Wednesday, May 8, 2019

Basics of How an Operating System Works -Top Ten OS Versions and Their Features

operating system (OS)
An operating system (OS) is a specialized software that handles computer software and hardware resources,  performs basic tasks and provides a lot of services for computer programs. Examples include Windows OS, DOS, Unix, Linux, Chrome OS, etc.

Basics of How an Operating System Works -Top Ten OS Versions and Their Features

What Is An Operating System (OS)?

 Operating System (OS) is a set of software that acts as an interface between the user and the computer and handles computer software and hardware resources. Operating System is also known as the main operator of the computer, and an interpreter or a means of communication between the user and the computer, and responsible for managing the computer.
The operating system is defined as a set of basic programs that manage the computer, organize all its tasks, and make it easier for the user to take advantage of the equipment and accessories that make up the device, and enables him to benefit from different application programs such as word processing program or computational business programs.
The operating system can also be defined as the main program of any computer that is responsible for operating the device and running the rest of the programs properly. When the computer is turned on, the device copies the operating system files from the hard drive to memory, so that the CPU can execute the device commands without having to know the details of the processes inside the computer. The operating system requires programmers at the highest level to write, develop, maintain, these programs are called system programming languages.

Functions of Operating System

Each operating system performs different functions depending on the type of computer. Large computers that need to connect to other devices, or allow more than one person to use them at the same time, need an operating system to help them deal with computers and peripherals. Personal computers have a simpler operating system; It deals with one user and simple operations.

 How an operating system works?

When you turn on your computer, the first program that is typically started is a set of instructions saved in the computer's ROM. This program scans the physical resources of the system and makes sure that everything works correctly.
The power-on-self-test (POST) checks the CPU, memory, and basic input-output systems (BIOS) for errors, and stores the result in a dedicated memory location.
Once the POST finishes successfully, the program will start loading them into the ROM (sometimes called BIOS or Firmware) to activate the computer drives. In most modern computers, when the computer activates the hard drive, it finds the first piece of the operating system: bootstrap loader.
The bootstrap loader is a small program that has one function: it loads the operating system into memory and allows startup.

The functions of the operating systems are summarized as follows:

Datapath with the Control Unit: The operating system manages data flow and its path; by controlling the transition between computer hardware units.

Input/Output Controllers (IOC): This is done by controlling the process of entering data into the computer via input units, such as the keyboard or mouse, monitoring processes, and then displaying data on output units such as the monitor or the printer.
Troubleshooting: The system runs special software when a particular fault occurs, which detects faults, and reports them.

Computer Memory Controllers: Some operating systems have the ability to run more than one program at the same time and some allow more than one user to work on the device at the same time. The role of the operating system here is to distribute the main memory to more than one user; if more than one user is connected to the computer.

User Interface (UI): The operating system is a means of communication between the computer and the user; it acts as an interpreter between the user and the computer. It helps the computer user to follow the software and commands that were executed by displaying them on the command prompt screen to direct the computer in the correct manner by displaying the user interfaces.

Application software download: The role of the operating system here is to transfer application software from the storage media to the main memory and then to the CPU to be implemented.

Mechanism of Action
The operating system follows a flowchart to perform the tasks entrusted to it, and passes through several stages that can be summarized as follows:

Operation: The operating system reads the instructions stored in the ROM (Read Only Memory) and executes when the computer is turned on.

Checking: The operating system checks input units and output units to make sure they are safe.

System Load: After confirming the integrity of I / O modules, the operating system is loaded from hard and soft disks.

Order Processing: This is done by taking commands from the computer user; to be executed by the operating system.

System operation: System operation is the most important stage; the system begins to execute the user orders immediately after the completion of the process of loading and order processing, through the application software.

End process and repeat in command: At the last stage the operating system returns to the first step, and is waiting for new orders from the user, to start the same way again

Types of Operating Systems

Since the first operating system was created, the operating system has developed over time to accommodate the most sophisticated functions. Let's have a look at some of the most common types of operating systems used today.

Batch operating system
In a batch operating system, the user will prepare the work and assign it to a computer operator as a punch card device. The computer operator then sets up a group of jobs according to their computing needs and implements them in batches to make sure faster-processing speed. This is most suitable for those programs which require long calculation time without user's participation such as statistical analysis of large part of the data.

Network operating system
The network operating system runs on a server and allows access to computing resources to share files and printers between computers in the network and provides more stability and security of the system. Users, data, applications, and security are managed on the server.

Distributed Operating Systems
The specific feature of the distributed operating system is that it has many central processors that are used by many users to run many real-time applications. The distributed operating system also ensures that there are some floaty loads on the host machine while doing some heavy calculations. This property has dramatically increased data exchange between sites and enabled the sharing of resources.

Multiprogramming Operating System
A multiprogramming operating system is an operating system that enables the software to run many programs on the computer at the same time.
The main purpose of multiprogramming operating systems is to improve system throughput and resource usage. This purpose is achieved by arranging the computing functions in a way that ensures that the CPU always works to implement them at any one time.

Time Sharing Operating System
A time-sharing operating system is a special type of multiprogramming operating system that is designed to accommodate many users and allows multiple computer programs to be run concurrently. It means that multiple users can access the same computer resources at the same time and they will not need to wait to use these resources.

Real-Time Operating Systems
In a real-time operating system, it is important that the inputs are obtained and processed in a very short period of time. As a result, the operating system will have to guarantee that the events will be processed at a fixed time. There are two types of real-time operating systems: Hard real-time operating system and Soft real-time operating system. Some of these systems may allow multi-tasking features, but with specific features and special algorithms for scheduling to ensure that the shifting of the tasks is done according to their priorities so that the deadline for each task is completed.

Types of an operating system in terms of the number of programs
Multi-Tasking: Here the user is allowed to handle more than one program at the same time.
Single-Tasking: This system does not allow the user to run more than one program at the same time.

Types of operating systems in terms of the number of users
Multi-User software: A system that enables the software to be run on a computer by more than one user at the same time.
Single-User software: A system that does not allow more than one user to run software on the computer at the same time.

Operating System Versions

Top Ten OS Versions and Their Features
The most important versions of the operating systems include:

Windows Operating System: Windows OS is one of the most common systems because it is easy to use and learn. It is based on the Graphical User Interface, and its versions ( Windows 95, Windows 98, and Windows ME - Millennium Edition, Windows NT 31, Windows 2000, Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10, Windows Server, Windows CE).

Disk Operating System (DOS): The disk operating system, a single-tasking PC operating system, is one of the first-generation operating systems, developed in 1981 by IBM, and has been developed by Microsoft to produce a copy (MS-DOS). This system is compatible with INTEL.

Macintosh Operating System: Macintosh is the first company to use graphical interfaces in 1984s and developed the operating system to use text and file editing. This is because of the ease of dealing with the system. MacOS is also suitable for commonly used applications and allows multi-tasking. Despite the advantages and ease of use of these devices, it is less prevalent than IBM compatible devices.

Unix Operating System: Unix is a family of multi-tasking multi-user operating system derived from the original AT & T Unix, it was established in 1969s, the development began in the 1970s and developed completely in 1973. Unix is used in the operation of servers. It is worth mentioning that it can be used with all types of computers; because of the ease of writing commands, and running applications and programs, and the multiple functions. It has the advantage of protecting documents from being accessed, and the possibility of working on all types of computers. The system has two methods of handling: linear interface, graphical interface. One of the systems produced by Unix is Linux.

Linux Operating System: This system is the master of systems because most of the famous sites rely on it and are built on the basis of its work. It is not suitable for laptops and is characterized by a great speed compared to other systems, for example, Android OS is a Linux-based OS built on the basis of the Mac system.

Chrome Operating System: Chrome OS is a kind of special systems and it is based on the Linux kernel and designed by Google. Its desktop is unique as it is based on Chrome's system and apps only and is specifically made to run ChromeBooks devices, but can also be downloaded on other computers.

Haiku Operating System: Haiku is a free and open-source operating system like Linux, which is simple, beautiful and fast-paced, launched in 2001. Haiku is a personal use system.

Menuet Operating System: MenuetOS is one of the least space systems in the computer world; it only needs 1.44 MB of hard disk space for the computer to complete its installation and the operation, and this system is programmed using assembly language.

eComStation Operating System: eComStation is an operating system created by Microsoft and IBM but remained under IBM only after leaving Microsoft. This system is not free and low-use and low-profile.

Tails Operating System: TAILS is protection, encryption, privacy, and confidentiality operating system on the World Wide Web. TAILS is one of Linux distributions and uses its own web browser called Tor to ensure identity encryption, privacy protection, and user confidentiality. This system can not be installed on the computer's hard disk but is used as a live system; it runs automatically when you play the CD that contains it.

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