[TUHS] The origin of /home

[Jeremy C. Reed]

On Fri, 28 Sep 2018, Tony Finch wrote:

> > I intentionally eschew /home on a few systems. 4.4BSD had a convention of
> > placing user home directories in /a, /b, etc. 4.4BSD-Lite also had
> > /var/users. Both of which I occasionally use.
> 
> The /a convention seems to go back quite a long way. I was looking through
> old password files to see where the home directories were, e.g.
> 
> https://www.tuhs.org/cgi-bin/utree.pl?file=4.1cBSD/etc/passwd
> 
> has a lot of /a/guest whereas 4.3BSD has /usr/guest

And the 4.3BSD docs show the /a, /b, /c
https://www.tuhs.org/cgi-bin/utree.pl?file=4.3BSD/usr/man/man8/adduser.8

  Traditionally, user files live on a file system different from /usr.
  Typically the user file systems are mounted on a directories in the
  root named sequentially starting from from the beginning of the
  alphabet, eg /a, /b, /c, etc.  On each such file system there are
  subdirectories there for each group of users, i.e.: ``/a/staff'' and
  ``/b/prof''.  This is not strictly necessary but keeps the number of
  files in the top level directories reasonably small.

By the way, Berkeley early on (at time of the first Berkeley tape) had a 
separate /etc/htmp database to list user's home (or alternate home) 
directories (so didn't have to search "large password files" which were 
"unreasonably slow") and terminal type (part of the precursor to 
termcap). The home's then were like /mnt/staff/mosher, 
/mnt/quals/katseff, /mnt/chuck/, /mnt/jeff. Joy's early 2BSD csh docs 
show /mnt/bill and /usr/ken as "home directory" examples. And 3BSD's 
adduser docs show:

  Traditionally, user files live on the file system /mnt and there are
  subdirectories there for each group of users, i.e.: 
  ``/mnt/staff'' and ``/mnt/prof''.

This got changed for 4BSD (4.0BSD):

  Traditionally, user files live on a file system which has the machines 
  single letter net(1) address as the first of two characters.  Thus on 
  the Berkeley CS Department VAX, whose Berknet address is ``csvax'' 
  abbreviated ``v'' the user file systems are mounted on ``/va'',
  ``/vb'', etc.  On each such filesystem there are subdirectories 
  there for each group of users, i.e.: ``/va/staff'' and ``/vb/prof''.  
  This is not strictly necessary but keeps the number of files in the 
  top level directories reasonably small.

(where net(1) is Schmidt's Berkeley Network)

As for 4.3BSD the only reference I find of /home is from the aardvark 
game from Mike Urban of UCLA (/home/urban). (That is the earliest 
reference of a directory called /home/ I found.)