Why do you want to write a device driver

Q)Why do you want to write a device driver?
A:- Basically device driver are written to communicate with the hardware and which is OS specific.

When a calling program invokes a routine in the driver, the driver issues commands to the device.

Once the device sends data back to the driver, the driver may invoke routines in the original calling program.

Drivers are hardware-dependent and operating-system-specific.

They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.