[TUHS] First Unix-like OSes not derived from AT&T code?

[Ronald Natalie]

The screen was a IBM 6091, the IBM rebrand of a Sony tube.   We had 
serial number 2 in our office.     Amusingly, the RT we had came all 
locked up,. but I found that turning the key to the wrehch position and 
booting it got me a maintenance shell that on one option invoked more 
that I could shell escape out of to get.a root shell.    There haven’t 
been too many UNIX systems I’ve not been able to get into.   The 
funniest was showing some guy in the Pentagon out to bust out of the 
SunTools screen lock.

IBM made a big thing about telling how the thing had a 24bit 
framebuffer, but the *&@$&* X Server on it only had eight bit visuals.   
  I did a port of our code base to it because that was what I did back 
then (we had the premier intelligence image processing system that ran 
on just about any UNIX system out there:   Sun (Spark and 68K), MIPS 
(both the MIPS workstation and the DEC SPIM), SGI, Ardent, Stellar, 
MassPar, Various 386 things (of which I was fond of the MultibusII 
systems), HP, DEC Alpha, etc….  We even ran on Apollo Domain and some of 
the early NT for both the PC and the iTanic.