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

Tue May 3 13:23:46 CDT 2016

On Tue, 3 May 2016, Al Kossow wrote:

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

Well, but is this not an software abstraction for a non existing
encapsulation feature of the underlying hardware? DGs Extended BASIC
also implemented time sharing without the hardware offering this
feature and probably many other examples exist (Even if you beat
me: Early Windows?)...

If the language does not offer any critical commands, this works
as well as users can not do nasty things.