I learned that Solaris is still used commercially. I remember buying "The OpenSolaris Bible" in 2008. Bad timing.

The key missing context is:

Solaris implemented the core part of the /usr merge 15 years ago already, and completed it with the introduction of Solaris 11

But more generally, Sun had a lot of smart people that cared deeply both about the *NIX Desktop and the general user experience. A trip through the PSARC archives[1] will show that things like the /usr merge were carefully considered and reasoned about. Some of those people are still working on Solaris today, although sadly, I'm no longer one of them.

The Linux and BSD folks should take advantage of the good things that Sun left behind and carry them forward wherever possible.

DISCLAIMER: I'm a former Solaris Principal Software Engineer so slightly biased ;)

[1] https://illumos.org/opensolaris/ARChive/PSARC/

Thank you for your service. Solaris felt more considered and reasoned than AIX and microchannel Linux I was learning in ~95 and so helped me learn more.

Ah, it's awesome you worked there. Thank you for context.

My "bad timing" comment was in reference to Sun getting sold in 2010. As an IT focused college kid, I realized there wasn't much value in learning Solaris system administration. That doesn't mean it didn't have amazing things as an operating system!

I’m also confused why all system supplied data is in /usr instead of say /sys.

Because that potentially allows all distro-supplied files to live under one (eventually read-only) directory.

So, somebody imagined/wished that all distros will switch to /usr/* and them will ship / part ? :> I don't think so. Totally wrong direction.

And init binary in /usr is complete braindeadness...

Also MS behind anything means they are trying to get rid of your options, eg by complicating things into "enterprise level" and keep pushing windows as userware.

But there is other possibility: minimal root that is easy to manage, switch, etc. etc. and rest of the system :)

> But there is other possibility: minimal root that is easy to manage, switch, etc. etc. and rest of the system :)

Yeah, libostree ("git for operating systems binaries") benefits from merging /usr. It might even be a requirement to have merged /usr to be able to use it.

https://en.m.wikipedia.org/wiki/OSTree

> I’m also confused why all system supplied data is in /usr instead of say /sys.

Wasn't that basically a historical accident? IIRC in very early UNIX, "/usr" used to be like the modern "/home", but they happened to have a big disk for that mount and started putting system files there.

The motivation is because systemd is compelling them to change it. Systemd decides how Debian may operate, and decides how users, processes, and files work, not the Debian Technical Committee.

It explicitly says in that link that systemd doesn’t need it and it’s beneficial to non-systemd distros.

That was then, and systemd is mandating it this year.

FDO and systemd(et al) breaking things for everyone else as usual.