Skip to main content

What operating System do?




A computer system can be divided roughly into four components: the hardware/ the operating system, the application programs/ and the users.

The hardware - the Central Processing Unit, the memory and the input/output device provides the basic computing resources for the system. The application programs such as word processors/ spreadsheets/ compilers, and Web browsers-define the ways in which these resources are used to solve users' computing problems. The operating system controls the hardware and coordinates its use among the various application programs for the various users.




There are two kind of views a system have, which means an outer view and a view from inside of the devices - about its internal functionalities which tells about how process actually has been completed.

User View

The user's view of the computer varies according to the interface being used. Most computer users sit in front of a PC, consisting of a monitor/ keyboard/ mouse, and system unit. Such a system is designed for one user to monopolize its resources. The goal is to maximize the work (or play) that the user is performing.

Goals : 
                - ease to use.
                - complete resource utilization.

A user sits at a terminal connected to a mainframe or a minicomputer, other users are accessing the since computer through other terminals. These users share resources and may exchange information. The operating system in cases is designed to maximize resource utilization to assure that all available CPU time, memory, and I/0 are used efficiently and that no individual user takes more than her fair share.

System View

From the computer's point of view, the operating system is the program most intimately involved with the hardware. In this context, we can view an operating system as a resource allocator. A computer system has many resources that may be required to solve a problem: CPU time, memory space, file-storage space, I/0 devices, and so on. The operating system acts as the manager of these resources. Facing numerous and possibly conflicting requests for resources, the operating system must decide how to allocate them to specific programs and users so that it can operate the computer system efficiently and fairly. As we have seen, resource allocation is especially important where many users access the same mainframe or minicomputer. 

A slightly different view of an operating system emphasizes the need to control the various I/0 devices and user programs. An operating system is a control program. A control program manages the execution of user programs to prevent errors and improper use of the computer. It is especially concerned with the operation and control of I/O devices.




Comments

Post a Comment

Popular posts from this blog

Spring Security with JWT for REST API

Spring is considered a trusted framework in the Java ecosystem and is widely used. It’s no longer valid to refer to Spring as a framework, as it’s more of an umbrella term that covers various frameworks. One of these frameworks is Spring Security , which is a powerful and customizable authentication and authorization framework. It is considered the de facto standard for securing Spring-based applications. Despite its popularity, I must admit that when it comes to single-page applications , it’s not simple and straightforward to configure. I suspect the reason is that it started more as an MVC application -oriented framework, where webpage rendering happens on the server-side and communication is session-based. If the back end is based on Java and Spring, it makes sense to use Spring Security for authentication/authorization and configure it for stateless communication. While there are a lot of articles explaining how this is done, for me, it was still frustrating to set it up for the f...
Post a Comment
Read more

Java Functional Interfaces

  The term   Java functional interface   was introduced in Java 8. A   functional interface   in Java is an interface that contains only a single abstract (unimplemented) method. A functional interface can contain default and static methods which do have an implementation, in addition to the single unimplemented method. Here is a Java functional interface example: public interface MyFunctionalInterface { public void execute(); } The above counts as a functional interface in Java because it only contains a single method, and that method has no implementation. Normally a Java interface does not contain implementations of the methods it declares, but it can contain implementations in default methods, or in static methods. Below is another example of a Java functional interface, with implementations of some of the methods: public interface MyFunctionalInterface2{ public void execute(); public default void print(String text) { System.out.println(t...
Post a Comment
Read more

Java Logger

In Java, logging is an important feature that helps developers to trace out the errors. Java is the programming language that comes with the logging approach. It provides a Logging API that was introduced in Java 1.4 version. It provides the ability to capture the log file. In this section, we are going to deep dive into the Java Logger API. Also, we will cover logging level, components, Logging handlers or appenders, logging formatters or layouts, Java Logger class, What is logging in Java? In Java, Logging is an API that provides the ability to trace out the errors of the applications. When an application generates the logging call, the Logger records the event in the LogRecord. After that, it sends to the corresponding handlers or appenders. Before sending it to the console or file, the appenders format that log record by using the formatter or layouts. Need for Logging It provides the complete tracing information of the application. It records the critical failure if any occur in ...
Post a Comment
Read more