My understanding of the terms is that online means it processes streams of data, but not that it is fast enough to keep up with the real world. Realtime means that it is fast enough to keep up with the real world. Realtime seems to be the appropriate term to me.

Do you have a different set of definitions?

Yes this is the correct term. Realtime processing in the operating system context vs the streaming data context are different things.

https://blog.syncsort.com/2015/11/big-data/the-difference-be...

Realtime software often means "hard real time"[1] which is a constraint where a response is guaranteed within a particular time.

This is a fairly specific area where special real-time deterministic operating systems are used etc.

I think your usage was fine, and the pedantic use of "real time" is dying anyway. There's a whole field of "soft real time" which blends into online, and some parts of the battery control SCADA systems may well be true real time anyway.

[1] https://en.wikipedia.org/wiki/Real-time_computing

I was just responding to the definition given. "observes data and makes decisions continuously" is not a proper expansion of "real-time".

The time scales it operates in are usually quite a bit larger than systems that would typically be discussed here, but I don't see how "online" would be a descriptor than "real-time".