In five years all application servers will be realtime capable... 📎
The predictability and hard timinig constraints are required otherwise the hardware could be damaged.
Real time constraints could be also interesting for general business applications... Reviewing the functional specifications of my recent projects (e.g. use cases), I found statements like: "the use case XYZ has to complete in 1 second" which is a (soft) kind of real time constraint. A real time application server would simplify the load tests and make the behavior of the software under load more predictable. Of course there is one drawback: the predictability is not free and costs about 10-30% of the throughput - but this should'n be a huge problem. On the other hand with a real time server the hardware could be better utilized.
An RTS application will become in the near future especially interesting for multi-project servers. The real time throughput-penalty of 10-30% can be compensated with faster hardware or bigger cluster. The "normal" application servers do not run on the 80%-utilitzation, so it shouldn't be a problem to convert them to an RTS-system - at least from the throughput perspective. So the resources of an applicationserver could be shared in a fair fashion between independent applications and the behavior under stress would be easier to predict...