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One of my mentors is one of the IBM engineers who developed the original AS/400’s capability-based security architecture way back in the early eighties. I can c
by qubex 7y ago
One of my mentors is one of the IBM engineers who developed the original AS/400’s capability-based security architecture way back in the early eighties. I can confirm that (according to her) the 128-bit addressing was indeed a very convenient manner of implementing the system. However, nobody ever expected (nor expects, I suspect) that those addresses will ever be used to actually access that amount of memory. It’s a truly astronomical amount of memory, on the order of grains-of-sand-on-countless-planets...
- simonh 7y agoTo put it another way it's not just enough to count the grains on sand on a beach, it's enough to count all the atoms in all the grains of sand on planet Earth. Give or take a few orders of magnitude[1]. [1]https://www.explainxkcd.com/wiki/index.php/2205:_Types_of_Approximation https://www.explainxkcd.com/wiki/index.php/2205:_Types_of_Ap...
- exikyut 7y ago$ echo '2^128' | bc | rev | sed 's/.../&,/g;s/,$//' | rev 340,282,366,920,938,463,463,374,607,431,768,211,456 ...rrright. Actually let me line up the https://en.wikipedia.org/wiki/Orders_of_magnitude_(data) https://en.wikipedia.org/wiki/Orders_of_magnitude_(data) 340,282,366,920,938,463,463,374,607,431,768,211,456 .. ?? YB ZB EB PB TB GB MB KB (There's no meaningful notation of size here - the denotations are just to show just how much data you can fit in 128 bits of space.) Blinks a few times Ultimately fails to mentally grasp and make useful sense of the number due to its sheer size As an aside, apparently DNA can store a few TB/PB (I don't remember which). The age of optimizing for individual bytes as a routine part of "good programming" is definitely over, I guess. (I realize this discussion is about address space and not capacity, but still)