Operating systems are typically composed of four types which are based on the kinds of computers that they control and the types of applications that are supported. The following are example of these categories:
- RTOS, also known as real-time operating system, is used to control industrial systems, scientific instruments and control machinery. A real-time operating system usually has no utilities called end-user and has a small amount of capabilities in user-interface, since this system will be a secured box when it is delivered to the user. A significant component of the real-time operating system is handling the computer resources so operations are executed at precisely the same duration of time, each and every time it happens.
- Single user, or single task, is an operating system that was created to handle the computer so one user could effectively use it doing one thing at a time. A good example of a single user, single-task modern operating system is a Palm handheld computer.
- With the multiple user operating system, a variety of different users are allowed to simultaneously operate the computer’s resources. There are requirements in the operating system that ensures users are balanced and each program they use has separate and sufficient resources. This ensures that the problems that go on with one user will not have an affect on the vast number of users in the community. Some examples of operating systems that have multi-user capabilities are MVS which are Unix, and mainframe operating systems.
It is important that single-user operating systems and multi-user operating systems that support networks are given differentiations. Novell Netware and Windows 2000 are each capable of supporting up to thousands of network user, but their operating systems are not multi-user operating systems. The only user for Netware or Windows 2000 is the system administrator.