1. Application
Software
System
Software

2. Software A computer is made up of tools and other
hardware that will help people work better
and more efficiently.
A computer contains two major sets of tools,
software and hardware.
Software is generally divided into systems
software and applications software.

3. System Software
Software designed to operate the computer hardware and provides infrastructure for application software which consists of operating system and utility software such as compilers, loaders, linkers, and debuggers.

4. System Software Basic types of system software: Operating system BIOS
Device driver
Utility software
Compilers
Assemblers
Debuggers

5. Operating System Device Driver BIOS Utility Software
Software consisting of programs and data that runs on computers, manages computer hardware resources, and provides common services for execution of various application software.
Allows the parts of a computer to work together and also provides a platform to run high-level system software and application software.
Device Driver
Provides basic functionality to operate and
control the hardware connected to or built
into the computer.
BIOS
BIOS which stands for Basic Input Output System contains code needed to run the keyboard, screen, disk drives and other functions
Utility Software
Helps to analyze, configure, optimize and maintain the computer.
Examples: disk cleaners, anti virus software, data compression programs,
disk drive partition utilities, storage, backup and archiving programs.

6. Compiler Debugger Linker
Program that translates source code into object code.
Compiler looks at the entire piece of source code ,
collects and reorganizes the instructions.
Allows the parts of a computer to work together and also provides a platform to run high-level system software and application software.
Debugger
A special program used to find errors(bugs) in other programs.
A debugger allows a programmer to stop a program at any
point and examine and change the values of variables.
Linker
Program that combines object modules to form an executable program. Many programming languages allow you to write different pieces of code called module separately. Eventually, you need to put all the modules together. This is the job of the linker.

7. Application Software Comprises of programs designed for an end
user such as word processors, database
systems, and spreadsheet programs.
Application software often includes
multiple applications bundled together
as a package or suite, like Microsoft Office
or OpenOffice which both contain a suite of applications for common office usage.
There are many types of applications software.

8. Types of application software for modern usage:
Word Processing Software
Database
Software
Spreadsheet
Software
Presentation
Software
Database is a structured collection of data. Database software allows the users to store and retrieve data from databases.
E.g.: ORACLE, Microsoft Access
Spreadsheet software allows users to perform calculations. They simulate paper worksheets by displaying multiple cells that make up a grid.
E.g.: Microsoft Excel
A software
that is used to display information in the form of a slide show.
E.g.: Microsoft PowerPoint
This software enables the users to create and edit documents.
E.g.: MS-Word, WordPad, Notepad
Multimedia Software
Educational
Software
Content
Access Software
Simulation
Software
A software that allow users to create and play audio and video media.
E.g.: Real Player, Media Player
Used in teaching and self-learning.
It has the capabilities of running tests and tracking progress.
A software used primarily to access content without editing.
E.g.: Media Players, Web Browsers, Help browsers, Games
Software for simulation of physical or abstract systems for either research, training or entertainment purposes.
E.g.: flight simulators and scientific simulator

9. E.g.: Fedora, Ubuntu, Redhat
Major Operating Systems
for Personal Computers
Linux
Mac
A Unix-like computer OS assembled under the model of free and open source software development and distribution
E.g.: Fedora, Ubuntu, Redhat
A series of graphical user interface-based OS developed by Apple Inc. for their Macintosh line of computer systems.
E.g.: Mac OS X
Windows
Windows XP
Windows 98
Windows 95
Windows 2000
Windows Vista
Windows 7
Windows 8
Unix
Unix is an operating system developed by Bell Labs to handle complex scientific applications using command line interface.

10. Functions of Operating System
Processor
Management
Input/output
Management
Memory
Management
Co-ordination and assignment of the different output and input device while one or more programs are being executed.
Allocation of main memory and other storage areas to the system programs as well as user programs and data.
Assignment of processor to different tasks being performed by the computer system.
File
Management
Establishment &
enforcement of a
priority system
Manages reading and writing in the file system and they are protected from access by unauthorized users.
Determines and maintains the order in which jobs are to be executed in the computer system.

11. Important characteristics of Operating System
Multitasking
Multi-user
An operating system that is capable of allowing multiple software processes to run at the same time.
A multi-user operating system allows for multiple users to use the same computer at the same time and different times
Single stream
Programs and data were submitted in groups or batches
Multithreading
Allows different parts of a single program to run concurrently.