MacOS has the ability to prioritize audio threads to avoid scheduling misses [0]. Linux has a set of patches [1] to give it soft real-time capabilities. I don't know as much about Windows, but I assume it has similar capabilities.
And it's not like this is ABS firmware, where someone might die if you miss your deadline, and where hard real-time OSes are used. But you do get glitches in the audio stream, which in performance contexts is still pretty bad.
What are you talking about ? Most people working with sound today do so by using a DAW like Ableton, QBase or Fruity Loop that work on Windows or sometimes Mac Os
They're not hard-realtime, so they definitely can miss a few samples. You can workaround that by reconfiguring an external device rather than generating the samples locally, but that's not what Ableton or FL do.
Win and Mac have soft-realtime scheduling and the mentioned software does what it can without guarantees https://help.ableton.com/hc/en-us/articles/209072289-How-to-... I've been to a live gig before where the performance was paused a few times because artist's mac was misbehaving.
And it's not like this is ABS firmware, where someone might die if you miss your deadline, and where hard real-time OSes are used. But you do get glitches in the audio stream, which in performance contexts is still pretty bad.
[0] https://developer.apple.com/documentation/audiotoolbox/workg... [1] https://wiki.archlinux.org/index.php/Professional_audio#Real...