There are really less than ½ dozen "Unix" OSes. 99% of them are variants on a theme.
#1
There's AT&T UNIX, including System V. That includes UnixWare, SCO OpenServer, Solaris and OpenSolarism and HP-UX .
Are any other SysV descendants still on sale?
#2
There's BSD.
That covers 4 FOSS BSDs I can think of offhand, plus AFAIK IBM AIX is derived from BSD. Anything else commercial?
#3
There's macOS. XNU is based on Mach. I can't think of any other current Mach derivatives. The HURD if you're generous.
#4
There's Linux, including Android and ChromeOS.
#5
There's QNX.
#6
There's Minix 3, which now mostly uses the NetBSD userland but has its own kernel.
Is that it?
Any other self-hosting, native on bare metal, Unix-like OSes?
I know a few things can emulate UNIX well enough to pass the Open Group tests if they cared to: IBM z/OS, OpenVMS. MS has 2: NT's POSIX environment, plus WSL1. But their native OS design is not Unix-like nor meant to be Unix-compatible.
Plan 9 isn't a UNIX although it is the one true direct offspring of UNIX. And Inferno is even less UNIX-like.
Serenity OS is not self-hosting and barely runs on bare metal.
HelenOS and Redox OS are only remotely superficially Unix-like.
Everything else is either dead, or historical and only runs in VMs or on emulators.
AIX is SysV-derived. IBM’s BSD was AOS (long discontinued).
> I know a few things can emulate UNIX well enough to pass the Open Group tests if they cared to:
The Open Group owns the UNIX trademark (they got it from AT&T via Novell), so legally they decide what it means. And they’ve decided it means the standard, and any system which implements the standard (how it does so is irrelevant), passes the test suite, signs the license agreement and pays the fees (which fund maintenance of the standard and tests) is UNIX. By that official definition (the only official definition), z/OS is just as much a UNIX as AIX is.
No problem and thanks for the clarification. FWIW I have been catching up with HN after a fortnight's holiday and I noticed a bunch of incisive and interesting comments from you, for which my thanks and congrats.
Any other SysV derivatives still on sale I haven't mentioned? Not sure I can think of any myself.
Re the UNIX™, yes, I know, and I've written about this a few times myself. Some Register readers got quite incensed with me. :-D
I think my point is clear enough though: if we consider the design and architecture, rather than compatibility, it is easy enough to distinguish Unix-like OSes that do not aspire or attempt Unix-compatibility from non-Unix-like OSes which either are, or are close to or formerly offered but no longer do, Unix compatibility... and I think that's a useful and important distinction.
22. Unix History (levenez.com) 36 points by gandalfff 5 hours ago | flag | hide | 1 comment
What a coincidence
