by - An operating system is a collection of programs that manages the overall operation of a computer system.
- OS acts as an interface between the user and the computer hardware.
- OS is the most fundamental of all the system programs because it controls all the system resources (CPU, memory, input/output devices, program, files, etc.) and provides a base upon which all other application programs are written.
- An operating system is a program that acts as an intermediary between a user of a computer and computer hardware.
- It enables the computer hardware to communicate and operate with computer software.
- the purpose of an OS is to provide an environment in which a user can execute programs in a convenient and efficient manner.
- The operating system controls and coordinates the use of the hardware among various application programs for various users.
Function of OS
- User interface:
The operating system acts as an interface between a user and the computer hardware. An OS provides a platform on the top that application programs can run. The user interacts with the hardware system through the operating system.
2. program execution:
The operating system loads a program into memory and runs that program. The running program must also be able to end its execution either normally or abnormally.
3. input/output operation:
A running program may require input or output from a file or an i/o device. Users usually can’t handle the i/o devices directly and therefore, os provides a means for this.
4. file system implementation.
The program needs to read and write files. Programs also need to create and delete files by their name. All these are implemented by the operating system.
5. Resource management and resource allocation:
OS efficiently manages and allocates computer resources such as CPU, memory, main memory, and input/output device to different jobs. When multiple users are logged on the system or when multiple jobs are running at the same time, the available resource must be allocated to each of them. All these are managed with the help of several routines.
Resource management includes multiplexing resources in two different ways: time and memory.
6. Accounting
The operating system also keeps track of which user has how many and which kind of computer resources.
7. protection and security:
Security of computer systems, data stored on them, and network security are emerging as critical issues. Therefore, every OS is supposed to provide security to computer systems, data, users, and programmers.
The OS can allow and disallow access from another system, and provide user accounts, passwords, and encryption facilities to protect the system. This prevents unauthorized instruction and use by any irrelevant person and provides security.
8. Memory management.
It manages the allocation of RAM (random-access memory) to specific jobs and determines the necessity for virtual memory which increases the capacity of the memory without increasing its size. As a result, a computer that has a relatively small memory can process larger jobs. Virtual memory is a memory management scheme that overcomes limitations by allowing the execution of a process without the need to load the process in the main memory completely.
9. process management.
The process is a program that is loaded into RAM. In a multiprogramming environment, the OS decides the order in which processes have access to the processor, and how much processing time each processor has. Process management allocates a processor to execute a chosen process.
10. Device management
An OS manages all device communication using their respective device drivers. The device management allocates a device to a process.
OS performs the following activities for device management:
- It keeps track of all devices connected to the system and designates a program responsible for every device known as the input/output controller.
- An OS decides which process gets access to a certain device and for how long.
- It also allocates devices in an effective and efficient way and de-allocates devices when they are no longer required.
