Why is an operating system needed in a computer and what are its benefits?
Operating System is a computer software that works to manage computer hardware, software as well as provide some general services to the computer programs.
Types of software in a computer – 1) System software 2) Application software.
System software
This software works to provide service to computer hardware, data, program files and other application software.
It is a type of interpreter that tells the user by translating the language of the machine.
The computer knows only one language, which is the language of 0 and 1, 1 means true or on and 0 means false or off.
But computer is an electrical and electronic machine then how does computer know what are 0’s and what are 1’s?
Computers only send and receive electrical signals and have a standard code for each character.
Let’s understand it like this – as soon as you type A from your computer’s keyboard, a standard code goes in the computer which is ‘1000001’ All these types of codes which are also called ASCII (American Standard Code for Information Interchange) . All these codes are executed by loading into RAM (RANDOM ACCESS MEMORY) from the hard drive of the computer.
So when you press the button A (1000001) from the computer, your keyboard sends current through 7 wires to the computer.
The first wire represents 1, then the current goes through the first wire, the computer does not get current through the remaining 2,3,4,5,6 wires which display 0. After this the current goes through the 7th wire. Boom! Now the computer comes to know that you have sent the code for A to the computer and it is displayed on your computer screen with the help of the circuits in the computer.
System software works to coordinate between computer hardware resources and the user. Therefore, the system software itself is called the operating system.
Application Software
This software is created to perform a certain task which is written by a programming language like C, C++, JAVA etc. and installed in the computer system. For example Electricity Bill Management System, Dealership Management System etc.
The journey of the operating system
It started with a computer that used to do one thing at a time, like a calculator. The BASIC operating system was introduced in the 1950s, which ran different programs automatically. In those days the computer operating system was not built for complex operations.
In 1960, hardware features like parallel processing, runtime libraries, interrupts were included.
Personal computers came in the 1980s and the operating systems present in them were exactly the same as used in large computers before this.
MAC OS is a graphical operating system created and sold by the Apple company. Its first OS was released in 1999 which is Mac OS X Server 1.0.
BILL GATES’ company Microsoft released its first OS in 1985. Windows 95 was released in 1995 which only used MSDOS as a bootstrap.
Windows ME came in the year 2000 and later Windows NT kernel came. Windows XP, Windows 7, 8 etc. came later.
Types of Operating System
- Batched Operating System for tasks like Payroll System, Transactions Process. Batch operating system execute jobs in batch automatically.
- Multi-Programmed Operating System.
- Timesharing Operating System.
- Distributed Operating System.
- Real-Time Operating System.
Main functions of operating system
Processor Management
First, the operating system has to make sure that each process and application gets enough processor time to function properly, and then use as many processor cycles as possible.
One of the main functions of the operating system is the scheduling of the work to be done by the processor. CPU has to process a lot of instruction simultaneously so scheduling is required which is managed by operating system. The operating system has to switch between different processes at the rate of thousands of times per second.
Processes are controlled and scheduled by the operating system for execution by the CPU. The operating system allows the application to start and suspend execution only if the interrupt is long enough and is interrupted by the user.
Interrupt is a signal to CPU which is send by hardware or by the software to grab CPU”s attention. Operating systems sometimes schedule processes on a priority basis and ignore interrupts so that it is possible to finish a certain tasks quickly.
Scheduling of processes is not the only task for the operating system. The next important function of CPU is the management of memory.
Memory Management
In memory management, the operating system has to perform two major tasks. First of all, it is ensured that each process gets enough memory for execution and does not run into the memory space of other processes.
There are different types of memory in a system, using them properly so that the process can run properly. The task of the operating system is to set memory limits for any software and individual applications.
For example, if we imagine a machine that has 1 megabyte of RAM. Now when the computer starts, first of all, during the process of computer booting, the operating system requires some space in the RAM to load itself, So let’s assume that the operating system needs 250 KB to run. Now after the operating system is loaded in RAM, various types of driver software starts loading to control the computer hardware.
So in a hypothetical computer, let’s say the drivers require 250 KB. So 250 KB for operating system and 250 KB for driver software, then complete 500 KB is saved in RAM. Now the applications start loading into the memory through the operating system and they are in a block size whose size is determined by the operating system. If the block size is 2 KB, then each process that is loading gets a piece of memory that is 2 KB, and all applications follow this fixed block size. These block sizes ensure that no block should get space of each other.
RAM has limited space, so it can be increased by adding another RAM, but it doesn’t make any sense if the processor accesses only one memory location at a time, so RAM remains unusable even after having more than one RAM. So hard disk space is cheaper than RAM and if the information located in RAM can be sent to the hard disk, then the space of RAM will increase many times, that too without any cost. This technique is called virtual memory.
Memory types are given here :
- Cache memory – This memory is a very fast memory which is closest to the CPU. Controllers of this cache memory with less memory find out what data the CPU needs to process and send that data to the cpu by taking it out of the RAM very fast. This is a kind of buffer memory, data is always located for the process of CPU.
- Main memory – Random Access Memory in which all programs are loaded to work. It is of volatile nature and data cannot be stored in it.
- Seondary Memory – This is called a permanent storage memory and all the program files are stored in the c:/ drive . It is advised not to store valuable data, personal files, photos, videos etc. in this drive to avoid any loss of the data in the time when operating system corrupts and one has to format the c:/ drive and reinstall the fresh operating system. It is better to take backup of your valuable data every time. This memory is more in size and stores data and applications permanently. This memory works like virtual RAM and is controlled by the operating system.
Device Management
Any hardware device installed in the computer cannot be made functional until there is a method to operate that device. A program is required to operate these devices and these programs are named as device drivers. Device means equipment and driver means the computer program that will run this device.
For example, let’s assume that a computer hardware device is a car and it cannot run on its own until a driver comes and starts the car and drives it. Similarly, the same function is performed by the device driver in the computer.
We can say that operating system is the soul of computer without which computer is nothing but just a metal box. It contains many software applications inside itself, in which the software applications are able to work.
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