This document provides an overview of software and operating systems. It begins by defining computer software and classifying it into two main categories: system software and application software. System software manages computer hardware and provides a platform for running other software. Application software allows users to perform useful tasks. The document then focuses on operating systems, describing them as the most important system software. It explains the basic functions of operating systems, such as controlling hardware access and managing files, and classifies operating systems based on features like single-user vs multi-user capabilities.
2. SOFTWARE
Computer software, or simply software, is that part of
a computer system that consists of encoded information or
computer instructions, in contrast to the
physical hardware from which the system is built.
The term "software" was first proposed by
Alan Turing and used in this sense by John
W. Tukey in 1957. In computer science and
software engineering, computer software
all information processed by computer
systems, programs and data.
Computer software includes computer programs,
libraries and related non-executable data, such as online
documentation or digital media. Computer hardware and
software require each other and neither can be realistically
used on its own.
3. SOFTWARE CLASSIFICATION
The two main classifications of software that all programs fit
under are:
• System software
• Application software
Without software, most hardware would sit
there doing nothing or perform specific tasks.
To make most hardware run we need to use
software, and your task here is to select the
correct type of software for each job.
4. SYSTEM SOFTWARE
software designed to operate the computer hardware and to
provide a platform for running application software. Modern
computers are complex machines
involving many different parts. To
keep it running well you will need
system software. System software
will handle the smooth running of all
the components of the computer as
well as providing general
functionality for other programs to
use, tools to speed up the computer,
tools to develop new software and
programs to keep you safe from attacks. There are several
different types of system software that we will look at in more
detail very shortly.
5. APPLICATION SOFTWARES
Application software is designed for people like me and you to
perform tasks that we consider useful. This might be the
ability of a scientist to work out statistical information using a
set of results, or someone who wants to play the latest
computer game. There are several categories of Application
software that we'll look into shortly:
6. OPERATINGSYSTEM
The operating system (OS) is the most important program that
runs on a computer. Every general-purpose computer must
have an operating system to run other programs
and applications. Computer operating systems perform basic
tasks, such as recognizing input from the keyboard, sending
output to the display screen, keeping track of
files and directories on the disk, and
controlling peripheral devices such as
printers.
For large systems, the operating system has even greater
responsibilities and powers. It is like a traffic cop -- it makes
sure that different programs and users running at the same
time do not interfere with each other. The operating system is
also responsible for security, ensuring that unauthorized users
do not access the system.
7. BASIC FUNCTIONS OF OS
Regardless of the size and complexity of the computer and the
operating system, all operating systems perform the same
four basic functions:
• Control hardware access
• Manage files and folders
• Provide a user interface
• Manage applications
8. CLASSIFICATION OF OS
An operating system is regarded as system software, a type of
software whose primary function is to operate and control
hardware. By managing the operations of the hardware, users
are shielded from the complexity of how the computer
performs its functions. Once an operating system is in place,
all other applications can be installed and used appropriately.
Users can then accomplish powerful tasks with ease.
The main operating system classifications include real-time
operating systems, single-user single task systems, single-user
multitasking systems and multi-user operating systems.
Single-user operating systems are designed to let the user
perform one task at a time, while single-user multitasking
systems allow users to perform multiple tasks simultaneously.
Multi-user operating systems allow multiple users to carry out
multiple operations at the same time
9. These systems typically need enormous computing resources to
function properly, such as large amounts of computer memory and
processing power. Typical examples of multi-user systems include
Open Virtual Memory Systems (OVMS), mainframe operating
systems and a variety of Unix-based systems.