Types of Operating systems.

Real-time Operating Systems: 

It is used to control industrial systems, scientific instruments and machinery. RTOS has very little user-interface capability, and no end-user utilities. A very important part of an RTOS is managing the resources of the computer so that a particular operation executes in precisely the same amount of time every time it occurs.

Single-user, Single-tasking Operating System:

This operating system is designed to manage the computer so that one user can effectively do one thing at a time. The Palm handheld computers are a good example of a modern single-user, single-task operating system.

Single-user, Multi-tasking Operating System:

This operating system most people use on there desktop and laptop computers. Windows 98 and Mac O.S. are examples of this operating system that will let a single user have several programs in operation at the same time. For example, a Windows user to be writing a note in a word processor while downloading a file from the Internet.

Multi-user Operating Systems:

A multi-user operating system allows many users to take advantage of the computer's resources simultaneously. The operating system must make sure that the requirements of the various users are balanced, and that each of the programs they are using has sufficient and separate resources so that a problem with one user doesn't affect the entire community of users. Unix, VMS, and mainframe operating systems are examples of multi-user operating systems.