There isn't much downside, but it probably involves a small amount of money (paid for the certification) and it means spending time making sure that everything remains 100% within spec. There's lots of little edge cases where BSDs differ from the spec and it means that Apple needs to take care not to drift from the spec.

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al_borland 3 days ago | parent | next [-]

Apple remaining in spec sounds like a good thing from a compatibility point of view.

Am I missing something? I’m not sure why it’s coming off like people are complaining about this?

	▲	Analemma_ 3 days ago \| parent [-]
		It’s a spec that doesn’t really matter in practice. Like some other comments said, Linux, BSD and Solaris are “Unix but not Unix(tm)”, and nobody cares.

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jorams 2 days ago | parent | prev [-]

As pointed out by amiga386 both here[1] and in earlier posts, macOS is not actually compliant with the Unix spec and never has been. This has apparently not been a hindrance for the certification of every single non-compliant version. Unix certification for Apple might not involve anything other than payment.

[1]: https://news.ycombinator.com/item?id=45239534