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.
Operating system is a system software which in short we also speak OS. In a way, it is like a soul in a computer. Without which the computer cannot function at all. It handles all the operations between computer hardware and software. This is a kind of interface between hardware and user users i.e. ours which connects us to each
For example, we take a house. If there is no land to build a house, then what is the use of brick, cement and sand? Now you tell me, will you build a house without land? Your answer will be no! In the same way you want to run the computer, you have mouse, keyboard, printer all the things but the OS is not installed, then yes you understand that the computer will not be on other.
Function of Operating System
1.Memory Management
Memory management refers to management of Primary Memory or Main Memory. Main memory is a large array of words or bytes where each word or byte has its own address.
Main memory provides a fast storage that can be accessed directly by the CPU. For a program to be executed, it must in the main memory. An Operating System does the following activities for memory management −
Keeps tracks of primary memory, i.e., what part of it are in use by whom, what part are not in use.
In multiprogramming, the OS decides which process will get memory when and how much.
Allocates the memory when a process requests it to do so.
De-allocates the memory when a process no longer needs it or has been terminated.
2.Processor Management
In multiprogramming environment, the OS decides which process gets the processor when and for how much time. This function is called process scheduling. An Operating System does the following activities for processor management −
Keeps tracks of processor and status of process. The program responsible for this task is known as traffic controller.
Allocates the processor (CPU) to a process.
De-allocates processor when a process is no longer required.
3.Device Management
An Operating System manages device communication via their respective drivers. It does the following activities for device management −
Keeps tracks of all devices. Program responsible for this task is known as the I/O controller.
Decides which process gets the device when and for how much time.
Allocates the device in the efficient way.
De-allocates devices.
4.File Management
A file system is normally organized into directories for easy navigation and usage. These directories may contain files and other directions.
An Operating System does the following activities for file management −
Keeps track of information, location, uses, status etc. The collective facilities are often known as file system.
Decides who gets the resources.
Allocates the resources.
De-allocates the resources.
5.Security − By means of password and similar other techniques, it prevents unauthorized access to programs and data.
6.Control over system performance − Recording delays between request for a service and response from the system.
7.Job accounting − Keeping track of time and resources used by various jobs and users.
8.Error detecting aids − Production of dumps, traces, error messages, and other debugging and error detecting aids.
9.Coordination between other software's and users − Coordination and assignment of compilers, interpreters, assemblers and other software to the various users of the computer systems.
Types of Operating System
1.Batch Operating System
In this operating system, the user will prepare the job and hand it to a computer operator in form of a device like a punch card. The computer operator would then group the jobs according to their computing requirements and execute them in batches to ensure a faster processing speed. It’s best suited for programs that require long computation times and no user involvement such as statistical analysis of large chunks of data.
The problems with Batch Systems are as follows −
- Lack of interaction between the user and the job.
- CPU is often idle, because the speed of the mechanical I/O devices is slower than the CPU.
- Difficult to provide the desired priority.
2.Time Sharing Operating System
This is a unique type of multiprogramming operating system. Like the typical multiprogramming operating system, it allows multiple tasks to run concurrently. However, this is unique in that it has been designed to accommodate multiple users. This means that multiple users can use the same computer resources. The best part about this operating system is that these users will not need to queue to access these resources.
Each of these users gets the impression that she is using her own computer despite the fact that it is just one computer that is being shared among a number of users. This is thanks to frequent switching of jobs by the CPU which ensures fast response times.
Advantages of Timesharing operating systems are as follows −
- Provides the advantage of quick response.
- Avoids duplication of software.
- Reduces CPU idle time.
Disadvantages of Time-sharing operating systems are as follows −
- Problem of reliability.
- Question of security and integrity of user programs and data.
- Problem of data communication.
3.Distributed Operating Systems
The distinguishing feature of distributed operating systems is the fact that they have multiple central processors. These processors are used to serve a number of users running a number of real-time applications. In other words, these operating systems pull together groups of distinct computers and make them function as one single computer.
These operating systems came into use when computer networks were developed to allow standalone computers to communicate with each other. This enabled resource sharing and dramatically increased data exchange between sites. Distributed operating systems also ensure that there is a lighter load on the host machine even when performing heavy computation.
The advantages of distributed systems are as follows −
- With resource sharing facility, a user at one site may be able to use the resources available at another.
- Speedup the exchange of data with one another via electronic mail.
- If one site fails in a distributed system, the remaining sites can potentially continue operating.
- Better service to the customers.
- Reduction of the load on the host computer.
- Reduction of delays in data processing.
4.Network Operating System
Like the name suggests, this operating system runs on a server and it allows computers on a network to access the computing resources. The management of the users, data, applications and security is done on the server.
This operating system allows file and printer sharing between computers in a network. This operating system provides more security and stability of the system. However, the costs associated with buying and running a server can tend to be quite high for small businesses.
The advantages of network operating systems are as follows −
- Centralized servers are highly stable.
- Security is server managed.
- Upgrades to new technologies and hardware can be easily integrated into the system.
- Remote access to servers is possible from different locations and types of systems.
The disadvantages of network operating systems are as follows −
- High cost of buying and running a server.
- Dependency on a central location for most operations.
- Regular maintenance and updates are required.
5.Real-Time Operating Systems
In these operating systems, it is vital that inputs are received and processed in an extremely short period of time. As a result, the operating system has to guarantee that the events will be processed in a given time. Some of these systems might allow multi-tasking, but with special algorithms for scheduling to ensure that switching of tasks takes place according to their priorities so that the deadlines are met for every task.
Examples of uses for real-time operating systems include air traffic control systems, medical imaging systems, weapon control systems, industrial control systems and scientific experiments.
There are two types of real-time operating systems.
Hard real-time systems
Hard real-time systems guarantee that critical tasks complete on time. In hard real-time systems, secondary storage is limited or missing and the data is stored in ROM. In these systems, virtual memory is almost never found.
Soft real-time systems
Soft real-time systems are less restrictive. A critical real-time task gets priority over other tasks and retains the priority until it completes. Soft real-time systems have limited utility than hard real-time systems. For example, multimedia, virtual reality, Advanced Scientific Projects like undersea exploration and planetary rovers, etc.
6.Multiprogramming Operating System
Like the name suggests, a multiprogramming operating system is an operating system that is capable of running multiple programs at the same time. The main aim in multiprogramming operating systems is to improve resource utilization and system throughput. This is achieved by organizing the computing jobs in a manner that ensures that the CPU always has a job to execute at any one time.
These operating systems are sometimes referred to as multitasking operating systems because they allow two or more processes to run simultaneously. This is to mean that data from two or more processes can be held in the primary memory at a given time.
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