>From my personal knowledge, having built LFS a few times, though this doesn't compare with other distributions as the purposes of /(root), /usr, /opt, and /usr/local have changed over the years:

/(root) is where boot-time software is to be installed that must be readily available when the system is brought up and init is sent into action.

/usr is where admin system and networked system services are installed. In Linux terms, just about all software is installed here including local system applications and add-on software. in BSD terms, this is where all administrative tools to the OS are installed that do not have the same priority as those needed at boot-time in /(root).

/usr/local is where user installed local packages are installed and ran from. In Linux terms, this directory is rarely used nowadays, but is still part of the FHS guidelines because you can use this directory. In BSD terms any packages from the ports collection are installed here to segregate user installed local applications and packages from the main BSD system.

/opt is where single purpose software that usually is self-contained, such as LibreOffice, Mozilla Firefox, and specialized libraries like QT are kept.

/home was developed to separate non-root user accounts from /root and the core of the system. Usually this is a separate partition usually using a long term storage file system like BtrFS, ZFS, JFS, ReiserFS, etc.

Now this may not be 100% accurate but it is a rough estimate of what these were purposed for.

I could be wrong... but I have been wrong from time to time.

-Jim

> Date: Thu, 30 Apr 2015 08:48:10 +0100
> From: katolaz@???
> To: reisenweber@???
> CC: dng@???
> Subject: Re: [Dng] [dng] vdev status updates
>
> On Thu, Apr 30, 2015 at 01:27:48AM +0200, Joerg Reisenweber wrote:
> > On Wed 29 April 2015 23:46:51 Didier Kryn wrote:
> > > They decided to put them on the second disk which contained user data
> > > and was therefore mounted at /usr
> > AFAIK that's "Unix System Resources" or somesuch, not "User"
> > /j
>
>
> Well, in the first few versions of Research Unix (and I believe at
> least until Version 7, in 1979) /usr was the folder where user home
> directories lived. /home came much later, AFAIK...
>
> My2Cents
>
> KatolaZ
>
> --
> [ Enzo Nicosia aka KatolaZ --- GLUG Catania -- Freaknet Medialab ]
> [ me [at] katolaz.homeunix.net -- http://katolaz.homeunix.net -- ]
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