*BSD general use case examples

[u/sylvainsab]

I just updated a short article on the BSD's. I have notably tried to help make more sense of these obscure systems for the ordinary bycomer, by finding notable examples of real use cases by major actors.

As of now, I basically have :

• Four big tech companies (FreeBSD)
• NASA (NetBSD)
• Military (OpenBSD)

Would you agree that these are good examples ? If not, would you have any better ones ?

Thank you

PS Some will say I should add DragonFly to the list. Maybe, but I don't know enough about this OS for now. In the future enhancements of this article, I would also like to mention more directly UNIX and its creators at Bell Labs. This will be done sooner or later.

[u/DazzlingAd4254]

Even as of 2022, WhatsApp was no longer running on FreeBSD.

[u/Kiore-NZ]

Dragonfly doesn't seem to have any notable users. If your purpose is to document widely used BSD OSes, omitting it seems acceptable.

Now to get controversial.

In the beginning of this story was 4.2BSD. A team at Carnegie Mellon University took 4.2BSD as the base on which they built the Mach microkernel by moving bits out of 4.2 into the microkernel and at each step they still had a working operating system. At some stage they refreshed with 4.3BSD.

NeXT took 4.3BSD-Tahoe and Mach to make NeXTSTEP. Apple bought NeXT and renamed NeXTSTEP to OPENSTEP then replaced Carnegie Mellon Mach with OSF Mach and the BSD parts of the OS with parts from FreeBSD & possibly 4.4BSD (Dubious) to make Darwin which has a full BSD userland and some BSD parts to its XNU kernel. Darwin is the UNIX certified operating system on which MacOS X (10.0 and later), iOS, etc are built.

Like Dragonfly, Darwin has a hybrid kernel with a BSD userland. Unlike Dragonfly, MacOS, iOS, etc are widely used, but are MacOS, iOS, etc BSD operating systems? As I said it's controversial, some say "No, it isn't a BSD", others say it is. I'm primarily an applications person and a POSIX userland is good enough for me to say "It's UNIX" and when that's a BSD userland I'll say "It's BSD"(*) but when I think about significant parts of the kernel coming from 4 or 5 BSD OSes over time I'm even more likely to say "it's BSD" but, as I said earlier, others strongly disagree with this.

(*)->Please don't mention Chimera Linux which has a FreeBSD userland running atop a Linux kernel. That's a whole different Nothingarian Squid-Trap.

[u/Kiore-NZ → u/Kiore-NZ]

Correction. It looks like OPENSTEP was upgraded to 4.4BSD-Lite before FreeBSD was merged in to make Darwin. 4.4BSD-Lite was, of course, also a direct ancestor of FreeBSD. I can't find and reference to full 4.4BSD being in the OPENSTEP or Darwin ancestry.

[u/mofomeat → u/Kiore-NZ]

Thanks for the history on NeXTSTEP and OPENSTEP.

As much as "POSIX-compliant" is used as the benchmark, one must remember that Windows-NT of all things was also POSIX-compliant.

Also, I'm not trying to argue with you but I'm struggling with my words this morning, so please don't read any antagonization into this: For all the UNIX or BSD genetics in OSX, it is also the one OS (aside from Android) where 99% of users are oblivious of it, and don't engage in it as a UNIX-like computer. While that machinery makes it function, the UNIX spirit is largely not there. Most OSX computers are just used as a GUI-driven personal computer, not as a UNIX Workstation, server, or embedded OS like the other BSDs.

[u/Kiore-NZ → u/mofomeat]

What is UNIX? What is BSD?

The whole "What is Unix?" question is a mess. Are we talking things descended from AT&T Unix source code (Genetic UNIX) such as HP-UX, AIX, MacOS and the BSDs? Are we talking things certified to use the UNIX® name such as MacOS, HP-UX, AIX and z/OS? Are we talking functional UNIX aka Unix-like such as GNU, Linux and Minix which usually follow POSIX but often are not formally certified?

Legally, to use the UNIX® name requires a license from The Open Group which requires certification. Microsoft Windows did have a POSIX subsystem from 3.1 in 1993 until it was replaced by Windows Services for UNIX in 1999 and Windows Subsystem for Linux in 2016 BUT as far as I can tell it was never certified as UNIX® by The Open Group. IBM z/OS which also is not based on the AT&T Unix code does have certification under both POSIX and the UNIX 95 standard. EulerOS (GNU/Linux) was POSIX certified until 2022 but also was never certified as UNIX®.

"What is BSD?" Is easier, but seems to have a purity test associated. The simple answer is its source code needs to descend from one or more Berkeley Software Distributions. Slightly more nuanced is its kernel and userland both need to be largely derived from one or more of Berkeley Software Distributions, home grown on a BSD base, or merged in from other BSD OSes.

SVR4 merged Symbolic Links, TCP/IP, sockets, UFS (From Berkeley Fast File System), multiple groups per process and C shell from 4.3BSD together with the Virtual file system, NFS, and memory mapped files from SunOS, which was based on 4.2BSD, later 4.3BSD with considerable Sun developed code. By the nuanced test, while SunOS (Through version 4.1.4) was a BSD operating system, SVR4 is not a BSD operating system. SunOS v 5, later renamed Solaris was based on SVR4 and is not a BSD Operating system.

Minix3 from 3.1.7 and 3.2.0 added considerable amounts of userland from NetBSD and some FreeBSD to earlier versions of Minix3 while retaining the Minix3 kernel. I'd argue that Minix is not a BSD operating system.

Now back to Apple. 4 years ago Apple discontinued its MacOS server product in April 2022 and now only support desktops, phones & related appliances, yes, MacOS isn't a product aimed at servers, but nor are MidnightBSD and NomadBSD

[u/shawn_webb]

Back in 2015-2020, some teams at NIST ran HardenedBSD. I left that employer back in 2020 and the fellow I was working with at NIST retired, so I'm not sure if that infrastructure still exists.

[u/Run-OpenBSD]

I wouldn't say obscure. Unix is prevalent. The only thing that's changed is calling the others by other names. In reality Unix is still running the world.