JSS 2 WEEK 10 LESSON NOTE

 

Jss 2

TOPIC: Operating System       

Introduction

Operating system is a system that manages both hardware and software resources in the computer. Computers require an operating system (OS) to work. The operating system comprises a group of programs that manages the computer system resources.

Categories of Operating Systems

Operating system is divided into three categories:

1.     Single user tasking operating systems: operating system in this category can be used by one user at a time and it can only handle one job or task at a time. One notable example of this operating system is the Microsoft disk operating system (MSDOS).

2.     Single user multi-tasking operating systems: this type of operating system  can accommodate one user at a time and can perform several operations at the same time. For example, you can be working on an MS Excel document, sending your MS word document to the printer and playing music at the same time. Example of such operating system is the Microsoft windows OS.

3.     Multi-user multitasking operating systems: this is the type of operating system that can accommodate many users at the same time and can perform many task at the same time. Example of this operating systems are windows server, UNIX, ZENIX, LINUX etc.

Functions of The Operating System

When you turn on your computer, the work of the operating system begins by performing certain initial operation. The initial operation performed by the OS is called BOOTING. Booting is the process of loading an OS into the computer memory. When the computer is turned on it undergoes a self-test known as power on self-test (POST).

The following functions are performed by the operating system:

a.     Allocating system resources: operating system allocates resources to both hardware and software by giving each device a period of time by which the resource will be used.

b.     System performance: the OS helps a user or administrator to check whether the computer or network is getting overloaded.

c.      System security: system security is part of the operating system, though additional software can add more security functions.

d.     Data management: operating system keeps all track of data on the disk.

e.     Task management: it controls the order and manner in which programs run and execute.

f.       Device management: operating system also controls data flow to and from peripheral devices.

g.     Memory management: operating system allocates adequate memory for running a particular program.

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