Functions of Operation System

What is an Operating System?

The operating system is a connecting medium between the user and the hardware. It helps the users to access the hardware in an efficient manner. It provides an environment in which all the hardware can be used efficiently by the user. It also makes sure that all the computer resources will be used in an efficient and smooth way without any problems. For example, when seniors pass their instructions to the juniors, and in the same way, the users gives the instructions to the operating system.

The operating system provides various functionalities, which are discussed below:

Controlling System Performance

One of the most important functions of the operating system is controlling the system's health. For this purpose, it monitors and observes the delay time between a service being requested and the requested service being served. This delay time is reduced as much as possible to improve the overall performance of the system.

Memory Management

In a computer system, we have primary memory, which is also called main memory, and it is made by the sequence of bytes. Each byte in the main memory has a unique address which helps it to check if it is occupied or not. For executing each program in its computer system, it should be in the main memory. Operating systems can easily check which bytes of main memory are empty and which are not. So it allocates the main memory for the program execution, and when the program is completed or terminated, then it deallocates the memory. Operating systems also keep a record that which byte of memory is assigned to which program.

Device Management

The operating system manages the communication between the computer system and the peripheral devices connected to the I/O port of the system. Peripheral devices use their respective drivers to communicate with the system. The operating system determines which program or process is accessed by which connection and device. It also makes sure when a program is executed or terminated, it will stop the communication between the device and the computer system.

Coordination between other software and the user

There is other software in the system which is coordinated by the operating system so that users can access them efficiently, like assemblers, compilers, etc.

Process Management

The process is a program under the execution. The operating system manages all the processes so that each process gets the CPU for a specific time to execute itself, and there will be less waiting time for each process. This management is also called process scheduling.

For process scheduling operating system uses various algorithms:

• First Come First Serve (FCFS) Algorithm: In this algorithm, which comes first is served first by the CPU until it is completed. It is a non-preemptive algorithm which means it cannot be terminated without completing it.
• Shortest Job First (SJF) Algorithm: The process which has the shortest burst time (execution time) that will be served first by the CPU.
• Longest Job First (LJF) Algorithm: This algorithm is based on the phenomenon that the process that has the longest execution time will be served first by the processor.
• Round Robin Algorithm: In this algorithm, there is a specific time quanta assigned for each process. If the process is not executed in time quanta, it is sent to the waiting queue for its next turn.
• Priority Scheduling Algorithm: Processes are given the priority based on different criteria and scheduled according to the highest priority. Criteria can be burst time or arrival time etc.

Resource Allocation

The operating system manages all the resources of the computer system. It ensures the use of all the resources by managing which resource is used by which process and for how much time.

Information and Resource Protection

All the data and information available on the machine are protected by the operating system. If any external resource tries to attack the computer resource and steal the data, then the operating system helps to prevent the attack.

Handling the I/O Operations

Input/output devices like mouse, keyboards, printers etc., are external I/O devices, and there are different natures of each device. The operating system appropriately manages the input and output operation of these devices.

Job Priority:

The work of job priority is creation and promotion. It determines what action should be done first in a computer system.

Special Control Program:

The operating systems make automatic changes to the task through specific control programs. These programs are called Special Control Program.

Scheduling of resources and jobs:

The operating system prepares the list of tasks to be performed for the device of the computer system. The operating system decides which device to use for which task. This action becomes complicated when multiple tasks are to be performed simultaneously in a computer system. The scheduling programs of the operating system determine the order in which tasks are completed. It performs these tasks based on the priority of performing the tasks given by the user. It makes the tasks available based on the priority of the device.

Security:

Computer security is a very important aspect of any operating system. The reliability of an operating system is determined by how much better security it provides us. Modern operating systems use a firewall for security. A firewall is a security system that monitors every activity happening in the computer and blocks that activity in case of any threat.

Monitoring activities:

The operating system takes care of the activities of the computer system during various processes. This aborts the program if there are errors. The operating system sends instant messages to the user for any unexpected error in the input/output device. It also provides security to the system when the operating system is used in systems operated by multiple users. So that illegal users cannot get data from the system.

Job accounting:

It keeps track of time & resources used by various jobs and users.