how can operating system knows which is software and which is hardware?

Question

i mean how can OS know which one is software and which one is hardware

Answer 1

it doesn't which is why we can have software that pretends to be hardware - for example the microsoft loopback adapter that simulates a network card

Answer 2

Humanly:
If a thing goes hot too often and make loud noice then it is hardware , if something obeys bill gates it is software, and if it disobeys giving blue screen it is hardware.

Technically:
Hardware have different addresses to identify them where as software uses message to communicate.