1. SOFTWARE

2. Types of Software
Application Software
System Software

3. Application Software
Performs specific tasks and works on top of the operating system.
Three main types
General Purpose
Special Purpose
Custom Written
APPLICATION SOFTWARE
OPERATING SYSTEM

4. General Purpose
Software that performs basic tasks that most users would need to do. Comes in a software suite or Integrated software.
Eg. Microsoft Office, PDF reader, Adobe Photoshop
ADVANTAGES
DISADVANTAGES
Relatively Cheap
Little or no Customization
Easy to learn
Comes in a package and cannot be separated
No compatibility issues
Easy to Install

5. Special Purpose Software designed to perform a specific task.
Eg. Accounting, Engineering Design, Music player.
ADVANTAGES
DISADVANTAGES
Meets a specific need
Can be expensive
Usually integrates with other software well
Has no other use other than what it was made for.

6. Custom Written Software
Software that is designed specifically for an organization to meet their individual needs.
Eg. Government databases, Large businesses.
ADVANTAGES
DISADVANTAGES
Meets the individual needs of the user
Very costly
Can be modified to meet new needs
Difficult to troubleshoot at times
Cannot be used for anything else.

7. System software

8. System Software
They enable the computer to run properly. Application programs depend on the System software to run.
There are 2 main types
OS (Operating System)
Utilities

9. Operating Systems (OS)
The operating system is the set of programs that controls all the hardware and application programs that make up the computer system.
They are the most important programs because every other program depends on it.
Eg.
PC-Windows, Linux, UNIX, Mac OS, DOS
Phone -Android, iOS, Symbian, Windows Mobile

10. The OS does many functions
Process Management
Allotting adequate time and resources to each process/program
File Management
Provides the ability to modify files and folders while keeping track of their physical location on the hard drive.
Memory Management
Manages the memory the computer has so that every program can get to load as quickly and efficiently as possible.

11. OS functions contd… Input/Output Management Security and Maintenance
Controls the communication with external hardware like keyboard, mouse, printers, monitor etc…
Security and Maintenance
Provides some level of security to ensure the software is safe from viruses and malware. Provides utilities to ensure backups and error corrections take place.
User Interface
Provides a user interface that the user can interact with to give inputs.

12. USER INTERFACES

13. User Interfaces THREE TYPES Command Line Menu Driven
Graphical User Interface (GUI)

14. Command Driven Interface
A user interface that requires the user to put in special commands line by line to do tasks.
Eg. MS-DOS, UNIX
DISADVANTAGES
Requires knowledge of the commands
ADVANTAGES
Tasks can be executed very quickly once the commands are known.

15. Menu Driven Interface
Interface where the user can select multiple commands from one or more menus
Eg. Turbo Pascal
DISADVANTAGES
A lot of options may lead to confusion
Some options may not be available
ADVANTAGES
User does not have to remember commands

16. Graphical User Interface (GUI)
Interface where images are used to represent the choices a user can make.
Eg. Windows, Linux, MacOS, iOS, Android
ADVANTAGES
Easy to understand and learn
DISADVANTAGES
Some tasks can take long because there are many menus to go through to get to one choice

17. Multitasking, Multiprocessing, Multiprogramming
The execution of two tasks at the same time.
MULTIPROCESSING
The use of 2 or more CPU’s to execute different tasks simultaneously
MULTIPROGRAMMING
When two or more programs run on the same processor working one after the other.

18. PROCESSING

19. Processing TYPES OF PROCESSING Batch Processing Online Processing
Real Time Processing

20. Batch Processing
When Data is collected and stored for a period of time and processed after.
Also known as offline processing.
Eg. Salaries in a company, Printing documents, Birth Certificates

21. Online Processing
When data is collected and processed immediately and cannot be changed.
Eg. ATM Machines, Flight Bookings, Online reservations

22. Real-time processing
When data is input processed and output continuously. Activities are constantly happening.
Eg. Real time flight bookings, Facebook feeds, Checking criminal records

23. Comparison Table TYPE OF PROCESSING ADVANTAGES DISADVANTAGES BATCH
Saves on time in the long run
Changes cannot be made easily once batch has not been run.
ONLINE
Takes information and processes it on demand
Changes are not made as quickly
REAL-TIME
Changes are made instantly
Requires high processing power