When did Memory- and IO Protection Emerge (Esp. in Minis)?

[Al Kossow]

On 5/3/16 11:15 AM, Paul Koning wrote:

> Keep in mind that mapping and protection are not required to build a multi-user system.  DEC did timesharing on the PDP-11/20 (RSTS-11) and on the PDP-8 without either.

The SDS-940 is an early small-ish timsharing system that had base-bounds memory protection, circa mid-60s
It was the platform that a lot of early timesharing services used.

TSS/8 used 4K segmentation with protection (memory expansion/timeshare control option)

The early BASIC minicomputer timesharing systems (line 2000TSB) had virtual BASIC machines for each user that swapped.