It's not.
The BIOS or "Basic Input Output System" is.
It allows the computer to recognise the hardware and the system to boot to the OS.
Generally, the acronym OS is an abbreviation for operating system. An operating system is the base program that runs the background programs on a computer.
A computer without an operating system will not operate.
A "System call" you be a function accessible from a programming language to the base hardware of the computer (eg to get the time).
operating system decide what your computer will do
An operating system manages the working operation of a computer
operating system is a complete operating system that works on a desktop computer, a notebook computer, or mobile computing device.
An operating system runs common services for computer programs and manages the computer hardware resources. An operating system is necessary to run application programs.
Most operating systems native to the computer system allows users to communicate with the computer system
An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. The operating system is a component of the system software in a computer system. Application programs usually require an operating system to function.
Operating System
The "Operating System" or OS
operating system is a set of computer programme.