OPERATING SYSTEMS Review

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INTRODUCTION

What is operating system?
Manages the computer hardware.
Act as intermediately between user and hardware.
Provides environment for applications/ processes to work better.
In how many parts a computer system can be divided?
Hardware,
Os
Application Programs
Users.


What is meant by context switching in an OS ?
A context switch is the computing process of storing and restoring the state (context) of a CPU such that multiple processes can share a single CPU resource. A context switch can mean a register context switch, a thread context switch, or a process context switch.



What are turnaround time and response time?
 Turnaround time is the interval between the submission of a job and its completion. Response time is the interval between submission of a request, and the first response to that request.



What’s the difference between trap and interrupt?
 An interrupt is a hardware-generated event, usually caused by an I/O device requesting service. An interrupt service routine (ISR) saves the CPU state, services the interrupt, then restores control to the interrupted process. A trap, on the other and, is a software-generated interrupt.



What is aging?
  Aging is the technique of gradually increasing the priority of processes that wait in the system for a long time. Thus it is a solution of starvation.
What is bus waiting?
The repeated execution of a loop of code while waiting for an event to occur is called busy-waiting. The CPU is not engaged in any real productive activity during this period.