Computer Intro

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DigitalAnalog Hybrid

Types of


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(a)correct and sufficient input that has been provided ,and

(a)High storage capability.

(a)This computers were smaller in size as compared to first generation.

Therefore, easily portable and required lesser space for installation.

(b)Easily portable because of small size.

(b)Logical procedures called algorithms used to compute them.

(b)Maintenance cost was low because hardware failures were rare.

(b)Voice recognition will likely to be a primary means of input.

Computers may be constructed differently than they are today.

(c) The PCs were the most important achievement among all

other computers (viz mainframe, minicomputers and

supercomputers) during fourth generation period. However ,highly

sophisticated technology was required for the manufacture of LSIchips.

(c)These computers had less power requirement and generated less heat

than previous generation computers.


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(c)They will the personal computers (called notebook

computers) will continue to be small and will have the feature of

parallel processing.

(d) Even more reliable than second generation computers.

(d)Less power required for this generation computers.

(d)These machines will be used anywhere and for every

purpose.

(e)Highly sophisticated technology required for the manufacture of IC

chips.

(f)Operating systems and of application software allowed the users to

work in time-sharing and real time on-line environment.

(g)Minicomputers of the third generation computers were also

economical and easily affordable even by smaller companies.

A digital computers is machine that accepts data and produces information

in a discrete form ,thus ,computers are extremely reliable . Most errors are

caused by humans ,not by computers. They work on the principle Garbage-

in Garbage out

a human error . Basically, the resulting information (output)is produced by

carrying out arithmetic and logical operation on accepted data (input).The

correctness and completeness of the output answers entirely depends on;

Achievements in Hardware and Software in Fourth

Generation Computers

Al thought, micro processor is a single chip which contains theneeded circuit, it could perform arithmetic and logical functions.

This further led to personal computer revolution. As personal

computers (PCs) were amazingly small, compact and inexpensive,

it was possible for everyone to have their own computer. During


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this era, it was not only the work place where computers were

deployed but also at homes . This was the transition period for the

organization to switch over to electronic and paperless offices.

(a) Although heat emission was less, computers were manufacturedusing transistors. However, air-conditioning was required .

Analog computer :

Analog computer is a computer which deals with a model of the problem , in

which the variables are represented by continuous physical quantities , such

as , angular position , temperature and voltage .

As analog information is mechanical , it process ltd, accuracy . There are

electronic analog computers generally in chemical plants monitoring

temperatures, pressures , voltage , etc.

(a) As more than ten thousands of vacuum tubes were there in first

generation computers, power consumption was very high since

each of vacuum tube required nearly half a watt of power.

As technology changes ,the differences between the types of machines

become more and more indistinct .

Characteristics of fifth generation computers (now and future)

Characteristics of first generation computers

Characteristics of Second Generation Computer

Characteristics Of Third Generation Computers

CLASSIFICATION OF COMPUTERS

Computer generation means a step of advancement in technology. It also

reflects the growth of computer industry. The advancement in technology

existed not only in hardware but also in software.

COMPUTER SYSTEMS


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Data Tampering

Digital computer :

Digital computer refers to a computer ,which represents, the data , whether

numbers , letters , or symbols, in binary form and they work numbers in the

form of separate discrete digits .

Fifth Generation Computers (1989-Present)

Fourth Generation Computers (1970-89)

(b) Frequent maintenance required, but less prone to hardware failures

than first generation computers.

Garbage-in Garbage-Out9 (GIGO)

GIGO(Garbage-in Garbage-out)-A computing axiom meaning that data

put into process is incorrect, the data output by the process will also be

incorrect.

Hardware :

Hardware Limitation

Hybrid computers :

Hybrid computers refers to computers that contain both digital and analog

circuit.

IBM 704

IBM also initiated development of a smaller machine, whose origin lay in

proposal for extension of punched card equipment. In late 1955,IBM began

deliveries of the 704, its successor to the 701.The 704s most notable

features were its core memory. The 704s processor had hardware floating

point arithmetic and three addressable index registers. In January 1957,IBM

announced the 709 as a compatible upgrade to the 704, but it did not enjoy

the same success.


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In commercial and administrative applications and for mathematical

computation ,digital computers are used exclusively.

Information can be stored and processed in number of ways .A computer

may be digital or analog or hybrid. They do have some principles incommon, but they employ different types of data representation and are in

general, submitted to different kind of work. The way computers process the

information can be broadly classified as .

Initially, Apple Computer Inc. launched the PCs, Apple 2nd in

1978. Then in 1980, PCs market was dominated by IBM, popularly

known as IBM PC. During fourth generation period, several other

manufacturers designed their own PCs known as IBM compatible

PCs, as this become standard for the PC industry.

INPUT AND OUTPUT DEVICES

INPUT DEVICES

INTRODUCTION

It was Large Scale Integration (LSI) era (Refer to key terms at

end of this chapter),when electronic component on a silicon chip

was doubled, as it was based on semi-conductor technology.

During this time it was possible to integrate more than 30,000

electrical components on a single chip. This progress led to Very

Large Scale Integration (VLSI), where integration of more than

one million electronic component on a single chip was possible.

Therefore, this technology evolved the microprocessor.

LIMITATIONS OF THE COMPUTER

Most computer users need no special knowledge of electronics. In broad

sense, data processing is said to be what computers do.

Software :


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Software Limitation

The Third Generation (1965-70)

(a)The common opinion is that future fifth generation computer

will be based on artificial intelligence them think and

reason.

THE COMPUTER GENRATIONS

The computer is device made up of combination of electronic and electronic

mechanical components . computer itself has no intelligence and is referred

as hardware . The hardware can not work alone , It needs to be connected

with other parts of its system. computer system have two main features ;hardware and software :

The First Generation (1950-60)

The first generation began around 1950, with the introduction of

commercial computers manufactured and sold in quantity . computers of the

first generation stored their programs internally and vacuum tubes (Refer to

key terms at end of this chapter) as their switching technology . each design

used a different mix of registers, addressing schemes , and instruction sets.Each of the memory technologies available at time had a drawback, which

led to a variety of machine design that favoured one approach over another.

Most first generation computers used serial memories until reliable magnetic

core memory become available in the mid-1950s.The main computers

introduction during this era were UNIVCI and IBM 704, which could be

programmed in assembly language , that are described below.

The first generation computers were having following characteristics such

as:

The goal of this study is to help learner to computer literate . In becoming

computer literate ,we will need to be aware of the importance of computers&

be able to use them to accomplish everyday tasks.


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The hardware is the part of the computer that you can touch , such as the

keyboard , disk drivers , monitor(also some time called a visual display unit

or computer screen) ,processing unit , mouse and printer .

The main characteristics of digital computers are that is automatic, generalpurpose and electronic. The user of computers is basically solving the

problems effectively and faster. There are three major elements in computers

system which help in solving problems, they are hardware, software, and

data. The relationship of these elements can be represented in equation;

Hardware + Software + Data = Solution

The main features of second-generation computers are as follows:

The main features supported by fifth generation computers are:The major achievement in hardware and software the

following:

The most obvious question which arises , is that what is a computer ? A

computer is an electronic device that operates under the control of a set of

instructions that are stored in its memory unit. A computer accepts data from

an input device and processes it in to useful information. Which is displays

on its output device.

The notion that there were three major generation of computers, based on

device technology ( vacuum tubes, discrete transistors, and integrated

circuits ), served well to characterize machines for the beginning of the

electronic era. But nearly all computers have used silicon integrated circuitry

since the 1970s, yes, it is true that IC technology advanced in those years,

and the microprocessor was a significant milestone, but computers today

still use a descendant of the IC technology invented by Robert Noyce and

Jack around 1959.

The Second Generation (1960-65)

The second generation computing lasted form about 1960 to 1965 , and

was characterized by discrete transistors (Refer to terms at end of this

chapter) for switching elements and ferrite magnetic core planes for internal


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memory. In software, this era saw the acceptance of high-level programming

languages like Fortran and Cobol ,although assembly language

programming remained common.

(c) The size of second generation computers were smaller than firstgeneration computers, thus, required smaller space for installation.

The software on the computer is needed to make the computer work .It is the

basic step by step instructions which are given to the processing unit to tell it

what to do next . Software is also known as computer programs . A typical

example of software is word processor allows the person using it to write ,

edit , save and print letters , memos and many other types of documents .

The term computer originated form the word compute or calculate

.Typically, data is processed using computer ,thus computer is also

popularly know as data processing.

The third generation computers were based on IC(integrated circuit)

Technology (Refer to key terms at end of this chapter).A second innovation

was the use of microprogramming to achieve compatibility obtained

instruction set form a read-only memory containing a micro program. The

IBM system 360 used channels for I/O-independent processor that handled

the transfer of data between primary memory and peripheral devices. Thisallowed IBM to market a common set of I/O. By all measures the 360 series

was very successful. IBM sales personnel recorded over a thousand orders

for systems within a month of the April 1964 announcement , and by 1970

there were over 18,000 installation worldwide .System /360 was unsuitable

for time-sharing. When IBM upgraded the 360 series to the System/370 in

1970, its architecture was extended to provide this feature and virtual

memory as will. A further extension of the 360 architecture was made in

1981,when the architecture, much extended, was still being used in the

1990s in two lines of IBM products, the 43xx series and the 30xx series,

which together were marketed as the System/390 series.

The UNIVACI was designed by J.Presper Exkert and John Mauchly, was

first delivered in 1951.It was the first American computers to be produced as

a series and sold to commercial customers. Most customers used the


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UMIVACI for accounting, statistical, and other application that would later

be known as data processing.

The UNIVACI was regularly designed and built. Its central processor

contained over 5,000 tubes, installed in cabinets that were arranged in a 10-foot (3m) by 14-foot (4.5m) rectangle.

There are some computers which employ both digital as well as analog

quantities . these are known as hybrid computers. for example, a digital

thermometer employs a mechanism which converts the temperature into

digital from observed in analog signals using analog-to-digital conversion.

Hybrid computers are the computers that are generally used in process

control environmental where an analog input provided to a computer which

processes it digitally and present the output in analog or digital from asrequired.

There has been dramatic increase in power of microprocessor

chip. The Ultra Large Scale Integration (ULSI) technology (Refer

to key terms) is responsible for the fifth generation computers,

having nearly 10 million electronic components on a single chip

(mega chips). According to the Moors law the speed and size of

the main memory and of hard disk, double in almost everyeighteenth month. This progress led to the powerful features

,which were generally used to be found in mainframes and will

available in microprocessor architecture in the fifth generation

computers.

(b)These computer were the fastest calculating device for the time. They

could perform computations in milliseconds.

(c) These computers had limited commercial use, because were

difficult to program.

This section of the chapter provides an overview of the several technologies

existed during the major development of five generation of computers.


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Thus , we can say thermometer and slide rule are also analog device .Analog

computer tends to be special- purpose machine designed for some scientific

or technical application.

TYPES OF COMPUTERS

UNIVACI

(d) Vacuum tubes emitted large amount of heat, due to this there were

many frequent burnt outs of vacuum tubes. This led to frequent

hardware failures. Therefore constant maintenance and proper air

condition was required.

(e) Vacuum tubes were the only electronic components available

during those days. Vacuum tube technology made possible the

advent of electronic digital computers.

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Computer Intro