What is an Operating System?
An Operating System (OS) is nothing more than a program. However, it is the most important program that runs on a computer. The OS is the responsible for running all the programs and applications that run in the computer.
The OS may or may not have a graphical user interface (GUI), but will have some sort of user interface (UI), even if it is just a command line. This UI is what allows the users to interact with the OS and command it to run which program and when.
It can be said that the OS is the manager of the computer, as it recognizes which hardware devices are connected to the computer, as well as handles the input and output from those devices. It also runs and manages multiple applications, as well as handles the sharing of internal memory among them. It also ensures that the different programs running do not interfere with each other. The operating system is also responsible for security. It ensures that unauthorized users do not access the system.