An operating system is a set of software programs, which manage computer hardware in a controlled fashion. The operating system controls the file-system, process management, memory management and peripherals.
Multi-user operating systems are used on large mainframe computers. A mainframe computer system has one very powerful processing unit, which may contain many microprocessors. Many users will all share this processing unit. They use terminals (a keyboard and a monitor) to access the mainframe computer.
A multi-user operating system lets more that one user work on a mainframe computer…