1.An operating system is an example of application software.

2.An operating system provides a basic user interface that allows the user to use the computer.

3.A computer can  have more than one operating system,but only one is in control at any given time.

4.Multiprogramming is the technique of using multiple CPUs to run programs.

5.In the 1960s and 1970s,a human operator would organize similar computer jobs into batches to be run.