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8/18/2019 Ch 1_Intro
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Introduction to
Computers
- Defnition, Characteristic, Applicable area,Evolution, History, and Classifcation ocomputers are covered in this handout.
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Input "#a$ data%&rocessin' "(,), *, - , sortin'%+utput or processed data "Inormation%tora'e
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CHAPTER ONE: Introduction to Computers
Objective:
Define the term computer
Identify the several characteristics of computer that made them useful and popular
Identify the evolution (Generation) of computers
Application of Computers
Identify the different types of computers
1.1. What is Computer?
A computer is an electronic device that accepts data, performs computations, and
makes logical decisions according to instructions that have been given to it; then
produces meaningful information in a form that is useful to humans !he name computer
comes from a "atin #ord computator, meaning, $to compute%
1.1.1. Characteristics of computers
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!oday, computers are every#here & in our offices, homes, appliances, automobiles &
the list is endless 'uch of the #orld runs on computers, and computers have profoundly
changed our lives, mostly for the better !he characteristics of a computer sho# the
capability and the potential of the computer for processing data !his saves time, space,
money, labors etc And they ans#er the uestions such as *hy computers are used+ *hy
have they become so popular+ ome of the characteristics of the computer are as follo#s
Speed
!he ability of the computers to carry out their instructions in a very short period of time
is one of the main reasons for their popularity Computers can perform tasks #ithin a
matter of seconds or minutes that #ould be impossible for a person to complete by hand
in lifetime
Its speed is measured by the amount of time it took to perform or carry out a basic
operation And its speed measured in terms of micro second (-. /0 / one millionths), nano
second (-./1 & one billionths), and 2ico second (-./-3 / one trillionths) 4ence a computer
#ith speed - microsecond can perform - million instructions in 5ust - second (6or
e7ample in one second this computer can perform the follo#ing tasks
o Calculate the grade point average for 8... students
o Calculate the total value of all books used by students in a university
Accuracy
9o# a days, computers are being used in life/and/death situations (6or e7ample, 5et pilots
rely on computer computations for guidance, 4ospitals rely on patient/monitoring
systems in critical & care units) #hich needs almost hundred percent accuracy 6rom this
#e can understand that computer is accurate and consistent :nless there is an error in the
input data or unreliable program the computer processes its task accurately
Capacity
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!he ability of computers to store and process vast amounts of data continues to gro# A
computer operating at 3.. '4 can move data from one location to another at a rate
e7cess of -3 billion characters (symbols) per second
Durability and reliability
Computers are durable and e7tremely reliable devices !hey can operate error/free over
long periods of time
Dilience
Computer, being a machine, does not suffer from the human traits of tiredness and lack of
concentration If four million calculations have to be performed, then the computer #ill
perform the last four/millionth calculation #ith the same accuracy and speed as the first
calculation
!ersatility
s mathematics
and design computations can also be efficiently used by the company to track inventory,
process payroll, pro5ect earnings, and fulfill all its reporting needs
!oday>s computers are versatile in #hat they can do; computers and their components are
used in applications never before envisioned 6or e7ample; in home appliances (#ashing
machines, ovens) home entertainment centers, traffic lights, automobiles, banking,
assembly plants, space probes, art, music, education, hospitals, and agriculture, to name
fe# !he versatility of the computers and its use in a #ide array of application are limited
only by the imagination of the human mind
"ote: ?ven if the above main characteristics of computers are increasing #ith time, the
cost and sie of computers are decreasing
1.1.#. Application of Computers
Why we use Computers+
!he follo#ing are some of the capability of Computers, #hich are reasons to use
Computers
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tore and process large amount of information #ith high speed and accuracy;
!ransmit information across continents via communication channels;
imulate events;
2erform comple7 mathematical computations and make comparisons;
'onitor ongoing industrial operations;
2erform repetitive processes #ith great ease, speed, and reliability;
!herefore, computers are applicable for any functions or process that reuires these
abilities
!he main areas of computer applications can be listed as follo#s
$earnin Aids
?7ample learning toys, programs range from simple arithmetic to calculus, from
?nglish grammar to creative #riting and foreign language, and from basic graphics to
engineering design models,)
%ntertainment
?7amples Games
Commercial or business applications
Computers are needed to perform business operations that reuire handling large
amounts of data everal computer applications are available to assist business in
#orking #ith large volumes of data
?7amples are
!e7t processing
Accounting and 6inance management
Inventory control
Database management
tatistical analysis
Scientific & enineerin and research applications
Computers are used for scientific research, comple7 mathematical calculations,
design #ork, and analysis and control of physical systems
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?7amples are
pace technology
'eteorological observatory systems
Astronomical investigations
Design of machines and
Control of manufacturing process
'nformation (tilities
Information utilities companies use large computers that store huge amount of
information about many different sub5ects !hese computer systems and their vast
amount of data are available for personal use 6or e7ample information utilities can
allo# a computer user to read the daily ne#s, research published #orks, send a letter to a
friend, play games, make airline reservations, obtain the latest stock market uotations,
and perform many other activities
?7ample Internet
?thiopian airline is a member of *orld/*ide reservation system called Gabriel system
!he main database is located at Atlanta, Georgia
'ore than @ airlines including ?A" share =e7tract=transmit information using
Gabriel
6acilities included
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'odems
%lectronic )an*in and Service:
?7ample
!eller 'achine (customers are issued cards that permit them to use other banks
teller machine>s)
Bnline banking (A bank customer can use his= her computer to check account
balances, transfer funds, pay bills)
Shoppin from +ome
Individual may no# shop by computer in the comfort of their home
+ousehold Control
A gro#ing number of the ne#er houses hold devices are computers controlled
6or e7ample ecurity systems, refrigerators, micro#ave ovens, #ashers, stereos, and
televisions !his computer controlled home security system monitors movements, broken
glass, unla#ful entry #ithout a security code, and so on, and alerts the local police
department
Weather and %nvironment
Computer euipment may sho# temperature ranges, precipitation levels and #ind
flo# and can be used in #eather forecasting Computer can also help in overcomingenvironmental haards
,ransportation
Computers have affected almost every kind of transportation 'any aircraft can
fly under the control of the computer; in this situation, the captain simply serves as a
manger by telling the computer #hat to do In Cars, computers have provided functional
controls such as spark and fuel control
-edical and +ealth Care
Computers have long been used by hospitals for routine record keeping !oday,
ho#ever, many people o#e their lives to the computer Computers are used in hospitals
as sensors (device that detect changes in blood pressure, heart rate, temperature), testing
(scan the body and provide 8/D figure), patient treatment
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outine and Danerous ,as*s
Computers are used in routine tasks And they can perform task in environments
to dangerous for human #orkers
Consultant /%0pert system
An ?7pert system is a computer program, #hich can solve problems from a
specific kno#ledge base !hese systems donEt replace e7pert humans because the
kno#ledge base of e7pert system is given from the skilled specialist
?7ample 'ycin (a medical diagnostic program by using sophisticated decision making
process)
1.#. %volution of Computers
Although computer professionals do not agree on e7act dates or specifics, computer developments are often categoried by generations Actually there are four generations
and ma5or characteristics that distinguish these generations are the follo#ing
Dominant type of electronic circuit elements used
'a5or secondary storage media used
Computer language used
!ypes or characteristic of operating system used
'emory access time (time to store or retrieve a #ord or data from memory)
Computer generations are usually categoried by dramatic improvement in the hard#are,
typically refold or better increases in speed and reliability
2irst eneration /1345s
:sed vacuum tubes as components for the electronic circuit
2unched cards #ere the main source of inputs, and magnetic
grams #ere used for internal storage
Bperate in a speed of milliseconds (thousands of a second)
and could handle more than -.,... additions each second
'ost applications #ere scientific calculations
!hey generate huge amount of heat
!hey solve one problem at a time
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!hey are room/sied and #eights up to 8. tones (8...FG)
!hey need 3..F* of po#er to operate, #hich contains -,... acuum !ubes
Second enerations /early 1365s
!ransistors #ere the main circuit components (!ransistors are a solid statedevice made from silicon #hich is smaller, cheaper, faster, dissipate less
energy and more reliable than vacuum tube but #ork in the same #ay #ith
the vacuum tube)
Invented by
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Computer storage s#itched from magnetic cores to integrated circuit boards that
provide modularity (e7pandable storage) and compatibility (interchangeable
euipment
9e# input=output methods such as optical scanning and plotters
oft#are become more important #ith sophisticated operating systems, improved
programming languages,
Feyboards and 'onitors introduced at this time
2ourth eneration /late 1385s7 early 1393s
Greatly e7panded storage capabilities and improved circuitry
4as "arge/cale Integrated Circuit ("I) #hich has several hundred
thousands of transistors placed on one tiny silicon chip
Computer memory operates at speeds of nano seconds (billionths of a
second) #ith large computers capable of adding - million numbers
per second
,he fifth eneration computer
!his computer generation is still in progress An architecture, #hich makes use
of the changes in technology and allo#s a simple and natural methodology for solving
problems, is being sought !hese computers #ill have intelligent processors ie,
processors #hich can dra# inferences :sers #ill also be able to interact #ith them in
natural languages such as ?nglish, German etc Japans are #orking intensively on the
pro5ect for developing the th generation
Summary of eneration of computers
eneration 1st #nd ;rd
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device
$anuae 'achine assembly 6ortran, CB
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more, the t#o beads above the cross bar are moved back, and an e7tra - (the Cary) is
added to the #ire on the left
!his process can be easily generalied to addition and subtraction of more than t#o
numbers
b =ascal>s Calculator: It is the first true mechanical calculator In
-0@3, at the age of -1, the 6rench philosopher and mathematician s calculator has one #heel corresponding to each po#er of -.; each
#heel has -. position, one for each of the digits (.,1) Although, 2ascal>s calculator
could only add and subtract, it could be used indirectly for multiplication (by
successive addition) and division (by successive subtraction) as #ell
c ,he Difference %nine: It is the forerunner of the modern
computer Charles
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/ Output #as to print or a card punch device
s ,abulatin -achine: 4erman 4ollerith
#as a statistician that in -. and develop his machine commissioned by the :
Census
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,he !on "eumann -achine: !he task of entering and altering
programs for the ?9IAC #as e7tremely tedious on 9eumann #as the consultant on
the ?9IAC pro5ect and for#ard the stored program concept , ie designing the
computer to get its instruction by reading them from memory alongside the data and a
program could be set or altered by setting the values of a portion of a memory
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!hermometer
oltmeter
peedometer
Gasoline pomp & Contains an analog Computer that converts the flo# of pumpedfuel into t#o measurements the price of the delivered gas and the uantity of
pumped fuel
Analog computers are used for scientific and engineering purposes Bne of the
characteristics of these computers is that they give appro7imate results since they deal
#ith uantities that vary continuously
!he main feature of analog computers is that they are very fast in operation as all the
calculations are done in parallel mode It is very easy to get graphical results directly
using analog computer 4o#ever, the accuracy of analog computers is less
ii. Diital Computers
Digital computers deal #ith discrete variables; they operate by counting rather
than measuring :nlike analog computers, they operate directly on numbers (or digits)
that represent numbers, letters, or other special symbols
In digital computers, analog uantities must be converted into digital uantity
before processing
Eamples
Abacus
Desk top pocket computers
!he general purpose computers
Digital computers have higher accuracy and speed than the analog ones
iii. +ybrid Computers
!hese computers incorporated the measuring feature of analog computer and
counting feature of a digital computer 6or computational purposes, these computers usethe analog components and for the storage of intermediate results, digital memories are
used
A hybrid computer processes the information by collecting input data #ith analog
method, converts it into digital uantities, processes the digital values and converts the
output from digital to analog form
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!hese computers are broadly used for scientific applications, various fields of
engineering and industrial control processes
Eample
Intensive Care :nit (IC:) section, in the hospital, uses analog devices to measure the
patient>s heart function, temperature and other vital signs !hese measurements may then
be converted into numbers and supplied to a digital component in the system !his
component is used to monitor the patient>s vital signs and to send an immediate signal to
the nurse>s station if any abnormal readings are detected
!) Classification According to "urpose
Computers can be applied or used for different purposes !hey can be used either for
special purposes or general#purposes$
i. Special =urpose Computers
!hey are designed to solve a single type of problem, that is, their components and
function are uniuely adapted to a specific situation involving specific application
!hese computes cannot be used for other applications unless their circuits are redesigned,
that is, they lacked versatility 4o#ever, being designed for specific tasks, they can
provide the result very uickly and efficiently
Eample !he public telephone bo7
!raffic control system
!icket machines (used in grocery, super market etc)
2ocket calculators etc
Counters
'ost analog computers are special purpose computers
ii. eneralpurpose computers!hey are designed to solve a range of problems through the use of $store program
concept%
!hese machines can be used for various applications, ranging from scientific as
#ell as business purpose applications !hough such computers are versatile and fle7ible,
they generally lack in speed and efficiency
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?7amples
0 'icro computers
0 'ini computers
0 uper computers etc
C) Classification According to %unctionality
At this stage, by a computer, #e mean a general/purpose digital computer
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&icroprocessor is a processor all of #hose components are on a single integrated/
circuit chip ince its C2: is integrated in a single circuit, it can serve only a single user
at a time 'ost of home and personal office computers are microcomputers
'icrocomputers include des'top, laptop, and handheld models such as 2DA
(2ersonal Digital Assistants)
Des'top computers !hey are the most common micro computers !hese micro
computers typically consist of a system unit, a display monitor, a keyboard, internal hard
disk storage, and other peripheral devices
aptop Computers A laptop is a portable computer, that is, a user can carry it
around ince the laptop computer resembles a notebook, they are also kno#n as
noteboo's !he main advantage of this computer is that one can use this computer
any#here and at anytime, especially #hen one is traveling and does not have a proper
place to keep it 'oreover, these computers do not need any e7ternal po#er supply as a
rechargeable battery is completely self/contained by them
andheld Computers A hand/held computer is a computer that can conveniently
be stored in a pocket and used #hile the user is holding it A 2DA user generally uses a
pen or electronic stylus, instead of a keyboard for input ince these computers can be
easily fitted on the palmtop, they are also kno#n as palmtop computers
!he performance and usage of personal computer is relatively increased #ith a
very high rate
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