What is Operating System? Types of OS, Features and Examples

What is an Operating System?

An Operating System (OS) is a software that acts as an interface between computer hardware components and the user. Every computer system must have at least one operating system to run other programs. Applications like Browsers, MS Office, Notepad Games, etc., need some environment to run and perform its tasks.

The OS helps you to communicate with the computer without knowing how to speak the computer’s language. It is not possible for the user to use any computer or mobile device without having an operating system. Introduction to Operating System

History Of OS

• Operating systems were first developed in the late 1950s to manage tape storage
• The General Motors Research Lab implemented the first OS in the early 1950s for their IBM 701
• In the mid-1960s, operating systems started to use disks
• In the late 1960s, the first version of the Unix OS was developed
• The first OS built by Microsoft was DOS. It was built in 1981 by purchasing the 86-DOS software from a Seattle company
• The present-day popular OS Windows first came to existence in 1985 when a GUI was created and paired with MS-DOS.

Examples of Operating System with Market Share

Following are the examples of Operating System with the latest Market Share

OS Name	Share
Windows	40.34
Android	37.95
iOS	15.44
Mac OS	4.34
Linux	0.95
Chrome OS	0.14
Windows Phone OS	0.06

Types of Operating System (OS)

Following are the popular types of Operating System:

• Batch Operating System
• Multitasking/Time Sharing OS
• Multiprocessing OS
• Real Time OS
• Distributed OS
• Network OS
• Mobile OS

Batch Operating System

Some computer processes are very lengthy and time-consuming. To speed the same process, a job with a similar type of needs are batched together and run as a group.

The user of a batch operating system never directly interacts with the computer. In this type of OS, every user prepares his or her job on an offline device like a punch card and submit it to the computer operator.

Multi-Tasking/Time-sharing Operating systems

Time-sharing operating system enables people located at a different terminal(shell) to use a single computer system at the same time. The processor time (CPU) which is shared among multiple users is termed as time sharing.

Real time OS

A real time operating system time interval to process and respond to inputs is very small. Examples: Military Software Systems, Space Software Systems are the Real time OS example.

Distributed Operating System

Distributed systems use many processors located in different machines to provide very fast computation to its users.

Network Operating System

Network Operating System runs on a server. It provides the capability to serve to manage data, user, groups, security, application, and other networking functions.

Mobile OS

Mobile operating systems are those OS which is especially that are designed to power smartphones, tablets, and wearables devices.

Some most famous mobile operating systems are Android and iOS, but others include BlackBerry, Web, and watchOS.

Functions of Operating System

Below are the main functions of Operating System: Functions of Operating System

In an operating system software performs each of the function:

1. Process management:- Process management helps OS to create and delete processes. It also provides mechanisms for synchronization and communication among processes.

1. Memory management:- Memory management module performs the task of allocation and de-allocation of memory space to programs in need of this resources.

1. File management:- It manages all the file-related activities such as organization storage, retrieval, naming, sharing, and protection of files.

1. Device Management: Device management keeps tracks of all devices. This module also responsible for this task is known as the I/O controller. It also performs the task of allocation and de-allocation of the devices.

1. I/O System Management: One of the main objects of any OS is to hide the peculiarities of that hardware devices from the user.

1. Secondary-Storage Management: Systems have several levels of storage which includes primary storage, secondary storage, and cache storage. Instructions and data must be stored in primary storage or cache so that a running program can reference it.

1. Security:- Security module protects the data and information of a computer system against malware threat and authorized access.

1. Command interpretation: This module is interpreting commands given by the and acting system resources to process that commands.

1. Networking: A distributed system is a group of processors which do not share memory, hardware devices, or a clock. The processors communicate with one another through the network.

1. Job accounting: Keeping track of time & resource used by various job and users.

1. Communication management: Coordination and assignment of compilers, interpreters, and another software resource of the various users of the computer systems.

Features of Operating System (OS)

Here is a list important features of OS:

• Protected and supervisor mode
• Allows disk access and file systems Device drivers Networking Security
• Program Execution
• Memory management Virtual Memory Multitasking
• Handling I/O operations
• Manipulation of the file system
• Error Detection and handling
• Resource allocation
• Information and Resource Protection

Advantage of using Operating System

• Allows you to hide details of hardware by creating an abstraction
• Easy to use with a GUI
• Offers an environment in which a user may execute programs/applications
• The operating system must make sure that the computer system convenient to use
• Operating System acts as an intermediary among applications and the hardware components
• It provides the computer system resources with easy to use format
• Acts as an intermediator between all hardware’s and software’s of the system

Disadvantages of using Operating System

• If any issue occurs in OS, you may lose all the contents which have been stored in your system
• Operating system’s software is quite expensive for small size organization which adds burden on them. Example Windows
• It is never entirely secure as a threat can occur at any time

What is a Kernel?

The kernel is the central component of a computer operating systems. The only job performed by the kernel is to the manage the communication between the software and the hardware. A Kernel is at the nucleus of a computer. It makes the communication between the hardware and software possible. While the Kernel is the innermost part of an operating system, a shell is the outermost one.

Features of Kennel

• Low-level scheduling of processes
• Inter-process communication
• Process synchronization
• Context switching

Types of Kernels

There are many types of kernels that exists, but among them, the two most popular kernels are:

1.Monolithic

A monolithic kernel is a single code or block of the program. It provides all the required services offered by the operating system. It is a simplistic design which creates a distinct communication layer between the hardware and software.

2. Microkernels

Microkernel manages all system resources. In this type of kernel, services are implemented in different address space. The user services are stored in user address space, and kernel services are stored under kernel address space. So, it helps to reduce the size of both the kernel and operating system.

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When computers were first introduced in the 1940’s and 50’s, every program written had to provide instructions that told the computer how to use devices such as the printer, how to store information on a disk, as well as how to perform several other tasks not necessarily related to the program. The additional program instructions for working with hardware devices were very complex, and time-consuming. Programmers soon realized it would be smarter to develop one program that could control the computer’s hardware, which others programs could have used when they needed it. With that, the first operating system was born.

Today, operating systems control and manage the use of hardware devices such as the printer or mouse. They also provide disk management by letting you store information in files. The operating system also lets you run programs such as the basic word processor. Lastly, the operating system provides several of its own commands that help you to use the computer.

DOS is the most commonly used PC operating system. DOS is an abbreviation for disk operating system. DOS was developed by a company named Microsoft. MS-DOS is an abbreviation for «Microsoft DOS». When IBM first released the IBM PC in 1981, IBM licensed DOS from Microsoft for use on the PC and called it PC-DOS. From the users perspective, PC-DOS and MS-DOS are the same, each providing the same capabilities and commands.

The version of DOS release in 1981 was 1.0. Over the past decade, DOS has undergone several changes. Each time the DOS developers release a new version, they increase the version number.

Windows NT (new technology) is an operating system developed by Microsoft. NT is an enhanced version of the popular Microsoft Windows 3.0, 3.1 programmes. NT requires a 386 processor or greater and 8 Mb of RAM. For the best NT performance, you have to use a 486 processor with about 16 Mb or higher. Unlike the Windows, which runs on top of DOS, Windows NT is an operating system itself. However, NT is DOS compatible. The advantage of using NT over Windows is that NT makes better use of the PC’s memory management capabilities.

OS/2 is a PC operating system created by IBM. Like NT, OS/2 is DOS compatible and provides a graphical user interface that lets you run programs with a click of a mouse. Also like NT, OS/2 performs best when you are using a powerful system. Many IBM-based PCs are shipped with OS/2 preinstalled.

UNIX is a multi-user operating system that allows multiple users to access the system. Traditionally, UNIX was run on a larger minicomputer to which users accessed the systems using terminals and not PC’s. UNIX allowed each user to simultaneously run the programs they desired. Unlike NT and OS/2, UNIX is not DOS compatible. Most users would not purchase UNIX for their own use.

Windows 95 & 98 (Windows 2000) are the most popular user-oriented operating systems with a friendly interface and multitasking capabilities. The usage of Windows 95 and its enhanced version Windows 98 is so simple that even little kids learn how to use it very quickly. Windows 95 and 98 are DOS compatible, so all programs written for DOS may work under the new operating system.

Windows 95 requires 486 processors with 16 megabytes of RAM or Pentium 75-90 with 40 megabytes of free hard disk space .

to consume — потреблять consumer— потребитель

to realize — понять, осознать

to enhance — увеличивать, расширять

top — верх, вершина on top of DOS — «сверху», на основе ДОС

are shipped — поставляются

to desire — желать

to ship — поставлять, доставлять

1. Answer the questions

1. What problems faced programmers in the 1940’s and 1950’s?
2. Why were the first programs «complex» and «time-consuming»?
3. What are the basic functions of operating system?
4. What does the abbreviation DOS mean?
5. What company developed the first version of DOS operating system? For what purpose was it done? Was the new operational system successful?
6. What is the difference between the PC-DOS and MS-DOS
7. What does the abbreviation NT stand for? Is NT DOS-compatible? What are the basic requirements for NT?
8. Who is the developer of OS/2?
9. What makes UNIX so different from the other operational systems?

10) What are the special features of Windows 95, Windows 98, Windows 2000?

2. Match the following:

1) Like NT, … is DOS compatible and provides a graphical user interface that lets you run programmes with a click of a mouse.

2). is the most commonly used PC operating system

3). is a multi-user operating system that allows multiple users to access the system

4). is an operating system developed by Microsoft, an enhanced version of the popular Microsoft Windows programs.

5) The usage of. is so simple that even little kids learn how to use it very quickly.

b) DOS

3. Which of the listed below statements are true/false? Specify your answer using the text.

1. When computers were first introduced in 40’s and 50’s programmers had to write programs

to instruct CD-ROMs, laser printers and scanners.

1. The operational system controls and manages the use of the hardware and the memory.
2. There are no commands available in operating systems, they are only in word processors.
3. Microsoft developed MS-DOS to compete with IBM’s PC-DOS.
4. NT requires computers with 486 CPU and 16 M random access memory.
5. OS/2 is DOS compatible because it was developed by Microsoft.
6. Traditionally, UNIX was run by many users simultaneously.
7. Windows 95 and Windows 98 are DOS compatible and have very «friendly» and convenient interface.