On Thu, Sep 27, 2018 at 11:34 AM Noel Chiappa <jnc@mercury.lcs.mit.edu> wrote:
    > From: Dan Cross

    > particular in sites with lots of users like universities and
    > production-focused corporate groups

The existence of /usr, /usr/bin, /etc, /lib, etc dates back to the Research
group at Bell, so I don't think we can look to these other environments for an
explanation.

Sorry, I was (very) unclear in this point. I was referring to two separate things:

1) Why things were spread out across multiple filesystems (space and/or performance considerations dating from the Bell Labs days), and
2) The notion that rigid structures built in at a very low level would naturally give rise to local naming conventions as "large" sites grew beyond the limitations built into the system. E.g., /udd/u1 etc vs /home vs /usr/users vs /net/somehostname vs /var/users vs whatever. As a concrete example is the use of name-dependent hierarchical home directory paths like "/home/c/r/cross" because one tried to put too many directories into /home (I have actually seen the UFS directory entry limit hit in /home on a machine that had >32k users). Anyway, eventually through whatever accident of history "/home" seems to have won as a de facto standard.

    > "Hmm. Well, we've got space in /usr: create /usr/bin

I seem to recall reading (don't recall where, OTTOMY) an explanation for the
creation of /usr/bin, and I think it was performance related; IIRC the issue
was that they wanted to keep the directory size down (both for disk block
caching, and search time, reasons). Or maybe that was later on, and it was
originally created for 'user-maintained' ancillary programs (another vague
memory)?

I think the latter might be a justification-after-the-fact: /usr as the filesystem containing stuff of interest to the users.

    > The more intriguing possibility from the antiquarian point of view is
    > whether someone coined "/home" and then THAT led to the rise of the "home
    > directory" nomenclature.

My memory is that the term "home directory" predates /home - perhaps on other
OS's such as TOPS-20, but I don't have time to research that. (I did look
quickly in the Multics docs, and it has 'working directory', i.e. current dir
- but it refers to the home dir as 'original WD', i.e. the WD at the time of
login.)

If I recall correctly, the mappings from "users" on TOPS-20 to directories is an injection, but I don't think they used the "home directory" nomenclature.

Certainly the analogy with one's directory as home is clear enough.

        - Dan C.