On Feb 1, 8:35*pm, "Lord Androcles, Zeroth Earl of Medway"
wrote:

Asimov's "positronic brain" for his robots was an unnecessary fantasy
for an artificially intelligent computer,

Yes, that's true.

And Star Trek filed the serial numbers off, and had "duotronic"
computers.

But, ironically, although there is no reason to think that computers
would work faster using positrons to carry information, integrated
circuits _did_ use _holes_ instead of electrons to carry information.

This had the benefit, in PMOS circuits, that gates could be more
tightly packed - although they were slower than the ones in NMOS
circuits which used electrons. So pocket calculators, which could be
slow, but had to be complex, were made from PMOS chips back in the
'seventies.

Today, though, CMOS circuitry, which, unlike either NMOS or PMOS
circuitry, doesn't require current to flow through it (except for
unavoidable leakage) when in a stable state, only when switching, is
used in the most advanced microelectronics as the lower power
consumption allows circuits to be made at a smaller feature size,
which would be far too hot if made from NMOS (even though that would
allow them to run faster, if they could be made to run, in fact they
would be too hot to run at all).

So, if "positronics" could refer to holes as positive charge carriers,
then in real life "duotronics" of a sort _has_ won out.

John Savard