CHAPTER2 Q4 CPU , Different parts of processor

Computer Eduation

Differenct parts of processor

Q 4: What is a CPU or a processor? Write in detail the different parts of a processor.

The Central Processing Unit/Processor:
A CPU is also called the processor and it is the main component of the computer. CPU is the brain of the computer and provides ability to computer for executing any given instruction and also tells the computer how to control the flow of instructions. In a computer system, all major calculations and comparisons are made inside the CPU and the CPU is also responsible for activating and controlling the operations of other units of a computer system. The quality of CPU inside a computer determines the quality of the computer.

Basic Parts of a processor:
A CPU has the following main parts:

ALU (Arithmetic and Logical unit):
This unit of the CPU is capable of performing arithmetic and logical operations. This unit of the CPU gets data from the computer memory and perform arithmetic and logical operations on it.
The arithmetic unit of ALU performs arithmetic operations like addition, multiplication, subtraction and division. The Logical unit of ALU performs logical operations such as comparison of two numbers. It tells us which number is greater and which is smaller. The common comparisons such as less than, equal to, or greater than are performed by the logical unit.

Memory Unit:
A processor has its own memory inside it in the shape of small cells. Each memory cell is called a “Register”. Registers are used to carry data temporarily for performing operations. There are total 13 registers in a processor. ALU gets data from registers and stores it in registers to perform arithmetic and logical operations. And data comes in registers from main memory of the computer.

Control Unit:
This unit of the processor controls all the activities of the processor and also controls the input and output devices of the computer. It acts just like a police inspector who controls the traffic on a road. The control unit controls the whole traffic of the computer. It tells the input device that it is now his turn to feed data in the computer and show result of data after execution on the output units. This unit also controls the flow of instructions, which are given to a computer. It obtains instructions from the program stored in main memory, interprets (translation of instructions into computer language) the instructions, and issues signals that cause other units of the computer to execute them.

Chapter 2 Q3 output devices (Monitor, Printer, Speaker,Projector

Computer Education

CHAPTER 2

Q 3: What is meant by output? Write a detailed note on output devices of a computer.

Output:
Output means result or the processed form of any thing. Suppose we want to get juice of carrot, for this we will enter carrots in juicer and juicer will provide us juice. Here juice is output of the juicer. The Juicer provides us output after processing.
So we can define that output is the processed form of input. Computer also provides us output of the data which we enter in it after processing. Output is the result of input.

Output Devices

The devices, which are used for output processed data are called output devices. A computer uses output devices to communicate with the world, which is outside the computer. Although there are many kinds of input devices, there are currently three common types of output devices:
· Monitor
· Printers
· Sound systems

The Monitor:
It is the most commonly used output device. The monitor is a soft copy (means we can modify contents of data and data is temporarily on the screen) output device. A monitor looks like a television and it displays alphanumeric and graphic output. A monitor is also called Visual display unit (VDU) or Cathode Ray Tube (CRT). The special program called Screen Dump Saves contents of the monitor screen.

Types of Monitor:
According to resolution, a monitor is of two types:
· High Resolution (Good quality of text and graphics on the screen)
· Low Resolution (Low quality of text and graphics)
Sizes of Monitor
According to screen size, a monitor is available in different sizes:
· 3 to 30 inch screens are available in the market.
· 15 and 17-inch screen are common now a day.

According to volume, a monitor is of two types:
· CRT (Cathode ray tube):
Monitors of this type screen are used commonly in homes, colleges and offices. These monitors are big and require big area to place, power and have weight more than 10 pounds. We cannot move these monitors easily.

· Flat - panel tube:
These monitors are also available nowadays in markets. These monitors are normally used in Laptop computers and we can also use these monitors in desktop computers. There are several types of flat-panel monitors, but the most common is the liquid crystal display (LCD) monitor.

According to display, a monitor is of two types:
· Monochrome
These monitors display images only in single colour. This colour can be white, green, blue, red or amber. This monitor can display shades of one colour and the computer industry uses the term gray scales to refer to the number of shades of a colour that can be shown on a monochrome monitor’s screen.

· Colour
This monitor shows graphics with full colours. These monitors produce images in three mixed colours, which are red, green and blue that is why these are also called RGB monitors. A typical monitor can display 256 to 65536 colours.

Touch Screen Monitor:
Touch Screen monitors allow the user to point directly at the computer display, usually to select from a menu of choices on the screen. Most touch-screen computers use sensors in, or near, the computer’s screen that can detect the touch of a finger. Touch screens are appropriate in environments where dirt or weather would render keyboards and pointing devices useless and where a simple interface is important.

Printers:

Printers are the most commonly used output devices that can be found in almost all computer centres. Printers are used to get prints of important documents on a paper. The output, which is generated by a printer, is called hard copy of the data. Printer is also called a hard copy output device.

Categories of printers:
Broadly there are two categories of printers:
· Impact printers
This printer uses the familiar typewriter approach of hitting a character against paper and inked ribbon.

· Non-impact printers
These printers do not hit or impact a ribbon to print. They use thermal electrostatic, chemical, and inkjet technologies. These printers move a print head across the page.

Classification of printers:
Printers are classified as:
· Character printers
· Line printers
· Page printers

Following are commonly used printers:

Dot-matrix printers:
These printers print each character as a sample of dots. The print head comprises a matrix of tiny needles, typically seven rows with nine needles in each (9 ´ 7 matrix). Printing quality of this printer is not good and speed of this printer is also very slow. The quality and price of dot-matrix printer depends on two factors.
i) Number of dots per inch termed as DPI
ii) Number of characters or words per minute

100 – 150 DPI
200 – 300 Character per minute
40 – 80 Words per minute



Laser Printers:
These are very high speed nonimpact printers which produce documents at speeds of over 20,000 lines per minute. This type of printers use a special beam of light called LASER. Where Laser stands for Light amplification by Simulated Emission of Radiation. With LASER, magnetic material in shape of powder is thrown on paper in the form of microscopic dots. The quality and cost of LASER printer depends on two factors:
· Number of dots per inch (DPI)
· Number of pages per minute

There are three qualities of a LASER printer:

Cheapest Quality Laser printer:
This type of laser printer can print
600 DPI
5 – 10 Pages per minute

Middle quality LASER:
This type of LASER can print
300 – 1200 DPI
10 – 20 Pages per minute

High quality LASER:
This type of LASER can print:
600 – 1200 DPI
30 – 300 Pages per minute

LATEST HIGH QUALITY LASER PRINTER


Inkjet Printers:
These are nonimpact character printers and similar to LASER printer. In this type of printer, ink is used in the shape of very tiny drops on the paper to form a character. This printer works slower as compared to LASER printers. Its speed is 1 to 6 pages per minute. These are cheaper in initial cost and quality of paper printing is same as laser printer but cost of per page is four times greater than a laser printer. Suppose if a LASER printer page costs you 1 rupee then an inkjet printer page will cost you 4 rupees. Remember that bubble jet and inkjet are the same printers.
Inkjet printer

Sound systems:
Just as microphones are now important input devices, speakers and their associated technology are key output systems. Today, when you buy a multimedia PC, you are getting a machine that includes a CD-ROM drive, high-quality video controller, speakers, and a sound card.
The speakers attached to these systems are similar to ones you connect to a stereo. The only difference is that they are usually smaller and they contain their own small amplifiers. Otherwise, they do the same thing any speaker does.

Projector:

Projector is also an output deivce.
It is used to show presentations. There two main types of projector.

Simple Projector
Multemedia projector.

Chapter 2 Q2 Input and output devices

Computer Education CHAPTER 2

Q 2: What is meant by input? Write a detailed note on input devices of a computer.

Input:
Input means to enter anything. Suppose we enter carrot in a juicer and it provides us juice of the carrot, so to get juice first we have to enter carrot into the juicer. In Computer sciences, first we have to enter data in the computer so that the computer can act on it.

Input devices

“The devices through which we can enter data into a computer are called input devices.”
Through input devices we can enter data, information, and instructions in a computer. Following are the different input devices of a computer.

Keyboard:
A keyboard is the most commonly used input device. We can enter all types of data through keyboard. We can enter alphabets, numbers, characters and symbols in a computer through the keyboard. The Keyboard has different buttons, which are called keys. A Keyboard is just like a typewriter.
There are 102 different keys of different type on a keyboard. A Keyboard has four types of keys which are:

· Numeric Keys
· Alphanumeric keys
· Screen Navigation and Editing keys
· Function keys

Keyboard

Numeric keys:
This area of a keyboard contains numeric keys 0-9 and is used to enter numeric data into the computer. We can enter roll number, age, height, width and other numeric data through this area of the keyboard.

Alphanumeric keys:
This area of a keyboard contains alphabetic and numeric keys. In this area of keyboard characters A-Z, a-z and numbers 0-9 are included. We can enter alphanumeric data through these keys.

Screen Navigation and Editing Keys:
The screen navigation keys are used to move cursor on the monitor screen from one point to another. The editing keys are used for modifying text on the text window. The arrow keys are a part of this area.

Function Keys:
Function keys starts from F1 and end up on F12. There are total 12 function keys on a keyboard. Their function is different in different softwares.



Mouse:
Mouse is an input device for the beginners of computer. The people who are not familiar with the use of keyboard of computer can work easily on the computer with the help of mouse. It is always placed on a pad while working. A mouse may have two or three buttons.

Mouse

The mouse controls the position of the cursor and moves it around a computer. When we move the mouse on the pad, a small arrow like pointer moves on the screen. The mouse is mainly used in the Windows environment and other graphical software packages.
We can select any data by clicking the left mouse button once and to open any software or command, we have to double click the left mouse button quickly.

Joystick:
Joystick is another output device. It is just like a lever. It is used for moving things around on the screen. It is often used for playing games on the computer.

Joystick

A joystick has two or three buttons. By moving the lever L of joystick, we can move things and by clicking buttons, we can take any action.

Light Pen:
Light Pen is another input device. It is pen shaped. It is held in hand and can detect the presence of light with photoelectric cell at its front end.

Digital Scanner:
A digital scanner has become a very popular input device for a PC. When a scanner is attached to the computer, the scanner can read information of colour or black and white picture.
The scanner sends information to the computer, which we place on the glass surface of the scanner. The computer can store this information forever, or can send it across the world by using Internet in few minutes.

Scanner

The image scanner or digital scanner is a very useful device. It translates printed images into an electronic format that can be stored in a computer’s memory. You can then use software to organize or manipulate the electronic image. For example, if you have scanned a photo, you can use Adobe Photoshop, a graphics software to increase the contrast or to adjust the colours.

The Trackball:
A trackball is a pointing device that works like an upside-down mouse. You keep your thumb on the uncovered ball and your fingers on the buttons. To move the cursor around the screen, you roll the ball with your thumb. Because you don’t move the whole device. A trackball requires less space than a mouse, so when space is limited, a trackball can be a boon.

Trackball

Trackballs gained popularity with the advent of laptop computers, which are typically used on laps or on small work surfaces without room for a mouse.

The Trackpad:
The Trackpad is a stationary pointing device that many people find less tiring to use than a mouse or trackball. The movement of a finger across a small touch surface is translated into cursor movement on the computer screen. The touch-sensitive surface may be just 1.5 – 2 inches square, so the finger never has to move far. The size also makes it well suited for a notebook computer.

Microphone:
By using microphone, we can record our voice in a computer. This device is very easy to use and we can record our voice with music in the computer through this device.

Digital Camera:
Digital camera is used to draw photos. By using this input device images or photos are sent directly to PC instead of storing on a usual camera film.

CHAPTER 2 Computer hardware and software

CHAPTER 2
Q 1: What are hardware and software?

Logically a computer system consists of two parts which are:
· Hardware
· Software

Hardware:
“ The Physical components of a computer are called hardware.”
The parts of a computer, which we can touch, and feel, are called hardware parts. Hardware components of a computer are properly designed and manufactured by different electronic companies. The Hardware components of a computer enable the user to communicate with the computer and to get result of input data from it. A Computer is the combination of different hardware goods.

Example:
Following are the different examples of hardware components of a computer.
· Keyboard
· Monitor
· Mouse
· Printer
· Processor
· Hard disk
· Floppy disk

Software:
A computer cannot solve any problem itself; we give instructions to it for solving problems.
“ The set of programs (set of statements in any computer language) to solve a problem or to control the hardware of a computer is called a software.”
The Software are logical parts of a computer. We cannot touch to these parts of a computer but can feel them. With the help of software the user of the computer can easily work on it. The Software also manage the hardware resources of a computer.

Short Test of History of Computer and computer Basics

CHAPTER 1
Short Test of History of Computer and computer Basics


Objective Type

Q: Fill in the blanks:
__________ is the brain of the computer.
CPU stands for _________.
CPU is also called __________.
The devices through which we can enter data or information into computer are called __________.
___________ is the father of the computer.
First generation starts from ______and ends at _______.
In 2nd generation computers _______ were used.
________ was used instead of IC in 4th generation computers.
Computer is an __________ device.
10. We can input and ______ data in a computer.

Answer to Objective

Fill in the blanks:

1) CPU 2) Central processing Unit
3) Processor 4) Input
5) Charles Babbage 6) 1942-1955
7) Transistors 8) microprocessor
9) Electronic 10) Store

Types of Computer

Q 5: Write in detail the different types of a computer.

The Types of computer
Computers are divided into three types according to their structure, speed and architecture.
Analog Computers
Digital Computers
Hybrid Computers

Analog computers:
“The computers which provide us continuous information are called analog computers.”
Analog computers represent physical quantities in the form of waves or in continuous form.

Examples:
Thermometer is the example of analog computers because it measures the length of a mercury column continuously.
A traditional clock is the example of analog computers because the needle of clock covers the distance of dial continuously.Weight machine and Speedo meter are other examples of analog computers.

The above diagram shows that an analog system is working continuously as the wave is moving continuously in the above diagram.

Characteristics of the analog computers:
1. These computers have no state
The Speed of analog computer is fast
These computers are not reliable
These computers became the base for digital computers
These computers are difficult to operate and use
These computers are easy to develop
These computers have small memory

Digital Computers:
“The computers which present physical quantities with the help of symbols or numbers and provide us discrete information are called digital computers.”

Examples:
Digital watch, digital petrol stations and the computer, which we use nowadays, are the examples of digital computers

Characteristics of the digital computers:
Digital computers have two states On (0) and Off (1).
These computers are easy to use.
Human being like to use digital computers.
These computers are reliable.
Digital computers have big memory.
Working speed of digital computers is slower as compared to analog computers.
These computers are further divided into different categories such as personal computers, Mainframe computers and super computers.

Hybrid Computers:
“The computers which have qualities of both digital and analog computers are called hybrid computers.”
Hybrid computer has the speed of analog and the accuracy of digital computer.
Example:
In ICU (Intensive care unit) of a hospital hybrid computers are used. These computers analog quality controls the temperature of the room digital quality informs the doctor about the blood pressure, temperature and physical status of the patient.
In Cement factory a hybrid computer is used where all calculations are performed by the digital computers; and actions like increase of material are performed by the analog computers.

Characteristics of the Hybrid computers:
These computers are reliable and provide accurate result.
These computers are fast and speedy.

Personal Computers/Desktop computers:
These are small size computers and are used by a single user. Desktop computers are also called Personal computers or PC. We can use these computers easily in offices, colleges, schools, universities, homes, and factories.

Characteristics of Desktop computers:
These computers have fast speed and accuracy
Small in size
Easy to operate
These computers are easy to move
These computers are cheaper
We can use desktop computers as a single user and multi-user environment

Laptop Computers/Notebook:
Lap top computers are another category of personal computers. These computers are small in size and light packed in. These computers are moveable because they work on batteries and can operate without an external power source. Laptop computers are also called Notebook computers because the size of these computers is about one- inch notebook and weight is from four to eight pounds.


Q 6: Differentiate Digital and Analog computers.

Difference between digital and analog computers:


Difference Analog Computers

Definition These computers provide us continuous information.
Representation of quantities These computers represent physical quantities in the form of waves or in continuous form.
State These computers have no state.
Use These computers are difficult to use.
Reliability These are not reliable computers
Development These computers are difficult to develop.
Memory These computers have small memory.
Base These computers became the base for digital computers.
Speed These computers have slow speed.
Example Thermometer, weight machine, Speedo meter

Digital Computer



Difference Digital Computers
Definition These computers provide us discrete information.
Representation of quantities
These computers represent physical quantities with the help of symbols or numbers.
State
These computers have two states On (0) and off (1).
Use
These computers are easy to use.
Reliability
These are reliable computers.
Development
These computers are easy to develop.
Memory
These computers have big memory.
Base

These computers were developed on the base of analog computers.
Speed

These computers have fast speed.
Example
Digital watch, digital petrol stations, computers.

History of Computer (1942-2007)

Q 3: Write a note on computer generations.

The Computer Generations:

In terms of the computer “Generation” is a step in technology. It provides a structure for the growth of the computer industry. At first, the term ‘generation’ was used to distinguish between changeable hardware technologies. Following are the different generations of a computer.

FIRST GENERATION (1942-1955)

First generation computers were made possible by the invention of “Vacuum tube”, which was a fragile glass device that could control and amplify electronic signals. Vacuum tube computers are referred to as first generation computers.

Examples: ENIAC, EDVAC, EDSAC, etc belong to first generation computers.

Advantages:

1. Vacuum tubes were the only electronic components available during those days.

2. Vacuum tube technology made possible the advent of electronic digital computers.

3. These computers were the fastest calculating devices of their time.

They could perform computations in milliseconds.

Disadvantages:

1. Too bulky (large) in size

2. Unreliable

3. Thousands of vacuum tubes that were used produced large amount of heat and burnt out frequently.

4. Air conditioning required
5. Prone to frequent hardware failures 6. Constant maintenance required

7. No portable

8. Commercial production was difficult and costly

9. Limited commercial use

SECOND GENERATION (1955-1964)

The Vacuum technology was replaced with Transistor (a smaller and more reliable). Transistors were invented in 1947. In second-generation computers, transistors were used as the brain of the computer.

Advantages:

1. Smaller in size as compared to first generation computers.

2. More reliable

3. Less heat generated

4. These computers were able to reduce computational times from milliseconds to microseconds. 5. Less prone to hardware failures

6. Better portability

7. Wider commercial use

Disadvantages:

1. Air-conditioning required

2. Frequent maintenance required

3. Manual assembly of individual components into a functioning was required

4. Commercial production was difficult and costly

THIRD GENERATION (1964-1975)

Advances in electronics technology continued and the advent of “microelectronics” technology made it possible to integrate large number of circuit elements into very small (less than 5 mm square) surface of silicon known as “Chips”. The new technology was called “integrated circuits” (ICs). The third generation was based on IC technology and the computers that were designed with the use of integrated circuits were called third generation computers. Advantages:

1. Smaller in size as compared to previous generation computers

2. Even more reliable than second generation computers

3. Working Speed of these computers was faster as compared to previous generations

4. Maintenance cost was low

5. Easily moveable

6. Totally general purpose and widely used for various commercial applications all over the world

7. Less power requirement than previous generation computers

8. Commercial production was easier and cheaper

Disadvantages:

1. Air-conditioning required in many cases

2. Highly difficult technology required for the manufacture of IC chips

FOURTH GENERATION (1975 ONWARD)

In this generation a revolution came in the field of computer due to the invention of microprocessor. In this generation ICs were replaced with microprocessor. A microprocessor is a small chip which contains thousands ICs onto a single chip. Invention of microprocessor reduced the size of the computer.

Advantages:

1. Smallest in size because of high components density

2. Very reliable

3. Heat generated is small

4. No air conditioning required in most cases

5. Much faster in computation than previous generations

6. Hardware failure is minor

7. Easily portable because of their small size

8. Totally general purpose

9. Big memory

10. Cheapest among all generations

Disadvantages:

1. Highly difficult technology is required for the manufacturing of microprocessor Chip

FIFTH GENERATION (YET TO COME)

Scientists are now at work on the fifth generation computer – promise, but not yet a reality. They aim to bring us machines with genuine

Computer Education and history of Computer

CHAPTER # 1

INTRODUCTION TO COMPUTERS

Q 1: Write a note on history of the computer.

The History of computer

“Necessity is the mother of invention”

The above saying is also true for computer because man was in search of fast and accurate calculating devices and for this he invented the computer. Anyhow today’s computer took many years to become such a wonderful machine. A brief history of the computer is as follow:

Abacus:
Abacus is the name of a calculating machine, which was invented by Chinese about 600 B.C. Abacus is also known as “soroban.” Chinese used this machine for simple calculations like addition and subtraction. This device permits the users to represent numbers by the position of bullets on a stand.

John Napier bone:
Another manual calculating device was John Napier’s bone or cardboard multiplication calculator. It was designed in the early 17th century and its upgraded version was in use even around 1890.

Blaise Pascal:
The first mechanical adding machine was invented by Blaise pascal in 1642. Later, in the year 1671, VonLeibnitz of Germany invented the first calculator for multiplication.

Punched Card:
In 1801, Joseph Marie Jacquard, a French engineer, developed punched card system for the power-looms. This system helped in creating specific weaving patterns on cloths automatically. This system was later on used with computing devices.

Charles Babbage:
Charles Babbage is called the father of the computer due to his work for it. He was a professor at Cambridge University. He introduced Difference Engine in the year 1822. In 1842 Charles produced an idea of Analytical Engine. The analytical engine could perform all the mathematical problems.

The Mark I computer (1937-44):
Mark I was the first fully automatic calculating machine, which was designed by Howard H. Aiken. Instructions were given to this machine with the help of punched paper tape. Mark-I is considered to be one of the first true computers because it could store information and instructions.



The ENIAC (1943-46):
ENIAC stands for Electronic Numerical Integrator and Calculator. It was the first electronic computer and was constructed by J.P Eckert and John Mauchly in 1946.

The EDVAC (1946-52):
EDVAC stands for Electronic discrete Variable Automatic Calculator. Dr. John Von Neumann developed this computer. This was the first computer to which we can give instructions and can also store data in it.

The UNIVAC (1951):
The Universal Automatic computer (UNIVAC) was the first digital computer. This computer was used in business and industries.

Commercial computers:
In 1952, the International Business Machines (IBM) Corporation introduced the 701 commercial computer.

Q 2: What is a computer? Write the uses and the characteristics of a computer.

Computer:
“Computer is an electronic device. It obeys instructions of the user. A Computer gets input of data and it provides us output of data in a meaningful form after processing. We can also store data or information in a computer and can also retrieve also get stored data from the computer. A computer also performs arithmetic operations like addition, multiplication and division.”

The word computer comes from a Latin word “Compute”. It means to calculate something. Basically computer is used to perform calculations but the calculation is not only one use of computer, we can use it for different purposes.

Uses of a computer:
Some common purposes of a computer are:

• A computer is used to perform arithmetic calculations
• A computer can solve complex scientific and arithmetic problems very easily and speedily.
• We can store data in a computer and can get stored data when we need.
• We can play games on a computer.
• We can watch movies on a computer.
• We can listen music on a computer.
• We can send messages to our friends, relatives and family members anywhere in the world by connecting our computer with Internet.
• Computers are used to make good defence of the country.
• Computers are helpful in offices, sciences, engineering and technology.
• Computers are very helpful in education; students can prepare their projects easily with the help of computer. Interest of study has been developed in people due to the computer.
• Medical science and Biotechnology are use computers to diagnose the diseases of people.
Above are some common benefits of computers, there are many more benefits which we get from computers.
Characteristics of computers

Following are the different characteristics of a computer.

Speed:
A computer is a very fast device. It can perform in a few seconds the amount of work that a human being can do in an entire year.

Accuracy:
The accuracy of a computer is always high and the degree of accuracy of a particular computer depends upon its design. But for a particular computer, each and every calculation is performed with the same accuracy.

Carefulness:
Unlike human beings, a computer is free from tiredness and lack of concentration, etc.

Usefulness:
Usefulness is one of the most wonderful things about the computer. One moment, it is preparing the results of particular examination, the next moment it is busy in preparing electricity bills, and in between, it may be helping an office secretary to trace an important letter in seconds.

Power of remembering:
As a human being acquires new knowledge, the brain subconsciously selects what it feels to be important and worth retaining in its memory and relegates unimportant details to the back of the mind or just forgets them. With computers, this is not the case. A computer can store and recall any amount of information because of its secondary storage capability.

No feelings:
Computers are free from emotions. They have no feelings and no sixth sense because they are machines. Although men have succeeded in building a memory for the computer, but no computer possesses the equivalent of a human heart and soul.