Apple/macOS removed from official Unix registry
opengroup.org210 points by john_alan 10 hours ago
210 points by john_alan 10 hours ago
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...
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=...
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?
If I remember correctly, two Linux variants were on the list at one time.
They were:
Inspur K-UX (expired on 3 February 2019)
Huawei EulerOS (expired in September 2022)
https://en.wikipedia.org/wiki/Inspur_K-UX
https://en.wikipedia.org/wiki/EulerOS
These were both based on Red Hat.
Huawei managed to get their RHEL fork (EulerOS) UNIX certified. However their certificate expired (probably due to sanctions?)
So legally at one point a Linux was Unix.
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.
Yup. And why is UUCP still in there? I mean, yes I have used it, so far back that the docs were written in Quenya. But requiring it now?
Btw, MacOS 27 (the current version) still has UUCP.
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.
For now SIP can be disabled (on mac, not of course on iOS that is completely closed) but I wonder for how much. It's clear that the desire of Apple is to make macOS a closed system like iOS, installing third party software outside the AppStore is more and more difficult, with Gatekeeper that asks you to enter the system settings and warn about "potential insecure stuff" each time you want to run an application downloaded from the internet not signed by Apple (yes I know that if you disable SIP you can get rid of Gatekeeper as well).
I think that piece by piece Apple wants to go into direction of making macOS just a desktop version of iOS, that is closed and impossible to modify. They will use of course security as an excuse, the practical thing is that with iOS they succeeded because they went to the market with an OS that was already closed, but making users accept that in new version downloading a software from the internet and installing it it's no longer possible takes time. But they are getting there soon to me.
Also worth keeping in mind that macOS is intended for use with commercial third party software that’s repeatedly been proven untrustworthy, doing things like prodding system internals and installing dodgy kernel extensions where neither is warranted.
SIP is as much defense from the likes of Adobe and Google as it is from more traditional malware.
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.
Tahoe:
https://www.opengroup.org//openbrand/register/xy.htm
I imagine that the cert will be listed for Golden Gate soon.
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.
If you want to start a new trend, you should do this with FIPS 140, which has to be recertified every year. "Apple crypto is no longer FIPS certified"
Even better, last year's 26 releases are still undergoing the process.
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.
It is strange now, but Apple made a big deal of marketing it as UNIX back then. Like at the front-page of apple.com. UNIX had a good reputation as solid and serious.
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.
If true, a better title would be "macOS is no longer UNIX certified".
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.
You're mixing it up with NT's "personalities" of which OS/2 was the primary target at the time. UNIX was purely for FIPS contracts
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.
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.
Why is the client OS important?
We just ssh/http to the real Linux machine that runs our things anyway. These days with commoditized VPN and symmetric residential Gigabit internet, that Linux box does not have to be in the cloud either (specially with LLMs guiding the sysadmin tasks).
Any thin client with a browser, an ssh client and an internet connection will do the job.
Less things that can go wrong.
Sometimes just having a local machine that you can do everything on is what you need
"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 is still there.
For those that don't know how to use a filter drop down, check UNIX 03 version.
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.
Shit. Gonna have to make MacOS the top priority so osjdosnxkwjdk centers my software in their mind.
I didn't realize macOS was actually certified UNIX since 2007, thought it was just marketing.
Is this Apple just not wanting to pay for the certification anymore or does it actually change anything for us devs?
There's a long story behind it, but Apple started saying that Mac OS X was UNIX, but UNIX was a trademark. So Apple decided that they either needed to alter OS X to conform to UNIX standards or buy the trademark. They chose the former.
> Is this Apple just not wanting to pay for the certification anymore or does it actually change anything for us devs?
It's probably not about paying and more about tiny differences. Will it change anything for you? Almost certainly not. In fact, it might make things better for you. If anything, Apple's adherence to the UNIX spec can sometimes mean subtle differences in tools between macOS and BSD/Linux. Do you want things like grep or sed that conform to the UNIX spec or that work like grep and sed work in the real world?
And these differences are often small edge cases that don't come up much, but a spec is a spec.
The money is inconsequential for Apple, but at this point it probably makes more sense to just stop calling it UNIX and not worry about shipping a version of a tool exactly meets the UNIX spec - it'd be more useful for their users if it matched the behavior on Linux/BSD.
Thanks for explaining.
That grep/sed difference on mac caused me issues so many times, always thought it was just Apple doing their own thing. I didn't realize it was a spec thing.
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.
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)
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.
macOS is still very much registered: https://www.opengroup.org/openbrand/register/apple.htm
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).
Does your company care about compatibility with UNIX® infrastructure or that it's compatible with Linux/BSD infrastructure?
People care that macOS has a lot of compatibility with Linux/BSD, but most don't care that it's UNIX® - just as people don't care that Linux/BSD aren't UNIX® compatible. Yes, Linux/BSD are very similar to UNIX® and mostly compatible, but they don't conform to the specification.
You (probably) don't care about the UNIX® specification. You care that your MacBook has good compatibility with Linux/BSD infrastructure. Many people assume that Linux/BSD are UNIX® and just don't pay for certification. They aren't UNIX® compatible. They are extremely similar, but they don't follow the spec 100%.
Sorry for putting the ® everywhere, but people often use UNIX when they mean nix-like operating systems and when we're talking about whether people care about macOS as a UNIX® or not, it matters whether were saying "people want macOS to be UNIX®" vs "people want macOS to have good compatibility with nix-like operating systems such as Linux and BSD like it does today." People usually care a lot about the latter and not about the former.
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.
Why not develop on the same env? I mean if I were you my macbook would just be an ssh client to the x86-64 dev box that emulates the target env. So many advantages to offshoring the compute to some server (my preference is your own hardware ofc but theres flexibility in cloud). For one, the laptop is not getting hot just being a dummy ssh client. I can spill a coffee on it during a build and nothing happens, build goes on and I am just out a thin client I can replace immediately with anything with ssh installed, my cellphone included if I am so desperate.
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.
They absolutely do not want their developers to mass migrate to another platform. Walk into any SF startup and you'll see 100% Mac laptops, except for the Finance guy who needs Excel on Windows, and that one dev who insists on Linux, and all those devs build webpages that work on Safari, and iOS apps before they (maybe) eventually get around to making an Android app.
Apple is highly incentivized to keep devs on Macs, even if it turned out to be a loss leader for them.
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.
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.
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.