Explain the basic concepts of OS

An operating system is the most important software that runs on a computer. Every general-purpose computer must have an operating system to run other programs. It also allows you to communicate with the computer without knowing how to speak the computer's language. It manages the computer's memory, processes, and a.ll of its software and hardware, i.e. manages all the other programs in a computer. The other programs are called applications or application programs. Most of the time, there are many different applications running at the same time, and they all need to access your computer's central processing unit (CPU), memory, and storage. The operating system coordinates all of this to make sure each program gets what it needs.

The structure of OS consists of 4 layers:

- Hardware (Hardware consists of CPU, Main memory, I/O Devices, etc.);

- Software i.e. Operating System (Software includes process management routines, memory management routines, I/O control routines, file management routines);

- System programs (This layer consists of compilers, Assemblers, linker etc.);

- Application programs(This is dependent on users need).

Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. In addition, users can interact directly with the operating system through a user interface such as a command language or a graphical user interface (GUI).

Classification of Operating systems

· Multi-user; Multiprocessing; Multitasking; Multithreading; Real time.

All modern operating systems use a graphical user interface, or GUI (pronounced gooey). A GUI lets you use your mouse to click icons, buttons, and menus, and everything is clearly displayed on the screen using a combination of graphics and text.

Each operating system's GUI has a different look and feel, so if you switch to a different operating system it may seem unfamiliar at first. However, modern operating systems are designed to be easy to use, and most of the basic principles are the same.

The three most common operating systems for personal computers are Microsoft Windows, Apple Mac OS X, and Linux.

An Operating system is basically a intermediary agent between the user and the computer hardware.

· Manages the computer’s resources (hardware, abstract resources, software)

· It’s a resourceallocator.

· It is also used to control programs to prevent errors and improper computer use.

· Itisinterruptdriven.