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

Dave Wade dave.g4ugm at
Thu May 5 03:15:35 CDT 2016

I thought we were talking Mini Computers. The Ferranti/Manchester Atlas had
virtual memory of a sort which provided protection, and indeed IBM bought
the Virtual Memory patents from Manchester University. I gather the PDP/11
received Memory Mapping boards early in its life, didn't these offer some


> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at] On Behalf Of Curious
> Marc
> Sent: 05 May 2016 01:07
> To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at>
> Subject: Re: AW: When did Memory- and IO Protection Emerge (Esp. in
> In the not mini but very maxi category, I just learned that IBM
> memory protection as an RPQ (customer feature) at the request of the MIT
> folks that built the first IBM time sharing system (CTSS, the predecessor
> Multics), on their IBM 7094. Around 1963, unless it was already
> in the IBM 7090 which would have been 1961. At least that's my cursory
> understanding of it from . I was very
> surprised it was that early!
> Marc
> Sent from my iPad
> > On May 4, 2016, at 3:02 PM, Chuck Guzis <cclist at> wrote:
> >
> > Is the CDC 1700 considered to be in the family of "minicomputers"?
> > (i.e. was the word invented before then?).
> >
> > If so, the 1700 had a rather elaborate system of memory and peripheral
> > protection.  Circa 1965 (at least that's the date on my manual).
> >
> > --Chuck
> >

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