Chapter 1.pptx

Chapter 1
Introduction to Computers
1.1. Definition
Computer: A computer is an electronic/programmable device that performs
input, processing, storing, and output according to programmed
instructions to carry out specific tasks.
Or Computer is an electronic device that converts data into information
Data: (singular: datum) is a collection of raw facts or figures that describe
something.
Information :is a processed data.
Representation: is the process of putting data in a machine readable form.
Storing: the process putting data in memory for future use.
Manipulation: processing data in the way desired
Presentation: putting the data in human readable and desirable format
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Tuesday, April 11, 2023

Chapter 1
Introduction to Computer
1.2. Historical Developments of Computers /Computer
Evolution
The abacus: (5000 years a go) This device allows users to make computations
using a system of sliding beads arranged on a rack.
Pascaline: (1642) a numerical wheel calculator which used eight movable dials
to add sums up to eight figures long.
Leibniz Machine:(1694) an updated version of pascaline in which it could also
multiply
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Chapter 1
1.2. Historical Developments of Computers /Computer
Evolution
Babbage Machine/ Difference engine (1812) This machine would have a
stored program and could perform calculations and print the results
automatically
By extending this concept to electronic circuits in the form of on or off, Atanasoff
and Berry had developed the first all-electronic computer by 1940.
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Chapter 1
1.3. Generations of Computer
First generation(1945-1956)
Use vacume tube
Low level language
Punched card
Memory access time in milliseconds
ENIAC(Electronic Numerical Integrator and Computer )
The ENIAC was 30X 50 feet long,
weighed 30 tons,
contained 18,000 vacuum tubes,
70,000 registers,
10,000 capacitors and
required 150,000 watts of electricity.
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Chapter 1
First generation(1945-1956)
EDVAC(Electronic Discrete Variable Automatic Computer)
Stored data and instruction
Limitations
The operating speed was quite slow.
Power consumption was very high.
It required large space for installation.
The programming capability was quite low.
The tubes produced a lot of heat and so they require ventilation
They were unreliable because when the vacuum tubes get hot they would
corrupt.
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Chapter 1
Second generation(1956-1963)
Transistor
Batch OS
Magnetic tape
COBOL, FORTRAN
were smaller, faster, more reliable and more energy-efficient than their
predecessors.
Some of the computers of the Second Generation were
IBM 1620: Its size was smaller as compared to First Generation computers and
mostly used for scientific purpose.
IBM 1401: Its size was small to medium and used for business applications.
CDC 3600: Its size was large and is used for scientific purposes.
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Chapter 1
Third generation(1964-1971)
ICs (Intgrated Circuit)
Magnetic Disk
Interactive OS
Computer Size further reduced
BASIC
were small in size, low cost, large memory and processing speed is
very high.
Some of the computers developed during this period were IBM-360,
ICL-1900, IBM-370, and VAX-750
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Chapter 1
Fourth generation(1971-Present)
LSI(Large Scale Integration): could fit hundreds of components
VLSI (Very Large Scale Integration): could fit thousands of components
ULSI (Ultra Large Scale Integration) : increased that number to millions
In 1981, IBM introduced its personal computer (PC) for use in the
home, office and schools.
Fifth generation(Present and Beyond)
Extremely high processing speed
Parallel processing
AI
Still in development stage…
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Chapter 1
1.3. Trends in Computer Development
a. Faster
Modern computers are at least 100,000 times faster than the first examples of digital
computers.
b. Cheaper
-In the early days of computing, vast amounts of money were needed just to build a
single computer. Today, computers are mass-produced, and many people can afford
to buy their own computer for their home.
c. More versatile
-The very early computers were designed for a single purpose (for example, census
counting). These days computers are capable of performing a wide range of tasks.
Therefore, they have become more versatile.
d. Smaller
-The ENIAC census counting computer was the size of a tennis court and the weight
of 6 elephants. Today, the part of a modern digital computer that does the processing
is about the size of a coin.
e. Easier to use
-One of the major improvements in computers over the years is their ease of use. To
begin with, the task of entering instructions into the computer was very time-
consuming and prone to error. Today computers are much easier to use.
f. More reliable
-The early computers often suffered from poor reliability of their components. Today,
if they are looked after properly, computers can work for many years without breaking
down.
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Chapter 1
1.4. Classification/Types of Computers
1.4.1. Based on purpose and type of data they process
a. Analogue Computers
use analog signals for calculating and transmitting data
Analog data is calculated using the concept of “measuring values”
like magnitude in terms of voltage, length, current, etc.
Electrical signals on a telephone line are nothing but analog data
representing the original voice.
e.g. Slide Rule, Thermometer, Hydrodynamics, Speedometer
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Chapter 1
b. Digital Computers
use digital signals to calculate and transmit data
The digital signal has only two states in which it can be
represented.
They are ON and OFF or HIGH and LOW or 1 and 0.
Digital data is calculated using the concept of “counting values”.
The result obtained from the digital computer is more accurate
when compared to the analog computers.
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Chapter 1
c. Hybrid Computers
use both analog and digital mechanisms .
In hospitals, the intensive care unit, an analog device measures a
patient’s heart function, temperature and other vital signs, these
measurements are then converted into numbers and supplied to a
digital component that monitors the patient’s vital signs and signals
to a nurse’s station.
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Chapter 1
1.4.2. Based on their size, speed and storage capacity, (based on capacity and
size of microprocessor).
a. Micro Computer
 at the lowest end of the computer range in terms of speed and
storage capacity
 Small desktop or portable computer, typically designed to be
used by one person at a time
 Its central processing unit is a microprocessor, contained on a
single integrated circuit.
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Chapter 1
1.4.2. Based on their size, speed and storage capacity, (based on
capacity and size of microprocessor).
b. Mini Computer
Designed to support more than one user at a time.
It possesses large storage capacity and operates
at a higher speed.
The mini computer is used in multi-user system in
which various users can work at the same time.
This type of computer is generally used for
processing large volume of data in an organization.
They are also used as servers in Local Area
Networks (LAN).
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Chapter 1
c. Mainframe Computer
They operate at very high speed, have very large
storage capacity and can handle the work load of many
users.
They are generally used in centralized databases.
They are also used as controlling nodes in Wide Area
Networks (WAN).
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Chapter 1
d. Super Computer
 The fastest and most expensive machines.
They have high processing speed compared to other
computers.
 They have also multiprocessing technique.
One of the ways in which supercomputers are built is
by interconnecting hundreds of microprocessors.
Supercomputers are mainly being used for whether
forecasting, biomedical research, remote sensing, aircraft
design and other areas of science and technology.
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Chapter 1
1.5. Characteristics of Computers
1. Speed -Computers can work very fast. It takes only few seconds for
calculations that we take hours to complete if we make use of computers.
,we determine the speed of computer in terms of microsecond (10-6 part of
a second) or nano-second (10-9 part of a second).
2. Storage
The Computer has an in-built memory where it can store a large amount of
data. It is also possible to store data in secondary storage devices
3. Accuracy
The degree of accuracy of computer is very high and every calculation is
performed with the same degree of accuracy. The accuracy level is
determined on the basis of design of computer. The errors in computer are
due to human and inaccurate data.
4. Automatic-Once a program is in the computer’s memory, it continues
without the need for human intervention until completion. But don’t be
confused that human intervention is unavoidable (for example it is human
that starts a computer).
5. Versatility-It means the capacity to perform completely different type of
work. You may use your computer to prepare payroll slips. Next moment
you may use it for inventory management or to prepare electric bills.
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Chapter 1
1.5. Characteristics of Computers
6. Diligence-A computer is free from tiredness, lack of
concentration, fatigue, etc. It can work for hours without creating
any error.
As long as there is no failure of power and no defect in the
machine itself, it will never be un-operational.
7. Can’t Think-Even if it is artificially intelligent, it does nothing
more than it is programmed to do nor does it know whether it could
do.
It does not create a brand new idea.
8. No Feeling -It does not have feelings or emotion, taste,
knowledge and experience. Thus it does not get tired even after
long hours of work
9. Power of Remembering-Computer has the power of storing
any amount of information or data. Any information can be stored
and recalled as long as you require it, for any numbers of years.
10. No IQ -Computer is a dumb machine and it cannot do any work
without instruction from the user. It performs the instructions at
tremendous speed and with accuracy. It is you to decide what you
want to do and in what sequence. So a computer cannot take its 18

1.6.Components of computer
 computer have two components namely
software and hardware
 Software
- software is a set of instruction or
command given to your computer, which
the computer obeys in order to perform
certain operation(s). It can be an
instruction or commands given to
computers to perform certain task and this
usually comes from the manufacturer e.g.
system software and application software.
Wolaita Sodo University, College of CS
& IT 19

Application software:
- These are programs designed by skilled
application programmers to meet the need of
the users. This is the power of the computer
to solve a specific task or problem. The
application software is referred to as
application packages. Application software
includes; Word Processing Packages like
M.S. Word, Word Perfect, Word Star, and
e.t.c. ,Spread Sheet Packages like Lotus 1-
2-3, M.S. Excel, M.S. Access etc. Accounting
packages, Dac Excel, Pacioli 2000 etc.,
Architectural packages; like Auto Card,
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System software
These are programs that run the
computer system and aids the
application programs perform its work. It
normally comes from the manufacturer .
Example: Operating system
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Hardware
 The physical part of computer, the
bits and piece of which is made up are
called hardware. It can simply be
defined as the physical part of
computer that one can see, touch and
feel. E.g. monitor (VDU), Mouse, UPS,
Keyboard, etc
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Cont..
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Chapter 1
1.7. Application of Computers
Main Application Areas:
Commercial application-The emphasis is on data processing: it covers
the use of computers for clerical, administrative and business uses
Scientific, engineering and research application
covers the use of computers for complex calculations, design, analysis
and control of physical system and analysis of experimental data or
results
Computer in Education
-The use of computers in education ranges from assisting teaching and
learning process to managing it. Hence the terms CAL (Computer
Aided Learning) and CAI (Computer Aided Instruction).
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Chapter 1
1.7. Application of Computers
Main Application Areas:
Computer in Medicine:
In medicine, computers are used
 for analyzing medical research
 to aid in diagnosis
 to hold details of patients
Computers in Manufacturing
Stock and production control (CAM-Computer Aided Manufacturing)
Engineering design (CAD -Computer Aided Design e.g. Auto CAD)
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