INTRODUCTION TO COMPUTING

What is a Computer?
- A computer is an electronic device that manipulates information or "data." It has the ability to store,
retrieve, and process data.
- is an electronic device, operating under the control of instructions stored in its own memory
- One of the most popular and versatile forms of Information Technology.

History of Computer

Historians believe that computing devices were in use as early as man learned how to count. They believe
our forefathers could only add and subtract as many things as they could remember in their minds. Presumably,
they used their fingers much in the same way as children do today. Later on, pebbles were used for counting and
for performing simple arithmetic. In fact, the word calculation comes from the Latin word “calculi”, which mean
pebbles.

Mechanical Computers
Abacus An early aid for mathematical computations. Its only value is that it aids the memory of
the human performing the calculation. A skilled abacus operator can work on addition
and subtraction problems at the speed of a person equipped with a hand calculator
(multiplication and division are slower) oldest surviving abacus was used in 300 BC by
the Babylonians.

Napier’s Bones In 1617 John Napier invented logarithms, which are a technology that allows
multiplication to be performed via addition.

Schickard's The first gear-driven calculating machine to actually be built in 1623 by a German
Calculating Clock professor Wilhelm Schickard in 1623.

Pascaline Invented by Blaise Pascal in 1642

An adding machine that could add long columns and numbers.

Leibniz Calculator Made by the German Gottfried Leibnitz. This machine can perform not only addition
but also multiplication through the use of repeated additions. The calculator was used
for computing scientific or mathematical tables

Jacquard Loom An automatic loom, invented by a French weaver Joseph-Marie Jacquard hundred
years later when the Leibnitz Calculator was invented. Jacquard used a punched card
to control the placement of each thread in order to create a design.

Arithmometer Constructed by Charles Xavier Thomas de Colmar of France.

Capable of adding, subtracting, multiplying and dividing.

Difference Engine Developed by British mathematician Charles Babbage. The engine was designed to
compute mathematical tables but it remained uncompleted since Babbage started
collaborating with Lady Augusta Ada Byron, the Countess of Lovelace, to produce
another machine.

Analytical Engine A general purpose computer designed by Charles Babbage and Lady Augusta Ada
Byron. The parts of the analytical engine include a mill, a store, punch cards for input,
typesetting for output, and the means to control the output.
The said machine was not completed because the tools needed are not available at
that time.
For the effort, Babbage is considered as the “Father of Computers” and for her
valuable contribution, Lady Augusta Ada Byron is often referred to as the “First
Programmer”

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Electromechanical Computers

Census Machine Invented by Dr. Herman Hollerith employee of the U.S. Bureau of Census.
Considered as the first electronic computer, the census counting machine involved the
use of a 3”x5” index card which contained encoded information by punching holes on
it. Later on, Punched Card Tabulating Machine and the punched card were invented.
With this, the census was finished in just three years.

Electromechanical Also used the punched-card technology. The EAM family of punch-card devices
Accounting Machine included the card punch, verifier, reproducer, summary punch interpreter, sorter,
collator, calculator and the accounting machine.

Automatic Electronic Also known as the Atanasoff Berry Computer (ABC) was an electronic computer that
Digital Computer first used the present binary system (base 2) for encoding data.

Mark I Harvard University professor Howard Aiken and IBM worked hand in hand to complete
the machine which was later named Mark I in 1944.
Mark I could do the four basic arithmetic operations.

Generations of Computer

The First Generation: The vacuum tube is an electronic tube about the size of a light bulb. It was used to
(1940-1956)The build radios and other electrically driven machine. Systems could multiply two-ten-digit
Vacuum Tube numbers in one-fortieth of a second.
It includes ENIAC, EDVAC, and UNIVAC 1. The ENIAC has no moving parts but used
18,000 vacuum tubes. The EDVAC used the concept where a program to control the
steps of calculation resides in the computer along with the data being used for
calculations. The UNIVAC 1 was the first commercial digital computer. It holds discrete
digits of information in form of electrical current or mechanical cams.

The Second The second generation computers used the transistor technology. It included the IBM
Generation: (1956- 604s, considered a card programming calculator, which was essentially an account
1963)The Transistor machine.
The second generation also marked the development of programming language to
assembly languages or symbolic languages. Symbolic languages used abbreviations
for instructions rather than numbers. After symbolic languages came high-level
languages which included FORTRAN and COBOL. These two are more English-like
than assembly languages.

The Third Generation: The third generation computers used the integrated circuit (IC) technology. The IC is a
(1964-1971)The complete electronic circuit on a small chip of silicon. The IC is reliable, compact and
Integrated Circuit costs less.
The IBM 360 ushered the third generation of computers. This period also marked the
efficiency of computer systems due to development of sophisticated software. Third-
generation were supplemented by minicomputers which were used in medium-size and
smaller business.

The Fourth Generation: The fourth generation computers used the microprocessor, a general-purpose
(1971-Present )The processor-on-a-chip. The microprocessor can be found almost everywhere – digital
Microprocessor watches, pocket calculators and personal computers.
The Apple II computer was a personal computer that offered an easy-to-use keyboard
and screen. The IBM PC was introduced and became the standard for the
microcomputer industry.

Fifth Generation - Fifth generation computing devices, based on artificial intelligence, are still in
Present and Beyond: development, though there are some applications, such as voice recognition, that are

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Artificial Intelligence 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 radically 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.

Collects data Produces

Processing information
(input) (output)

Information Processing Cycle

Three basic elements of the computing process

End-users - People who use computers and programs written by other people.

Hardware - refers to the physical components of a computer. These include the equipment associated with
a computer system such as input and output devices, the processor, and storage devices.
- refers to tangible parts that can be seen, touched and felt.

Software - refers to the planned, step-by-step instructions that tell the computer what to do. These step-
by-step instructions are collectively referred to as a program.

Basic Components of a Computer

1. Hardware

 The Central Processing Unit

The processor is the “brain” of the computer. It contains millions of extremely tiny electrical parts. It does
the fundamental computing within the system. Examples of processors are Pentium, Athlon and SPARC.

 Read Only Memory (ROM)

The memory is where data and instructions needed by the CPU to do its appointed tasks can be found. It is
divided into several storage locations which have corresponding addresses. The CPU accesses the
memory with the use of these addresses.

 Main Memory (RAM)

The main memory is very closely connected to the processor. It is used to hold programs and data that the
processor is actively working with. It is not used for long-term storage. It is sometimes called the RAM
(Random Access Memory).
The computer's main memory is considered as volatile storage. This means that once the computer is
turned off, all information residing in the main memory is erased.

 The Secondary Memory

The secondary memory is connected to main memory. It is used to hold programs and data for long term
use. Examples of secondary memory are hard disks and CD-ROMs.

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 Secondary memory is considered as non-volatile storage. This means that information residing in
secondary memory is not erased after the computer is turned off.

 Input / Output Device

Input and output devices allow a computer system to interact with the outside world by moving data into
and out of the system.
Examples of input devices are keyboards, mice, scanners, joysticks and microphones. Examples of
output devices are monitors, printers and speakers.

2. Software

Software is the program that a computer uses in order to function. It is kept on some hardware device like a
hard disk, but it itself is intangible. The data that the computer uses can be anything that a program needs.
Programs acts like instructions for the processor.

Some Types of Computer Programs:

 Systems Programs
- Programs that are needed to keep all the hardware and software systems running together smoothly
Examples:
Operating Systems like Linux, Windows, Unix, Solaris, MacOS

 Application Programs
- Programs that people use to get their work done
Examples:

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 Word Processor, Game programs, Spreadsheets, Databases

 Compilers
- The computer understands only one language: machine language. Machine language is in the form of
ones and zeros. Since it is highly impractical for people to create programs out of zeros and ones, there
must be a way of translating or converting a language which we understand into machine language, for
this purpose, there exists compilers.

Capabilities of Computer

1. High-speed processing - the computer can process data faster than any other machine with its speed of
1/1M of a sec.
2. Repetitiveness - a computer can perform the same operation millions of times in exactly the same way.
3. Accuracy - a computer's high-speed processing gives 99.99% error free results.
4. Arithmetic and Logical Operations - the computer can make decisions based on alternative course of
action.
5. Store and Retrieve Information - computers can store information in the memory and use them when
needed.

Limitations of Computer
1. A computer cannot generate information on its own. It must be told what to do, when to start, stop,
compute, and make the next move via a program
2. A computer can detect errors but generally cannot correct them on its own.
3. Computers cannot combine ideas or take the best parts or several ideas to come up with a brand new idea
of its own.
4. Computers need periodic maintenance support.
5. A Computer is subject to occasional breakdown and wears out.

Uses of Computer

In Education,  Track railroad cars

 Teaching and testing aid  Monitor airline traffic
 Learning by doing
 Computer-based instruction In Finance,
 E-Learning and Distance Learning  Record keeping to monitor expense
 Banking by phone or on-line request
In Retailing,  Credit cards
 Bar codes for pricing and inventory
 Recording and monitoring in Shipping In Agriculture,
 Crop growth information
In Energy,  Mixed breeding of plants
 Locate oil, coal, natural gas, and uranium  Feed combinations
 Monitor the power network  Livestock breeding and performance
 Meter reading or ground works monitoring

In Government,
 Forecast weather
For Law Enforcement,  Manage parks
 National fingerprint files  Process immigrants
 National files on criminal  Social Security benefits
 Computer modeling of DNA –  Taxes
Deoxyribonucleic Acid  Municipal and City Government Services

In Transportation,
 Cars- automatic
 Run rapid transit systems- LRT, MRT
 Load containerships

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At Home, In Health and Medicine
 Educational tool  Monitor patients
 Record keeping  Electronic imaging
 Letter writing  Diagnose illnesses
 Budgeting  Assist the disabled
 Drawing and editing pictures
 Newsletters
 Connecting with others
 Digital Entertainment For Robotics,
 Perform jobs that are dangerous for humans
 Factory work
 Mimic how human works

Classification of Computer

1. According to Purpose
2. According to Data Handled
3. According to Size or Capacity

1. According to Purpose

 General purpose- a machine that can be used to process many types of applications. Ex microcomputers

 Special purpose- a machine that can be used for a specific application or just ONE application. Ex:
Weather Forecasting and Airlines Reservation

2. According to Data Handled

 Analog computers-a computer that manipulates continuous or approximate types of data

 Digital computers - a computer that manipulates discrete types of data
 Hybrid computers- a computer that can manipulate both analog or digital types of data
3. According to Size or Capacity

 Microcomputer – smallest in size and the cheapest. It can handle thousands of records.

 Minicomputer – the medium size computer, bigger and more expensive than the microcomputer
– generally more powerful than microcomputers but are slower than mainframes.

 Mainframe – a large computer that can handle millions of data, Support multiple user, does server
tasks
– Used in banks, insurance companies, manufacturers, airlines, government
accounting services, and aerospace companies.

 Supercomputer – is a very large computer that manipulates billions of data.

 Personal Computers PCs (other name for Microcomputer)

Types of Personal Computers

 Desktop
 Laptop
 Netbook
 Handheld

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