On 2016-05-05 2:55 PM, Gottfried Specht wrote:
Thanks, Erik.
How do I remember this ca. 40 years later?
Well, while servicing these systems they would frequently stop with a "Memory
Protect Error" (various Operating Systems).
Guess what the intuitive action was: Replace the "Memory Protect Board" - which
n e v e r fixed the problem.
So digging into the technology it became clear, that the Memory Protect Board
in these cases had only fulfilled its duty: protect the memory below the fence
register from some other piece of hardware (usually a processor or DMA-board)
running havoc in memory. That learning stuck ...
Well, at least the directive wasn't "remove the Memory Protect board"? :-)
--Toby
Kind regards,
Gottfried
_____
Gottfried Specht | gottfr...@specht-online.com | +49 211 151695+49 151 2911
2915
-----Ursprüngliche Nachricht-----
Von: cctalk [mailto:cctalk-boun...@classiccmp.org] Im Auftrag von Erik Baigar
Gesendet: Donnerstag, 5. Mai 2016 10:36
An: General Discussion: On-Topic and Off-Topic Posts
Betreff: Re: AW: When did Memory- and IO Protection Emerge (Esp. in Minis)?
On Wed, 4 May 2016, Gottfried Specht wrote:
I'm not sure whether it qualifies for your full list, but the HP2100A
(that came out in 1971) had a "Memory Protect" hardware that
...
