Marc wrote...
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My 1974 HP 21MX, descendant of the HP 2100A, sure inherited this Memory Protect card. One
register that you load, prevents access to any memory below the address of the register.
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That's just the fence register (memory access interception) capability. There's
also the I/O & HLT instruction interception, interrupt interception, etc. mentioned
earlier.
M.E.M. was standard option (ie. Included) with most E/F machines.
I don't know if the 2114/5/6 had the same capabilities in the fence area....
J