Operating System

The operating system acts as an intermediary between the computer user and the computer hardware. The purpose of an operating system is to provide an environment in which users can run programs conveniently and efficiently. The operating system is the software that manages the computer hardware. The hardware must provide adequate mechanisms to ensure the correct operation of the computer system and prevent user programs from interfering with the normal operation of the system.

 Definition of Operating System:

• An operating system is a program that controls the execution of application programs and acts as an interface between computer users and computer hardware.
• A more common definition is that an operating system is a program (usually called a kernel) that has been running on a computer, and all other programs are applications.
• The operating system deals with the allocation of resources and services, such as memory, processors, devices, and information. Consequently, the operating system includes programs that manage these resources, such as flow controllers, schedulers, memory management modules, I / O programs, and file systems.

The role of the operating system

The operating system (OS) of your computer handles all of its software and hardware. Several computer applications are usually operating at the same time, and they all require access to your computer’s central processing unit (CPU), memory, and storage. All of this is coordinated by the operating system to ensure that each software receives the resources it requires.

Some of the most significant functionalities of an operating system are listed below.

• Memory Management
• Processor Management
• Device Management
• File Management
• Security
• System Performance Control
• Job Accounting
• Error Detection Aids
• Coordination with other software and users

Types Operating system

Operating systems are often pre-installed on each computer purchased. Most people stick with the operating system that came with their computer, although it is possible to update or even switch operating systems. Microsoft Windows, macOS, and Linux are the three most popular operating systems for personal computers.

A graphical user interface, or GUI, is used in modern operating systems (pronounced gooey). A GUI allows you to click icons, buttons, and menus using your mouse, and everything is clearly presented on the screen using a combination of visuals and text.

Each operating system’s graphical user interface (GUI) has a distinct appearance and feel, so switching to a new operating system may appear strange at first. Modern operating systems, on the other hand, are meant to be user-friendly, and the majority of the fundamental concepts are the same.

Windows by Microsoft

In the mid-1980s, Microsoft built the Windows operating system. Windows has several distinct versions, but the most current ones are Windows 10 (launched in 2015), Windows 8 (2012), Windows 7 (2009), and Windows Vista (2007). Windows comes pre-installed on the majority of new PCs, which contributes to its status as the world’s most popular operating system.

MacOS

macOS (formerly known as OS X) is an operating system developed by Apple. All Macintosh computers, or Macs, come with it preinstalled. Mojave (launched in 2018), High Sierra (2017), and Sierra are some of the particular versions (2016).

According to Stat Counter Global Stats, macOS accounts for fewer than 10% of global operating systems, which is much lower than the percentage of Windows users (more than 80 percent ). One of the reasons for this is that Apple computers are more costly. Many individuals, however, prefer the appearance and feel of macOS over that of Windows.

Linux

A series of open-source operating systems, Linux (pronounced LIN-ux) may be updated and delivered anywhere in the globe. In contrast to proprietary software like Windows that can only be updated by the business that owns it, open source software may In addition to being free, Linux offers a wide range of options in terms of distributions (or versions).

Less than 2% of the world’s operating systems are Linux-based, according to StatCounter Global Stat But Linux is the operating system of choice for most servers since it is easy to customise

Mobile device operating systems

Until now, all of the operating systems we’ve discussed have been intended to run on desktop and laptop computers Cellphones, tablet computers and MP3 players are mobile devices that use operating systems built particularly for them. These include Apple’s iOS and the Google Android mobile operating systems, As you can see in the image below, iOS is operating on an iPad.

Operating systems for mobile devices are generally not as comprehensive as those built for desktops and laptops, and they cannot run all the same software. However, you can still use them for many things, such as watching movies, surfing the Internet, managing calendars, and playing games.

Content Covered:

1. System Software

• Overview of all system software:
• Operating system
• I/O manager
• Assembler
• Compiler
• Linker
• Loader

2. Fundamentals of Operating System

• OS services and Components
• Multitasking
• Multiprogramming
• Timesharing
• Buffering
• Spooling

3. Process and Thread Management

• Concept of process and threads
• Process states
• Process management
• Context switching
• Interaction between processes and OS
• Multithreading

4. Concurrency Control

• Concurrency and Race Conditions
• Mutual exclusion requirements
• Software and hardware solutions
• Semaphores
• Monitors
• Classical IPC problems and solutions
• Deadlock
• Characterization
• Detection
• Recovery
• Avoidance and Prevention

5. Memory Management

• Memory partitioning
• Swapping
• Paging
• Segmentation
• Virtual memory
• Overlays
• Demand paging
• Performance of Demand paging
• Virtual memory concepts
• Rage replacement algorithms
• Allocation algorithms

6. I/O Systems

• Principles of I/O Hardware
• I/O devices
• Device controllers
• Direct memory access
• Principles of I/O Software
• Goals
• Interrupt handlers
• Device drivers
• Device independent I/O software
• Secondary-Storage Structure
• Disk structure
• Disk scheduling
• Disk management
• Swap-space management
• Disk reliability
• Stable storage implementation
• Introduction to Clock
• Clock hardware
• Clock software

7. File Systems

• File concept
• File support
• Access methods
• Allocation methods
• Directory systems
• File protection
• Free space management

8. Protection & Security

• Protection
• Goals of protection
• Domain of protection
• Access matrix
• Implementation of access matrix
• Revocation of access rights
• Security
• The security problem
• Authentication
• One-Time passwords
• Program threats
• System threats
• Threat monitoring
• Encryption
• Computer-security classifications

9. Linux System

• Linux introduction and file system – Basic features, advantages, installing requirement, the basic architecture of UNIX/Linux system, Kernel, Shell.
• Commands for files and directories cd, cp, mv, rm, mkdir, more, less, creating and viewing files, using cat, file comparisons, View files, disk-related commands, checking disk free spaces, etc.
• Shell programming: Shell programming basic, various types of shell, shell programming in bash, conditional and looping statements, case statements, parameter passing, and arguments, etc.