1. Course Code 114 Introduction to Computer Science
Lecture 2
Basics of Computer Science
Assoc. Prof. Hussam Elbehiery
Egypt 2018

4. Basics of Computer Science
A computer system is an integrated form of different components that work together to give a desirable result.
It has different component and each works for a specific purpose; however, they generate a common result as required by the user.

6. Components of Computer System
Hardware
The physical components collectively form the hardware of a computer system. Hardware comprises of the equipment that helps in the working system of the computer.
Software
The hardware components can only function when software components are added to the computer system. Software is a program that performs different commands given by a user.

7. Hardware Monitor − It displays (visual) the result.
CPU − It is the Central Processing Unit that controls the computer’s functions and transmits data.
Motherboard − It is mainly accountable to establish communication between components and transmission of information.
RAM − It is the Random Access Memory and responsible for the storage of programs that are currently running and also stores data temporarily.
Hard Disk Drive − It is a permanent memory storage device.
Floppy Disk Drive − It is hardly being used in recent times.
Optical disks − It is a device that also store data. For example, CD, DVD, etc.

8. Relationship between Hardware and Software
Hardware and software are mutually dependent on each other.
Software acts as an interface between the user and the hardware.
Both of them must work together to make a computer produce a useful output.
Software cannot be utilized without supporting hardware.
Hardware without set of programs is useless.
Software development is very expensive and is a continuing expense.
If hardware is the 'heart' of a computer system, then software is its 'soul'. Both are complimentary to each other.

10. Software Types of Software:
A program is a sequence of instructions written to solve a particular problem. Software is a set of programs.
Types of Software:
Depending on the basic features and functionality, software can be categorized as:
Operating Systems (OS)
Application Software (AS)
E-accessibility Software

11. Operating System
This software helps to load the basic program automatically as soon as the computer is started.
Operating Software
Examples
Microsoft Windows
XP, Vista, Win 8, Win 10, etc.
Mac OS X
Panther, Cheetah, Snow leopard, etc.
Linux
Debian, Ubuntu, Fedora, Knoppix, Redhat, etc.

12. Application Software
The software, which can be used on an installed operating system, is known as application software.
Application Software
Examples
Office programs
Microsoft Office, OpenOffice, LibreOffice, etc.
Web browser
Internet Explorer, Mozilla Firefox, Google Chrome, Opera, Safari, etc.
Antivirus Program
Norton, McAfee, Quick Heal, Avira, Kaspersky, etc.

13. E-accessibility Software
The E-accessibility software components additional facilities to users such as:
Voice recognition software
Screen reader
Magnifying tool
On-screen keyboard
Video games
Learning software, etc.

14. Computer systems
Computer is an electronic data processing device which:
Accepts and stores data input,
Processes the data input, and
Generates the output in a required format.

15. The Von Neumann model
John Von Neumann ( ), is worthy of special mention. He developed a very basic model for computers which we are still using today.
Von Neumann divided a computer’s hardware into 5 primary groups linked to CPU:
Input/Output units
Input
Output
Working storage
Permanent storage

16. Input Unit
This unit makes link between user and computer. The input devices translate the information into the form understandable by computer.

17. CPU (Central Processing Unit)
CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, intermediate results and instructions (program). It controls the operation of all parts of computer. CPU itself has following three components
ALU(Arithmetic Logic Unit)
Memory Unit
Control Unit
Output Unit
This unit is a link between computer and users. Output devices translate the computer's output into the form understandable by users.

18. All types of computers follow the same basic logical structure and perform the following five basic operations.

19. Advantages High Speed Accuracy Storage Capability Versatility
Reliability
Automation
Reduction in Paper Work
Reduction in Cost

20. Disadvantages No I.Q (In-phase and Quadrature components)
(Intelligence quotient)
Dependency
Environment
No Feeling

21. Computer - Input Devices
Following are few of the important input devices which are used in a computer:
Keyboard, Mouse, Track Ball, Joy Stick
Light pen, Scanner
Graphic Tablet
Microphone
Magnetic Ink Card Reader(MICR)
Optical Character Reader(OCR)
Bar Code Reader
Optical Mark Reader(OMR)

22. Computer - Output Devices
Following are few of the important output devices which are used in a computer.
Monitors
Graphic Plotter
Printer
Speakers

23. Input & Output Device Input Device Output Device Mouse Monitor
Microphone
Speaker
Keyboard
Printer
Camera
Earphone
Scanner
Projector
Trackball
Touchpad
Plotter
Joystick

24. CPU (Central Processing Unit)
Memory or Storage Unit
This unit can store instructions, data and intermediate results. This unit supplies information to the other units of the computer when needed.
It is also known as internal storage unit or main memory or primary storage or Random access memory (RAM).
Its size affects speed, power and capability. Primary memory and secondary memory are two types of memories in the computer.

25. Memory unit is:
The amount of data that can be stored in the storage unit.
That in which storage capacity is expressed in terms of Bytes.

26. Sr.No.
Unit
Description 1
Bit (Binary Digit)
A binary digit is logical 0 and 1 representing a passive or an active state of a component in an electric circuit. 2
Nibble
A group of 4 bits is called nibble. 3
Byte
A group of 8 bits is called byte. A byte is the smallest unit which can represent a data item or a character. 4
Word
A computer word, like a byte, is a group of fixed number of bits processed as a unit which varies from computer to computer but is fixed for each computer.
The length of a computer word is called word-size or word length and it may be as small as 8 bits or may be as long as 96 bits. A computer stores the information in the form of computer words.

27. Unit
Description
Kilobyte (KB)
1 KB = 1024 Bytes
Megabyte (MB)
1 MB = 1024 KB
GigaByte (GB)
1 GB = 1024 MB
TeraByte (TB
1 TB = 1024 GB
PetaByte (PB)
1 PB = 1024 TB

28. Control Unit
This unit controls the operations of all parts of computer but does not carry out any actual data processing operations.
Functions of this unit are:
It is responsible for controlling the transfer of data and instructions among other units of a computer.
It manages and coordinates all the units of the computer.
It obtains the instructions from the memory, interprets them, and directs the operation of the computer.
It communicates with Input/Output devices for transfer of data or results from storage.
It does not process or store data.

29. ALU (Arithmetic Logic Unit)
This unit consists of two subsections namely
Arithmetic section
Logic Section

30. Computer Generations
The generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software.
There are totally five computer generations known till date.
Each generation differed in their time period and characteristics. Following are the main five generations of computers.

32. Computer - Types

33. Assoc. Prof. Hussam Elbehiery
Thank you
With all my best wishes
Assoc. Prof. Hussam Elbehiery