An operating system performs essential tasks like providing an interface between the user and computer, running programs, managing input/output, tracking memory and files, controlling devices, and security. Common operating systems include Windows, macOS, Linux, iOS, and Android. Programs need to be specifically written for each operating system to function properly across different platforms.

2. Operating System
Every general purpose computer needs an operating system (OS). The OS
performs tasks such as:
providing an interface between the user and computer
running other programs
accepting and directing input from the keyboard, mouse etc.
sending output to the display
keeping track of programs and data in memory
keeping track of files and directories stored on disk drives
controlling peripheral devices (printer, scanner, disk drives)
security

3. Operating System
There are many different Operating Systems.
Programs written to work with one Operating System will not work with another
Operating System without a new version of the program being written.