What is an operating system?
State the functions of an operating system
Answers
Answer:
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. ... The dominant general-purpose desktop operating system is Microsoft Windows with a market share of around 76.45%.
An operating system has three main functions: (1) manage the computer's resources, such as the central processing unit, memory, disk drives, and printers, (2) establish a user interface, and (3) execute and provide services for applications software..
Answer:
The operating system manages computer resources, especially the allocation or assignment of the resources among other programs. Management tasks include scheduling the resources to avoid conflicts and interference between programs. The various functions of the operating system are shown in Figure.
Let us now discuss each function in detail.
4.2.1 Process Management
We know that a program is a set of logical instructions given to the computer. A program that is in an execution state is called a process. For example, a word processing program like MS-Word being run by a user on a personal computer is a process. A system task, such as sending output to a printer, can also be a process.
A process needs certain resources-such as CPU time, memory, files, and I/O devices to accomplish its tasks. These resources are allocated to the process either when they are created or while they are executing. The operating system helps in the allocation of resources to each process. The most critical task for an operating system is the allocation of the CPU time. Each process is allowed to use the CPU for a limited time, which may be a fraction of a second. It must then give up control and thus becomes suspended until its next turn. Thus, to maximize CPU utilization and allow multiple processes to run, process scheduling is performed by the OS. The operating system is responsible for the creation, deletion, and scheduling of various processes that are being executed at any point of time.
4.2.2 Memory Management
A computer program remains in main (RAM) memory during its execution. To improve CPU usage several processes are being executed simultaneously in the memory. The OS keeps track of every memory location, that is either assigned to some process, or is free. It also checks how much memory should be assigned to each process.
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