yea i agree, because operating system is a software not hardware, also rtos it's a kind of operating system, it is software only.
but maybe referred to your question, the rtos hardware is a microprocessor or microcontroller that can be support or plant with RTOS.
I have heard of hardware RTOS before from a digital designer where they were talking about implemented every thing in hardware and they had to change the design each time they change the application.
For example, each thread was a new set of registers.
Every global variable is a shared memory, etc etc
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Amr
RTOS OS is easy to use for programmer.
For example we can set number of task and their priority.
All tasks may run concurrently.
For example one task is displaying graphic and another is reading data.