I’m always a bit amazed of how things have progressed and on what Linux can still run.
This is an extreme example, but it’s also possible to run a modern Linux OS on SBCs like a Raspberry Pi Zero, and still have something somewhat usable depending on your needs.
To have a computer half the size of a credit card with more RAM than my full tower rig from 2001 is amazing. And it can even run software from that era with dosbox or wine.
My 15 years old laptop is still supported and can still read 1080p on YouTube, using Linux.
Linux devs just recently decided to drop support for 486 CPUs and some early Pentiums.
There’s just no competition.
Pretty much the only place it doesn’t run is where you have hard real-time requirements and on extremely small embedded micro controllers.
But isn’t there a RTOS Linux kernel?
Technically yes. But it can’t support many hard real-time use cases. For that you need a true RTOS, thought from the ground up for that purpose. Something like VxWorks, QNX, some flavors of L4.
I miss QNX.
It’s still around. The latest release (8.0) is free-as-in-beer for non-commercial use. It’s still proprietary though.
