Tutorial 01 - Introduction to Computer

TUTORIAL : 01 – INTRODUCTION TO COMPUTER DEPARTMENT OF COMPUTER SCIENCE & ENGINEERING

PREPARED BY : PROF. SOHIL VOHRA (ASST. PROFESSOR, DJMIT, MOGAR) CONTACT : [email protected]

01. Draw the block diagram of computer and explain.

Ans :

Block diagram of a computer is as shown.

Input Units : Computers need

to receive data and

instruction in order to

solve any problem. Therefore

we need to input the data

and instructions into the

computers.

o The input unit

consists of one or

more input devices.

Keyboard is the one of

the most commonly used

input device. Other commonly used input devices are the mouse,

Scanners, Joystick, etc.

o All the input devices perform the following functions.

Accept the data and instructions from the outside world /

user.

Convert it to a form that the computer can understand (i.e.

Binary Language / low level language).

Supply the converted data to the computer system for

further processing.

Storage Unit: The storage unit of the computer holds data and

instructions that are entered through the input unit, before they are

processed.

o It preserves the intermediate and final results before these are

sent to the output devices. It also saves the data for the later

use.

o The various storage devices of a computer system are divided into

two categories :

Primary Storage:

Stores and provides very fast.

This memory is generally used to hold the program

being currently executed in the computer, the data

being received from the input unit, the intermediate

and final results of the program.



The primary memory is temporary in nature.

The data is lost, when the computer is switched off

(i.e. volatile in nature).

In order to store the data permanently, the data has

to be transferred to the secondary memory.

E.g. RAM

Secondary Storage: It stores several programs, documents,

data bases etc.

The programs that you run on the computer are first

transferred to the primary memory before it is

actually run.

Whenever the results are saved, again they get stored

in the secondary memory.

The secondary memory is slower and cheaper than the

primary memory.

Some of the commonly used secondary memory devices

are Hard disk, CD, etc.,

Output Unit: The output unit of a computer provides the information and

results of a computation to outside world.

o Printers, Visual Display Unit (VDU / Monitor) are the commonly

used output devices.

Arithmetic Logical Unit: All calculations are performed in the

Arithmetic Logic Unit (ALU) of the computer.

o It also does comparison and takes decision.

o The ALU can perform basic operations such as addition,

subtraction, multiplication, division, etc and does logic

operations viz, >, <, =, „etc.

o Whenever calculations are required, the control unit transfers

the data from storage unit to ALU once the computations are done,

the results are transferred to the storage unit by the control

unit and then it is send to the output unit for displaying

results.

Control Unit: It controls all other units in the computer.

o The control unit instructs the input unit, where to store the

data after receiving it from the user.

o It controls the flow of data and instructions from the storage

unit to ALU.

o It also controls the flow of results from the ALU to the storage

unit.

o The control unit is generally referred as the central nervous

system of the computer that control and synchronizes its working.



Central Processing Unit: The control unit and ALU of the computer are

together known as the Central Processing Unit (CPU).

o The CPU is like brain performs the following functions:

It performs all calculations.

It takes all decisions.

It controls all units of the computer.

02. Give applications of Computer.

Ans :

Mathematical Calculations :

Business : E.g. in Banks for online transactions and producing other

financial reports

Telecommunications : Internet, Fax, Email, Video Conferencing etc.

Entertainment : Watching movies, Playing Games

Medical Field : For different Cardiac and Xray application

Education : E-learning process, and information sharing on the

internet.

Space Technology :

Word Processing and Data Processing

* NOTE : Explain all the point yourselves with appropriate examples.



03. Give characteristics of Computer

Ans : Speed :

o A computer is a very fast and accurate device.

o It can process thousands of instructions within a few seconds for

which a human being can take several days or months.

Accuracy

o Degree of accuracy of the computer is very high.

o Errors can occur in computerized system also but most of them

occur due to human mistakes rather than technical problems in the

computer.

Versatility

o We can perform many different tasks on the computer at a time.

o One moment it might be busy in calculating the statistical data

of a business organization for annual performance evaluation and

at next moment it is capable of working on inventory control.

Automation

o A machine is no sooner than done to be automatic if it, works by

itself without human intervention.

o Computers are automatic machines, because one started on a job,

they carry on, until the job is finished, without any human

assistance.

o However, computer being machines can not start them selves. They

cannot go out find their own problems and solutions.

o They have to be instructed.

Diligence

o A computer is free from dullness and lack of concentration.

o It can continuously work for hours without creating any error

human beings in doing regular types of jobs, which requires great

accuracy.

o Computer can perform the number of calculation with exactly the

same accuracy and speed as the first one.

No. I.Q.(Intelligence Quotient)

o A computer is not a magical device. It is no intelligence of it‟s

own.

o User can determine what tasks the computer will perform. So a

computer cannot take its own decision as you can.

o A computer can not take it own decision in this regard.

Large Storage :

o Computer is free from problems like exhaustion, lack of

concentration, confusion, etc., unlike human beings.



04. Explain following giving examples :

a. Input Devices

Ans : An input device is any peripheral (piece of computer hardware

equipment) used to provide data and control signals to an information

processing system (such as a computer).

It is a Hardware Device.

The most common input devices are the mouse and keyboard.

However, joysticks, touch screens, webcams, and microphones are

considered input devices as well.

Types of Input Devices :

o Mice and other Pointing devices :

Other than the keyboard, mice are the most common

type of input device.

Nearly every computer has one, and they make

navigating the screen much easier than trying to use

just a keyboard.

Mice usually use a ball, light, or a laser to track

movement.

Similar peripherals, such as a touch screen or

laptop's touchpad, trackballs, graphics tablets, and

even joysticks are “pointing” input devices.

Touch screens are becoming an increasingly popular

pointing device, and someday may replace mice

altogether.

o Keyboards :

The keyboard is the most common input device.

It is almost unheard of for a computer to be without

some form of keyboard, be it a full QWERTY keyboard

or a smaller number pad.

It is possible to interact with most computers

solely through the keyboard, without even a mouse,

because they are usually the default input device.

Touch screens may eventually overcome the keyboard as

well, by providing an onscreen keyboard to save

space.

o Audio/Video Input.

Webcams and digital cameras can also be considered

input devices.

They provide visual data to the computer in the form

of images and video.

Some webcams can even be used as pointing devices by

tracking the location of a person's hands or face.



Microphones and digital musical instruments, such as

midi keyboards, are audio input devices that provide

the computer with audio data.

b. Output Devices

Ans : Output devices are pieces of computer hardware that allow a

computer system to communicate information to a user or another system.

This information can be in any form, and includes sound, images,

and even tactile experiences.

Output devices can usually only be used to send data from the

computer; items called input devices allow users and other

systems to send data to the computer.

Some of the most common output devices allow computers to present

information visually.

E.G. Monitors, Printers, Plotters, Video projectors, Computer

Speakers etc.

Text, pictures, and other images are displayed on the monitor,

allowing users to interact with computer programs and receive

data.

They function in a way similar to monitors,

but display images over a much larger area.

Printers allow the computer to produce

documents, pictures, and images on paper

through the use of inks and other dyes.

c. Operating Systems

Ans : An operating system, or OS, is a software

program that enables the computer hardware to

communicate and operate with the computer software.

Without a computer operating system, a computer would be useless.

An OS takes care for all input and output in a computer system.

It manages users, processes, memory management, printing,

telecommunication, networking etc.

The operating system provides a layer of abstraction between the

user and the bare machine.

Users and applications do not see the hardware directly, but view

it through the operating system.

Operating systems provide a software platform on top of which

other programs, called application programs, can run.



The application programs must be written to run on top of a

particular operating system.

For PCs, the most popular operating systems are DOS, OS/2, and

Windows, but others are available, such as Linux.

Graphical user interfaces allow you to enter commands by pointing

and clicking at objects that appear on the screen.

Operating systems can be classified as follows:

o multi-user : Allows two or more users to run programs at

the same time. Some operating systems permit hundreds or

even thousands of concurrent users.

o multiprocessing : Supports running a program on more than

one CPU.

o multitasking : Allows more than one program to run

concurrently.

o multithreading : Allows different parts of a single program

to run concurrently.

o real time: Responds to input instantly. General-purpose

operating systems, such as DOS and UNIX, are not real-time.

An operating system performs these services for applications:

o In a multitasking operating system where multiple programs

can be running at the same time, the operating system

determines which applications should run in what order and

how much time should be allowed for each application before

giving another application a turn.

o It manages the sharing of internal memory among multiple

applications.

o It handles input and output to and from attached hardware

devices, such as hard disks, printers, and dial-up ports.

o It sends messages to each application or interactive user

(or to a system operator) about the status of operation and

any errors that may have occurred.

o It can offload the management of what are called batch jobs

(for example, printing) so that the initiating application

is freed from this work.

o On computers that can provide parallel processing, an

operating system can manage how to divide the program so

that it runs on more than one processor at a time.



05. Differentiate between Hardware and Software giving examples

Ans :

Hardware Software

Types: Motherboard, CPU, RAM,

BIOS, power supply, video

display controller,

computer bus, CD-ROM

drive, floppy disk, zip

drive.

System

software, Programming

software,

and Application

software.

Examples: CD-ROM, monitor, printer,

video card, scanners,

label makers, routers, and

modems.

Adobe Acrobat,

Internet Explorer ,

Microsoft Word ,

Microsoft Excel

Inter dependency: Hardware starts

functioning once software

is loaded.

To deliver its set of

instructions, Software

is installed on

hardware.

Definition: Devices required to store

and execute (or run) the

software.

Collection of

instructions that

enables a user to

interact with the

computer. Software is

a program that

enables a computer to

perform a specific

task, as opposed to

the physical

components of the

system (hardware).

Function: Hardware serve as the

delivery system for

software solutions. The

hardware of a computer is

infrequently changed,

incomparison with software

and data, which are “soft”

in the sense that they are

readily created, modified,

or erased on the computer

To perform the

specific task you need

to complete. Software

is generally not

needed to for the

hardware to perform

its basic level tasks

such as turning on and

responding to input.

Fault: Hardware faults are

physical.

Software faults are

not.

Lifetime: Hardware wears out over

time.

Software does not wear

out over time.

Failure: Hardware failure is

random. Hardware does have

increasing failure at the

last stage.

Software failure is

systematic. Software

does not have an

increasing failure

rate.

Reliability: Hardware stays at steady

reliability level in

useful life.

Software needs

constant testing after

upgrades.



06. Explain Algorithms and Flowcharts by providing

a. Characteristics

b. Advantages

c. Disadvantages

d. Examples

06.A. Algorithms :

An Algorithm is just a detailed sequence of simple steps that are

needed to solve a problem.

An algorithm is a sequence of instructions, which are followed in

order to complete a task. An algorithm can be presented or written

in words, in a program (structured code) for a computer or as a

flowchart.

An algorithm is a sequence of unambiguous (having only one meaning )

instructions for solving a problem, i.e., for obtaining a required

output for any legitimate input in a finite amount of time.

Characteristics of Algorithm:

01. Finiteness : terminates after a finite number of steps

02. Definiteness : rigorously and unambiguously specified

03. Input : valid inputs are clearly specified

04. Output : can be proved to produce the correct output given a

valid input

05. Effectiveness : steps are sufficiently simple and basic.

Example of Algorithm: finding the average of two numbers

Algorithm:

Input: two numbers x and y

Output: the average of x and y

Steps:

1. input x 2. input y 3. sum = x + y 4. average = sum /2 5. output average



06.B. Flowchart :

A flowchart is a graphical representation of an algorithm.

These flowcharts play a vital role in the programming of a problem

and are quite helpful in understanding the logic of complicated and

lengthy problems.

Once the flowchart is drawn, it becomes easy to write the program in

any high level language.

Often we see how flowcharts are helpful in explaining the program to

others.

Hence, it is correct to say that a flowchart is a must for the

better documentation of a complex program.

Flowcharts are usually drawn using some standard symbols; however,

The following are some guidelines in flowcharting:

o In drawing a proper flowchart, all necessary requirements

should be listed out in logical order.

o The flowchart should be clear, neat and easy to follow. There

should not be any room for ambiguity in understanding the

flowchart.

o The usual direction of the flow of a procedure or system is

from left to right or top to bottom.

o Only one flow line should come out from a process symbol.

or



o Only one flow line should enter a decision symbol, but two or

three flow lines, one for each possible answer, should leave

the decision symbol.

o Only one flow line is used in conjunction with terminal

symbol.

o If the flowchart becomes complex, it is better to use

connector symbols to reduce the number of flow lines. Avoid

the intersection of flow lines if you want to make it more

effective and better way of communication.

o Ensure that the flowchart has a logical start and finish.

o It is useful to test the validity of the flowchart by passing

through it with a simple test data.

o Example of a simple Flowchart showing if a student is Pass or

fail based on marks.



Read num

F T

grade = "pass"

End

Start

num >=60

grade = "Fail"

Print grade



Characteristics of Flowchart

Vertical Linear Design

The overall design of most flowcharts is a vertical pictorial of

various elements that flow downward until the user reaches a

decision or solution.

Certain parts of the chart move to the left or right horizontally

to accommodate additional decision making elements, but overall

the direction is vertical.

Inputs

The inputs of the flowchart are the questions asked of the user.

The answers will allow the user to move through the chart to the

ideal solution.

Outputs

The output of the flow chart is either the solution or the next

tier of a pattern of questions that will eventually lead to a

final output.

Directional Arrows

The arrows in a flow chart are key to its movement---they

represent the choices the user has in the flow between the inputs

and outputs. The arrows are commonly labeled with a simple "yes"

or "no" but can also have more specific answers.

The head of the one-way arrow shows the direction of movement for

the flow chart and helps the user move on to the next step of the

decision making process.

Start and End Boxes

A flowchart has a well-defined start and end. The start box is

usually either the first input question or the title of the

problem.

Even if the user cannot reach a solution by answering the

questions, there is a box that represents the termination of the

flow of inputs and outputs.

The box may be clearly labeled "End" or simply be a note stating

that a solution is impossible.



The Advantages of flowcharts are as follows:

1. Communication: Flowcharts are better way of communicating the logic of a system to all concerned.

2. Effective analysis: With the help of flowchart, problem can be analyzed in more effective way.

3. Proper documentation: Program flowcharts serve as a good program documentation, which is needed for various purposes.

4. Efficient Coding: The flowcharts act as a guide or blueprint during the systems analysis and program development phase.

5. Proper Debugging: The flowchart helps in debugging process. 6. Efficient Program Maintenance: The maintenance of operating

program becomes easy with the help of flowchart. It helps the

programmer to put efforts more efficiently on that part

Disadvantages of Flowcharts:

1. Complex logic: Sometimes, the program logic is quite complicated. In that case, flowchart becomes complex and clumsy.

2. Alterations and Modifications: If alterations are required the flowchart may require re-drawing completely.

3. Reproduction: As the flowchart symbols cannot be typed, reproduction of flowchart becomes a problem.

4. The essentials of what is done can easily be lost in the technical details of how it is done.

Documents

Tutorial 01 - Introduction to Computer