Chapter 8, Problem 1RETC

Program Plan Intro

Operating System:

A program that is initially loaded into the computer memory and manages all the other programs and resources of a computer is called Operating system.

• The operating system manages the applications and the hardware, such as disk drive, memory, and peripheral devices.
• The users interact with the operating system by using the command language or shell, and the graphical user interface.
• An application makes the service request by the application programming interface to use the operating system.
• Operating system performs different type of services
  • Determining the running application and its order
  • Time allotment to each application

Explanation of Solution

Main objective of early operating systems:

• In early days, computer system has no Operating system at all, and is characterized as serial processing. By using a serial processing technique the programs are executed.
• Earlier, the cost of computer systems were high and because of that computer time was used efficiently without any wastage of time.
• The time slots are reserved by the users in advance, and during the allotted period, they occupy the computer exclusively.
• A card is used to represent the program and with the help of card readers, the programs are loaded into memory.
• Before loading the program, the user has to load the compiler to compile the program. The user has to find errors if any and should re-punch all cards from beginning.
• In given time, if the user failed to complete the task, then the user has to wait for long time to execute again. This was a waste of time for the user.