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

Al Kossow aek at bitsavers.org
Tue May 3 13:46:17 CDT 2016

On 5/3/16 11:23 AM, Erik Baigar wrote:

> Well, but is this not an software abstraction for a non existing
> encapsulation feature of the underlying hardware?

Yes, or you can design a language with array bounds checking and no
arbitrary pointer dereferencing. Burroughs Algol, HP SPL, Xerox Mesa,
or their modern reinventions, built on segmented stack architectures.

On the microcomputer side, companies built MMUs for microcomputers that
had bank switching and protection. Digital Research MPM, for example.

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