Operating System Functions

There are two main functions are provided by the operating system. Following section will describe these functions separately.

Operating system as an Extended Machine

With this functionality the operating system is to present the user with the equivalent of an extended machine or virtual machine that is easier to program than the underlying hardware. For an example if a programmer wants to read a file from the hard disk, then he/she will just mention the file name and the location of the file to the operating system, because the operating system hides the functionality of the hardware from the programmer and present a nice, simple view of named files that can be read and written with ease.Otherwise the programmer should know the functionality of the hard disk and

how to retrieve files from the disk.

Operating system as a Resource Manager

Memories, processors, disks, network interfaces and printers are some of the devices which are connected to the computer in the modern day. Hence it is the job of the operating system to make sure all the resources such as memories, processors, disks, printers are systematically allocated among the
programs. In resource management resources are shared among programs in two ways. They are time and space multiplexing. When the resources are shared by using time multiplexing, different programs and users get a specific time slot to use the specified resource. For example if there is only one Central Processing Unit (CPU) and multiple programs, then the operating system will allocate the CPU for a specific time for a one program then to another program. When it comes to space multiplexing instead of taking turns by the users each program gets part of the resource. For example if we consider main memory as the resource this will be divided up among several running programs. Therefore several programs can be executed simultaneously within the system. Hence as explained the operating system will manage all the resources attached to the computer system in an effective manner.

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