Linked by Thom Holwerda on Fri 10th Aug 2007 20:46 UTC, submitted by SReilly
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> Singularity and JNode wil bring an interesting twist to the whole scene since they don't require context
> switches at all
That isn't quite right. From what I understand Singularity does away with virtual memory (Relying on code verification techniques and managed code to keep things tight) but doesn't regress away preemptive multitasking or get rid of the concept of a context switch.




Member since:
2005-12-31
About the completely event-based OS: You would still want to isolate work into different "processes" such that bugs or malicious code won't hose the whole system (except for systems in which you can exclude both, but that would only be possible in embedded devices or similar custom systems). That means you get one event handler thread per process. Then some processes would want to do background work - this can be done on an event basis, but this is usually hard to implement since you'd fiddle around with events just to re-create the concept of a background thread. Soon you're back to the old model.
Singularity and JNode wil bring an interesting twist to the whole scene since they don't require context switches at all. But even JNode (don't know about singularity) is all the old model when it comes to concurrency and the likes. Making it completely event-based would bring up other questions, such as: what if an event handler locks up? May another handler be run concurrently, and if so, what about synch locks?