Operating System Components | Operating System Components

Operating System Components

Memory Management

Memory management refers to management of both memory (Primary Memory or Main Memory.) Main memory is a large array of words or bytes where each word or byte has its own address.

Main memory is a volatile storage device. Main memory provides a fast storage that can be accessed directly by the CPU. An Operating System does the following activities for memory management −

·        Keeps tracks of primary memory, i.e., what part of it are in use by whom currently or not in use.

·        In multi-programming, the OS decides which process will get memory when and how much.

·                Allocates and De-allocates memory space as needed.

Processor Management

A process is a program in execution. A process needs certain resources, including CPU time, memory, files, and I/O devices, to accomplish its task.

In this OS decides which process gets the processor and how much time. This function is called process scheduling. An Operating System does the following activities for processor management −

·        Keeps tracks of processor and status of process. The program responsible for this task is known as traffic controller.

·        Allocates the processor (CPU) to a process.

·        De-allocates processor when a process is no longer required.

Device Management

An Operating System manages device communication via their respective drivers. It does the following activities for device management −

·        Keeps tracks of all devices. Program responsible for this task is known as the I/O controller.

·        Decides which process gets the device when and for how much time.

·        Allocates the device in the efficient way.

·        De-allocates devices.

File Management

A file is a collection of related information defined by its creator. A file system is normally organized into directories for easy navigation and usage. These directories may contain files and other directions.

An Operating System does the following activities for file management −

·        Keeps track of information, location, uses, status etc. The collective facilities are often known as file system.

·        Decides who gets the resources.

·        Allocates and De-allocates the resources.

Services Provided by Operating System

Program execution

The purpose of computer system is to allow the users to execute programs in an efficient manner. The operating system provides an environment where the user can conveniently run these programs.

Following are the major activities of an operating system with respect to program management −

• Loads a program into memory.
• Executes the program.
• Handles program's execution.

I/O Operation

This involves the use of I/O devices.

An Operating System manages the communication between user and device drivers.

• I/O operation means read or write operation with any file or any specific I/O device.
• Operating system provides the access to the required I/O device when required.

File system manipulation

This is an important task that is also performed by the operating system.

Following are the activities of an operating system with respect to file management :-

• Opening a file from the storage disk.
• Program needs to read a file or write a file.
• The operating system gives the permission to the program for operation on file.
• Operating System provides an user to create/delete files.
• Operating System provides create the backup of file system.

Communication

In case of distributed systems which are a collection of processors that do not share memory, peripheral devices, or a clock, the operating system manages communications between all the processes.

Error handling

The main function of operating system is to detect the errors. An error may occur in CPU, in I/O devices or in the memory hardware. The OS constantly checks for possible errors.

Resource Management

In case of multi-user or multi-tasking environment, resources such as main memory, CPU cycles and files storage are to be allocated to each user or job.

Protection

Protection refers to a mechanism or a way to control the access of programs, processes, or users to the resources defined by a computer system. Protection involves ensuring that all access to system resources is controlled.