Assorted bins and libs, why?

[G.TOMASEVICH]

In reference to existence of /bin, /usr/bin, etc., I can see conflicting
considerations:
One wants to have publicly available user written commands without an
extremely long PATH.  We have /bin, /usr/bin, and /usr/jerq/bin, plus any
private bin that a user has.  The directories /usr/bin and /usr/lib have
general write permission, but not /bin or /lib.  It just occurred to me
that this is a security hole.  Maybe everything that comes with /usr/bin
and /usr/lib should be moved into /bin and /lib, assuming a large root
filesystem.  Then we have the path problem someone mentioned.
On the other hand, if there are many commands in one directory, then it
could have more than ten blocks, which causes searching to be slow when
the indirectly addressed part of the directory must be searched.
This all assumes filesystem size is not an issue.
	George Tomasevich, AT&T Bell Laboratories