the.com/real time processing
computing that refuses to keep you waiting, on penalty of being useless.
means a system that guarantees a response within a strict time limit, because a late answer is treated as a wrong answer.
from emerged from 1960s aerospace and industrial control systems, where computers had to react to physical events as they happened, not batch them for later like the punch-card mainframes before them.
hard vs softhard systems fail completely if deadline is missed
not speedpredictability matters more than raw processing power
airbags decidein under 30 milliseconds, no exceptions allowed
for instance
anti-lock brakes — recalculates wheel slip roughly 15 times per second
nasdaq matching engine — executes trades in microseconds to set official prices
mars rover landing — 2021 perseverance touchdown ran on onboard deadlines, no earth help
pacemaker firmware — must pace heartbeat within milliseconds or the patient notices