A device driver is a program that controls a particular type of device that is attached to your computer. There are device drivers for printers, displays, CD-ROM readers, diskette drives, and so on. A device driver is a program that controls a particular type of device that is attached to your computer.
An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also include accounting software for cost allocation of processor time, mass storage, printing, and other resources.
Since the operating system shell is actually an application, it may easily be replaced with another similar application, for most operating systems. In addition to shells running on local systems, there are different ways to make remote systems available to local users; such approaches are usually referred to as remote access or remote administration.
Utility software helps the user to control, manage, and maintain a computer's operating system, hardware and application software. These programs are designed to perform specific functions like finding files, backing up data, playing multimedia files, viewing images and so on.