Linked by Thom Holwerda on Thu 18th Nov 2004 10:19 UTC
QNX I think that everyone reading OSNews will have heard at least something about QNX. You can regard this article as an introduction, but also as a review, and as a "Is-QNX-Ready-For-The-Desktop? article". To start off, I put together a short explanation of the merits of using a microkernel. Let me start off by saying that QNX Software Systems (QSS) does not aim towards the desktop with their Neutrino RTOS.
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@ pkj
by djm on Fri 19th Nov 2004 14:20 UTC

2. QNX, being a RTOS, actually uses a simple O(1) scheduler. What it means is that, if multiple GUI applications are run the performance would start to go downhill much faster compared to other *NIX OS.

Care to elaborate on this?

Sounds like the scheduler is similar to AmigaOS, simple priority based round-robin scheuler. Very simple and efficient and predictable provided you have minimal active applications.

If your apps don't do huge amounts of background work, then this shouldn't be an issue, but having several apps actively sharing the CPU can reduce responsiveness noticably, though tweaking priorities will resolve this (I used to let Imagine ray-trace on my Amiga in the background by dropping its priority to -1 so that any application I was actively ineracting with always had priority and there was no slow down to the user, though clearly Imagine would take longer to render...)

Of course, on the Amiga there were 3rd party schedulers you could plug in with minimal effort that offered more sophisticated systems.