System software that is responsible for the management of computer hardware, software resources, and also provides common services for computer programs is known as an operating system (OS). The operating system is what ‘breathes life’ in any computer system.
The operating systems that are time-sharing can schedule tasks for the better efficacy use of the system and might also include the accounting software for the allocation of the cost of the processor time, mass storage, printing, and numerous other resources.
For some hardware functions like input and output, and memory location the operating system acts as an intermediary between the computer hardware and the programs. However, the application code is basically executed directly by the hardware and can frequently make system calls to an OS function or can be interrupted by it. Operating systems can be found on many devices that contain a computer, from cell phones and video game consoles to web servers and supercomputers.
The operating system also affects the user experience and interface. Read this informative article about Operating system and user interface
Operating System Services
The service provider to both, the users and to the programs is known as an operating system. It helps in providing programs a suitable environment to execute. Users use it to provide the services for executing the programs in a more convenient manner.
However, the services provided by the operating system can differ from one operating system to another. For the convenience of the programmer and to make the programming task much easier, the operating system services are provided and used. The common services that are provided by an operating system are-
1. User interface (UI): It allows the user to interact with the OS or it can interact with the CS itself. Almost all OS have a UI and this UI can take several forms like Command Line Interface (CLI), Graphical User Interface (GUI).
2. Program execution: When an OS starts loading a program into memory and executes the program, it is called program execution. Also, in this, the program must be able to end its execution either normally or abnormally.
3. I/O operations: It means reading or writing operation with any file or any specific I/O device. OS provides access to the required I/O device when it is needed by a user because a user usually cannot directly control I/O devices.
4. File system manipulation: When a program needs to read a file or write a file the operating system gives it permission for operating on the file. Permission can be varied from read-only, read-write, denied, and so on.
5. Communication: Two or more processes often require data to be transferred between or among them. The processes can either be on one computer or on different computers, but they can always be connected through a computer network. Hence, communication can be defined as the implementation by the two methods either by shared memory or by message passing.
6. Error detection: An error occurs sometimes in CPU in I/O devices or in the memory. Hardwires constantly check for those possible errors, OS takes appropriate action to ensure consistent computing when any error occurs. For the system to just not break down, and it should not just seize your computing ability completely, the OS must have a required way in which it manages those errors so that computing is consistent and it is still carried on even if some errors are encountered.
7. Resource allocation and management: In the case of multi-user or multi-tasking environments, resources like the main memory and CPU cycles and the storage files have to be allocated to the respective user or job.
8. Protection and security: As there are multiple users and concurrent execution of multiple processes at the same time, various processes must be protected from each other’s activities and also for the security of each user to have authentication by means of a password, to gain access to resources whenever it is needed.
9. Accounting: Logs of each user are important and must be kept safely. It is also necessary to keep a record of how much or what kind of computer resources the user is using. This log also can be used for accounting purposes or simply for accumulating the usage statistics. It could be a valuable tool for researchers who need to reconfigure the system or improve the computing services.
The Dual Mode of Operations
Two modes of operations in which a program can be executed are-
1. User Mode: When the program does not have direct access to memory, hardware, and such resources then the program is known to be executed in the user mode.
2. Kernel Mode: When the program has direct access to memory, hardware, and such resources the program is said to be executed in kernel mode. When a program is executed in kernel mode it is believed to be in a privileged mode because then it can have direct access to some resources.
Conclusion
The operating system is the software that actually makes the computer functional. Without the OS, a system is simply a hardware machine, unable to perform the desired operations. So, a proper understanding of the OS is a must for computer science enthusiasts and even for students of all fields as OS-run devices are an integral part of everyone’s life.
Read more: Types of software available
Written By - Pavas Shrigyan
Edited By - Neha Kundu
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