What is operating system? Discuss role/functions of OS as a resource manager..
An operating system (OS) is a collection of software that manages computer hardware resources and provides various services for computer programs. It acts as an intermediary between the user of a computer and the computer hardware.
View of OS as a Resource Manager
- A computer consists of a set of resources such as processors, memories, timers, disks, printers and many others.
- The Operating System manages these resources and allocates them to specific programs.
- As a resource manager, Operating system provides controlled allocation of the processors, memories, I/O devices among various programs.
- Multiple user programs are running at the same time.
- The processor itself is a resource and the Operating System decides how much processor time should be given for the execution of a particular user program.
- Operating system also manages memory and I/O devices when multiple users are working.
- The primary task of OS is to keep the track of which programs are using which resources, to grant resource requests, to account for usage, and to resolve conflicting requests from different programs and users.
- An Operating System is a control program. A control program controls the execution of user programs to prevent errors and improper use of computer.
- Resource management includes multiplexing (sharing) resources in two ways: in time and in space.
- When a resource is time multiplexed, different programs or users take turns using it. First one of them gets to use the resource, then another, and so on.
- For example, CPU and printer are time multiplexed resources. OS decides who will use it and for how long.
- The other kind of multiplexing is space multiplexing, instead of the customers taking turns, each one gets part of the resource.
- For example, both primary and secondary memories are space multiplexed. OS allocates them to user program and keeps the track of it.
