Basics of Computers What is Computer - Webs · Basics of Computers By Dr.B.T. Sampath Kumar ... Abacus Napier's Bone Slide ... Slide Rule 7 9 8 4 9 Mechanical Devices Blaise Pascal's

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Basics of Computers

By

Dr.B.T. Sampath KumarAsst. Professor

Dept of Library and Information Science Kuvempu UniversityShivamogga, INDIA

What is Computer

Computer is …

Figure.2: Computer

-An Electronic Device

-Accepts the data

-Stores the data

-Does arithmetic and Logical

operations

-Gives the output in a neat

desired format

System Logical Organisation

Input Output

Main Memory

ALU CU

Sec. Memory

ALU: Arithmetic

& Logic Unit

CU: Control Unit

CPU CPU: Central Processing Unit

System Unit

What is System?

-System consists of two

or more parts, - Which are inter

- connected,

- coordinates &

- cooperates- for a specific purpose

Characteristics of Computer

� Speed

1 millisecond (ms) = 1/103 second1 microsecond (µs) = 1/106 second1 nanosecond (ηs) = 1/109 second

1 picosecond (ps) = 1/1012 second

Characteristics of Computers

� Reliability and Accuracy

� Versatility

Banks

Railway s

Weather

forecastingResearch

Institutions

Satellite

launching

Hospitals

School and

College

Home/Hote

ls

Retail

Stores Industries

Applications of Computer

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� Diligence

� Memory Capacity

� Capability to be

programmed

� Automation

Types of Computers

� On the basis of Working Principles� Analog Computer

� Digital computer

� Hybrid computer

� On the basis of the flexibility of operation � General purpose computer

� Special purpose computer

� On the basis of Efficiency

� Main frame computer

� Mini computer

� Microcomputers

� Laptop Computers

� Notebook Computers

� Super Computers

Types of Computers

� On the basis of Working Principles

� Analog Computer

� Digital computer � Hybrid computer

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� On the basis of the flexibility of operation

� General purpose computer

� Special purpose computer

� On the basis of Efficiency

� Main frame computer

� Mini computer

� Microcomputers

� Laptop Computers

� Notebook Computers

� Super Computers

� Mainframe computer� They are sensitive to variations in temperature,

humidity, dust etc., and hence they should be kept in controlled environment (e.g. air conditioned rooms).

� Special and qualified operators and programmers are required for their operation.

� They support wide-range of peripherals (peripherals is a term used to denote collectively the input or output and secondary storage devices).

� They have large data storage capacity.� They can make use of wide variety of software

Mini computer

� They have limited data channel capacity.

� They offer limited range of peripherals.

� Limited software is available.

� Facility for direct operation of the machine by the end user.

� Favorable cost/performance ratio.

� Air conditioning is not necessary and is provided in many cases only for dust control.

Micro computer

� Microchips

Laptop computer

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Super Computers

� More data capacity

� Used in satellite centers, research and Development organization

� Needs skilled personnel

History of Computer:Manual Devices

� Abacus

� Napier's Bone

� Slide Rule

7 9 8 4 9

Figure.1: Structure of Typical Abacus

Mechanical Devices

� Blaise Pascal's Arithmetic Machine

� Jacquard's Loom

� Babbage's Analytical Engine

� Hollerith's Punched Card Tabulating Machine

Blaise Pascal's Arithmetic Machine

Figure.5: Blaise Pascal's Arithmetic Machine

Jacquard's Loom

Between 1802 and 1804

Joseph Marie Jacquard, a French textile manufacturer

invented this loom

Babbage's Analytical Engine

Store

Control Unit

Mill

Output UnitInput Unit

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Hollerith's Punched Card Tabulating Machine

• Census of 1880 of 50 million

had taken over 7 years to

complete

•The census of 1890 of 63

million took only 3 years

Automatic Calculating Devices

� MARK-I

� ENIVAC

� EDVAC and EDSAC

Mark-I

� Mark-I was completed in 1944. It was a huge machine 15 feet long, 2.4 feet height and 0.6 wide. The time taken for average multiplication and division were

about 4-11 seconds respectively. The input and output were by punched cards and paper tapes. It was the first general-

purpose digital and the first electromechanical computer.

Mark-I

ENIAC (Electronic Numerical Integrator and Calculator)

� It was first electronic calculator completed in 1964and was developed by John Mauchly and Presper Eckert.

� It occupied a room measuring 9x15 m and contained 18,000 vacuum tubes.

� The ENIAC performed 5000 additions per seconds. This calculator consumed 150 kilowatts of power and needed to be water-cooled.

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EDVAC (Electronic Discrete Variable Automatic Computer) and

EDSAC (Electronic Display Storage Automatic Computer

� This is mainly based on John Von Neuman'sideas who is father of modern computers was first to introduce the stored program concept in a computer.

� Another computer using internal storage called EDSAC (Electronic Display Storage Automatic Computer) was completed in 1949 at the University of Manchester.

� It was some significance since it was the first computer to contain a checkable program of instruction within own memory.

� The storage capacity is 1024 words of 44 bits each, auxiliary capacity is 20,000 words and the access times of primary memory is 0.48 to 384 microsecond.

� In this machine the program was fed into the storage unit by means of a punched paper type. The first program for EDVAC was written by John Von Nueman. Thus he showed that

computers could be used for non-scientific computations.

Generation of Computers

First Generation Computers� Comparatively large in size as compared to

present day computers.� Generated lot of heat, they were not

consistent and reliable, as the valves tended to fail frequently.

� Low capacity internal storage.� Individual, non-related models.� Processors operated in the milliseconds speed

range.� Internal storage consisted of magnetic drum.

Second Generation Computers

� Smaller in size compared to the first generation computers.

� Generated a lower level of heat, as components were much smaller.

� Greater degree of reliability because of solid state technology.

� Higher capacity of internal storage.

� Use of core storage instead of magnetic drum.

� Processor operated in the microsecond speed.

� High cost direct accesses storage

Third Generation Computers

� Smaller in size as compared to second generation computers.

� Higher capacity internal storage.� Remote communication facility.� Multi-programming facility.� Reduced cost of direct access storage.� Processors, which operate in nanoseconds speed

range.� Ranges of computers with a common architecture

whereby models were upward compatible.� Use of high level language such as COBOL and

FOTRAN.� Wide range of optional peripherals.

Fourth Generation Computers

� The use of Very Large Scale Integrated circuits (VLSI) has made the fourth generation (micro) computers very compact, much less expensive, faster,

more reliable and much greater data processing capacity than third generation computers.

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Fifth Generation Computers

� Easy to use computers with high intelligence and natural human input and output mechanism

� Reliable and efficient software development by new languages, new computer architectures and systems software which overcomes previous problem and

� Improved overall function and performance aimed at making computers smaller, lighter, greater capacity, more flexible and more reliable