CSC 191 (Credit hours 3)

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Oct 25, 2013 (4 years and 18 days ago)

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Basic Computer


B.pharm PU


1


CSC 191 (Credit hours 3)


Computer Science (Introductory)

B. Pharm., First Year, First Semester


Course Objectives:


The objective of the course is to provide the students with a general view of computer architecture, its operation and
applic
ation, familiarize the students with the existing technologies, and provide them with hands on experience on
personal computers.


Course Contents:

1.

Introduction to Computers

3 hours

History of Computers, Classification of Computers, Functioning of
Computers, Computer Hardware,
Software, Firmware


2.

Number System

6 hours

Decimal number system, Binary number system, Hexadecimal number system, Octal number system, Conversion of a
number from one system to other, Addition and Subtraction of binary numbers
, Compliments, Subtraction by 2’s
compliment method


3.

Boolean Algebra and Logic Gates

5 hours

Introduction, Basic operations of Boolean algebra, DeMorgan’s Theorem, Boolean variable and function,
Boolean postulates, Dual and compliments of Boolean expressio
n, SOP and POS standard forms,
Canonical forms of Boolean expression, Simplification of Boolean expressions by Karnaugh method, Logic
Gates
-
AND, OR, NOT, NOR, XOR, XNOR


4.

Arithmetic Logic Unit and Memory Element

2 hours

Half adder, Full adder, Flip
-
flop, R
-
S flip
-
flop


5.

Memory

3 hours

Classification, RAM, ROM, Floppy disk, Hard disk


6.

Input Output Devices and Computer Network

5 hours

Role of input and output devices, Keyboard, Mouse, Scanners, MICR, Video terminals, Printers, Plotters,
Digital to analog conver
sion, Introduction to computer network, Sharing, Network types

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7.

Word Processing

4 hours

Introduction, Concept of file, Inputting the text, Formatting, Inserting the files and Symbols, Mail merge
facility, Grammar checking, Auto correct feature (MS
-
Word is
to be used)

8.

Spreadsheet Analysis

4 hours

Introduction to spreadsheets, Workbook and worksheet, Formula, Formatting and Graphics (MS
-
Excel is to be used)


9.

Database Management

4 hours

Data, Database, Input, Processing, Storage, Output (MS
-
Access is to be
used)


10.

Internet and Multimedia

4 hours

Introduction to Internet, e
-
mail, Introduction to slide, Making a presentation (MS
-
PowerPoint is to be used)


11.

Programming Concepts

5 hours

Difference between a computer and calculator, Algorithm, Flowchart, Program, P
rogramming language


Reference Books:

1.

B. Ram:
Computer Fundamentals
, 1999, Willey Eastern Publication, New Delhi.

2.

O. S. Lawrence:
Schaum’s Outline of Computers & Business
, 2000, Mc
-
Grew Hill International., New
Delhi.

3.

Suresh Basandra:
Computer Systems
Today
, 1999, Galgotia Publication, New Delhi.

4.

M. Busby and R. A. Stultz: Office 2000
, 2000, BPB Publication, New Delhi.













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Computer

A computer is an electronic machine operating under human/user control that accepts data using some
input devices
performs certain operations and displays the results in output devices.

Computers are used in wide areas of fields like house, schools, colleges, hospitals, business, and industries.
They are used to accomplished job in fast and efficient way. Computer is
devices that can not do noting alone
without certain programs and instruction. A program is a set of code /instructions which causes a computer
to perform particular operations.


Computer System


The computer is called computer system because of different
components work together to produce the
desired result to the user. The various components of computers of computer systems are as follows:

Hardware:

All the physical components of the computer system are called hardware such as Monitor, CPU,
and Mouse et
c.

Software:

The collection of instruction or logical components that instruct the hardware to perform certain
task is called software.

Producer:

The way of operating computer is called procedure.

Data /instruction:

The raw data under which computer work

and produce the useful information.

Connectivity:

When two or more computers and other peripherals are connected to communicate in the
computer system.


Computer Architecture

Computer architecture is the theory behind the design of a computer. The digital

computer can be divided
into 3 major sections are CPU, Memory and I
-
O unit. The simple architecture of computers are as follows. The
CPU and other Units are linked with the parallel communication channels data channels, address channels
and controls chann
els are called bus/cable.




Processor (CPU):

The processors is a computer chip( Heart of computer) that receives the data input form the
input devices , processes the data in some way by performing calculations or reorganizing it, stores the
results in
memory until it sends them to an output devices or stores them in a backup storage devices. The
CPU is divided into 3 major sections are follows:

Control Unit (CU):

The control unit manages program instruction, so that data is received form input devices
and send to output devices at right time. It sends output control signals at a speed that is measured in
meghthertz (MHz).


Arithmetic and Logical Unit:

The arithmetic and logical Unit carries out all the arithmetic and logical operations that are needed t
o
produces data.

Register Unit:

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It is special temporary storage location of CPU. Registers are very quickly accept, store and transfer data and
instruction that are being used currently.

Bus
:

A bus is simple a parallel communication pathway over which inf
ormation and signals are transferred
between several computer components.

Address bus:

The address bus is used to carry address signals for addressing data in different location in
computer memory. So that it is Unit directional bus.

Data bus:

The data bus

is used to communicate data form CPU and other internal unit of computer system.
Data bus is bi
-
directional.

Control bus:

The control signals transmitted on the control bus to ensure that proper timing does occurs.


Aff
ecting Factors for Speed of CPU

Sys
tem Clock Rate:

It is the rate of an electronic pulse used to synchronize processing and measured in MHZ
( 1 MHz= 1 million cycles per second).

Bus Width:

The amount of data the CPU can transmit at a time to main memory and to input and output
devices. A
n 8 bit bus moves 8 bits of data at a time. They are 8, 16, 32, 64, and 128 so far.

Word S
ize:

The amount of data than can be processed by the CPU at one time. An 8 bit processor can
manipulate 8 bits at a time. Processors can 8, 16, 32, 64 and so far. The

bigger the number means the faster
the computer system.


Characteristics of Computer

Speed:

Computer performs complex calculation at a very high speed. The speed of computer at performing a
single operation can measure in terms of Millisecond,
M
icrosecond
, Nanosecond and Picoseconds
.

1/1000
(10
-
3)

sec
-
1 Millisecond

1/100000
0(10
-
6)
-

1 Microsecond

1/1000000000(10
-
9)
-
1 Nanosecond

1/1000000000000(10
-
12) Picoseconds

Storage:

A
large amount of data can store in computer memory. The storing capacity is measured
in terms of
Bytes, Kilobytes, Megabytes, and gigabytes and Terabytes

1024 Bytes= 1 Kilobytes (KB)

1024 Kilobytes =1 Megabytes (MB)

1024 Megabytes= 1 Gigabytes (GB)

1024 GB= 1 Terabytes (TB)

Accuracy:


A

computer can perform all the calculation and comparis
on accurately. Sometimes errors may
produce by computers due to the fault in machine or due to Bugs in the programs. If input data are not
correct, this may also lead to incorrect output. The computer follows the simple rules of GIGO (Garbage in,
Garbage O
ut).

Reliability:

Computer never tired, bored or lazy to

do task
i.e the computer is capable of performing task
repeatedly at the same level of speed and accuracy even if it has to carry complex operations for a long
period of time. Computers are quite cap
able to performing automatic, once the process is given to computer.

Automatic:

Computer is an automatic machine. Everything that is given to computers is processed and dome
by computers automatically according to the instruction proved
.

Versatility:

A com
puter has wide range of application areas ie computers can do many types of jobs. IT can
perform operations ranging form single mathematical calculations to high complex and logical evaluations for
any extended periods of times. Some of the areas of comput
ers applications are Educations, Sciences.
Technology, Business, Research etc.

Diligence:

A computer can perform respective tasks without being bored, tired and losing concentration. It
can continuously work for several hours without human intervention aft
er the data and program are feed to
it. They can handle complicated and complex task. There is not aging effect on computer ie efficiency does
not decrease over the years of use.


Limitations of Computers

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1.

Sometime the failure in devices and programs can pr
oduce unreliable information.

2.

Computer is dull machine. I
t
does not have intelligence on it.

3.

Computer can not draw conclusion without going through all intermediate steps.



His
torical Development of Computer

The computer which is one of the most advanced
discoveries of making has got a long history. Around 3000
years before the birth of Jesus Christ, there were no any kind of number system. So people had to remember
a lot of information. They felt the need to count the cattle. Then they started counting us
ing their fingers. But
the limited number of finger had made difficult for them to remember more facts. So they used stone for
counting. As result around fifth century Hindu Philosopher could develop new methods of counting using
numbers 1 to 9. In 8
th

cen
tury Alkhawarism of Iraq developed 0. Since there are ten digits these number
systems method was called decimal system.


Mechanical Era/ the
A
ge of
M
echanical
C
alculator

The most significant early computing tools is
ABACUS,

was developed in 1000
-
1500 AD, a wooden rack
holding parallel rods on which different sizes balls are stung. The arithmetic operations can be carried out
with the help of breads on the wire. The frame consists of upper parts and lower parts. The upper par
t is
called heaven and lower is called earth. Each part consists of five beads on earth part and heaven parts
consist of two beads. This is used for addition and subtraction. In 1500,
Leonardo da Vinchi

developed
mechanical calculator, that was very heavy
. A Scottish mathematician,
John Napier (1614)

invented another
calculator which was made of bone had more functionality add and multiplication of numbers. These are
analog computers which have been replaced modern times by pocket calculators. The signific
ant evolution of
computing system was the invention of by French Mathematician,
Blaise Pascal (1642).

La Pascal machine
could also multiply, divide and find square root. In 1822 a professors of mathematician,
Thomas (Charles
Xavier Thomas)

developed a mach
ine called differential engine was the first commercially mechanical
calculators. Charles Babbage (1792
-

1871) at Cambridge was developed the first digital computer. By 1822 he
built an automatic mechanical calculator called
difference engine
. Unfortunatel
y, Babbage analytical engine
was never completed because its design required fabrication precision beyond what was feasible at that
time. In
1840 Augusta (first programmer)

suggested binary storage.

In 1887 an American statistician
Herman Hollerith

const
ructed a tabulating machine to compute the statics
of 1890 US census. He used the punch cards to store data. This machine can read 200 punched cards per
minutes. In 1900
Johan Amberose Fleming

invents the vacuum tube to store data and instruction, which w
as
very big. The major step in the evolution of computer system is invention of punch card which was first used
during the U.S similarly;
Lee de Frost invented triode and Semiconductors
. After his retirement in
1913
Thomas J Watson

becomes president of the company which become International Business Machines
Corporation in 1924.


Electronic Era/Age of Electronic Mechanical Computer

The electronic era was the time when computers were made with electronics components. Following are
some of the historical keys dates and inventions in this era.

1937
-

John V. Atanasoff
Designed the first special purpose digital electronic computer.

Professor
Howard
Akine

constructed electro
-
mechanical computer
named Mark I,

which can perform according t
o pre
programming instructions automatically. It was based on Charles Babbage principle after 100 years of his
death. Although it was very huge with 51 feet log and 8 ft height and 3 ft wide using 18000 vacuum tubes,
similarly
Howard Aiken

modified Mark 1
and invented
Mark II
which used
19000 vacuum tubes
.

1945
-

John w Mauchly and Presper Eckert built ENIAC (Electronic Numerical Integrator and Calculator)

for
the U.S. army. ENIAC was the first machine to use more than 2000 vacuum tubes and 18000 vacuum tube

ENICA was the first high speed general purpose electronic digital computer was produce.

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1946 UNIVAC (Universal Automatic Computer) was designed by Persper Eckert and John Mauchly,

inventors of the ENICA. The UNIVAC was completed in 1950. It was the firs
t commercial computer produced
in the United States.

1948
-

Howard Aiken developed the Harvard Mark III
electronic computer with 5000 tubes. The Harvard
Mark III, also known as ADEC (Aiken Dahlgren Electronic Calculator) was an early computer that was partl
y
electronic and partly electronic mechanical. It was built at Harvard University under US Navy.

1952
-

Remington Rand bought the ERA in 1951

and combined the UNIVAC product in 1952; the UNIVAC
1101 was used to calculate the presidential election.

1950
-
Nati
onal Bureau of Standards(NBS)

i
ntroduced its standards Eastern Automatic Computer with 10000
newly germanium diodes in its logic circuits, and the first magnetic disk drive designed by Jacob Rainow.

1953
-
Tom Watson and IBM

introduced model 604 computers, i
ts first with transistor, which becomes the
basic of the model 608, the first solid state computer for the commercial market.

1964
-

IBM produce SABRE, the first airline reservation tracing system for American airlines, IBM announce
system 360 all purpose
computer using for 8 bit character word length.

1968
-

DEC introduced the first mini computer
, the PDP
-
8 named after the mini skirt, DEC was founded in
1975 by Kenneth H. Olsen who came for the sage project at MIT and began sales of PDP in 1960.

1969
-
develo
pemtn began son ARPAnet,

founded by DOD (Department of Defense)

1970


First
microprocessors and Dynamic RAMs

were developed

Hoff

developed the first microprocessors
4004.

1971
-

Intel

produces large Scale Integrated circuits that were used in the digital d
elay line, the digital audio
device.


Gilbert Hyatt at micro computer company introduced 4 bit 4004, a VLSI of 2300 components for
Japanese company business to create a single chip for calculator. Similarly IBM introduced the first 8 inch
memory disk; it w
as called then floppy disk.

1972
-

Intel made the 8 pins 8008 and 8080 microprocessors
; Gary Kildall wrote his control program/
m
icroprocessor disk operating system to provide instructions for floppy disk drivers to work with 8080
processors.

1973
-

IBM dev
eloped the first true sealed hard disk drive called Winchester

after the rifle company, using
two 30 mb plates. Robert Metcalfe at Xerox Company created Ethernet as the basic for local area network.

1975
-
Bill Gates and Paul Allen found Microsoft Corporatio
n
.

1976
-

Job and Woznik developed the Apple personal computer
; Alan Shugart introduced 5.25


floppy disk.

1980
-

IBM signed a contract with Microsoft Company of Bill Gates and Paul Allen

and Steve Ballmer to
supply an operating system for IBM PC model.

198
4
-

Apple

computer introduced the Macintosh personal computer in January 24.

1985 Microsoft developed Windows 85
, was the first window.

1991
-

World Wide Web (WWW)

was developed by Tim Berner Lee and released by CERN.

1993
-

The first web browser called Mosai
c was crated by student Marc Andresen and programmer Eric Bina
at NCSA in the first 3 months of 1993. The beta version of 0.5 of X UNIX was released in Jan 23 1993.

1994
-

Netscape Navigator 1.0 was released DEC 1994, and given a way free soon gaining 75%
world market.

1996 Intel corporation introduces pro(X 86) microprocessors

1997
-

Intel corporation produced Pentium II

1999
-

Intel Corporation produced Pentium III

2000
-

Intel corporation produced Pentium IV

History of Computer in Nepal



In 2018 BS an
electronic calculator called “FacIt” was used for census.



In 2028 BS, Census, IBM 1401 a second generation mainframe computer was used.



In 2031 BS a center for Electronic Data Processing, later renamed to National computer Center (NCC),
was established fro

national data processing and computer training.



In 2038 BS ICL 2950/10 a second generation mainframe computer was used for the census.


Generations of Computers

In 1962 scientis
ts decided to classify computer into different classes according to the devices
technology and system architecture. The history of computer development is often referred to in
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reference to the different generations of computing devices. A generation refer
s to the state of
improvement in the product development process. This term is also used in the different
advancements of new computer technology. With each new generation, the circuitry has gotten
smaller and more advanced than the previous generation bef
ore it. As a result of the miniaturization,
speed, power, and computer memory has proportionally increased. New discoveries are constantly
being developed that affect the way we live, work and play.

Each generation of computers is characterized by major t
echnological development that
fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, and
more powerful and more efficient and reliable devices. Read about each generation and the
developments that led to the current de
vices that we use today.


First Generation
-

1940
-
1956: Vacuum Tubes

The first computers used vacuum tubes for circuitry and
magnetic drums for memory, and were often enormous,
taking up entire rooms. A magnetic drum, also referred to
as drum, is a metal
cylinder coated with magnetic iron
-
oxide material on which data and programs can be stored.
Magnetic drums were once use das a primary storage
device but have since been implemented as auxiliary
storage devices.

The tracks on a magnetic drum are assigned
to channels located around the circumference of the
drum, forming adjacent circular bands that wind around the drum. A single drum can have up to 200
tracks. As the drum rotates at a speed of up to 3,000 rpm, the device's read/write heads deposit
magnetize
d spots on the drum during the write operation and sense these spots during a read
operation. This action is similar to that of a magnetic tape or disk drive.

They were very expensive to operate and in addition to using a great deal of electricity, generat
ed a
lot of heat, which was often the cause of malfunctions. First generation computers relied on machine
language to perform operations, and they could only solve one problem at a time. Machine languages
are the only languages understood by computers. Whi
le easily understood by computers, machine
languages are almost impossible for humans to use because they consist entirely of numbers.
Computer Programmers, therefore, use either
high level programming languages

or an assembly
language programming. An asse
mbly language contains the same instructions as a machine language,
but the instructions and variables have names instead of being just numbers.

Programs written in


high level programming languages

retranslated into assembly language or
machine language b
y a compiler. Assembly language program retranslated into machine language by
a program called an assembler (assembly language compiler).

Every CPU has its own unique machine language. Programs must be rewritten or recompiled,
therefore, to run on differen
t types of computers. Input was based on punch card and paper tapes, and
output was displayed on printouts.

The UNIVAC and ENIAC computers are examples of first
-
generation computing devices. The
UNIVAC was the first commercial computer delivered to a busin
ess client, the U.S. Census Bureau
in 1951.

Acronym for Electronic Numerical Integrator and Computer, the world's first operational electronic
digital computer, developed by Army Ordnance to compute World War II ballistic firing tables. The
ENIAC, weighing

30 tons, using 200 kilowatts of electric power and consisting of 18,000 vacuum
tubes, 1,500 relays, and hundreds of thousands of resistors, capacitors, and inductors, was completed
in 1945. In addition to ballistics, the ENIAC's field of application inclu
ded weather prediction,
atomic
-
energy calculations, cosmic
-
ray studies, thermal ignition, random
-
number studies, wind
-
tunnel design, and other scientific uses. The ENIAC soon became obsolete as the need arose for faster
computing speeds.

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Some
Characteristics:



Very large in size and slower than other generation.



Thousand of vacuum tubes were used in a single computer. So they produce large amount of
heat and prone to frequent hardware failure.



Punch cards used as secondary storage.



Machine level

programming used.



Cost was very high and not available for commercial use.



Computing time is milliseconds.


Second Generation
-

1956
-
1963: Transistors

Transistors replaced vacuum tubes in the second generation
computer. Transistor is a device composed of

semiconductor
material that amplifies a signal or opens or closes a circuit.
Invented in 1947 at Bell Labs, transistors have become the key
ingredient of all digital circuits, including computers. Today's
latest microprocessor
contains tens of millions of

microscopic
transistors. Prior to the invention of transistors, digital circuits
were composed of vacuum tubes, which had many
disadvantages. They were much larger, required more energy,
dissipated more heat, and were more prone to failures. It's safe
to
say that without the invention of transistors, computing as we know it today would not be possible.

The transistor was invented in 1947 but did not see widespread use in computers until the late 50s.
The transistor was far superior to the vacuum tube, allo
wing 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 vast
improvement

over the vacuum tube. Second
-
generation computers still relied on punched cards for
input and printouts for output.

Second
-
generation computers moved from binary machine language to symbolic, or assembly,
languages, which allowed programmers to specify in
structions in words. 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. The first computers of this generation were developed
for the atomic energy industry.


Characteristics



Transistor were smaller faster and higher reliable compared to tubes. Transistor can do the
task of 1000 tubes. They occupie
d less space and were ten times cheaper than those using
tubes.



These transistors had no filament, so they did not generate heat. That is they required less
electricity less electricity and emitted less heat than vacuum tubes.



Magnetic cores were developed

for primary storage and magnetic tapes and magnetic disk for
secondary storage.



Second generation compeers replaced machine language with assembly language. COBAL
(common Business oriented Language) and FORTAN (formula translation) are in common
use durin
g this time.



The operating speed was increased up to the microseconds range.


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Third Generation
-

1964
-
1971: Integrated
Circuits

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.

A nonmetallic chemical element in the carbon family
of elements. Silicon
-

atomic symbol "Si"
-

is the
second most abundant element in th
e earth's crust,
surpassed only by oxygen. Silicon does not occur
uncombined in nature. Sand and almost all rocks
contain silicon combined with oxygen, forming silica.
When silicon combines with other elements, such as
iron, aluminum or potassium, a silica
te is formed. Compounds of silicon also occur in the
atmosphere, natural waters, and many plants and in the bodies of some animals.

Silicon is the basic material used to make computer chips, transistors, silicon diodes and other
electronic circuits and swi
tching devices because its atomic structure makes the element an ideal
semiconductor. Silicon is commonly doped, or mixed, with other elements, such as boron,
phosphorous and arsenic, to alter its conductive properties.

A chip is a small piece of semi cond
ucting material (usually silicon) on which an integrated circuit is
embedded. A typical chip is less than ¼
-
square inches and can contain millions of electronic
components (transistors). Computers consist of many chips placed on electronic boards called pr
inted
circuit boards. There are different types of chips. For example, CPU chips (also called
microprocessors) contain an entire processing unit, whereas memory chips contain blank memory.

Semiconductor is a material that is neither a good conductor of ele
ctricity (like copper) nor a good
insulator (like rubber). The most common semiconductor materials are silicon and germanium. These
materials are then doped to create an excess or lack of electrons.

Computer chips, both for CPU and memory, are composed of
semiconductor materials.
Semiconductors make it possible to miniaturize electronic components, such as transistors. Not only
does miniaturization mean that the components take up less space, it also means that they are faster
and require less energy.

Inste
ad of punched cards and printouts, users interacted with third generation computers through
keyboards and monitors and interfaced with an operating system, which allowed the device to run
many different applications at one time with a central program that
monitored the memory.
Computers for the first time became accessible to a mass audience because they were smaller and
cheaper than their predecessors.

Characteristics



Using ICs proved to be highly reliable, relatively inexpensive and faster.



Less human lab
or was required at assembly stage.



Computers become portable. They were smaller in size but had high memory.



The computer used programming language such as Pascal and Fortan.



Fourth Generation
-

1971
-
Present: Microprocessors

The microprocessor brought
the fourth generation of computers, as
thousands of integrated circuits we rebuilt onto a single silicon chip.
A silicon chip that contains a CPU. In the world of personal
computers, the terms microprocessor and CPU are used
interchangeably. At the heart o
f all personal computers and most
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workstations sits a microprocessor. Microprocessors also control the logic of almost all digital
devices, from clock radios to fuel
-
injection systems for automobiles.

Three basic characteristics differentiate microprocesso
rs:



Instruction Set
: The set of instructions that the microprocessor can execute.



Bandwidth
: The number of bits processed in a single instruction.



Clock Speed
: Given in megahertz (MHz), the clock speed determines how many instructions per
second the proc
essor can execute.

In both cases, the higher the value, the more powerful the CPU. For example, a 32
-
bit microprocessor
that runs at 50MHz is more powerful than a 16
-
bitmicroprocessor that runs at 25MHz.

What in the first generation filled an entire room
could now fit in the palm of the hand. The Intel
4004chip, 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.

Abbreviation of central processing unit, and

pronounced as separate letters. The CPU is the brains of
the computer. Sometimes referred to simply as the processor or central processor, the CPU is where
most calculations take place. In terms of computing power, the CPU is the most important element of

a computer system.

On large machines, CPUs require one or more printed circuit boards. On personal computers and
small workstations, the CPU is housed in a single chip called a microprocessor.

Two typical components of a CPU are:



The arithmetic logic unit (ALU), which performs arithmetic and logical operations.



The control unit, which extracts instructions from memory and decodes and executes them, calling
on the ALU when necessary.

In 1981 IBM introduced its first computer for t
he home user, and in 1984 Apple introduced the
Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas
of life as more and more everyday products began to use microprocessors.

As these small computers became more pow
erful, they could be linked together to form networks,
which eventually led to the development of the Internet. Fourth generation computers also saw the
development of GUI's, the mouse and handheld devices

Characteristics



Highly accurate and totally reliab
le.



Operation speed increased beyond Picoseconds and MIPS (million of instruction per second).



These chips reduced the physical size of computer and increased their power.



Magnetic and optical storages devices.


Fifth Generation
-

Present and Beyond: Artif
icial Intelligence

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.

Artificial Intelligence is the branch of computer
science concerned with making computers behave like
humans. The term was coined in 1956 by John
McCarthy at the Massachusetts Institute of
Technology. Artificial intelligence includes:



Games Playing
: programming computers to play
games such as chess and ch
eckers



Expert Systems
: programming computers to make
decisions in real
-
life situations (for example, some expert systems help doctors diagnose diseases
based on symptoms)



Natural Language
: programming computers to understand natural human languages

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Neur
al Networks
: Systems that simulate intelligence by attempting to reproduce the types of
physical connections that occur in animal brains



Robotics
: programming computers to see and hear and react to other sensory stimuli

Currently, no computers exhibit
full artificial intelligence (that is, are able to simulate human
behavior). The greatest advances have occurred in the field of games playing. The best computer
chess programs are now capable of beating humans. In May, 1997, an IBM super
-
computer called
D
eep Blue defeated world chess champion Gary Kasparov in a chess match.

In the area of robotics, computers are now widely used in assembly plants, but they are capable only
of very limited tasks. Robots have great difficulty identifying objects based on app
earance or feel,
and they still move and handle objects clumsily.

Natural
-
language processing offers the greatest potential rewards because it would allow people to
interact with computers without needing any specialized knowledge. You could simply walk up

to a
computer and talk to it. Unfortunately, programming computers to understand natural languages has
proved to be more difficult than originally thought. Some rudimentary translation systems that
translate from one human language to another are in exist
ence, but they are not nearly as good as
human translators.

There are also voice recognition systems that can convert spoken sounds into written words, but they
do not understand what they are writing; they simply take dictation. Even these systems are qui
te
limited
--

you must speak slowly and distinctly.

In the early 1980s, expert systems were believed to represent the future of artificial intelligence and
of computers in general. To date, however, they have not lived up to expectations. Many expert
syste
ms help human experts in such fields as medicine and engineering, but they are very expensive
to produce and are helpful only in special situations.

Today, the hottest area of artificial intelligence is neural networks, which are proving successful in an
u
mber of disciplines such as voice recognition and natural
-
language processing.

There are several programming languages that are known as AI languages because they are used
almost exclusively for AI applications. The two most common are LISP and Prolog.

Cha
racteristics



They will be able to understand natural language, speak command, capacity to see their
surrounding and will think power called Artificial Intelligence (AI).



In contrast to present DIPS/ LIPS (Data/ logic Information processing System), the 5
th

generation will have KIPS (knowledge Information Processing System).



Will support parallel processing in full fledge

I
n the beginning

...




A generation refers to the state of improvement in the development of a product.


This term is
also used in

the different advancements of computer technology.


With each new generation, the
circuitry has gotten smaller and more advanced than the previous generation before it.


As a result
of the
miniaturization
,
speed
,
power
, and
memory

of computers have propor
tionally
increased.


New discoveries are constantly being developed that affect the way we live, work and
play.

T
he First Generation:


1946
-
1958

(The Vacuum Tube Years)



The first generation computers were huge, slow, expensive,
and often undependable.


In
1946
two Americans, Presper
Eckert
, and John
Mauchly

built the
ENIAC

electronic computer
which used vacuum tubes instead of the mechanical switches of
the
Mark I
.


The E
NIAC used thousands of vacuum tubes, which
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took up a lot of space and gave off a great deal of heat just like light bulbs do.


The ENIAC led to
other vacuum tube type computers like the
EDVAC

(Electronic Discrete Variable Automatic
Computer) and the
UNIVAC

I
(UNIVersal Automatic Computer).



The vacuum tube was an extremely important step in the advancement of computers.


Vacuum
tubes were invented the same time the
light bulb

was invented by Thomas Edison and worked very
similar to light bulbs.


It'
s purpose was to act like an
amplifier

and a
switch
.


Without any moving
parts, vacuum tubes could take very weak signals and make the signal stronger (
amplify it
).


Vacuum
tubes could also stop and start the flow of electricity instantly (
switch
).


These
two properties made
the ENIAC computer possible.



The ENIAC gave off so much
heat

that they had to be cooled by gigantic air
conditioners.


However even with these huge coolers, vacuum tubes still overheated regularly.


It
was time for something ne
w.

T
he Second Generation:


1959
-
1964

(The Era of the Transistor)





The transistor computer did not last as long as the vacuum tube computer lasted, but it was no
less important in the advancement of computer technology.


In 1947 three
scientists,
John Bardeen
,

William Shockley
, and
Walter Brattain
working at
AT&T's Bell Labs

invented what would replace the vacuum tube forever.


This
invention was the
transistor

which functions like a vacuum tube in that it can be
used to relay and switch electronic signals.




There were obvious differences between the transistor and the vacuum
tube.


The transistor was faster, more reliable, smaller, and much cheaper to b
uild than a vacuum
tube.


One transistor replaced the equivalent of
40 vacuum tubes
.


These transistors were made of
solid material, some of which is
silicon
, an abundant element (second only to oxygen) found in
beach sand and glass.


Therefore they were v
ery cheap to produce.


Transistors were found to
conduct electricity faste
r and
better

than vacuum tubes.


They were also much
smaller

and gave off
virtually
no heat

compared to vacuum tubes.


Their use marked a new beginning for the
computer.


Without thi
s invention, space travel in the 1960's would not have been
possible.


However, a new invention would even further advance our ability to use computers.


T
he Third Generation:


1965
-
1970

(Integrated Circuits
-

Miniaturizing the Computer)





Transis
tors were a tremendous breakthrough in advancing the
computer.


However no one could predict that thousands even now millions of
transistors (circuits) could be compacted in such a small space.


The
integrated
circuit
, or as it is sometimes referred to as
semiconductor chip
, packs a huge number
of transistors onto a single
wafer

of
silicon
.
Robert Noyce

of
Fairchild Corporation

and
Jack Kilby

of
Texas Instruments

independently discovered the amazing attributes of integrated
circuits.


Placing such large numbers of transistors on a single chip vastly increased the power of a
single computer and lowered its cost considerably.




Since the invention of integrat
ed circuits, the number of transistors that can be placed on a
single chip has
doubled

every
two

years, shrinking both the size and cost of computers even further
and further enhancing its power.


Most electronic devices today use some form of integrated
c
ircuits placed on printed
circuit boards
--

thin pieces of
bakelite

or
fiberglass

that have electrical
connections etched onto them
--

sometimes called a
mother board
.




These third generation computers could carry out instructions in
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billionths of
a second.


The size of these machines dropped to the size of small file cabinets.

Yet, the
single biggest advancement in the computer era was yet to be discovered. The Fourth
Generation:


1971
-
Today (The Microprocessor)



This generation can be char
acterized by both the
jump to
monolithic

integrated

circuits
(
millions

of
transistors

put onto one integrated circuit chip) and the
invention of the
microprocessor

(
a single chip that
could do all the processing of a full
-
scale
computer
).


By putting milli
ons of transistors onto one
single

chip more calculation and faster speeds could be
reached by computers.


Because electricity travels
about a foot in a billionth of a second, the smaller the distance the greater the speed of computers.



However wh
at really triggered the tremendous growth of computers and its significant impact
on our lives is the invention of the microprocessor.


Ted Hoff, employed by Intel (Robert Noyce's
new company) invented a chip the size of a pencil eraser that could do all t
he computing and logic
work of a computer.


The microprocessor was made to be used in calculators, not computers.


It led,
however, to the invention of personal computers, or microcomputers.



It wasn't until the 1970's that people began buying computer for personal
use.


One of the

earliest personal computers was the Altair 8800 computer
kit.


In 1975 you could purchase this kit and put it
together to make your own personal computer.


In 1977
the Apple

II was sold to the public and in 1981 IBM
entered the PC (personal computer) market.



Today we have all heard of Intel and its Pentium®
Processors and now we know how it all got started.


The
computers of the next generation will
have millions upon
millions of transistors on one chip and will perform over
a billion calculations in a single second.


There is no end in sight for the computer movement.



Classification of Computer

On the basic of

Size

Micro Computer

Mini Computer

Mainframe Computer

Super Computer

Work

Analogue Computer

Digital Computer

Hybrid Computer

Brand

IBM Computer(Apple/Macintosh)

IBM PC

Model

XT Computer

AT Computer

PS2 Computer

Operation

Server

Client

Computer Sizes and Power


Computers can be generally classified by size and power as follows, though there is considerable
Supercomputers

Minicomputer
s

Mainframes

Workstations

Personal Computers

Least powerful

Most powerful

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overlap:



Personal
C
omputer
: A small, single
-
user computer based on a microprocessor.



Workstation:

A powerful, single
-
user computer. A workstation is like a personal computer, but it
has a more powerful microprocessor and, in general, a higher
-
quality monitor.



Minicomputer:

A multi
-
user computer capable of supporting up to hundreds of users
simultaneously.



Mainframe:

A powerful multi
-
user computer capable of supporting many hundreds or thousands
of users simultaneously.



Supercomputer:

An extremely fast computer that can perform hund
reds of millions of
instructions per second.


Supercomputer

The highly calculation
-
intensive tasks can be effectively performed by means of supercomputers.
Quantum physics, mechanics, weather forecasting, molecular theory are best studied by means of
supe
rcomputers. Their ability of parallel processing and their well
-
designed memory hierarchy give
the supercomputers, large transaction processing powers.

Supercomputer is a broad term for one of the fastest computers currently available. Supercomputers
are v
ery expensive and are employed for specialized applications that require immense amounts of
mathematical calculations (number crunching). For example, weather forecasting requires a
supercomputer. Other uses of supercomputers scientific simulations, (anima
ted) graphics, fluid
dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g.
in petrochemical prospecting). Perhaps the best known supercomputer manufacturer is Cray
Research.



Super computer are the most powe
rful and fastest computers among digital computers.



These computers are capable of handling huge amounts of calculations that are beyond human
capabilities. They can perform billions of instructions per second (BIPS).



Super computers have the computing cap
ability equal o 40,000 microcomputers.



A Japanese supercomputer has calculated the value of PI (π) to 16 million decimal places.



These computers costs in 15 to 20 millions dollar range (most expensive).



They are mostly used in temperature forecast and scie
ntific calculations.



Examples: CRAY X
-
MP/24, NEC
-
500, PARAM, ANURAG. Among them PARAM and
ANURAG are super computer s produced by Indian are exported in European countries.



These were some of the different types of computers available today. Looking at the rate of
the advancement in technology, we can definitely look forward to many more types of
computers in the near future.






The Columbia Supercomputer
-

once one of the fastest.



Supercomputers are fast because they're really many computers working together.



Sup
ercomputers were introduced in the 1960's as the worlds most advanced computer. These
computers were used for intense calculations such as weather forecasting and quantum physics.
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Today, supercomputers are one of a kind, fast, and very advanced. The term s
upercomputer is
always evolving where tomorrow's normal computers are today's supercomputer. As of November
2008, the fastest supercomputer is the IBM Roadrunner. It has a theoretical processing peak of
1.71 pet flops and has currently peaked at 1.456 pet
flops.


Mainframe

Mainframe was a term originally referring to the cabinet containing the central processor unit or
"main frame" of a room
-
filling Stone Age batch machine. After the emergence of smaller
"minicomputer" designs in the early 1970s, the tradit
ional big iron machines were described as
"mainframe computers" and eventually just as mainframes. Nowadays a Mainframe is a very large
and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously.
The chief difference
between a supercomputer and a mainframe is that a supercomputer channels all
its power into executing a few programs as fast as possible, whereas a mainframe uses its power to
execute many programs concurrently. In some ways, mainframes are more powerful t
han
supercomputers because they support more simultaneous programs. But supercomputers can execute
a single program faster than a mainframe. The distinction between small mainframes and
minicomputers is vague, depending really on how the manufacturer wants

to market its machines.



Mainframe computers are very large and powerful



It is general purpose computer designed for large scale data processing



Very large sixe with approximate an area of 10000 sq.ft.



It supports large no of terminals.



They are suitable f
or large offices like bank, hospitals.



They can be used in networking systems



Some popular systems are IBM 1401, ICL 2950/10, ICL 39, and CYBER 170.


Mainframe computer

Mainframes are computers where all the processing is done centrally, and the user terminals are
called "dumb terminals" since they only input and outp
ut (and do not process).

Mainframes are computers used mainly by large organizations for critical applications, typically bulk
data processing such as census. Examples: banks, airlines, insurance companies, and colleges.


Minicomputer/Workstation

It is a midsize computer. In the past decade, the distinction between large minicomputers and small
mainframes has blurred, however, as has the distinction between small minicomputers and
workstations. But in general, a minicomputer is a multiprocessing sy
stem capable of supporting from
up to 200 users simultaneously.



Minis are smaller than Mainframe computers.



They are medium sized computers.



They can support 50 terminals.



They require area of 100 sq.ft.



These computers are useful for small business indus
tries and university.



Examples: Prime 9755, VAX 7500, HCL, MAGNUM etc.

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Workstations are high
-
end, expensive computers that are made for more complex procedures
and are intended for on
e user at a time. Some of the complex procedures consist of science,
math and engineering calculations and are useful for computer design and manufacturing.
Workstations are sometimes improperly named for marketing reasons. Real workstations are
not usuall
y sold in retail.



The movie Toy Story was made on a set of Sun (Sparc) workstations



Perhaps the first computer that might qualify as a "workstation" was the IBM 1620.


Microcomputer

It is a type of computer used for engineering applications (CAD/CAM), des
ktop publishing, software
development, and other types of applications that require a moderate amount of computing power and
relatively high quality graphics capabilities. Microcomputers generally come with a large, high
-
resolution graphics screen, at larg
e amount of RAM, built
-
in network support, and a graphical user
interface. Most microcomputers also have a mass storage device such as a disk drive, but a special
type of microcomputers, called a diskless workstation, comes without a disk drive. The most c
ommon
operating systems for workstations are UNIX and Windows NT. Like personal computers, most
workstations are single
-
user computers. However, workstations are typically linked together to form a
local
-
area network, although they can also be used as stan
d
-
alone systems.



A computer which is based on microprocessor is called microcomputer.



It is a small, low cast digital computer.



It requires small space, even can place in desktop.



They are mainly use in home offices shop stores. It can be connected to net
working system.



Eg: IBM PC Macintosh etc.


Personal computer:

It can be defined as a small, relatively inexpensive computer designed for an individual user. In price,
personal computers range anywhere from a few hundred pounds to over five thousand pounds.

All are
based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip.
Businesses use personal computers for word processing, accounting, desktop publishing, and for
running spreadsheet and database management applicat
ions. At home, the most popular use for
personal computers is for playing games and recently for surfing the Internet. Personal computers
first appeared in the late 1970s. One of the first and most popular personal computers was the Apple
II, introduced in

1977 by Apple Computer. During the late 1970s and early 1980s, new models and
competing operating systems seemed to appear daily. Then, in 1981, IBM entered the fray with its
first personal computer, known as the IBM PC. The IBM PC quickly became the pers
onal computer
of choice, and most other personal computer manufacturers fell by the wayside. P.C. is short for
personal computer or IBM PC. One of the few companies to survive IBM's onslaught was Apple
Computer, which remains a major player in the personal

computer marketplace. Other companies
adjusted to IBM's dominance by building IBM clones, computers that were internally almost the same
as the IBM PC, but that cost less. Because IBM clones used the same microprocessors as IBM PCs,
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they were capable of r
unning the same software. Over the years, IBM has lost much of its influence
in directing the evolution of PCs. Therefore after the release of the first PC by IBM the term PC
increasingly came to mean IBM or IBM
-
compatible personal computers, to the exclus
ion of other
types of personal computers, such as Macintoshes. In recent years, the term PC has become more and
more difficult to pin down. In general, though, it applies to any personal computer based on an Intel
microprocessor, or on an Intel
-
compatible
microprocessor. For nearly every other component,
including the operating system, there are several options, all of which fall under the rubric of PC

Today, the world of personal computers is basically divided between Apple Macintoshes and PCs.
The princip
al characteristics of personal computers are that they are single
-
user systems and are based
on microprocessors. However, although personal computers are designed as single
-
user systems, it is
common to link them together to form a network. In terms of pow
er, there is great variety. At the
high end, the distinction between personal computers and workstations has faded. High
-
end models
of the Macintosh and PC offer the same computing power and graphics capability as low
-
end
workstations by Sun Microsystems,
Hewlett
-
Packard, and DEC.


Personal Computer Types

Actual personal computers can be generally classified by size and chassis / case. The chassis or case
is the metal frame that serves as the structural support for electronic components. Every computer
system requires at least one chassis to house the circuit boards and wiring. The chassis also contains
slots for expansion boards. If you want to insert more boards than there are slots, you will need an
expansion chassis, which provides additional slots.
There are two basic flavors of chassis designs

desktop models and tower models

but there are many variations on these two basic types. Then come
the portable computers that are computers small enough to carry. Portable computers include
notebook and sub no
tebook computers, hand
-
held computers, palmtops, and PDAs.

Tower model

The term refers to a computer in which the power supply, motherboard, and mass storage devices are
stacked on top of each other in a cabinet. This is in contrast to desktop models, in
which these
components are housed in a more compact box. The main advantage of tower models is that there are
fewer space constraints, which makes installation of additional storage devices easier.

Desktop model

A computer designed to fit comfortably on t
op of a desk, typically with the monitor sitting on top of
the computer. Desktop model computers are broad and low, whereas tower model computers are
narrow and tall. Because of their shape, desktop model computers are generally limited to three
internal m
ass storage devices. Desktop models designed to be very small are sometimes referred to as
slim line models
.

Notebook computer

An extremely lightweight personal computer. Notebook computers typically weigh less than 6 pounds
and are small enough to fit eas
ily in a briefcase. Aside from size, the principal difference between a
notebook computer and a personal computer is the display screen. Notebook computers use a variety
of techniques, known as flat
-
panel technologies, to produce a lightweight and non
-
bulk
y display
screen. The quality of notebook display screens varies considerably. In terms of computing power,
modern notebook computers are nearly equivalent to personal computers. They have the same CPUs,
memory capacity, and disk drives. However, all this
power in a small package is expensive. Notebook
computers cost about twice as much as equivalent regular
-
sized computers. Notebook computers
come with battery packs that enable you to run them without plugging them in. However, the
batteries need to be rec
harged every few hours.

Laptop computer


A small, portable computer
--

small enough that it can sit on your lap. Nowadays, laptop computers
are more frequently called notebook computers.

Sub notebook computer

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A portable computer that is slightly lighter an
d smaller than a full
-
sized notebook computer.
Typically, sub notebook computers have a smaller keyboard and screen, but are otherwise equivalent
to notebook computers.

Hand
-
held computer

A portable computer that is small enough to be held in one’s
hand. Although extremely convenient to
carry, handheld computers have not replaced notebook computers because of their small keyboards
and screens. The most popular hand
-
held computers are those that are specifically designed to
provide PIM (personal infor
mation manager) functions, such as a calendar and address book. Some
manufacturers are trying to solve the small keyboard problem by replacing the keyboard with an
electronic pen. However, these pen
-
based devices rely on handwriting recognition technologie
s,
which are still in their infancy. Hand
-
held computers are also called PDAs, palmtops and pocket
computers.

Palmtop

A small computer that literally fits in your palm. Compared to full
-
size computers, palmtops are
severely limited, but they are practical

for certain functions such as phone books and calendars.
Palmtops that use a pen rather than a keyboard for input are often called hand
-
held computers or
PDAs. Because of their small size, most palmtop computers do not include disk drives. However,
many
contain PCMCIA slots in which you can insert disk drives, modems, memory, and other
devices. Palmtops are also called PDAs, hand
-
held computers and pocket computers.

PDA

Personal Digital Assistants (PDAs):

It is a handheld computer and popularly known as
a palmtop. It
has a touch screen and a memory card for storage of data. PDAs can also be effectively used as
portable audio players, web browsers and smart phones. Most of them can access the Internet by
means of Bluetooth or Wi
-
Fi communication.

Short for

personal digital assistant, a handheld device
that combines computing, telephone/fax, and networking features. A typical PDA can function as a
cellular phone, fax sender, and personal organizer. Unlike portable computers, most PDAs are pen
-
based, using a
stylus rather than a keyboard for input. This means that they also incorporate
handwriting recognition features. Some PDAs can also react to voice input by using voice recognition
technologies. The field of PDA was pioneered by Apple Computer, which introd
uced the Newton
MessagePad in 1993. Shortly thereafter, several other manufacturers offered similar products. To
date, PDAs have had only modest success in the marketplace, due to their high price tags and limited
applications. However, many experts believ
e that PDAs will eventually become common gadgets.

PDAs are also called palmtops, hand
-
held computers and pocket computers.

On the Basic of working principle
:
Based on the operational principle of computers, they are
categorized as analog computers
,
Digital computer

and hybrid computers.

Analog Computers:

These are almost extinct today. These are different from a digital computer
because an analog computer can perform several mathematical operations simultaneously. It uses
continuous variables for mat
hematical operations and utilizes mechanical or electrical energy.

The computer which process analogue quantities (Continuous data) is called an analogue computer.
For example Watch with hands is an example of analogue device.

o

Analogue computer operates by

measuring rather than counting.

o

They are slower than digital computer.

o

They are designed to compute physical forces as temperature and pressures.

o

They are mostly used in engineering and scientific application.

o

Analogue computers are used in hospital to
measure the size of stone in kidney and mental
disease diagnostics (CT scan with photos).

Digital Computer

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The computer with accepts discrete data is known as digital computer. For example
digital watch is called digital because they go for one value to th
e nest with displaying all
intermediate value. But can display only finite number.



A binary number consisting of 0’s 1’s represents each quantity in such a computer. There
is no way to represents the values in between 0 and 1. So all data that compute proc
ess
must be encoded digitally, as series of zeros or ones.



Digital computers are mostly used for general purpose.



Digital computers are faster than analogue.



It has large memory capacity.



Example: IBM PC, Apple/Macintosh.

Hybrid Computers:

These computers
are a combination of both digital and analog computers. In this
type of computers, the digital segments perform process control by conversion of analog signals to
digital ones.

Following are some of the other important types of
hybrid
computers.

It can tra
nsfer data from analogue to digital and vice
-
versa.



During launching of rocket the analogue computers measures the speed of the rocket,
temperature and pressure of atmosphere. Then these measurements are converted into
digital signals and



In hospital anal
ogue devices measure the temperature and blood pressure of patient, and
then these measurements are converted into digital signals and fed to the digital computer.

On the Basic of Operation

Server



Inside of a
Rack unit

Server

Simi
lar to mainframes in that they serve many uses with the main difference that the users (called
clients) do their own processing usually. The server processes are devoted to sharing files and
managing log on rights.

A server is a central computer that conta
ins collections of data and programs. Also called a network
server, this system allows all connected users to share and store electronic data and applications. Two
important types of servers are file servers and application servers.

Client Computer

These
computers which are used in network always ask for request to its server for its operation is
called client computer. The personal computer sometimes called as client computer.


A personal computer (PC)

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PC is an abbreviation for a Personal Computer, it is also known as a Microcomputer. Its physical
characteristics and low cost are appealing and useful for its users. The capabilities of a personal
computer have changed greatly
since the introduction of electronic computers. By the early 1970s,
people in academic or research institutions had the opportunity for single
-
person use of a computer
system in interactive mode for extended durations, although these systems would still ha
ve been too
expensive to be owned by a single individual. The introduction of the microprocessor, a single chip
with all the circuitry that formerly occupied large cabinets, lead to the proliferation of personal
computers after about 1975. Early personal c
omputers generally called microcomputers, sold often in
kit form and in limited volumes and were of interest mostly to hobbyists and technicians. By the late
1970s, mass
-
market pre
-
assembled computers allowed a wider range of people to use computers,
focus
ing more on software applications and less on development of the processor hardware.
Throughout the 1970s and 1980s, home computers were developed for household use, offering some
personal productivity, programming and games, while somewhat larger and more

expensive systems
(although still low
-
cost compared with minicomputers and mainframes) were aimed for office and
small business use.


On the basic of Brand

IBM PC

IBM PC is a microcomputer produced by IMB Company. Dr.Herman Horierith established IBM in
19
23. It is a leading the market of mainframe and PC’s. It used the processors, multimedia devices
and some other hardware’s parts, developed by some other companies like Intel. But use the principal
of its own. So all the computer developed by IBM Company i
s called IBM Computer.

IBM Compatible:

IBM compatible can use hardware amd software designed for IBM PC. The internal architecture of
IBM compatible is similar to IBM PC. So they are called duplicate computers. Example Epson, Acer
etc.

Apple/Macintosh

Appl
e Corporation was established in 1970 in USA. Its computer are called Apple/Macintosh (Mac)
computer. The internal architecture of these computers is totally different form that of IBM.
Therefore they need their own software.


On the basic of Model

XT comp
uter:

XT (Extra Technology) computer are old technology computers with much slower processing spent
(not more than 4.77 MHZ) Advance GUI based software like windows cannot be run in these
computers. Everything was based on text based system. Serial number
of processors was like 8080
and 8088, which were developed by Intel company are used. Complex calculation and large
processing I/O devices were not flexible and faster. It used 4 bits processor length.

AT computer:

AT (Advanced Technology) computers are th
e new technology computers. They are faster in
processing (more than 2 GHZ). It can run any type of software with high GUI and color. Serial
number of process is 80286, 80386 and Pentium. Any type of complex and long processing can be
done depending on th
e capacity of computers. I/O devices are interactive, flexible and faster. Word
length exceeds 64 bits. Coprocessors re used to help the main processors for complex mathematics.

PS2 Computer:

Actually, those are not totally different model of computer but
are refinement of AT computers.
These models were built after 1990’s and mostly used in laptop computers. Rechargeable and battery
operational systems with faster flexible I/O devices are some important characeteists of these
computers. OS2 operating syste
m was used at the beginning but the now day’s widows operating
system is in leading

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Computer software

Software is a computer program which is a sequence of instructions designed to direct a computer
to perform certain task. The software enables a computer
to receive input, store information, make
decisions, manipulate and output data in the correct format. A program consists of instruction that
tell the computer what to do, how to behave. When we buy a computer we don’t automatically get
every program produ
ced in the world. It may load operating system (like Window XP) if we want to
write the text, presentation some slides, do some calculation then we must installed the office
package, that is another software.

System software:

The most essential for comput
er operation and directs inter operation of system
and its hardware, services, utility, drivers and other preferences configuration files. The programs
that are the past of computer system which includes assemblers, compilers, file management,
system util
ity.

For example: windows 85, windows 89, window XP, window Red hat, Window Vista etc.

Application software:

the types of software which is used for user’s specific application are called
application software. IT consists of a number of programs designed to perform specific user
application. Eg Word, Excel, PowerPoint, Photoshop, CorelDraw, Spss, Stata, Epiinfo
etc




Questions

Directions:


Answer each of the questions after reading the article above.


Write in complete
sentences.


You must think and be creative with your answers.


1.

In each of the
4 generations

what was the cause for the increase of
speed
,
power
, or
memory
?

2.

Why did the
ENIAC

and other computers like it give off so much
heat
?


(Be very specific)

Basic Computer


B.pharm PU


22


3.

What
characteristics

made the
transistors

better than the
vacuum

tube
?

4.

How was
space travel

made possible through the invention of transistors?

5.

What d
id the
microprocessor

allow the computers to do? and What was the
microprocessor's
original purpose?

6.

When was the
first computer

offered to the public and what was its name?

7.

Intel

was started by who?

8.

What is
monolithic

integrated

circuits
?


9.

How do you think society will be different if scientists are able to create a chip that will
perform a
trillion

operations in a
single

second
?


Computer Program and Programming Language

Computer program is a set of instruction that when executed, causes t
he computer to behave in a
predetermined manner. Without program computers are unless and cannot do anything. However
most people are confused that are intelligent devices but concept is wrong. Computer cannot
understand human natural language like English

or Nepali. To instruct a computer to perform a
certain job we need language which can understand by the computer. The languages which are used
to instruct the computer to do certain jobs called computer programming languages. There are
many programming la
nguages like C,C++,Pascal, Basic etc.


Number System

The distinct symbols, characters, alphabets which are used to measure the physical quantity is term
as number system. The various number
systems are used for encoding and decoding of data in
computer. The distinguishing of the number system is of its base.


Rules for
C
onversion

The quotient and remainders are noted in each step.

The quotient of one stage is divided by 2,8,16 respectively at

the next stage.

The process repeat up to less than its base numbers/divider.

The first digit is known as most significant digits and the right most digit is known as least significant
digit.

Number conversion table


Decimal

Binary

Octal

Hex
-
decimal

Decim
al

Positional
weight (Right
to left) ones,
tens,
hundreds,
thousands

0,1,2,3,4,5,6,7,
8,9

(Base of 10)


(
25
)

10

2

25

1

2

12

0

2

6

0

2

3

1

2

1





(11001)
10


(63)
10

8

63

7



7




(77)
8



(66)
10

16

66

2



4




(
42)
16


Divider

2

5(dividend)

2 (quotient)


-
4


1 remainder


Basic Computer


B.pharm PU


23


Binary

Positional
weight


( right to
left)
1,2,4,8,16,32,



(111)
2


1

1

1

2

1

0

2

2

2

4

2

1


(
7
)
10


1,0

Base of 2

(101100)
2

1

0

1

1

0

0

2

1

0

2

1

0

2

2

2

2

2

2

4
*
1

2
*
0

1
*
1

4
*
1

2
*
0

1
*
0

4

0

1

4

0

0

5

4

(54)
8

Select three digits frame and
convert its decimal
equivalent

(101111)
2

1

0

1

1

1

1

1

0

3

2

1

0

2

2

2

2

2

2

2
*
1

1
*
0

8
*
1

4
*
1

2
*
1

1
*
1

2

0

8

4

2

1

2

15(F)

(2F)
16

Select 4 digits frame and
convert in decimal equivalent

Octal

Positional
weight (Right
to left)
1,8,64,512,40
96,..

(56)
8

5

6

1

0

8

8

5*8

1*6

40

6

(46)
10


(5
3)
8

5

3

101

011


(
101011
)
2


0,1,2,3,4,5,6,7

Base of 8

144

8

1

4

4

001

100

100

0

0110

0100


6

4

(
64
)
16


Hex
-
decimal

Positional
weight (Right
to left)
1,16,256,409
8..

2B
16

2

B (11)

0010

1011


1

0

16


16

32

11

(43)
10


(7E
)
16

0111

1110


(
01111110
)
2


3DE
16

3


D

E

11

1101

1110

111

011

110

1

7

3

6

1736
8

Make 3 digits frame then
convert its decimal
equivalent

0,1,2,3,4,5,6,7,8,9

,10(A),11(B),12(C),

13(D),14(E),15(F)

Base of
16

Conversion of Fractional Number

Those numbers which has both integer part as well as fractional part is called real number or floating point
number. The real numbers
may be Positive (+ve) or Negative (

v) are used for scientific calculation it is often
necessary to carry out calculations with very large or may be very small numbers. It is also possible to convert
fractional or decimal number system into other number sy
stem. The fractional number system is that
number system that can represent closer to the original number system. It is also called as floating point
number that represent decimal pattern.






For example: (0.635)
10

6

3

5

6
*
10
-
1

3
*
10
-
2

5
*
10
-
3

6
*1/
10

3
*1/
100

1*1/
1000

0.6

0.03

0.
00
5

(0.635
)
10














For example: (0.10111)
2

to
D
ecimal

1

0

1

1

1

1*2
-
1

0*2
-
2

1*2
-
3

1*2
-
4

1*2
-
5

1*1/2

0*1/4

1*1/
8

1*1/
16

1*1/
32

0.5

0

0.125

0.0625

0.03125

(0.71875)
10



















Basic Computer


B.pharm PU


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Convert the fractional binary number (1101.1010)
2

into decimal



1101



.1010




1

1

0

1

1

0

1

0

1*2
3

1*2
2

0*2
1

1*2
0

1*2