How does operating system act as …

essentially there are 4 layers here that will help you understand this

• Hardware
• Firmware
• System software
• Applications

So basically the H/W and System software(OS) interact with each other through an entry point (boot code/bootstrapping)) that is in the form of Firmware(on-boarded on the H/W itself and/or through device drivers).

This inter-dependability is developed in order for the hardware to perform operations to the commands passed by the System software.

Now applications usually make requests to the System software to help it perform a task using a hardware component.

To understand this better I’ll provide you with a high level example here of Printing.

So You have a Word doc in place to be printed.

The Hardware Printer has its onboard firmware as well as a device driver in your Systems memory( your CPU) to connect these both. Now the System Software is directly in contact with the device driver and knows that if a print command is requested by some application(in our case MS word) then I have to use this device driver code as an entry point to communicate with the printer.

So this is the flow of that operation:

1. You click on Print option
2. MS-Word makes a request to the System Software(say Windows) to inform of a print command to be executed on its ‘be-half’ by the system software
3. The system software uses the device driver code to forward that request to the printer
4. The printer’s on-board firmware understands the incoming request and data (your file to be printed) and does the required Job.