Other real-time system definitions

Real-time operating mode ( DIN 44 300 )
The operating mode of a computer system in which programs for the processing of data arriving from the outside are permanently ready, so that their results will be available within predetermined periods of time; the arrival times of the data can be randomly distributed or be already a priori determined depending on the different application.
Koymans, Kuiper, Zijlstra - 1988
A real-time system is an interactional system that maintains on-going relationship with an asynchronous environment, i.e..... an environment that progresses irrespective of the real-time system, in an uncooperative manner.
Real-time (software) (IEEE 610.12 - 1990)
Pertaining a system or mode of operation in which computation is performed during the actual time that an external process occurs, in order that the computation results can be used to control, monitor or respond in a timely manner to the external process.
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