Operating System

  Layered Systems: In the layered system structure, operating system is organized as hierarchy of layers, each of the layers is constructed upon one another. The first system constructed in this way was the THE system built at the Technische Hogeschool Eindhoven in the Netherlands by E. W. Dijkstra and his students. The THE system was a simple batch system for a Dutch computer. Layer 0 assign with allocation of the processor, switching between processes when timers expired.    Above layer 0, the system consisted of sequential processes, each of which could be programmed without having to worry about the fact that multiple processes were running on a single processor. In other words, layer 0 provided the basic multiprogramming of the CPU. Layer 1 was used to the memory management. It distributed space for processes in main memory used for holding parts of processes. Layer 1 was taking care of making sure pages are transport into memory whenever they are needed. Layer 2 handled

Monolithic Operating   System: A monolithic an operating system architecture where the entire operating system is working in kernel space. The monolithic model differs from other operating system architectures. The monolithic operating system is a very basic operating system in which file management, memory management, device management, and process management are directly controlled within the kernel.   Monolithic system is also known as simple system. This approach the entire operating system runs as a single program in kernel mode. The operating system is written as a collection of procedures, linked together into a single large executable binary program. When this technique is used, each procedure in the system is free to call any other one, if the latter provides some useful computation that the former needs. Having thousands of procedures that can call each other without restriction.             To construct the actual object program of the operating system when this appr

Services Provided by Operating System: An operating system provides an environment for the execution of user 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 operating system. These operating system services are provided for the convenience of the programmer, to make the programming task easier and more efficiently. The following diagram is shows various operating system-                                Figure: Operating System Services These are the following services provided by operating system- User Interface : Almost all operating systems have a user interface. This interface can take several forms. One is a command-line interface, which uses text commands and a methods for entering them. Another is a batch interface, in which commands and directives to control those commands, they are entered into files and those files are executed (that file is kn

Operating System components : An Operating system is an interface between users and the hardware of a computer system. It is system software that is viewed as an organized collection of software consisting of procedures and functions, providing an environment for the execution of programs. The operating system manages resources of system software and computer hardware resources. It allows computing resources to be used in an efficient way. Programs interact with computer hardware with the help of operating system. These are the important component of operating system as follows:               Process Management: The operating system manages many types of activities ranging from user programs to system programs like printer spoiler, name servers, file server etc. Each of these activities is summarize in a process. The five major activities of an operating system in regard to process management are : Creation and deletion of user and system processes Suspension and