Explain a multiprogramming operating system?
A multiprogramming operating system: It is system which allows more than one active user program or part of user program to be stored in main memory concurrently. Multi programmed operating systems are fairly complicated. All the jobs which enter the system are maintained in the job pool. This pool includes all processes residing upon mass storage awaiting allocation of main memory. If some jobs are set to be brought in memory, and there is not sufficient room for them, so the system should choose between them. A multiprogramming system is a time-sharing system.