Multi-user, Multi-tasking Operating System

They are highly sophisticated and are designed to handle many people running their programmes on the computer at the same time.

Examples of this kind of operating system include various versions of UNIX, Linux, IBM's z/OS, OS/390, MVS and VM.

Now the operating system has to manage:

• Each user logged on to the system, their workspace and so on.
• Allocate resources to the jobs they want to run.
• Keep logs of how much processing time and resources they use
• Work out the most efficient use of computer processing cycles
• Maintain security

For example, a multi-user, multi-tasking operating system would need to be used for a server farm. 

Batch - 'A 'batch' is the name given to the task of doing the same job over and over again, the only difference being the input data presented for each iteration of the job and perhaps the output file.' 

A Batch process is a process that occurs over and over at a certain point in time. For example defragging in a computer. 

Real time - 'A real-time operating system is found in systems which aim to control a series of actions by using a computer.'