Alone, a computer cannot operate with just its hardware, it need to be told what to do. A computer software is a list of instructions that tells a computer how to perform a specific task.
An operating system is a collection of programs the allows the computer to communicate with the hardware and to work together. It also control the running of the other programs. This operating system is either built into the computer memory or loaded from a disk when you turn on the computer.
Apple Mac OS, Microsoft Windows and Linux examples of major operating systems. Each of them have many versions of Operating systems that are in use such as Apple Mac X, Windows XP, Windows Vista, Windows 2000, Windows 8.1, Redhat Linux and Ubuntu. Tablets and Smartphones have their own operating systems. All operating systems go through changes over time as the hardware improves and need for security and performance increases. This especially true for Microsoft Windows and this is the reason we have many versions of Microsoft Windows, the Windows 8.1 being the latest.
An operating system consist of different utilities programs. Functions of these utilities program is to perform housekeeping and maintenance task for the computer. One example is to recover a word document that you had deleted on accident.
This programs perform specific tasks that user can accomplish like typing document, designing a poster, creating a website. They include, word processing programs, database programs, spreadsheet programs, computer games, and many more.