Operating System – A Brief OverviewIntroduction -
- An Operating System is a program that manages the computer hardware. It provides a basis for the application programs. An operating system acts as an interface between user of a computer and the hardware of the computer. Operating System is important for every modern computing devices i.e. mobile phones, personal computer, super computer.
Example of Operating System –
- MS DOS, WINDOWS 7, UNIX, Ubuntu, WINDOWS 10 etc.
Structure of Operating System -
A computer system is divided into four components i.e. the hardware, the operating system, the application programs and the users.
- The Hardware- This part consists of Central Processing Unit (CPU), memory and input/output devices. It provides basic computing resources.
- The Operating System- It includes file management, process management, memory management and I/O control routines. It provides the means for the proper use of resources of the computer system.
- Application Programs- It defines the ways in which the resources are used to solve the computing problems of the users.
- Users- The users sit at the terminal connected to the mainframe or minicomputer. These users share the resources and may exchange information.
Objectives of the Operating System -
- Operating System makes the computer more user-friendly and convenient.
- It allows the resources of the computer system which must be used in efficient manner.
- It permits the effective development, test and the new functions of the system without indulging with the service.
Features of Operating System -
- Device Management - It keeps the track of all devices. It decides that which of the processes gets device. It also determines the place and timing.
- Memory Management- It also tracks the primary memory and allocates it when a process or program requests for it.
- File Management - It allocates and withdraws resources and decides its recipient.
- Processor Management - It allocates CPU or the processor to a process when it is required.
- Security- It prevents the unauthorized access by the third party to the programs and data by providing password and other security measures.
- It controls the system performance and records the delay between request and response.
- It coordinates between Users and Software.
Types of Operating System-
Batch Operating System -
- The user does not interact directly with computer.
- It transfers control from one job to the next automatically.
- Operator sorts the programs into batches and run the batches when the computer is available.
Multi-Programmed Operating System-
- It keeps several jobs in memory simultaneously.
- It increases CPU utilization by organizing the jobs in such a way that the CPU always has one job to execute.
Time-Sharing Operating System-
- It is a logical extension of multi-programming operating system.
- It executes multiple jobs by switching among them, but the users can interact with each program while running.
- It provides direct communication between user and system.
Single User Operating System-
- It can be used on a single computer and is developed for a single user at any given time.
Multi User Operating System-
- It allows more than one user on multiple computers to access the single system with one operating system on it.
Real Time Operating System-
- It is used when a there is a rigid time requirement. It has well-defined fixed time constraints.
- Time interval is required in this operating system to process.
- It is of two types, I.e. hard real-time system and soft real-time system.
- It functions properly if it returns the result correctly within the time constraints.