[Cryptography] Why full-fledged quantum computers might always be five years away

[Jerry Leichter]

> Well, early 1960s. (Wikipedia claims 1959 introduction.)
Indeed.  What's a decade at this remove.

> But you missed the biggie: it couldn't do arithmetic on its own. Rather, there were tables in RAM giving the results of addition and subtraction operations.
Nickname CADET - Can't Add, Doesn't Even Try.  Multiplication and division (implementated as repeated subtraction!) as well.  The Model II added hardware addition and subtraction but the multiplication remained.

I didn't mention this because for most users of the machine it was an implementation detail - the instructions to do arithmetic were all there.  Even many generations later, some models of VAXes used software implementations of the more complex instructions, and no one thought much about it.
                                                        -- Jerry