[TUHS] Any oldtimers remember anything about the KS11 on the 11/20?

[Rudi Blom]

Probably already known, but to be sure

Interesting options: MX11 - Memory Extension Option: this enabled the
usage of 128 KW memory (18-bit addressing range); KS11: this option
provided hardware memory protection, which the plain /20 lacked. Both
options were developed by the Digital CSS (Computer Special Systems).
http://hampage.hu/pdp-11/1120.html

PS the page listed below has a very nice picture of the 'two fathers
of UNIX" working on a PDP-11/20
http://hampage.hu/unix/unix1.html