An operating system is a program that enables communication between computer hardware and software. It manages both hardware and software resources and is considered the backbone of a computer. Operating systems can be classified as multi-user, multi-processing, multi-tasking, multi-threading, or real-time depending on their capabilities. The three most popular desktop operating systems are Windows, Mac OS, and Linux.

1. COMPUTER
OPERATING
SYSTEM
By –
Norser

2. Classification of software
Software
a. System software
1. Operating System
2. Language processor
3. Device Driver
4. Utilities
b. Application software
1. General purpose application S/W
2. Specific purpose application S/W
3. Customised S/W

3. Introduction to computer operating
system
An operating system is a program designed to run
other programs on a computer
A computer’s operating system is its most important
program
It is considered the backbone of a computer,
managing both software and hardware resources

4. Introduction to computer operating system(content)
An operating system, or OS, is a software program that enables the
computer hardware to communicate and operate with the computer
software
Without a computer operating system, a computer would be useless

6. Classification of Operating systems
Multi-user:- Allows two or more users to run programs at the same time.
Some operating systems permit hundreds or even thousands of concurrent
users.
Multi-processing :- Supports running a program on more than one CPU.
Multi-tasking:- Allows more than one program to run concurrently.
Multi-threading :- Allows different parts of a single program to run
concurrently.
Real time :- Responds to input instantly. General-purpose operating
systems, such as DOS and UNIX, are not real-time.

7. Most Popular Desktop Operating
Systems
The three most popular types of
operating systems for personal and
business computing include Linux,
Windows and Mac.

8. Windows
Microsoft Windows is a family of
operating systems for personal
and business computers.
Windows dominates the
personal computer world,
offering a graphical user
interface (GUI), virtual memory
management, multitasking, and
support for many peripheral devices.

9. Mac
Mac OS is the official name of the
Apple Macintosh operating system.
Mac OS features a graphical user
interface (GUI) that utilizes windows,
icons, and
all applications that run on a
Macintosh computer have a similar
user interface.

10. Linux
Linux is a freely distributed open
source operating system that runs
on a number of hardware platforms.
The Linux kernel was developed
mainly by Linus Torvalds and it is
based on Unix.

11. List of operating systems