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I am looking for specific details as to why isn't GNU/Linux currently SUS (Single UNIX Specification) v3 or even better SUS v4 compliant?

What application APIs and user utilities does it miss or implement in a non-SUS compliant way?

phuclv
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Shinnok
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2 Answers2

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To get a certification you need to pay, and it's actually really expensive. That's why BSD-like and GNU/Linux OS vendors don't apply for it.

So there isn't even a reason to check whether GNU/Linux is compliant or not.

http://en.wikipedia.org/wiki/Single_UNIX_Specification#Non-registered_Unix-like_systems

Most of all, the GNU/Linux distribution follows the Linux Standard Base, which is free of charge, and recognized by almost all Linux vendors.

http://en.wikipedia.org/wiki/Linux_Standard_Base


Edit: As my answer is not completely correct, I'll add the @vonbrand comments:

Linus (and people involved in the development of other parts of Linux distributions) follow the pragmatic guideline to make it as close to POSIX as is worthwhile. There are parts of POSIX (like the (in)famous STREAMS) that are ill-conceived, impossible to implement efficiently, or just codification of historic relics that should be replaced by something better.

... therefore, does it make it harder to obtain a certification?

Sure. POSIX mandates some interface, which Linux just won't ever have. Case closed.

ctrl-alt-delor
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tmow
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    I wonder why Red Hat and the like never try to get certified. I mean I know why Debian doesn't. – xenoterracide Jan 20 '11 at 13:24
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    The point is, why to spend money for a certification when customers don't ask for it? – tmow Jan 20 '11 at 16:42
  • It is not just about money. It would require fairly major changes to Red Hat and the other GNU/Linux distributions to become UNIX-compliant. – fpmurphy Jun 05 '11 at 14:10
  • Yes, @fpmurphy , sure and it actually costs a lot of money. In fact the cost is not limited to the certification itself, but also on the effort of being compliant... – tmow Jun 06 '11 at 12:00
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    Linus (and people involved in the development of other parts of Linux distributions) follow the pragmatic guideline to make it as close to POSIX as is worthwhile. There are parts of POSIX (like the (in)famous STREAMS) that are ill-conceived, impossible to implement efficiently, or just codification of historic relics that should be replaced by something better. – vonbrand Jan 23 '13 at 15:01
  • @vonbrand this makes harder to obtain a certification? – tmow Jan 24 '13 at 10:28
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    @tmow, sure. POSIX mandates some interface, which Linux just won't ever have. Case closed. – vonbrand Jan 24 '13 at 10:48
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    @vonbrand thx. added your comments in the answer – tmow Jan 24 '13 at 12:31
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    Your answer is wrong: The Opengroup made a special contract for Linux some years ago and settled the price to one Dollar. Approx. 18 months ago, I did some negotiations with the Austin Group and this resulted in a general availability for free for interested OSS projects. – schily Sep 05 '18 at 12:56
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    @schily the answer was written a long time before that offer happened. Perhaps you could add your own answer recounting those events! – Stephen Kitt Sep 05 '18 at 13:07
  • This is not corret as what I mentioned happened in 2005 – schily Sep 05 '18 at 13:36
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    @vonbrand can you elaborate what interfaces are those? Since there are actually Linux distros that got the certification since 2012 – phuclv Oct 23 '18 at 03:58
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First it's simply because there's little incentive doing that. Users don't care whether a distro is Unix-certified or not. As long as it fits their purposes they'll use it. Moreover the certification costs money, and getting it doesn't make sure that the distro will get more money for development and maintenance

However if you look at Single UNIX Specification's Currently Registered UNIX systems or POSIX-certified systems you'll see 2 Linux distros in the list

The Open Group official register of UNIX Certified Products also confirms that they conform to UNIX 03 Product Standard A.K.A. SUS v3

Is there a Linux distro that's UNIX certified?

phuclv
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