chapter 1 C++A.pptx lecture note on programming

1. Introduction to Computer
Objectives:
At the end of this chapter, students are expected to:
 Be able to describe the word computer differently
 List the advantages of using computers over the non-computer world
 Identify the limitations of computers that users need to take note of
 Explain the five computer generations that human-being has passed
through
 Identify the basic hardware and software components of a computer
 Differentiate computers by size, type, purpose

The Nature of Information
• Information is the core of computers and communications
technology
• Different terminologies related to information:
A. Data: Data is specific numerical or symbolic representations of facts
about the world. Data is the element to be input, stored, and
manipulated by the computer.
One can think of data as a “raw material” that needs to be processed
before being turned into something useful.
B. Information: Information is a useful organization and selection of
facts, not the number of facts available. Information is organized data.

Cont………….
C. Knowledge:
Knowledge involves the evaluation and understanding of information. It
refers to the meaning of information concerning human interests and
purposes
D. Wisdom:
Wisdom is the ability to know when and how to apply knowledge. It is
the ability to imagine the consequences of our actions for ourselves and
others

Definition of Computer
• Definition 1: A computer is an electronic machine, operating under
the control of instruction stored in its memory, that can accept data
(input) manipulate the data according to specified rules (Process),
produce results (output), and store the result for future use.
• Definition 2: A computer can be defined as an electronic device that
accepts data as an input, process data as information, and gives the
information as the output.
• Definition 3: A computer can be defined as a machine which works
under the control of a well-structured set of instruction which accepts
raw fact (input), process the raw facts (process) and produce
meaningful information (output).

• From the above definitions, one can identify that a computer:
• Accepts input,
• Processes data,
• Stores data, and
• Produces output.

Characteristics of Computer
• Automatic
• Speed: The ability of computers to carry out their instructions in a very short
period is one of the main reasons for their popularity.
• Accuracy: Nowadays, computers are being used in life-and-death situations
(For example, jet pilots rely on computer computations for guidance,
• Reliability: Computers can carry out the same type of work repeatedly
without throwing up errors due to tiredness or boredom, which are very
common among humans.
• Versatility: Computers can carry out a wide range of work from data entry
and ticket booking to complex mathematical calculations and continuous
astronomical observations.

• Storage Capacity: Computers can store a very large amount of data at
a fraction of the cost of traditional storage of files. Also, data is safe
from normal wear and tear associated with paper.
Having the above-mentioned characteristics, a computer is found very
advantages due to the following capabilities:
• Computers can do the same task repetitively with great ease, speed,
and reliability
• Computers do not get tired or bored
• Computers can take up routine tasks while releasing human resource
for more intelligent functions

• Store and process large amount of information with high speed and accuracy
• Transmit information across continents via communication channels
• Simulate events
• Perform complex mathematical computations and make comparisons
• Monitor ongoing industrial operations
However, computers have also limitations like:
• Computers can perform tasks that are only programmed to do
• Computers operate on data that are provided by users
• Computers cannot give any conclusion without going through immediate
instructions
• Computers have limited use in qualitative conditions
• Computers require regular checking

Applications of Computers
• Education and Research
• Business
• Engineering
• Electronic banking and service
• Communication: The integration of computers and communication
technologies is what is being referred to as ICT.
• Manufacturing: Computers have made industrial processes more efficient
through optimization scheduling, process control, and using robots to perform
automated manufacturing process control which is otherwise dangerous to
human beings.
• Transportation: Computers have affected almost every kind of transportation.

• Medical and Health Care
• Consultant (Expert system): An Expert system is a computer
program, which can solve problems from a specific knowledge base.
• These systems don't replace expert humans because the knowledge
base of an expert system is given by the skilled specialist.
• Example: MYCIN (a medical diagnostic program by using a
sophisticated decision-making process).

Generation of Computer
• The computer technology we use today is not a result of one-night
innovation, instead, it has evolved through different stages.
• The major characteristics that distinguish the various generations are
the following:
• The dominant type of electronic circuit elements used
• Major secondary storage media
• Computer language used
• Type or characteristics of the operating system used
• Memory access time

First Generation Computer (1946 -1959)
• The first-generation computers used vacuum tubes for
circuitry and magnetic drums for memory, and were
enormous, taking up entire rooms.
• They were very expensive to operate and used high
electricity, generated a lot of heat, which cause malfunctions.
• First-generation computers relied on machine language
which is the lowest-level programming language understood
by computers, to perform operations, and they could only
solve one problem at a time.

Second Generation Computer (1959-1965)
• In the second generation of computers, transistors replaced vacuum
tubes; the transistor was invented in 1947 but did not see widespread
use in computers until the late 1950s.
• The transistor was greater than the vacuum tube, allowing computers
to become smaller, faster, cheaper, more energy-efficient, and more
reliable than their first-generation predecessors.
• Though the transistor still generated a great deal of heat that subjected
the computer to damage, it was a great improvement over the vacuum
tube.

• High-level programming languages were also being developed at this
time, such as early versions of COBOL and FORTRAN.
• These were also the first computers that stored their instructions in their
memory, which moved from a magnetic drum to magnetic core
technology.
• Third Generation Computer (1965-1971)
• In the third generation, the development of the integrated circuit was
the hallmark of the third generation of computers.
• Transistors were miniaturized and placed on silicon chips, called
semiconductors, which drastically increased the speed and efficiency of
computers.

Fourth Generation Computer (1971 -1980)
• The microprocessor brought the fourth generation of computers, as
thousands of integrated circuits (Very Large-Scale Integrated
microprocessor) were built onto a single silicon chip.
• What is the first generation filled an entire room could now fit in the
palm? The Intel 4004 chip, developed in 1971, located all the
components of the computer from the central processing unit and
memory to input/output controls on a single chip.

Fifth Generation Computer (1980-onwards)
• Fifth-generation computing devices, based on artificial intelligence,
are still in development, though there are some applications, such as
voice recognition, that are being used today.
• The use of parallel processing and superconductors is helping to make
artificial intelligence a reality.
• Quantum computation and molecular and nanotechnology will
completely change the face of computers in years to come.
• The goal of fifth-generation computing is to develop devices that
respond to natural language input and are capable of learning and self-
organization

Parts of a Computer System
• Every single full-functional computer contains various components. A
computer generally consists of two major components called
• Hardware components and
• Software components.
Hardware Components
• Hardware components of a computer refer to those physical
components of a computer that could be touched and be felt.

Cont…
• These components could be used to input data to the computer, to
process the input data for any sort of data manipulation, to see an
output of the computer, or to store the output data for further usage.
• Generally, hardware components of a computer system could be
categorized as:
• An input unit,
• Processing unit,
• Output unit, and
• Storage unit.

Input Unit
• Keyboard: The keyboard is a typewriter-style device that can use the
alphanumeric keys or buttons for the input given by the user to the
computer system.
• A typical wired keyboard from DELL

• Mouse: A mouse is a pointing device that fits comfortably under the
palm of your hand.
• It is the most widely used pointing device on Desktop computers.
• The mouse is used to move the cursor on your computer screen, to
give instructions to your computer, and to run programs and
applications.
• It can be used to select menu commands, move icons, size windows,
start programs, close windows, and others.
• Figure 2: A typical wired mouse from DELL

• Click: Click means press and release the left mouse button once. It is
used to select an item.
• Right Click: Right-click means to press and release the right mouse
button once. It is used to display a set of alternative commands from
which one can choose a command.
• Double Click: Double click means quickly press the left mouse button
twice in a fast sequence. It is used to open a document or a program.
• Drag and Drop: place the cursor over an item on the screen and then
press and hold down the Left Mouse Button. Holding down the button,
move the cursor to where you want to place the item, and then release
the button.

Trackball:
• This is a ball that is like an inverted mouse, which is rotated with the
fingers or palm.
• Figure 3: A wireless trackball

• Touchpad: The touchpad is a small, flat surface. With this device, the
fingers can be used to move the mouse pointer to various locations
• Figure 4: A laptop touchpad

• Light Pen: The light pen is a light-sensitive stylus, or pen-like device,
connected by a wire to the computer terminal.
• A user brings the pen to the desired point on the display screen and
presses the pen button, which identifies the screen location of the
computer.
• Figure 5: A light pen for a tablet

Bar-code Readers:
• Bar codes are the vertical zebra-striped marks you see on most
manufactured retail products.
• Bar-code readers are photoelectric scanners that translate the bar-code
symbols into digital code.

Character Recognizing Devices:
• These devices are used in the bank to read to the numbers at the
bottom of the check, to read to the number plates of the cars, and
generally printed characters when scanning.
• Figure 7: A character recognizing device

MIDI Board:
• MIDI stands for Musical Instrument Digital Interface.
• It provides a standard for the interchange of musical information
between musical instruments, synthesizers, and computers.
• Figure 8: MIDI board connected to a laptop

Sensor:
• A sensor is an input device that collects specific kinds of data directly
from the environment and transmits it to a computer.
• Sensors are found very useful in earthquake detection, tracking the
depth of the sea, and lots of other areas.
• Figure 9: Different types of sensors

Scanner:
• Scanner is an input device that can read text or illustrations printed on
paper & translate the information into a form that a computer can use.
• Figure 10: Epson Perfection V850 Pro Scanner

Digital Camera:
• Digital camera is an electronic device that is used to capture and store
photographs electronically in a digital format that can be read by a
computer.
• The image can be transferred directly from the camera to a computer
• Figure 11: Sony DSC-W830 Digital Camera (Silver)

Microphone:
• A microphone is a device that can be used to input sound information
to a computer system from the environment.
• It can be used with a voice recognition system to record sound.
• Figure 12: Shure SM58-LC Dynamic Microphone

Processing Unit (Central Processing Unit-CPU)
• Responsible for any sort of data manipulation or execution of
instruction so that appropriate information can be displayed and/or
required data can be stored to the desired destination.
• Generally, the CPU is known also as the brain of a computer as it
controls all processing inside a computer.
• CPU has the following fundamental features:
It is part of computer hardware that executes program instructions.
The CPU is like the human brain and it oversees and controls all of the
activities of the computer.

 The CPU manages and coordinates the entire computer
including the input and output units.
 The CPU is the collection of electronic circuits made up
of millions of transistors placed into integrated circuits.
 Integrated circuits are also called chips or microchips
 Each transistor is an electrical switch that can be in one
of the two states: “on” or “off”.
 Small transistors allow more transistors to be packed in
one single chip, thus eliminating the need for separate
chips
• CPU has two major components: The Arithmetic Logic Unit
and the Control Unit.

Structure- Computer
Computer
Main
Memory
Input
Output
Systems
Interconnection
Peripherals
Communication
lines
Central
Processing
Unit
Computer

Structure- The CPU
Computer Arithmetic
and
Login Unit
Control
Unit
Internal CPU
Interconnection
Registers
CPU
I/O
Memory
System
Bus
CPU

Output Unit
• The job of an output unit is just the reverse of that of an input unit. It
supplies the information obtained as a result of data processing to the
outside world.
• Thus, it links the computer with the external environment. As
computers work with binary code, the results produced are also in the
binary form.
• Hence, before supplying the results to the outside world, it must be
converted to a human-readable form.

Monitor:
• It displays the output of a computer. There are different types of
monitors depending on different criteria.
• Based on the color types monitors could support, a monitor could be
monochrome, grayscale, or color monitor.
• Depending on the technology monitors are made of, monitors could be
cathode ray tubes (CRT), liquid crystal display (LCD),
electroluminescent, or XGA.

• Speech Synthesizer: This device converts digital data into speech-like
sounds.
• Video Conferencing system: Videoconferencing is a method whereby
people in different geographical locations can have a meeting and see and
hear one another – using computers and communications.
• Printers: Printers are used to produce “hard copy” of documents,
programs, and data.
• Some printers use serial communication (RS232 standard) while others
use parallel communication to transfer information from the PC to the
printer.
• In serial communication, data is transferred one bit at a time while in the
case of parallel communication; one byte (8 bits) is transferred at one time.

Storage Unit
• The data and instruction that are entered into the computer system
through input units have to be stored inside that computer before the
actual processing starts.
• Similarly, the results produced by the computer after processing must
also be kept somewhere inside the computer system before being
passed on to the output units.
• Moreover, the intermediate results produced by the computer must
also be preserved for ongoing processing.
• It provides space for storing data and instructions, space for
intermediate results, and also for the final results

• The storage unit of all computers is comprised of the following two
types of storage:
• 1. Primary Storage: The primary storage, also known as main
memory, is used to hold pieces of program instructions and data,
intermediate results of processing, and recently produced results of
processing of the jobs that the computer system is currently working
on.
• These pieces of information are represented electronically in the main
memory chip’s circuitry, and while it remains in the main memory, the
central processing unit can access it directly at a very fast speed.
• However, the primary storage can hold information only while the
computer system is on.

• As soon as the computer system is switched off or reset, the
information held in the primary storage disappears.
• Additionally, the primary storage normally has limited storage
capacity because it is very expensive.
• The primary storage of modern computer systems is made up of
semiconductor devices.
• Primary storage could be read-only memory or random-access
memory.
• Read-Only Memory (ROM): Non-volatile chips always hold the
same data; the data in them cannot be changed except through a
special process that overwrites the data.
• It is usually done at the factory.

Random Access Memory (RAM):
• A Memory that can be instantly changed is called read-write memory
or random-access memory (RAM).
• When people talk about computer memory in connection with
microcomputers, they usually mean the volatile RAM.
• It is best simply to remember that the data in ROM does not change
while the data in RAM changes constantly.
• RAM can hold information only while the computer system is on.

Secondary Storage:
• The secondary storage, also known as auxiliary storage, is used to take
care of the limitations of the primary storage.
• That is, it is used to supplement the limited storage capacity and the
volatile characteristic of primary storage.
• This is because secondary storage is much cheaper than primary
storage and it can retain information even when the computer system
is switched off or reset.
• There exist two technologies for secondary storage: magnetic storage
devices and optical storage devices.

Magnetic Storage Devices:
• The medium contains iron particles, which can be polarized, i.e., given
a magnetic charge in one of two directions.
• Each particle’s direction represents a 1 or a 0, representing each bit of
data that the CPU can recognize.
• A disk drive uses read/write heads containing electromagnets to create
magnetic charges on the medium.
• Floppy disk, hard disk, magnetic tapes are examples of magnetic
storage.

Hard disk drive:
▪ Inside the case of the hard disk drive are a set of rigid rotating disks,
called platters, stacked on a spindle.
As the platters rotate at high speed, Read/Write heads move back and forth
recording or reading magnetic information on both sides of the platters.
The speed with which the heads can find data is called “average access
time”.
• Hard disk drives are normally installed inside the computer case although
external hard disk drives, which connect to the computer by a cable, are
also available.
• The hard disk drive is selected based on its storage capacity (measured in
“Gigabytes” (GB) or greater) and its access time

• Operating system and application software normally reside in hard
disk drives.
• Documents created using application software may also be placed on
hard disk drives.
• Figure 14: A hard disk drive

Optical Storage Devices:
• Offer high-capacity storage medium. Optical drives use reflected light
to read data.
• The disk’s metal surface is covered with dents (pits) and flat spots
(lands), which cause light to be reflected differently.
• Light cannot be reflected back from pits (data = 0) and lands reflect
light back to its source (data = 1). CD-ROM, DVD-ROM, CD-R, CD-
RW are examples of optical storage.
• CD–R is a standard and technology allowing you to write to and read
from a Compact Disc, but not erase or change what you record.

This technology is compatible with existing CDs, i.e., you can read
these discs in existing CD–players.
Today, we have speeds as much as 52X. A single CD–R can hold up to
650MB of information.
• CD–RW is a rewritable CD–ROM technology. CD–R/W drives can
also be used to write CD–R discs, and they can read CD–ROMs.
But, CD–R/W disks have lower reflectivity than CD–ROMs, and CD–
ROM drives must be of the newer multi-read variety to read them.
CD–R/W was initially known as CD–E (or CD–Erasable).
• Digital Video Disc (DVD), also called Digital Versatile Disc, is
similar to CD–ROMs but able to store far more music, video, or data.
DVDs are of the same physical size as today's CDs but can store as
much as 17GB, compared to the 650MB on today's CD–ROMs.

• DVD: The DVD represents a new generation of high-density CD-
ROM disks, which are read by a laser and which have both write-once
and re-writable capabilities.
• It stands for Digital Video Disk.
• Flash Memory Cards: Flash-memory cards consist of circuitry on PC
cards that can be inserted into slots connecting to motherboards.

Software Components
• Software is the set of instructions that can be stored and run by
hardware.
• In other words, the software is a collection of data or computer
instructions that tell the computer how to work.
• Hardware is typically directed by the software to execute any
command or instruction.
• You cannot see or touch the software, although you can see the
packages it comes in.
• The software can be divided into three kinds depending upon the
nature of work this software does: Application software, System
software, and Language software.

Application Software:
• It is a program or group of programs designed for end-users. Most of
the applications we use in our daily life such as photo editing tools,
games, web browsers, file viewers, music players are typical examples
of application software.
• Application software is also known as either application or app. There
are five categories of application software.
• Entertainment Software
• Home/Personal Software
• Educational/Reference Software:

• Productivity Software: Productivity software consists of programs
found in most offices, homes, almost all computers.
• The purpose of this software is simply to make users more productive
at performing particular tasks.
• This software is used by most people on a day-to-day basis. Some of
them are word processing software, spreadsheet software, database
server, financial software, and web-based software
• Specialty Software: software developed to achieve a particular task
especially is called specialty software.
• System Software: System software is next level closer to the
hardware of the computer.

• It helps to make the instructions given by the application software
understandable to the computer.
• It is a software that enables the application software to run on the computer.
• System software can further be classified as the operating system,
programming language, and utilities.
• Operating System: The operating system acts as the master control
program that runs the computer.
• Examples of operating systems are MS-DOS, Windows-2000, XP,
Windows 7, Windows 8.1,
• Windows 10, Unix, and Macintosh operating system. The operating
system (OS) consists of the master system of programs that manage
the basic operations of the computer.

• These programs provide resource management services of many kinds,
handling such matters as the control and use of hardware resources,
including disk space, memory, CPU, time allocation, and peripheral
devices.
• Figure 15: Operating System and other software and hardware layers

• The operating system is responsible for
A. booting,
B. managing storage media,
C. user interface,
D. managing computer resources,
E. managing files, and
F. managing tasks.
• Types of Operating Systems
Operating systems can be classified depending on the number of
programs they can handle and the number of users that can be working
on the system at a time: -

1. Single-user operating system: A single-user operating system
normally only allows one user to access the system at a time.
• Example of a single user operating system include MS_DOS
Microsoft Disk Operating System.
2. Bach-mode Operating systems: Batch processing refers in general
to a computer system in which jobs (programs +data) are entered and
then run one or more a time under the control of the operation system.
• It is the oldest operating system.
3.Time-sharing Operating system: A time-sharing system is an
interactive system in which several users at terminals all have access to
the computer at the same time.
• An operating system for such a system is called timesharing. UNIX is
the most popular time-sharing operating system.

4. Real-time operating system: A real-time system is a system that is
capable of processing data so quickly that the results are available to
influence the activity currently taking place.
• Examples include airplane seat reservations and a computer-controlled
plant.
5. Multitasking: Executing more than one program concurrently. (one user)
How does a computer handle more than one program?
The answer is that the operating system directs the processor (CPU) to
spend a predetermined amount of time executing the instruction for each
program, one at a time.
• A small amount of each program is processed and then the processor
moves to the remaining programs, one at a time, processing small parts of
each.
• This cycle is repeated until processing is complete

6. Multiprogramming: Executing different users’ programs
concurrently. (Multiple users)
As with multitasking, the CPU spends a certain amount of time
executing each user’s program, but it works so quickly that it seems as
though all the programs are being run at the same time.
7. Multiprocessing: Simultaneous processing of two or more programs
by multiple computers.
(Single or multiple users) With multiprocessing, two or more computers
or processors linked together to perform work simultaneously, meaning
at precisely the same time.
This can entail processing instructions from different programs or
different instructions from the same program.

• Language Software: Software is written in a programming language.
A program is a set of instructions that tells the computer what to do
and how to do certain tasks.
• For example, C is a programming language and ‘C compiler’ is the
language software.
• Programming languages can generally be classified as low-level
languages and high-level languages. Low-level language may be
machine languages and assembly languages.
• Machine language: Machine language is the natural language of the
computer.
• A program written in machine language is ready for immediate
execution. Machine language is very difficult to understand for
humans.

• Assembly language: Assembly language consists of English-like
abbreviations.
• It is easier to understand than machine language. Programs written in
assembly language need to be translated into machine language before
they can be executed.
• The program that translates assembly language programs to machine
language is called an assembler. High-level languages are English-like
instructions. They are easier to learn than low-level languages.
• Utility Software: Utility software is programs that are intended to
perform tasks related to the maintaining of your computer's health,
either hardware or data. Some utility software is included with the
operating system.
• Examples of utility programs include file defragmentation, data
configuration, backup, antivirus, and screen saver programs.

Classification of Computers
Classification by Size
• Based on size and performance, computers can be classified into four
types:
• 1. Micro Computer: A microcomputer is a computer whose CPU is a
microprocessor.
• A microprocessor is a processor all of whose components are on a
single integrated circuit chip. Personal computers are kind of
microcomputer.
• Personal computers are called so because they are designed for the
personal use of the individual or individual small business units’ office
automation unit or professionals.

• Mini Computer: They are the smaller version of the mainframes. Generally,
they offer the same computing power as their bigger counterparts.
• The most important advantage of a mini-computer over the mainframe is
that it is cheaper smaller in size and reliable
• Mainframe Computer: They are very big and offer maximum computing
power.
• A large number of peripherals can be attached to them. They are generally
used in large networks of computers with the mainframe being the model
point of the network
• Super Computer: They are the most expensive of all the computers. These
computers are big general-purpose computers capable of executing more
than 10,000 million instructions per second and have storage capacities of
millions of bits per chip.

• These computers are used to solve multi-variate mathematical
problems such as atomic nuclear and plasma physics seismology,
aerodynamics, etc.
• The supercomputer is typically capable of handling hundreds of
millions of floating points.
• Operations per second (MFLOPS). The speed of supercomputers is
generally measured in “FLOPS” (Floating Point Operations Per
Second).

Classification by Type
• Based on the working principle, the computer can be classified into
three types:
• Analog Computer: process data that vary continuously with time,
such as variations in temperature, speed, the chemical composition of
petroleum products, or current flowing through a conductor.
• Analog computers operate by measuring. They deal with continuous
variables.
• Generally, they are computers designed for special purposes. E.g.,
Thermometer, voltmeter, speedometer

• Digital Computer: process digital data. All the PCs currently in wide use
are digital computers.
• Digital computers deal with discrete variables. They operate by counting
rather than measuring.
• Hybrid Computer: Hybrid computer utilizes the best qualities of both
analog and digital computers.
• They are suited for situations where digital processing of data
collected in analog form is desirable.
• For example – in a hospital, intensive care unit analog device may
measure a patient’s heart function, temperature, etc. these
measurements may then be converted into numbers and supplied to
digital devices.
• Other areas are guided missile system new aircraft design etc.

Classification by Purpose
• Purpose wise computer can be classified into two types: general-
purpose computer and a specific purpose computer.
• General-purpose computer: This computer can store different
programs and can thus be used in countless applications.
• It can perform any kind of job with equal efficiency simply by
changing the application program stored in the main memory.
• Special-purpose computer:
• It is the one that is designed to perform only one special task. The
program or instruction set is permanently stored in such a machine. It
cannot be used for any other purpose.
• These computers are often used to perform specific functions such as
controlling a manufacturing process or directing communications.

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