's userbase.
This doesn't mean anything. The official Unix registry is completely irrelevant to the modern world. Nobody uses OSX pretending it's compatible with Solaris. Like Microsoft, Apple only cared about this certification because it used to be a checkbox on certain government procurement tenders.
unix registry silently removed from relevance.
linux compatibility is way more relevant now.
Solaris as well, apparently
They used to marketing Mac OS X around Unix, but not anymore.
At that time they were trying to lure people from other Unixen such as Solaris for workstation use. Not any more.
Unix? What's this?
This is inevitable, there is no escaping it.
How is SCO still a thing?
It now looks like a museum of obsolete operating systems.
Xnu’s Not Unix!
Who is running Xinu today?
It'd matter if this certification came with an extensive test suite guaranteeing some degree of compliance. Instead, you have macOS defaulting to an antediluvian bash as /bin/sh full of ridiculous bugs like this:
Note that they even ship dash as a much better /bin/sh...These days it defaults to zsh instead of bash. The shipped bash is ancient due to (I believe) being last version released as GPL-2.0.
In many ways, macOS is kind of driving towards irrelevance.
Apple wants it to be more like iOS (so they can control what you do on it) while users want a normal computer they can do computer things on without it spewing ads or applying political pressure when someone tries to hold Apple accountable (e.g. the EU trying to make Apple stop abusing their market position).
> In many ways, macOS is kind of driving towards irrelevance.
You mean the second most used desktop OS with about 15% of the global consumer OS market? About 30% of consumer desktops in the US alone? That “irrelevant” macOS?
Indeed it is one in the same. The middle layer of MacOS has been rotting for years, the introduction of gatekeeper and SIP has made downloading and running programs or observing your system a pain. Software developers are being pushed toward App models and many other examples exist. For people who simply need a computer that works MacOS is moving futher away from that goal with every release.