No filesystem permission discussion would be complete without mentioning United States Patent US 4135240.

Set user ID!   
setuid 
setgid

(Hmmmm, I believe there is an Et al. missing after the inventors name, Dennis Ritchie, on the face of this patent, right?)

Bill Corcoran 



On Jul 31, 2019, at 1:18 PM, Warner Losh <imp@bsdimp.com> wrote:



On Wed, Jul 31, 2019, 12:09 PM Toby Thain <toby@telegraphics.com.au> wrote:
On 2019-07-31 5:59 a.m., Stephan Han. wrote:
> Hello Unix enthusiasts.
>
> I'd like to know who or the group of people behind implementing this
> filesystem permission system.
> Since we are using this system for nearly 40 years and it addresses all
> the aspects of the permission matter without any hustle.

It may not address "all aspects" since it has been necessary for some
purposes to extend the permission model substantially over time, such as
ACLs, SELinux, etc.

He did say they solved the problem without hassle. All those other things introduced hassle.  :) There is also all the various capacity frameworks to self limit what you are allowed to do as any easy to administer exploits...

Warner

--Toby


> I'm inspired to know who/how came up with this theory?
> Also if it derived from somewhere else or If there's an origin story
> about this, it would be worth to share.
>
> Cheers.
> Stephan
>
> --
> No When