Q 9.1 - Viewpoints of Operating Systems
Operating systems can viewed from several vantage points, three of which are Services that the system provides, Interface employed by the system and Components and their interconnections.
The operating system provides an environment for the execution of programs, with regards to services. It makes certain services available to programs and to the users of those programs. Specific services may differ from one operating system to another, but there are common clases. With regard to user interface, almost all operating systems have a user interface (UI), command line or graphical user interface, that enables users to communicate with the system. Lastly the components and their interconnections aspect of the operating system has to do with the various components of a computer system. These are the input, output, system unit which composes the arithmetic logic unit, the central processing unit and the main memory. The rest are external memory and the user.