[OmniOS-discuss] Internal pkg error during a test r151010 to r151014 upgrade

[Chris Siebenmann]

> History lesson: until people could afford to purchase more than one
> disk and before Sun invented the diskless workstation (with shared
> /usr), everything was under /.

 As Richard knows but other people may not, this is ahistorical on
Unix. From almost the beginning[*] Unix had a split between the root
filesystem and the /usr filesystem, based (as far as I understand
it) on the physical disks involved at Bell Labs CSRG on their Unix
machine. This is part of why the split of commands between /bin and
/usr/bin existed for years. Sun's diskless machines did not invent a
split /usr, they just took advantage of existing practice and made it
read-only and shared.

(Even that read-only'ing took some amount of re-engineering, because
of course originally /var did not exist and there was, for example,
/usr/tmp, /usr/spool, /usr/adm, and /usr/log. SunOS created /var and
relocated those via symlinks (and eventually program changes) in order
to make /usr read-only.)

	- cks
[*: Historical evidence available via www.tuhs.org suggests no later
    than the Third Edition in 1973.
]