Control objectives of an operating system:
i) The operating system must protect itself from users. User applications must not be able to gain control of, or damage in any way, the operating system, thus causing it to cease running or destroy data.
ii) The operating system must protect users from each other. One user must not be able to access, destroy or corrupt the data or programs of another user.
iii) The operating systems must protect users from themselves. A user‘s application may consist of several modules stored in separate memory locations, each with its own data. One module must not be allowed to destroy or corrupt another module.
iv) The operating system must be protected from itself. The operating system is also made up of individual modules. No module should be allowed to destroy or corrupt another module.
v) The operating system must be protected from its environment. In the event of a power failure or other disaster, the operating system should be able to achieve a controlled termination of activities from which it can later recover.