Using the method of virtual work, determine separately the force and couple representing the reaction at H.
2. Operating System Structures An operating system provides the environment within which programs are executed. Internally, operating systems vary greatly in their makeup, since they are organized along many different lines. The design of a new operating system is a major task. It is important that the goals of the system be well defined before the design begins. These goals form the basis for choices among various algorithms and strategies. An operating system from several vantage points. One view focuses on the services that the system provides; another, on the interface that it makes available to users and programmers; a third, on its components and their interconnections 2.1: Operating-System Services An operating system provides an environment for the execution of programs. It provides certain services to programs and to the users of those programs. The specific services provided, of course, differ from one operating system to another, but we can identify common classes. These operating system services are provided for the convenience of the programmer, to make the programming task easier. Figure 2.1 shows one view of the various operating-system services and how they interrelate. 1 One set of operating system services provides functions that are helpful to the user. • User interface. Almost all operating systems have a user interface (UI). This interface can take several forms. One is a command-line inte
