Computer Science (New) - For Class IX - UNIT. 1 - Fundamentals of Computer - Descriptive Questions Answers

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Chapter No.1 - Fundamentals of Computer
Descriptive Questions Answers

Q.1: Describe the ages of Computer? OR Demonstrate the understanding about the history of computer? OR Describe major innovation in evolution of computer?
Ans: Evolution Of Computers Or Ages Of Computer OR History Of Computer:
The computers which we see today are modern shape of computers which have been evolved since centuries. The evolution of computers is generally divided in following three eras.

• Mechanical Era (Dark Age)
• Electro-Mechanical Era (Middle Age)
• Electronic Era (Modern Age)

(I) MECHANICAL ERA (DARK AGE)

• Men have been trying to invent machines that can solve mathematical problems.
• In mechanical era, human became successful to make simple machines that could help performing simple arithmetic operation, in other words computing.
• These machines were manually operated since the electricity was not invented.
• Some of the important machines of this era are:

(a) Abacus (3000 B.C.):

• The history of computer begins with the birth of abacus. It is considered as first computer prototype..
• Abacus was invented about 5000 years ago. It was invented in China about 3000 B.C. It is also known as counting frame.
• Construction:
  It was a wooden rack which has metal rods with beads mounted on them.
  The beads were moved by the abacus operator according to some rules to perform arithmetic calculations.
• Tasks Performed:
  It is used to teach basic arithmetic operations (addition. subtraction, multiplication and division) to the students.
  Abacus is still used worldwide. It is most ancient of digital computer. 

(b) Napier's Bones (1612 A.D.)

• Scottish mathematician John Napier developed Napier's Bones, in 1612. It is also called Napier's Rods.
• Construction:
  It was a small machine that contained ten rods.
  The rods were made up of bones, wood or metal, which are marked with numbers.
  
• Task Performed:
  Napier's Bones was used for multiplication and division.
  It was also the first machine to use the decimal point.

(c) Slide Rule (1622 A.D.)

• English mathematician William Oughtred invented a Slide Rule in 1622 A.D. based on the emerging work on logarithms by John Napier.
• Construction:
  This was basically a pair of two moveable rules placed side by side.
  They comes in a diverse range of styles and generally appear in a linear or circular form with a standardized set of markings called scales.
  These scales were used for mathematical computations.
• Task Performed:
  Slide Rule was used to multiply and divide numbers.
  The modern slide rules are still used in some countries.

(d) Pascaline or Pascal's Calculator (1642 A.D.)

• French mathematician Blaise Pascal invented a mechanical calculator which was called Pascaline or Arithmetic Machine or Adding Machine.
• He developed this machine to help his father who was a tax collector (accountant).
• Construction:
  It was a wooden box with a series of gears and wheels.
  When a wheel is rotated one revolution, it rotates the neighboring wheel.
  A series of windows is given on the top of the wheels to read the totals.
• Task Performed:
  Pascaline can perform addition and subtraction by eight figures.
  User had to adjust wheels in order to perform these calculations.

(e) Leibniz's Calculator (1694 A.D.)

• Leibniz's Calculator was developed by the German mathematician Gottfried Wilhelm Leibniz. It was also called stepped reckoner.
• Construction:
  It was made of fluted drums.
• Task Performed:
  It was the first calculator that could perform all four basic arithmetic operations; addition, subtraction, multiplication and division.

(f) Babbage's Difference and Analytical Engines (1822 and 1837 A.D.)

• Charles Babbage was an English mathematician and mechanical engineer, the most deserving name in the history and development of computer.
• He is known as Father of Computer because he developed the first complete computing machine ( a true computer).
• DIFFERENCE ENGINE:
  His first invention was Difference Engine. It was an automatic mechanical calculator.
  Construction:
  i) Difference Engine was a large machine, made of metal and was powered by steam.
  ii) The Difference Engine had storage (mechanical memory) that could hold the data temporarily for processing and to store results.
  iii) It was based on pre-defined formulas and consist of three basic parts:
  a) Arithmetic and Logic Unit (ALU)
  b) Memory Unit (MU)
  c) Control Unit (CU)
  Task Performed:
  i) It was used to allow a user to enter calculations and get printed results.
  ii) The Difference Engine worked on difference equations.
  
  
• ANALYTICAL ENGINE:
  i) Then, Charles Babbage designed but could not build a very big machine in 1837. This was named Analytical Engine.
  Construction And Task Performed:
  i) The proposed design included an ALU with basic programmatic flow control.
  ii) It was programmed using punched cards and contained integrated memory.
  iii) Historians consider it to be the first design concept of a general-purpose, automatic mechanical computer because of its comprehensive design.
  v) The machine was designed to consist of four components:
  a) The mil (calculating Unit)
  b) The store
  c) The reader
  d) The Printer
  These components are essential components of every computer today.

(II) ELECTRO-MECHANICAL ERA (MIDDLE AGE)

• This era starts from the mid of 19 century. In this era scientists became able to develop faster and more accurate computing machines as they were powered by steam and electricity.
• One of such machines was Tabulating Machine.
• The following Electro-Mechanical devices were used for data processing in the Middle Age of computer.

(a) Herman Hollerith's Tabulating Machine (1890 A.D.)

• It was invented by American inventor Herman Hollerith in 1890. He was inspired by Jacquard's idea of punched cards.
• It could tabulate statistics and record or sort data or information.
• Hollerith's first tabulator was used for the U.S. 1890 Census.
• Hollerith Tabulating Machine became very famous and used in many offices of U.S. Government.
• His tabulating machine could read and sorted out data from punched cards.
• He also developed a punched card of 3 X 5 inches in order to record data.

(III) ELECTRONIC ERA (MODERN AGE)

• The advancement in the vacuum or electron tube gave birth to the electronic era.
• In this era the true computers were invented which worked on the principle of input, store, process and output.
• Continuous advancement in electronic engineering increased efficiency and speed of computers considerably.
• The electronic era may be categorized in generations on the basis of core technology used to build computers.

Mark-I:

• The first Electro-Mechanical Computer was developed at harvard university by Howard Aiken with his students and engineers of IBM completed the project in 1944 and known as Mark-I.
• It was the first programmable digital computer.
• It could store information and instruction and it was the realization of Babbage's dream.

GENERATION OF COMPUTER

• The computers are categorized in five generations.
• Each generation is characterized by a major technological development that fundamentally changed the way computers operate, cheaper, more powerful and more efficient and reliable devices.

(a) First Generation of Computers (1940 to1956):
Main Features

• Technology Used: Vacuum Tubes
• Size: Very large in size (Main frame)
• Language: Low level Machine language (i.e. 1's and 0's).
• Main memory (primary internal storage): Magnetic drums
• External storage: Punched card
• I/O Device: Punched cards and papers
• Operating system: Batch processing operating system (i.e human operates to set system, no proper operating system)
• Use: Scientific and research purpose.

Example:  ENIAC, EDVAC, UNIVAC

Advantages:

• Vacuum tubes were as electronic components.
• Electronic digital computers were developed for the first time.
• These computers were the fastest calculating devices of their time.
• Computations were performed in millisecond.
• Punch cards were used for input and output.

Disadvantages:

• Too large in size.
• These computers were unreliable.
• Vacuum tubes produce large amount of heat.
• Frequent hardware problems that required constant maintenance.
• Non-portable computers.
• Limited commercial use.

(b) Second Generation of Computers (1956 to 1963):
Main Features

• Technology Used: Transistors.
• Size: smaller and faster (main frame), cheaper and more efficient.
• Language: Assembly language and a high language FORTRAN
• Main memory (internal storage): Magnetic core (RAM and ROM)
• External storage: Magnetic tapes and magnetic disk
• I/O Device: Punched card
• Operating system: Batch processing and Multi-programming
• Use: commercial productions, scientific and engineering analysis and design

Example: IBM 7094 and IBM 1401

Advantages:

• Transistors were used as internal components.
• Smaller in size as compared to first generation computers.
• Reliability increased.
• Magnetic tape and were used as wider secondary storage.
• Heat produces less than previous generation computers.
• Computation were perform in micro second.
• Less hardware and maintaince problem.
• Less electricity consumption as compared to 1^s generation computer.
• Better portability.
• Commercially used.

Disadvantages:

• Commercial production was so expensive.
• Frequently maintenance required.
• Air-conditioning required for computers.

(c) Third Generation of Computers (1964 to 1971):
Main Features

• Technology Used: Integrated Circuits (ICs).
• Size: Mini (decreased size  and increased the speed and efficiency, less expensive)
• Language: High level programming language such as Pascal and COBOL
• Main memory (internal storage): PROM and DRAM
• External storage: Floppy disk
• I/O Device: Keyboard (input), Monitor (output)
• Operating system: Time sharing and realtime (Unix operating system)
• Use: The use of computers was extended to database management and automatic industrial control

Example: IBM 360 and IBM 370, TDC-316

Advantages:

• Smaller in size due to use of VLSI and much reliable.
• Computations speed was much faster than previous.
• These computers were reliable computers.
• No air-conditioning required.
• Electricity consumption was less than previous generation computers.
• Minimum maintenance required.
• Hardware failure was negligible.
• Computation speed was in picoseconds.
• Heat generation was negligible.
• Totally general purpose computers.
• Portable computers.
• Cheapest in prices.

Disadvantages:

• Very advanced technology required to make a microprocessor.
• Air-conditioning required in rare cases.

(d) Fourth Generation of Computers (1971 to Present):
Main Features

• Technology Used: Microprocessors.
• Size: micro computer (faster, less expensive, smaller and more reliable)
• Language: More high languages like C, C++, Java etc.
• Main memory (internal storage): Semi-conductor memories RAM and ROM (EPROM and SRAM)
• External storage: Magnetic storage
• I/O Device: Monitor (output)
• Operating system: Time sharing, real time and distributed operating system,  with development of Graphical User Interfaces (GUIs) (DOS and UNIX
• Use: in every field of life like space applications, business and art work.

Example: Apple Macintosh, IBM PC.

Advantages:

• Smaller in size compared to previous generation computers due to the use of Integrated Circuit (IC).
• Computations speed was in Nano seconds.
• Reliability increased in these computers.
• Heat generation was rare.
• Less electricity consumption.
• Hardware failure was very rare.
• These computers were general purpose.
• Very easy portable computers.
• Commercially production was cheaper and easier.

Disadvantages:

• Very advance technology was required to make the ICs.
• Air-conditioning required in some cases due to ICs.

(e) Fifth Generation of Computers (Present and Beyond):
Main Features

• Technology Used: Artificial Intelligence Technology, still being developed
• Size: very tiny in size
• Language: AI (Artificial Intelligence) include; Machine Learning, Deep Learning. Natural Language Processing, Robotics and Expert Systems.  These computers or controlled machines like robot will also be able to process human languages.
• Main memory (internal storage): EEPROM, SIMM, DIMM
• External storage: Modified magnetic and optical disk etc
• I/O Device: Keyboard, pointing device, scanner (input) Monitor, printer (output) etc.
• Operating system: GUI based, Microsoft windows 95 and onward, Windows NT. 
• Use: In all fields of life. Computers will be capable of self- learning, reasoning and generalization.

Example: laptop, notebook, digital diary, Android, Pocket PC, Palm top, Humanoid Robots

Advantages:

• All previous advantages with amazing Improvement.
• Very huge storage capacity available in this generation.
• Long bit processors were built.
• Laptop and Palmtop computers introduced.
• Artificial intelligence languages developed In this generation.

Disadvantages:

• Disadvantages not reported.

Q.2: Discuss the features of all generations with the help of generation table?
Ans: GENERATION TABLE:

Generation	First 1st	Second 2nd	Third 3rd	Fourth 4th	Fifth 5th
Duration (Period)	1940-1956	1956-1963	1964-1971	1971 to Present	Present and Beyond
Technology Major Innovation	Vacuum tubes	Transistors	ICs	Microprocessors (LSIC and VLSIC)	Artificial Intelligence Technology (ULSIC)
Internal Storage (Main Memory)	Magnetic Drums	Magnetic core (RAM and ROM)	PROM and DRAM	EPROM and SRAM	EEPROM, SIMM abd DIMM
External Storage	Punched Cards	Magnetic Tapes and Magnetic Disk	Floppy Disk	Floppy Disk and Hard Disk	Optical Disk
I/O Devices	Punched Cards and papers	Magnetic Tapes, Punched Cards, papers for output	Keyboard for Input and Monitor for output	Monitor for output	Keyboard, Pointing device, Scanner as input and Monitor as main output
Language	Machine Languages (Low level)	Assembly Languages and High Language FORTRAN	High Level Languages	4GL 4th Generation Languages	Artificial Intelligence and Expert System
Operating System	Batch  processing (No operating System)	Batch processing and Multi programming (Manually handled Punched Card)	Unix Operating System	Dos, Unix	GUI based Windows, Unix
Size	Main Frame	Small in size Main Frame	Mini	Micro	Tiny Computers
Examples	ENIAC, UNIVAC, EDVAC, EDSAC	IBM 7094 and IBM 1401, NCR-300	IBM 360 and IBM 370, Honey Well 316	Apple Macintosh, IBM PC	Laptop, Tablet PC, Notebook, Digital diary, Palmtop, Pocket PC and Humanoid Robot etc

Q.3a: Classify the computers as per their size, technology used to date and purpose?
Ans: Classification Of Computers:
Computers can be classified into different ways as:

• According to Technology
• According to Size
• According to Purpose

(i) According to Technology

Computers are classified in three types according to technology or type of data they handle, such as:

1. Analog Computers
2. Digital Computers
3. Hybrid Computers

(a) Analog Computers:

• Analog Computers are used to process analog data.
• Analog data are in the form of continuously varying physical quantities like pressure, temperature, voltage, speed and weight.

Uses: Analog computer are commonly used for scientific and engineering problems, chemical industries, electric power plants and petroleum refineries.
Examples of Analog computer: are Speedometer of a car, Voltmeter, Mechanical watches, Thermometer, Analog Multimeter etc.

(b) Digital Computers

• Digital Computers are most commonly used type of computers.
• Digital computers are specialize in counting.
• They are used to process information with quantities using the binary number system (0's and 1's).
• Digital computer has memory to store and solve problems.
• Digital computer is to handled alphabetic and alphanumeric data with precision and speed.

Uses: Digital Computers are used in home, educational institutes, offices, business, scientific fields, etc.
Examples: Digital watch, calculator, digital computer etc.
  
(c) Hybrid Computers

• Hybrid Computers are the combination of Analog and Digital Computer system.
• These computers combine analog and digital features of computers in a single machine.
• A Hybrid Computer uses analog to digital and digital to analog conversion. It may input or output either digital or analog data.

Examples: Gas Station, CT Scan Machine, Radar System etc.

(ii) According to Size

Digital Computers are further divided into four groups according to their size, such as:

1. Super Computers
2. Mainframe Computers
3. Minicomputers and
4. Microcomputers

(a) Super Computers

• Super Computers are the most powerful, fastest and largest computers.
• They are designed to perform complex calculations at fastest speed.
• They are extremely expensive.

Uses: These computers are widely used to model very large dynamic system in scientific applications such as aerodynamics, design simulations, processing of geological data, satellite tracking, weather forecasting and nuclear research.

(b) Mainframe (Macro) Computers

• Mainframe Computers are powerful multi-user and multiprocessors computers.
• They are the biggest and the most productive general purpose systems.
• They can process huge amount of calculations at very high speed.
• Mainframes are also very expensive and require a lot of technical expertise to be installed and operated.
• It serves hundred of terminals all at the same time.
• A terminal consists of a monitor and keyboard that allow a person to enter information and retrieve it from the computer.

Uses: They are used in banks and many large business organizations where several users work simultaneously.

(c) Minicomputer

• These are smaller than mainframe computers, but they are more powerful than Microcomputers.
• Minicomputers usually use multi-user operating system.
• Multiple users can use the Minicomputers through terminals.
• It is capable of supporting 4 to 200 users at a time.

Uses: Minicomputers may be used as network servers and Internet servers.
Examples: DEC VAX and IBM AS/400 are good examples of minicomputers.

(d) Microcomputers

• Microcomputers are also called Personal Computers (PCs).
• The use of microprocessor has made computers cheaper yet faster and more reliable.
• These are the smallest computers designed to be used by individuals.

Uses:
a) PCs can be used for variety of tasks like documentation, calculations, illustration and entertainment.
b) The power of network and internet has also made it more useful.
c) Now computers are also used for communication and socialization.

(iii) According to Purpose:

According to purpose, computers are either:

1. General purpose or
2. Special purpose

(a) General Purpose Computers

• Most computers in use today are General Purpose Computers.
• These computers can process variety of tasks.
• General purpose computers are strong in versatility but are normally weak in speed and efficiency as compared to special purpose computers.

Uses: These computers can store and execute different programs in their memory. Therefore, various tasks like word processing (typing and editing), payrolls, accounts, inventory control, manipulating facts in a database, making scientific calculations and statistical data analysis, budgeting and sale analysis and controlling security system of an organizations are achieved by these computers.
Examples: Desktops, laptops, tablets and smart phones are examples of General Purpose Computers.

(b) Special Purpose Computers

• As the name states, Special Purpose Computers are designed to perform specific tasks.
• Special Purpose Computers repeatedly perform single job more efficiently.
• They are also known as Dedicated Computers.

Uses: These computers are useful in traffic lights control system, navigational system, aviation, collecting highway tolls, industrial process control, weather forecasting, satellite racking and ATMs.

Q.3b: Write down the names of different ways of computer classification?
Ans: Classification Of Computer:
Computer can be classified into differential as shown below:

Q.4:Explain the role and uses of computers in different fields of life.
Ans: ROLE OF COMPUTER:
The role of computer in our lives is increasing day by day. We are living today in the information era and the information has become one of the most valuable assets. To process this information, we make use of computers in various fields in our daily life.
Computers have been integrated in our life in different shapes and sizes like desktops, laptops, mobile phones, gaming consoles and smart devices.
Our lives have become so dependent of computers that we cannot work even a single day without the help of it.
We have automated many of the repetitive tasks with the help of more advanced, faster and accurate computers and brought our routine tasks, office works, businesses, researches and industrial applications to a new level.

COMPUTERS IN DIFFERENT FIELDS OF LIFE:
Computers are largely used in every field of life, Such as:

• Manufacturing
• E commerce
• Education
• Medical
• Banking
• Communication
• Entertainment
• Engineering
• Agriculture
• Architecture
• Business
• Defense and
• Sports

 are highly influenced by computers.

(a) Use Of Computers Today's World (Present):
21st century is the era of technological revolution. Previously, technology was only used to access and share information. However, with the passage of time, the rapid change in technology has made it nearly impossible to perform any human activity without its use.

Use In Daily Life:

• (a) Mobile Phone apps
  Computers are playing an important part in our daily life. Mobile phone app helps in:
  (i) Gathering News and weather updates
  (ii) Travelling information and bookings
  (iii) Money transfer, billing and banking
  (iv) Taxi bookings
  
  
• (b) Online Services:
   are becoming a trend in our society too, like:
  (i) Food home delivery and
  (ii)Online shopping
  
  
• (c) Use To Perform Managerial Task:
  Many managerial tasks are also done by computer software, like:
  (i) Schools management
  (ii) Library and
  (iii) Hospital management
  
  
• (d) Entertainment fields:
   Computers are also providing variety of choices for entertainment like:
  (i) Games:
   online games in which players from different parts of the world can participate simultaneously.
  
  (ii) Movies:
  a. 3D graphical software has given a new look to movies in which different comic characters can act with human actors.
  b. Photo, sound and video editor software not only help artists and singers to produce extraordinary creations but also inexperienced people can enjoy their productivity with ease of use.

Use Of Computers Tomorrow (Future):
The emerging technologies are also getting better day by day and we can imagine that how computer will be used in future.

• Artificial Intelligence
• Robotics
• Wireless Communication and
• Virtual Realities

are some areas which are shaping the modern world.

Q.5a: Discuss how computer is affecting our lifestyle by providing variety of choices for entertainment.
Ans: Entertainment fields:
Computers are also providing variety of choices for entertainment like:
(a) Games:

• online games in which players from different parts of the world can participate simultaneously.

(b) Movies:

• 3D graphical software has given a new look to movies in which different comic characters can act with human actors.
• Photo, sound and video editor software not only help artists and singers to produce extraordinary creations but also inexperienced people can enjoy their productivity with ease of use.

Q.5b: Discuss how computer is affecting our lifestyle by providing variety of choices for day to day tasks. OR Discuss the emerging computer technology for tomorrow's world?
Ans: Use Of Computers Tomorrow (Future)
The emerging technologies are also getting better day by day and we can imagine that how computer will be used in future. Artificial Intelligence, Robotics, Wireless Communication and Virtual Realities are some areas which are shaping the modern world.

1. Artificial Intelligence:

• A.I is based on simulating human intelligence in machines that can easily mimic and execute tasks from simple to more complex operations.
• The term A.I. may also be referred to any machine that displays qualities associated with a human brain such as learning, reasoning and problem solving.

Uses:

• A.I. is also used for Machine Learning. It learns from our daily routines and suggests us different options. Like google maps suggest the best ways for our daily commute.
• A.I. is vastly used in scientific experiment, healthcare and space technologies.

2. Robots:

• Robots are the machines that can be controlled by a computer and are capable of carrying out a complex series of actions automatically.
• Robots can be controlled by an external control device or through programming.
• Robotics deals with designing, creating and programming of the robot and enhancing it by taking sensory feedback and processing information.

Uses:

• Robots are commonly used in manufacturing, industry, science, medicine and education.

3. Wireless Communication:

• Wireless communication has become an integral part of our lives. Wireless communication technology transmits information using electromagnetic waves like IR (Infrared), RF (Radio Frequency), satellite, etc.

Uses:

• Global Positioning System (GPS) is now used to find real time location of people and objects.
• Smart phones that include 3G, 4G and 5G networks have transformed the conventional use of telephones. These phones not only provide better coverage but also fast mobile internet experience.
• Wireless communication is also giving new meaning to the socialization and human interactivity.

4. Virtual Reality:

• is an artificial environment that is created with software and presented to the user in a way that the user feels it as a real environment.

Uses:

• Virtual reality can be used for the simulation of a real environment for training and education.
• It is also used for development of an imagined environment for a game or interactive story.
• It is very important to orient students about the contemporary and upcoming technologies.

Q.6: Tell about scope of the different careers in IT sector.
Ans: Careers In IT Field
Today Computer Science plays a key role in all fields of life.
Computer Science (CS) jobs are ranked as having some of the highest salaries in the world.
It's no surprise that Computer Science and Information Technology (IT) are changing tomorrow's job market.
Here is some different careers that are present in the IT sector.

(i) Software Engineer:
A Software Engineer is a person who uses different programming languages to develop software products like games, Learning Management System (LMS), business applications, educational and entertainment software.

(ii) Network Administrator:
Network Administrator is an IT expert who manages an organization’s network. He or She is responsible for installing, maintaining and upgrading any software or hardware required to efficiently run a computer network.

(iii) Database Administrator
A Database Administrator (also known as DBA) is a skilled professional who maintains a secure database environment in an office, business or organization.

(iv) Web Designer:
Web is short for World Wide Web or www. This is another name for internet. Web designers are people who build websites. They prepare a site's content with eye-catching designs, attractive images and strong text. They rely on many web designing tools to ensure an interactive website. How the site works and how it looks is the responsibility of web designers. They are also responsible for maintaining and updating an existing site.

(v) Graphic Designer:
Graphic is another word for image. Graphics Designers develop overall layouts of brochures, magazines and other types of published advertisements and documents. They do this by using various computer graphics software. This task is usually accomplished by combining art and technology, conveying ideas through images, layout of websites and printed matter.

(vi) Information Security Analyst:
These people protect networks. They plan and carry out security measures to ensure that no loss of data (or information) occurs. We can call them the police force of the internet. Computer technology has expanded into online banking and businesses.
Computer hackers are always on the lookout for customer account details that they can use to steal money. Information Security Analysts ensure that no such theft occurs.

(vii) Computer Science or IT Teacher
Another very rewarding career for Computer Science graduates and post-graduates is teaching in schools, colleges and universities. These instructors instill in their students the importance of computers in today's world, and the impact these machines will have in their later lives.

Q.7: Define software and hardware?
Ans: SOFTWARE:

• Software is a set of instructions that a computer uses to perform a task. It is a general term for a computer program.
• Software is the programs and applications that run on computer and make the computer usable.
• There are two main types of software; System Software and Application Software.

Example: Windows, Visual Basic, Microsoft word, Microsoft Excel , Adobe etc. are the examples of Software.

COMPUTER HARDWARE:

• Hardware is the physical or tangible parts of the computer that run programs and applications. Or Computer hardware is a collection of all the physical parts or components of a computer.
• Hardware can be seen and touched.

Example: Hardware is a collective term. It includes the computer casing, the CPU or Central Processing Unit, computer memory, VGA graphics card, sound card, and the motherboard, cables, connectors, power supply and peripheral devices such as keyboard, mouse etc.

Q.8a: Define system unit? Explain the function of different parts of system unit or Hardware like: Motherboard, Processor? Also Enlist components present on Motherboard?
Ans: System Unit:
A System Unit is the part of a desktop computer that contains the primary devices. The system unit performs operations and produces results for complex calculations.

Components of System Unit:
It includes the:

• Motherboard
• CPU
• RAM and Other components
• As well as the case in which these devices are enclosed

(i) Motherboard:
The motherboard is the main board which connects different parts of computer.

• Construction:
  a) We can find CPU, memory slots, expansion slots and a number of chipsets on motherboard.
  b) Motherboards are made of layered fiberglass.
  c) These layers contain copper lines that form the circuitry by which electrical signals are provided to all parts of computer.
  d) Various components of computer may be attached, detached and upgraded on motherboard.
  e) According to need of the user. Motherboards also have connectors called ports. These ports are used to connect input, output and other peripheral devices.
  
  
• Function:
  Just like nervous system it allows communication between all parts of the computer.
  
  
• Components Of Motherboard:
  It includes the following general components:
  a) Microprocessor (CPU)
  b) Slots
  c) Ports
  d) Buses
  e) RAM and ROM
  f) Other electronic components for example resistors, capacitors, diodes, transistors, jumpers etc.

(ii) Microprocessor (CPU):
Definition:
Microprocessor is also called (CPU ) Central Processing Unit. CPU or microprocessor is the brain of computer.

• Construction:
  a) The microprocessor is a chip containing millions of tiny transistors. These transistors manipulate data.
  b) Microprocessor is made up of silicon.
  c) A microprocessor that has faster clock speed (measured in GHz) and more cores and cache works faster.
  d) The CPU is housed in the computer's mother board.
  
  
• Function:
  a) CPU or microprocessor is the brain of computer.
  b) Microprocessor performs all the calculations necessary to make the computer work. These calculations are performed at very high speed and accuracy.
  c) The microprocessor fetches, decodes, executes and stores all the instructions given by the user or any other device.
  d) The speed of computer mainly depends upon the speed of microprocessor.
  e) CPU interprets the data and instructions. It generates control signals.
  f)  It also produce the address bit needed by memory.

Q.8b: Describe Components of a microprocessor:
Ans:Components Of Microprocessor:
There are typically five components of a microprocessor.

(a) Arithmetic Logic Unit (ALU):
1. ALU performs all the actual calculations like arithmetic operations and logical comparisons.
2. Arithmetic operations include addition, subtraction, multiplication and division while logical comparisons include comparing, selecting and matching of data.

(b) Control Unit (CU):
1. Control Unit is responsible for controlling the transfer of data and instructions among other units of a computer.
2. This unit controls the operations of all parts of the computer but does not carry out any actual data processing operations.
3. CU functions just like a traffic policeman.
4. It manages and coordinates all the units of the computer.

(c) Clock:
1. Clock generates pulses and instructions are executed on the basis of pulses.
2. Clock speed is measure in MHz and GHz.

(d) Registers:
1.It is a temporary storage area that holds the data that is being processed.
2. It is also known as programming model which may be of 8 bits, 16 bits, 32 bits or 64 bits.

(e) Cache:
1. Cache is an intermediate storage area, which is available inside microprocessor.
2. The immediate processed information is stored in cache.
3. The cache inside the microprocessor is called internal cache and outside is called external cache.

Q.9:Define input devices? Describe different types of input devices? OR Differentiate between various input devices?
Ans: Input Devices:
Input devices are used to enter data into computers. They enable the user to send data, information, or control signals into the memory unit of the CPU of a computer.
These are physical devices (equipment) that read or translate data consisting of alphabets, numbers or other symbols into electronic impulses, which can be understood by the computer.

Types Of Input Devices:
These devices can be categorized into:

• Text Entering
• Pointing
• Image Scanning
• and other Devices.

(i) Text Entering Devices:
Keyboard: It is the most common text entering device and used to enter data usually in text format or to perform other controlling functions.
Function:
When a key is pressed, keyboard controller chip sends its corresponding code in keyboard buffer called scan code, which is then processed by CPU.

(ii) Pointing Devices (Mouse and its variants):
It includes mouse, joy stick, track ball and track pad.
Function:
They are used for the quick movement of cursor on screen needed usually in graphic mode.

(iii) Image Scanners:
Image scanners include Optical Mark Recognition (OMR), Optical Barcode Reader (OBR) and Optical Character Recognition (OCR).
Function:
Scanners convert image into electronic format understandable by computers through light sensing.
They also work on Optical Recognition which occurs when a device scans a clear printed surface and translates the image into machine-readable formats that a computer understands.

(iv) Other Types of Input devices:
There are also other input devices. For example:

• Microphones:
  are used to accept sound input and convert it in digital audio format. Microphones are also used for voice recognition which can convert voice input into text files.
  
  
• Touch Screen:
  is also used for input. It accepts input directly on monitor by touching finger or any object on the screen.
  
  
• Magnetic Ink:
  Character Recognition (MICR) and Magnetic Strip Reader are also used for input.

Q.10: Define output devices? Recognize different output devices?
Ans: Output Devices:

• A hardware device that sends data from a computer (CPU) to another device or user is called an output device.
• The most common output devices of a computer are monitor and printer.

Types Of Output Devices:
There are two types of output devices.

1. Soft Copy Output Devices
2. Hard Copy Output Devices:

(i) Soft Copy Output Devices
It is screen display or voice output. It is volatile output and lost when other output is shown or computer is turned off.
Example OF Soft Copy Output Devices:
Following are some of the devices used to give output in soft form.

(a) Monitors:
It is TV like device that displays data by small bright dots called pixels.
Monitors are of two types.

• Cathode Ray Tube (CRT)
• Flat Panel Display (FPD)

(b) Data Projectors
Data projectors are used to show colorful slides and images directly from computer disk on a wall or large screen through an optical lens. They are also called digital light projectors and video projectors.

(c) Speakers:
Speakers give output in form of sound. They are good for people with visual disabilities or where display is not easy.

(ii) Hard Copy Output Devices:
It is output on paper. It is nonvolatile output that is relatively stable and permanent form.
Example OF Hard Copy Output Devices:
Hard Copy Output Devices are:

(a) Printers:
They usually give output on paper and can print both text and graphics.
There are two types of printers:

• Impact
• Non-Impact

(b) Plotters:
Like printer it gives images on paper but typically used to print large format images such as maps, construction drawing, advertising hoardings etc.

Q.11: Define storage devices ? Describe different types of storage devices? 
Ans: Storage Devices:
A storage device refers to a hardware used to store information.

Types Of Storage Devices:
There are two types of storage devices:

1. Primary storage device (Primary memory)
2. Secondary storage device (Secondary memory)

(i) Primary Storage Devices:

• Primary storage is also known as main memory or internal storage.
   Primary storage devices are used by computer during processing.
• They are quite smaller in storage capacity.
• Most primary storage devices are found inside the computer, and they have the fastest access to data.
• Primary devices include RAM and ROM.
• ROM:
  i) ROM is the Read Only Memory.
  ii) It is non-volatile. It means it does not lose its data or programs that are written on it at the time of manufacture.
  iii) It is permanent memory. that contains all important data and instructions needed to perform important tasks like the boot process.
  iv) ROM is quite small in capacity. It stores the major setting of computer permanently.
  
  
• RAM:
  i) RAM is Random Access Memory.
  ii) RAM is volatile, means it loses its content as the power supply is disconnected.
  iii) This is used to store data and instructions temporarily.

(ii) Secondary Storage Devices:

• Secondary storage is also known as mass storage devices or external memory or backing storage.
• Secondary storage devices have a larger storage capacity and can store data permanently.
• It is non-volatile memory device.
• Users save their data on secondary storage devices.
• Hard Disk, CD and DVD, SD Card and USB flash disk are the examples of secondary storage devices.

Q.12: Describe the four basic operations of computer? Draw the block diagram of computer's basic operations?
Ans: BASIC OPERATIONS OF A COMPUTER:
A computer is a machine that acts according to the instructions given by the user. A computer performs four basic operations:

1. Input
2. Processing
3. Output and
4. Storage.

(i) Input:

• It is the process of entering raw data, instructions and information into the computer.
• Computer input has many forms. It can be from a command entered using input devices such as a keyboard or a mouse.
• It can be data sent from another computer on a network.

(ii) Processing:

• Processing is done inside the computer by CPU.
• Processing is the conversion of input into output. After processing, data is turned into meaningful information.
• This is carried out with the help of arithmetic and logical operations.
• It takes the raw data from storage, processes it and then sends back the processed data to storage.

(iii) Storage:

• Storage refers to the holding or saving data.
• The computer has primary memory and secondary storage to store data and instructions.
• It stores the data before sending it to CPU for processing and also stores the processed data before displaying it as output.
• RAM, ROM and Hard Disk are the devices that are used for storage.

(iv) Output:

• Output is the result of a computer processing.
• Output may be viewed on a monitor screen, heard through speakers or printed on paper.
• Monitor screen, speakers and printer are called output devices.

Block Diagram Of Computer's Basic Operations

Q.13:Define Computer software and describe its type?
Ans: COMPUTER SOFTWARE:
Software is a set of instructions that a computer uses to perform a task. It is a general term for a computer program.

Types Of Software:
There are two main types of software:

1. System Software and
2. Application Software

1. System Software:

• System software is a computer program that coordinates all activities and functions of a computer.
• It also controls all the operations of the computer hardware.
• Types Of System Software
  It includes:
  i) Operating systems
  ii) Device drivers
  iii) Utility programs and
  iv) Language translators.
  
  
• (i) Operating System:
  a) Operating system is the master control program that manages all the system resources.
  b) It creates an interface between computer system and user.
  c) Windows and Linux are commonly used operating systems.
  
  
• (ii) Device Drivers:
  a) Device drivers are computer programs that control a particular device when it is connected to a computer.
  b) Any hardware that we have in our computer must have a device driver to communicate with operating system.
  c) A device driver is a translator between the operating system and the hardware device.
  d) For many devices, operating system has drivers preinstalled in them. This gave rise to the concept of Plug and Play, where the device would be attached to the computer and the operating system will instantly recognize it.
  e) A non-plug-and-play device would require to go through several steps of installing drivers and setting up the device before it would work.
  
  
• (iii) Utility Programs:
  a) Utility means being useful.
  b) Utility programs are useful computer programs that help to manage, maintain and control computer resources.
  c) Operating systems usually have pre-installed programs that can serve the purpose, but utility software provides further functionality.
  d) One example of utility program is an antivirus software. This computer program helps to protect a computer from viruses and other harmful files.
  e) Hard Disk tools are also part of utility programs. They manage hard disk drives and other storage devices.
  f) This includes utilities to scan the hard disks for any potential problems.
  g) Disk cleaner utility is used to remove any unnecessary files while disk defragmenter is used to reorganize file on a hard disk drive to increase performance of disk.
  
  
• (iv) Language Translators:
  a) Language Translators are used to translate human readable instructions into machine language.
  b) Computer can only understand machine language which is composed of 0's and 1's.
  c) The computer languages are used to make computer programs (software).
  d) Generally, software is written in high-level languages, using natural language words.
  e) Language translator are of three types:
  i. Assembler
  ii. Compiler and
  iii. Interpreter.
  
  (i) Assembler: The assembler translates the program written in assembly language into machine language instructions for execution.
  (ii) Compiler: It translates the entire high-level language program at once into machine language before it is executed.
  (iii) Interpreter: It translates the high-level language program line by line into machine language.

2. Application Software:

• Application Software is used to complete specific tasks, such as creating documents, databases, spreadsheets and presentations.
• Computer games, media players and web browsers are also the examples of application software.
• User needs to install application software to accomplish specific tasks.
• Application software are not pre-installed on operating system. They are installed separately.
• For example, making spreadsheet is not possible with Windows. For that application software such as MS Excel is used.
  
  

Types Of Application Software
There are different types of application software:
(i) Productivity Software
(ii) Business Software
(iii) Entertainment Software
(iv) Educational Software

• (i) Productivity Software:
  a. This kind of application software is used to produce things such as documents, spreadsheets, databases and presentations.
  b. Many of the productivity software are intended to be used in businesses and offices.
  c. MS Office for Windows is an example of productivity software.
  
  
• (ii) Business Software:
  a. Business Software are used to manage business activities efficiently.
  b. It is used to provide many business functions such as billing, database management and inventory management.
  
  
• (iii) Entertainment Software
  a. This type of software provides amusement and fulfills a user's hobby.
  b. The most common entertainment software are video games.
  
  
• (iv) Educational Software
  a. Educational software is used for teaching and learning.
  b. This kind of software is used in many schools to enhance knowledge of students in learning different subjects.