1. 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 classic example. Such applications often require special operating systems (because everything else must take a back seat to response time) and speed-tuned hardware. 2. 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." Used to describe a system that must guarantee a response to an external event within a given time. (1997-11-23)
