Dentistry College - University of Tikrit Computer Science ...

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Dentistry College - University of Tikrit

Computer Science

The First Stage - First Semester - 2018-2019

Ass. Lec. Tamara A. Anai

1Ass. Lec. Tamara A. Anai

Basic Concepts of Computer:

Computer is an electronic device which is used to store the data, as per given instructions it gives results quickly and accurately.

• Data : Data is a raw material of information.

• Information : Proper collection of the data is called information.

Computer Science

• Data type :

is a classification of the type of data that a variable or object can hold in computer programming. Data types are an important factor in virtually all computer programming languages, including C#, C++, JavaScript, and Visual Basic.

Examples of data types

• Boolean (e.g., True or False)

• Character (e.g., a)

• Date (e.g., 03/01/2016)

• Floating-point number (e.g., 1.234)

• Integer (e.g., 1234)

• String (e.g., abcd)

• Others

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Information Processing Cycle

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The Five Generations of Computers

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Generations of Computer

• The computer has evolved from a large-sized simple calculating machine to asmaller but much more powerful machine.

• The evolution of computer to the current state is defined in terms of thegenerations of computer.

• Each generation of computer is designed based on a new technologicaldevelopment, resulting in better, cheaper and smaller computers that aremore powerful, faster and efficient.

• Currently, there are five generations of computer. In the followingsubsections.

Computer Science

First Generation Computers (1940-1956)

The first computers used vacuum tubes(a sealed glass tube containing a

near-vacuum which allows the free passage of electric current.) for

circuitry and magnetic drums for memory.

They were very expensive to operate and in addition to using a great deal of

electricity, generated a lot of heat.

Example : Electronic Numerical Integrator and

Computer (ENIAC) .

First Generation Computers

Advantages :

• It was only electronic device

Disadvantages :

• large in size

• Vacuum tubes burn frequently

• Maintenance problems

Second Generation Computers (1956-1963)

• Transistors replaced vacuum tubes and ushered in the second generation of computers.

• Second-generation computers moved from binary machine language to symbolic.

• High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN.

• Example : IBM 1401

Second Generation Computers

Advantages :

• Size reduced The very fast

Disadvantages :

• They over heated quickly

• Maintenance problems

Third Generation Computers(1964-1971)

• The development of the Integrated Circuit (IC).

• Allowed the device to run many different applications at one time.

• Example: IBM System/360

Advantages :

ICs are very small in size

Improved performance

Production cost cheap

Fourth Generation Computers(1971-present)

• The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.

• From the central processing unit and memory to input/output controls—on a single chip.

• . Fourth generation computers also saw the development of GUIs, the mouse and other devices.

• Example: Macintosh 128k

Fifth Generation Computers(present and beyond)

• Fifth generation computing devices, based on artificial intelligence.

• Are still in development, though there are some applications, such as voice recognition.

• The use of parallel processing and superconductors is helping to make artificial intelligence a reality.

• Example: Super computer

Features of a Computer

High speed, accuracy large storage capacity, high reliability and versatility are some of the important features of computers.

• SPEED : In general, no human being can compete to solving the complex computation, faster than computer.

• ACCURACY : Since Computer is programmed, so what ever input we give it gives result with accurately.

• STORAGE : Computer can store mass storage of data with appropriate format.

• POWER OF REMEMBERING : It can remember data for us.

• Computer can work for hours without any break and creating error.

• We can use computer to perform completely different type of work at the same time.

Computer Science

Uses of Computer in Our Daily Life

Use of computer on regular basis in our life is very important. Technically in

daily life computer is used to convert raw facts and data into meaningful

information and knowledge. Computer science is explored and challenged by

humans daily.

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1. Uses of the computer in Education

2. Use of computer in the business

3. Uses of the computer in hospitals

4. Uses of the computer in the

banking sector

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5. Uses of the computer in government offices

6. Uses of the computer in the home

7. Uses of the computer in marketing

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8. Computer used by various people around the world

for different reasons and purposes

•Kids

•High school students

•College students

•Job seekers

•Business owners

•Computer Professional & IT people

9. Uses of computer in new habits—Impact of computer in our life

10. Uses of computer to change life

Computer Science

Types of Computers1. Analog Computers

Analog computers are used to process continuous data. Analog computers

represent variables by physical quantities. Thus any computer which solve

problem by translating physical conditions such as temperature, pressure,

or voltage into related mechanical or electrical related circuits as an analog

for the physical phenomenon being investigated in general it is a computer

which uses an analog quantity and produces analog values as output.

Analog computers are very much speedy. They produce their results very

fast. But their results are approximately correct. All the analog computers

are special purpose computers.

Computer Science

Ass. Lec. Tamara A. Anai 24

2. Digital Computers

Digital computer represents physical quantities with the help of digits or

numbers. These numbers are used to perform Arithmetic calculations and

also make logical decision to reach a conclusion, depending on, the data

they receive from the user.

3. Hybrid Computers

Various specifically designed computers are with both digital and analog

characteristics combining the advantages of analog and digital computers

when working as a system. Hybrid computers are being used extensively in

process control system where it is necessary to have a close representation

with the physical world.

Computer Classification

• Computers can be classified by size and power to:1. Personal computer (PCs)2. Workstation:3. Minicomputer:4. Mainframe:5. Supercomputer

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•Personal computer (PCs): a small, single-user computer based on a microprocessor. In addition to the microprocessor, a personal computer has a keyboard for entering data, a monitor for displaying information, and a storage device for saving data.

• Workstation: a powerful, single-user computer. A workstation is like a personal computer, but it has a more powerful microprocessor and a higher-quality monitor.

• Minicomputer: multi-user computer capable of supporting from 10 to hundreds of users simultaneously.

• Mainframe: powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.

• Supercomputer: an extremely fast computer that can perform hundreds of millions of instructions per second.

• Compare between the previous type of computers based on • Price• Processing Speed • Storage Capacity• Powerful• Single-user or Multi-user• Computer Size

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There are 3 main types of PCs

Laptop computer

• Is a portable computer.

• Personal computer that can be easily carried and used in a variety of locations.

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Netbook Computer

• A netbook is a type of laptop that is designed to be even more portable.

• Cheaper and less powerful than laptops or desktops.

• They are generally less powerful than other types of computers, but they provide enough power for email and internet access, which is where the name "netbook" comes from.

Mobile Devices

• A mobile device is basically any handheld computer.

• It is designed to be extremely portable.

• Some mobile devices are more powerful

• Types:

1.Tablet Computers

2.Smartphones

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Tablet Computers• Designed to be portable.

• The most obvious difference is that tablet computers don't have keyboards or touchpads.

• Best used for tasks like web browsing, watching videos, reading e-books, and playing games.

Smartphones

• A powerful mobile phone

• Designed to run a variety of applications in addition to phone service.

• Compare it with the tablet?

• Internet access is an important feature of smartphones. (3G or 4G)(Wi-Fi Service)

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Hardware

• Computer hardware is the collection of physical elements "Tangible objects”

• That constitutes a computer system.

• The actual machinery, wires, transistors, and circuits … etc.

Computer Components

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Software

• Computer Programs

• Instructions and data

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Computer Units

1.Input Unit 2.Output Unit 3.Central processing Unit 4.Primary Memory Unit 5.Secondary storage Unit

Input Devices • Input device is any peripheral (piece of computer

hardware equipment to provide data and control signals to an information processing system such as a computer or other information appliance.

• Input device Translate data from form that humans understand to one that the computer can work with. Most common are keyboard and mouse

Computer Science

Input Devices

Output Unit

• An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer)

• converts the electronically generated information into human-readable form.

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Output devices Examples

1. A monitor

CRT: Cathode Ray Tube LCD: Liquid crystal display

most familiar these days

Output devices Examples

2. Printer:

• Transfers data from a computer onto paper

Printer types:

1-Laser Printer.

2-Ink Jet Printer.

3-Dot Matrix Printer

Central Processing Unit

• CPU

• known as microprocessor or processor

• It is responsible for all functions and processes

CPU Components

• The CPU is comprised of three main parts

1. ALU (Arithmetic Logic Unit)

2. Control Unit (CU)

3. Registers: Stores the data that is to be executed next.

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Arithmetic Logic Unit (ALU)

• Executes all arithmetic and logical operations.

• Arithmetic calculations like as addition, subtraction, multiplication and division.

• Logical operation like compare numbers, letters, or special characters

Control Unit (CU)

Control Unit (CU): controls and co-ordinates computer components.

• Read the code for the next instruction to be executed.

• Increment the program counter so it points to the next instruction.

• Read whatever data the instruction requires from cells in memory.

• Provide the necessary data to an ALU or register.

• If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.

Registers• Registers :Stores the data that is to be executed next, "very

fast storage area".

Unit of Measurement -Speed

• The speed of CPU measured by unit called Hertz (Hz)

• 1 Hz represent 1 cycle per second.

• The speed of CPU is known as Computer Speed.

Computer Science

CPU SPEED MEASURES

1 hertz or Hz 1 cycle per second

1 MHz 1 million cycles per second or 1000 Hz

1 GHz 1 billion cycles per second or 1000 MHz

Computer Hardware

Central Processing Unit (CPU)

MicroprocessorAss. Lec. Tamara A. Anai 50

Computer Science

The CPU is usually protected

from Heat by a

Fan combinationAss. Lec. Tamara A. Anai 51

Computer Science

Motherboard

Primary Memory

• 1. RAM.

• 2.ROM

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Primary Memory

1. RAM: Random Access Memory: is a memory scheme within the computer system responsible for storing data on a temporary basis, so that it can be promptly accessed by the processor as and when needed.

• It is volatile in nature, which means that data will be erased once supply to the storage device is turned off.

• RAM stores data randomly and the processor accesses these data randomly from the RAM storage.

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Primary Memory

2. ROM (Read Only Memory): ROM is a permanent form of storage. ROM stays active regardless of whether power supply to it is turned on or off. ROM devices do not allow data stored on them to be modified.

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Secondary Memory

• Stores data and programs permanently

• its retained after the power is turned off

• Main Examples 1. Hard Disk2. Optical Disk3. Flash memory

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Hard Disk

• Called Disk drive or HDD

• stores and provides relatively quick access to large amounts of data.

• Stores data on an electromagnetically charged surface or set of surfaces.

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Optical Disk & Flash

• an optical disc drive (ODD) is a disk drive that ses laser light to store data.

• There are three main types of optical media: CD, DVD, and Blu-ray disc

CD “Compact Disk” can store up to 700MB

DVD “ Digital Video Disk “ can store up to 8.4 GB

Blu-ray disc. can store up to 50 GB

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3. Flash Disk

• A storage module made of flash memory chips. A Flash disks have no mechanical platters or access arms, but the term "disk" is used because the data are accessed as if they were on a hard drive. The disk storage structure is emulated.

• What are the differences between RAM as a main memory and HDD as a Secondary Memory?????

Computer Science

Software

• Software is a generic term for organized collections of computer data and instructions, often broken into two major categories two major categories:

1. system software 2. application software

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System software

• Known as Operating System (OS)

• is responsible for controlling, integrating, and managing the individual hardware components of a computer system

• Windows is an example of OS.

• example of System Software:

• 1) Microsoft Windows

• 2) Linux

• 3) Unix

• 4) Mac OSX

• 5) DOS61Ass. Lec. Tamara A. Anai

Computer Science

Application software

• is used to accomplish specific tasks other than just running the computer system.

• It may consist of:• a single program, such as an image viewer; • a small collection of programs (often called a software

package) that work closely together to accomplish a task, such as a spreadsheet or text processing system;

• a larger collection (often called a software suite) of related but independent programs and packages that have a common user interface or shared data format, such as Microsoft Office,

Computer Science

Computer Programming Languages

Computer Science

Computer Programming Languages:

• A programming language is an artificial language that can be used to control the behavior of a machine, particularly a computer

• Programming languages, like human languages, are defined through the use of syntactic and semantic rules, to determine structure and meaning respectively.

Computer Science

Machine language:

• It is the lowest-level

programming language.

• Machine languages

are the only languages

understood by computers.

Computer Science

Machine language:

• While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers.

For example, an x86/IA-32 processor can execute the following binary instruction as expressed in machine language:

Binary: 10110000 01100001 (Hexadecimal: 0xb061)

Computer Science

Assembly Level Language:

• An assembly language is a low-level language for programming computers.

• The word "low" does not imply that the language is inferior to high-level programming languages but rather refers to the small or nonexistent amount of abstraction between the language and machine language, because of this, low-level languages are sometimes described as being "close to the hardware."

Computer Science

Assembly Level Language (contd…):

• A utility program called an assembler, is used to translate assembly language statements into the target computer's machine code.

• Example: Assembly language representation is easier to remember (more mnemonic)

mov al, 061h

This instruction means:

Move the hexadecimal value 61 (97 decimal) into the processor register named "al".

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Example (Adds 2 numbers):

name "add"

mov al, 5 ; bin=00000101b

mov bl, 10 ; hex=0ah or bin=00001010b

add bl, al ; 5 + 10 = 15 (decimal) or hex=0fh or

bin=00001111b

Computer Science

High-level language:

• High-level languages are relatively easy to learn because the instructions bear a close resemblance to everyday language, and because the programmer does not require a detailed knowledge of the internal workings of the computer.

• Each instruction in a high-level language is equivalent to several machine-code instructions, therefore it is more compact than equivalent low-level programs.

• High-level languages are used to solve problems and are often described as problem-oriented languages

Computer Science

High-level language (Contd…):

Examples of HLL:• BASIC was designed to be easily learnt by first-time programmers;

• COBOL is used to write programs solving business problems;

• FORTRAN is used for programs solving scientific and mathematical problems.

• With the increasing popularity of windows-based systems, the next generation of programming languages was designed to facilitate the development of GUI interfaces;

for example, Visual Basic wraps the BASIC language in a graphical programming environment.

• Support for object-oriented programming has also become more common, for example in C++ and Java.

Computer Science

Example (C program to add 2 numbers):

#include<stdio.h> //header files

Void main()

int a, b, c; // declaration of 3 variables

printf(“Enter two numbers:\n”);

Scanf(“%d”, &a); // read 1st number

Scanf(“%d”, &b); // read 2nd number

c=a+b; // compute the sum

printf(“Sum of 2 numbers is %d”, c); //print sum

Computer Science

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