A RTOS is not really an OS, just a super-fast way of dealing with I/O streams. More driver/firmware than OS, if you ask me. But some companies need fancy words for marketing, I guess.
> not really an OS, just a super-fast way of dealing with I/O streams
Saying this without any animosity, but you would probably be interested in reading about the history of operating systems. Desktop OSes are a (very visible) minority, and it's the opposite way in my opinion: a desktop OS is an OS + a large suite of tools + a shell.
It's literally something that operates the system so that every program written doesn't have to handle all the low level IO, that enables task management, etc.
RTOS literally means "OS with real-time capabilities", you can't say in general that an RTOS is not really an OS. QNX is very clearly an OS. Linux with real-time modifications is clearly an OS. And even with really small variants, like ThreadX in this case, they have many markers of an OS: It provides threads, with scheduling, synchronization and memory isolation (if the hardware supports that). It has a networking stack and file system abstractions. What exactly is it missing that makes it clearly "not an OS"?
