real time

adj. Describes an application which requires a program to respond to stimuli
within some small upper limit of response time (typically milli- or
microseconds). Process control at a chemical plant is the canonical example.
Such applications often require special operating systems (because
everything else must take a back seat to response time) and speed-tuned
hardware. 2. adv. In jargon, refers to doing something while people are
watching or waiting. I asked her how to find the calling procedure's program
counter on the stack and she came up with an algorithm in real time.

