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

Chuck Guzis cclist at sydex.com
Tue May 3 14:05:36 CDT 2016

Again, not minicomputer, but the Burroughs B5000 did have "invalid
address" detection, which would case the machine to switch from "normal"
to "control" state with an interrupt.  The problem with comparing the
B5000 architecture to anything else is that it was quite liberally like
nothing else.

Some may argue that the IBM S/360 had I/O protection, but those of us
who played games with CCWs in user mode might take exception to that
statement.:)   One of the favorite CCW-writing exploits was to ring the
1052 console bell then execute a TIC (transfer in channel) back to the
bell-ringing CCW.  On one occasion that I'm aware of, this so panicked
the operator that he pulled "emergency stop"...

Ah, the good old days...


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