11stst chapter chapter

Writer:-Rashedul HasanWriter:-Rashedul Hasan

Editor:-Jasim Uddin.Editor:-Jasim Uddin.

11stst Chapter. Chapter.

What Computer isWhat Computer is -Characteristics of Computer-Characteristics of Computer -History of Computer-History of Computer -Computer Generation-Computer Generation -Types of Computer -Types of Computer

What computer isWhat computer is

The word Computer derives from The word Computer derives from “Compute” means “To calculate”“Compute” means “To calculate”

Calculating device that can perform Calculating device that can perform arithmetic operation at high speed.arithmetic operation at high speed.

But to define a computer merely as a But to define a computer merely as a calculating device is to ignore over calculating device is to ignore over 80% of its Function.80% of its Function.

Data processorData processor

Input process output

Data process Information

Store Retrieve

Data & InformationData & Information

Data: Data is Raw material used as Data: Data is Raw material used as input to Data processing.input to Data processing.

Information: Information is processed Information: Information is processed data obtained as output of Data data obtained as output of Data processing.processing.

Data ProcessingData Processing

Processing in general terms, is a Processing in general terms, is a series of actions or operations that series of actions or operations that converts some input into useful converts some input into useful output.output.

Hence, Data processing is a series of Hence, Data processing is a series of actions or operations that converts actions or operations that converts data into output. data into output.

Data processing Data processing transforms transforms raw data raw data into information.into information.

Input Input DevicesDevices

Input dataFrom

ExternalSource

InputData

In Internal

form

CPU & Memory

Process-ed

Data In

Internalform

output output DevicesDevices

ResultsOf

Process-ing In

Humanacceptable

form

What Computer is?What Computer is?

Four basic functions Four basic functions of computers of computers include:include:• Receive inputReceive input• Process informationProcess information• Produce outputProduce output• Store informationStore information

Characteristics of ComputerCharacteristics of Computer

Automatic: An automatic machine Automatic: An automatic machine works by itself without human works by itself without human intervention. Computers are intervention. Computers are automatic machine as once started automatic machine as once started on a job, it carry out the job normally on a job, it carry out the job normally without human assistance until it is without human assistance until it is finished. We only need to instruct finished. We only need to instruct computer using coded instruction. computer using coded instruction.

Speed: a computer is very fast Speed: a computer is very fast device. It can perform in a few device. It can perform in a few seconds, the amount of work that a seconds, the amount of work that a human being can do in an entire human being can do in an entire year. year.

Computer can perform its tasks in a Computer can perform its tasks in a microsecond (10microsecond (10-6-6), nanosecond (10), nanosecond (10--

99) and even in picoseconds (10) and even in picoseconds (10-12-12), ),

Accuracy: computers are very Accuracy: computers are very accurate. A computer can perform accurate. A computer can perform every calculation with the same every calculation with the same accuracy over again and again. accuracy over again and again.

However errors can occur in However errors can occur in computer due to incorrect input data computer due to incorrect input data or unreliable programs. or unreliable programs.

Garbage in garbage out [GIGO]Garbage in garbage out [GIGO]

Diligence: Computer is free from Diligence: Computer is free from monotony, tiredness and lack of monotony, tiredness and lack of concentration. concentration.

It do not call for strike, movement for It do not call for strike, movement for pay rise and does not create any pay rise and does not create any political instability. political instability.

Versatility: It is the most important Versatility: It is the most important characteristics of computer. One characteristics of computer. One moment it is preparing results of an moment it is preparing results of an examination, next moment it is busy examination, next moment it is busy preparing salary sheet, and in preparing salary sheet, and in between it may play your favorite between it may play your favorite songs.songs.

This is called multitasking ability. This is called multitasking ability.

Power of remembering: People may Power of remembering: People may forget many things over the time. forget many things over the time. But in case of computer, it can recall But in case of computer, it can recall any amount of information stored in any amount of information stored in its memory. its memory.

No I.Q. : Computer has no No I.Q. : Computer has no intelligence of its own. Its I.Q. is zero, intelligence of its own. Its I.Q. is zero, at least until today. A computer at least until today. A computer cannot take its own decision. Only a cannot take its own decision. Only a user determines what tasks a user determines what tasks a computer will perform. computer will perform.

No feelings: Computer has no No feelings: Computer has no emotion. Based on our feelings, emotion. Based on our feelings, taste, knowledge and experience we taste, knowledge and experience we often make certain judgments in our often make certain judgments in our day-to-day life whereas computer day-to-day life whereas computer can not make such judgments.can not make such judgments.

what is good & what is bad. what is good & what is bad.

History of ComputerHistory of Computer

Pascal (1623-62) Pascal (1623-62) was the son of a tax collector was the son of a tax collector and a mathematical genius. He designed the and a mathematical genius. He designed the first mechanical calculator (Pascaline) based on first mechanical calculator (Pascaline) based on gears. It performed addition and subtraction.gears. It performed addition and subtraction.

Leibnitz (1646-1716) Leibnitz (1646-1716) was a German was a German mathematician and built the first calculator to do mathematician and built the first calculator to do multiplication and division. It was not reliable multiplication and division. It was not reliable due to accuracy of contemporary parts.due to accuracy of contemporary parts.

History of ComputerHistory of Computer Babbage (1792-1872) Babbage (1792-1872) was a British inventor was a British inventor

who designed an ‘who designed an ‘analytical engineanalytical engine’ ’ incorporating the ideas of a incorporating the ideas of a memorymemory and and card card input/outputinput/output for data and instructions. for data and instructions. Never Never actually built.actually built.

Babbage is largely remembered because of the Babbage is largely remembered because of the work of Augusta Ada who was probably the first work of Augusta Ada who was probably the first computer programmer.computer programmer.

Many people refer him as a father of computer.Many people refer him as a father of computer. Burroughs (1855-98) Burroughs (1855-98) introduced the first introduced the first

commercially successful mechanical adding commercially successful mechanical adding machine machine 1,000,0001,000,000 were sold were sold byby 1926.1926.

History of ComputerHistory of Computer Hollerith Hollerith developed an electromechanical developed an electromechanical

punched-card tabulator to tabulate the data for punched-card tabulator to tabulate the data for 1890 U.S. census. Data was entered on 1890 U.S. census. Data was entered on punched cards and could be sorted according to punched cards and could be sorted according to the census requirements. The machine was the census requirements. The machine was powered by electricity. He formed the Tabulating powered by electricity. He formed the Tabulating Machine Company which became International Machine Company which became International Business Machines (IBM). IBM is currently the Business Machines (IBM). IBM is currently the largest computer manufacturer, employing in largest computer manufacturer, employing in excess of 300,000 people.excess of 300,000 people.

History of ComputerHistory of Computer

Aiken (1900-73) Aiken (1900-73) a Harvard professor with a Harvard professor with the backing of IBM built the Harvard Mark I the backing of IBM built the Harvard Mark I computer (51ft long) in 1944. It was based computer (51ft long) in 1944. It was based on relays (operate in milliseconds) as on relays (operate in milliseconds) as opposed to the use of gears. It required 3 opposed to the use of gears. It required 3 seconds for a multiplication.seconds for a multiplication.

History of ComputerHistory of Computer Eckert and Mauchly Eckert and Mauchly designed and built the ENIAC in designed and built the ENIAC in

1946 for military computations. It used vacuum tubes 1946 for military computations. It used vacuum tubes (valves) which were completely electronic (operated in (valves) which were completely electronic (operated in microseconds) as opposed to the relay which was microseconds) as opposed to the relay which was electromechanical.electromechanical.

It weighed 30 tons, used 18000 valves, and required 140 It weighed 30 tons, used 18000 valves, and required 140 kwatts of power. It was 1000 times faster than the Mark I kwatts of power. It was 1000 times faster than the Mark I multiplying in 3 milliseconds. ENIAC was a decimal multiplying in 3 milliseconds. ENIAC was a decimal machine and could not be programmed without altering machine and could not be programmed without altering its setup manually.its setup manually.

History of ComputerHistory of Computer

Atanasoff Atanasoff had built a specialised had built a specialised computer in 1941 and was visited by computer in 1941 and was visited by Mauchly Mauchly before the construction of the before the construction of the ENIAC. He sued Mauchly in a case which ENIAC. He sued Mauchly in a case which was decided in his favour in 1974!was decided in his favour in 1974!

History of ComputerHistory of Computer Von Neumann Von Neumann was a scientific genius and was a was a scientific genius and was a

consultant on the ENIAC project. He formulated plans consultant on the ENIAC project. He formulated plans with Mauchly and Eckert for a new computer (EDVAC) with Mauchly and Eckert for a new computer (EDVAC) which was to store programs as well as data. which was to store programs as well as data.   

This is called the stored program concept and Von This is called the stored program concept and Von Neumann is credited with it. Almost all modern Neumann is credited with it. Almost all modern computers are based on this idea and are referred to as computers are based on this idea and are referred to as VVonon N Neumann machines.eumann machines.    

He also concluded that the binary system was more He also concluded that the binary system was more suitable for computers since switches have only two suitable for computers since switches have only two values. He went on to design his own computer at values. He went on to design his own computer at Princeton which was a general purpose machine.Princeton which was a general purpose machine.

Examples of machines in the Examples of machines in the computer evolution:computer evolution:

14th C14th C. - . - Abacus - Abacus - an instrument for performing calculations an instrument for performing calculations by sliding counters along rods or in groovesby sliding counters along rods or in grooves

17th C. - Slide rule 17th C. - Slide rule - a manual device used for calculation - a manual device used for calculation that consists in its simple form of a ruler and a movable that consists in its simple form of a ruler and a movable middle piece which are graduated with similar logarithmic middle piece which are graduated with similar logarithmic scalesscales

1642 1642 - Pascaline--a mechanical calculator built by Blaise - Pascaline--a mechanical calculator built by Blaise PascalPascal

1804 1804 - Jacquard loom--a loom programmed with punched - Jacquard loom--a loom programmed with punched cards invented by Joseph Marie Jacquardcards invented by Joseph Marie Jacquard

1850 1850 - - Difference Engine Difference Engine , Analytical Engine--Charles , Analytical Engine--Charles Babbage and Babbage and Ada ByronAda Byron Babbage's description, in 1837, of Babbage's description, in 1837, of the Analytical Engine, a mechanical digital computer the Analytical Engine, a mechanical digital computer anticipated virtually every aspect of present-day computers.anticipated virtually every aspect of present-day computers.

Examples of machines in the Examples of machines in the computer evolution:computer evolution:

1939 -1942 - Atanasoff Berry Computer - 1939 -1942 - Atanasoff Berry Computer - built at Iowa State built at Iowa State by Prof. John V. Atanasoff and graduate student Clifford Berry. by Prof. John V. Atanasoff and graduate student Clifford Berry. Represented several "firsts" in computing, including a binary Represented several "firsts" in computing, including a binary system of of arithmetic, parallel processing, regenerative system of of arithmetic, parallel processing, regenerative memory, separation of memory and computing functions, and memory, separation of memory and computing functions, and more. Weighed 750 lbs. and had a memory storage of 3,000 bits more. Weighed 750 lbs. and had a memory storage of 3,000 bits (0.4K). Recorded numbers by scorching marks into cards as it (0.4K). Recorded numbers by scorching marks into cards as it worked through a problem.worked through a problem.

1946 - ENIAC1946 - ENIAC--World's first electronic, large scale, general---World's first electronic, large scale, general-purpose computer, built by Mauchly and Eckert, and activated at purpose computer, built by Mauchly and Eckert, and activated at the University of Pennsylvania in 1946. the University of Pennsylvania in 1946. ENIAC recreated on a ENIAC recreated on a modern computer chipmodern computer chip. The ENIAC is a 30-ton machine, filled . The ENIAC is a 30-ton machine, filled with 19,000 vacuum tubes, 6000 switches, and could add 5,000 with 19,000 vacuum tubes, 6000 switches, and could add 5,000 numbers in a second, a remarkable accomplishment at the time. numbers in a second, a remarkable accomplishment at the time. A reprogrammable machine, the ENIAC performed initial A reprogrammable machine, the ENIAC performed initial calculations for the H-bomb.calculations for the H-bomb.

1940s 1940s - - Colossus Colossus - Alan Turing's vacuum tube computing - Alan Turing's vacuum tube computing machines broke Hitler's Enigma codes.machines broke Hitler's Enigma codes.

Examples of machines in the Examples of machines in the computer evolution:computer evolution:

1950s -1960s - UNIVAC - "punch 1950s -1960s - UNIVAC - "punch card technology" card technology" The first The first commercially-successful computer, commercially-successful computer, introduced in 1951 by Remington Rand. introduced in 1951 by Remington Rand. Over 40 systems were sold. Its memory Over 40 systems were sold. Its memory was made of mercury-filled acoustic was made of mercury-filled acoustic delay lines that held 1,000 12-digit delay lines that held 1,000 12-digit numbers. It used magnetic tapes that numbers. It used magnetic tapes that stored 1MB of data at a density of 128 stored 1MB of data at a density of 128 cpi. UNIVAC became synonymous with cpi. UNIVAC became synonymous with computer (for a while).computer (for a while).

Evolution of ComputingEvolution of Computing

1950

1960s

mid-1970s

2001

No Computers

PCs introduced!

Very expensive computers for large

companies. Computer

professionals ran the show.

Powerful PCs on every desktop.

Explosion of applications.

Computer GenerationComputer Generation

Generation in computer talk is step Generation in computer talk is step in technology. in technology.

It is used to distinguish between It is used to distinguish between various hardware technologies. various hardware technologies.

Totally 4 computer generations Totally 4 computer generations known till today.known till today.

COMPUTER GENERATIONSCOMPUTER GENERATIONS

1. 1. VACUUM TUBES: 1946-1959VACUUM TUBES: 1946-1959

VACUUM TUBESVACUUM TUBES

Tubes from a 1950s computer. Tubes from a 1950s computer.

VACUUM TUBESVACUUM TUBES

a a vacuum tubevacuum tube is a device used to is a device used to amplify, switch, otherwise modify, or amplify, switch, otherwise modify, or create an electrical signal by create an electrical signal by controlling the movement of controlling the movement of electrons in a low-pressure space. electrons in a low-pressure space.

Characteristics of 1Characteristics of 1stst Generation Generation computercomputer

Too big in size. Too big in size. Used vacuum tube.Used vacuum tube. Power consumption of these computers was Power consumption of these computers was

very high.very high. Magnetic drums were developed to store Magnetic drums were developed to store

information and tapes were also developed information and tapes were also developed for secondary storage.for secondary storage.

Power consumption of these computers was Power consumption of these computers was very high. very high.

Limited commercial use. Limited commercial use. Mainly used for Mainly used for scientific computations. scientific computations.

Commercial production was difficult and Commercial production was difficult and costly. costly.

COMPUTER GENERATIONSCOMPUTER GENERATIONS

1.1. VACUUM TUBES: 1946-1959VACUUM TUBES: 1946-1959

2.2. TRANSISTORS: 1957-1963TRANSISTORS: 1957-1963

TransistorsTransistors

TransistorsTransistors

TRANSISTORSTRANSISTORS

a a transistortransistor is a semiconductor is a semiconductor device commonly used to amplify or device commonly used to amplify or switch electronic signals. switch electronic signals.

The transistor is the fundamental The transistor is the fundamental building block of modern electronic building block of modern electronic devices.devices.

Comparison with vacuum tubesComparison with vacuum tubesAdvantagesAdvantages

Small size and minimal weight, allowing the Small size and minimal weight, allowing the development of miniaturized electronic devices. development of miniaturized electronic devices.

Highly automated manufacturing processes, resulting Highly automated manufacturing processes, resulting in low per-unit cost. in low per-unit cost.

Lower possible operating voltages, making transistors Lower possible operating voltages, making transistors suitable for small, battery-powered applications. suitable for small, battery-powered applications.

No warm-up period for cathode heaters required after No warm-up period for cathode heaters required after power application. power application.

greater energy efficiency. greater energy efficiency. Higher reliable. Higher reliable. Extremely long life. Some transistorized devices Extremely long life. Some transistorized devices

produced more than 30 years ago are still in service. produced more than 30 years ago are still in service.

Characteristics of 2Characteristics of 2ndnd Generation Generation computercomputer

Faster, smaller and more reliable.Faster, smaller and more reliable. Smaller in size than first generation computer and were more Smaller in size than first generation computer and were more

reliable and less prone to hardware failure. reliable and less prone to hardware failure. They were more than ten times faster than the first They were more than ten times faster than the first

generation computer.generation computer. Consumed almost one-tenth the power consumed by a tube.Consumed almost one-tenth the power consumed by a tube. Were less expensive.Were less expensive. Commercial production was still difficult and costly.Commercial production was still difficult and costly. Another major feature of the second generation was the use Another major feature of the second generation was the use

of high-level programming languages such as Fortran and of high-level programming languages such as Fortran and Cobol. These revolutionised the development of software for Cobol. These revolutionised the development of software for computers.computers.

COMPUTER GENERATIONSCOMPUTER GENERATIONS

1. VACUUM TUBES: 1946-19591. VACUUM TUBES: 1946-1959

2. TRANSISTORS: 1957-19632. TRANSISTORS: 1957-1963

3.3. INTEGRATED CIRCUITS: 1964-1979INTEGRATED CIRCUITS: 1964-1979

INTEGRATED CIRCUITSINTEGRATED CIRCUITS

INTEGRATED CIRCUITSINTEGRATED CIRCUITS

an an integrated circuitintegrated circuit (also known (also known as as ICIC, , microcircuitmicrocircuit, , microchipmicrochip, , silicon chipsilicon chip, or , or chipchip) is a ) is a miniaturized electronic circuit miniaturized electronic circuit (consisting mainly of semiconductor (consisting mainly of semiconductor devices) that has been manufactured devices) that has been manufactured in the surface of a thin plate of in the surface of a thin plate of semiconductor material. semiconductor material.

Generation of I.C.Generation of I.C.

The first integrated circuits contained only The first integrated circuits contained only a few transistors. Called "a few transistors. Called "Small-Scale Small-Scale IntegrationIntegration" (" (SSISSI), they used circuits ), they used circuits containing transistors numbering in the containing transistors numbering in the tens. tens.

The next generation in the development of The next generation in the development of integrated circuits, taken in the late integrated circuits, taken in the late 1960s, introduced devices which 1960s, introduced devices which contained hundreds of transistors on each contained hundreds of transistors on each chip, called "chip, called "Medium-Scale IntegrationMedium-Scale Integration" " ((MSIMSI). ).

They were more powerful then 2They were more powerful then 2ndnd generation computer. They were capable generation computer. They were capable of performing 1 million instruction per of performing 1 million instruction per second.second.

They were smaller then 2They were smaller then 2ndnd generation generation computer requiring smaller place.computer requiring smaller place.

They consumed less power & dissipated They consumed less power & dissipated less heat.less heat.

Was suitable for commercial uses.Was suitable for commercial uses. They were easier to upgrade. They were easier to upgrade.

COMPUTER GENERATIONSCOMPUTER GENERATIONS

1. VACUUM TUBES: 1946-19591. VACUUM TUBES: 1946-1959

2. TRANSISTORS: 1957-19632. TRANSISTORS: 1957-1963

3. INTEGRATED CIRCUITS: 1964-19793. INTEGRATED CIRCUITS: 1964-1979

4.4. VERY LARGE-SCALE INTEGRATED VERY LARGE-SCALE INTEGRATED (VLSI) CIRCUITS:(VLSI) CIRCUITS: 1980- PRESENT1980- PRESENT

**

Very Large-Scale IntegrationVery Large-Scale Integration

The final step in the development The final step in the development process, starting in the 1980s and process, starting in the 1980s and continuing through the present, was continuing through the present, was "Very Large-Scale Integration" (VLSI). "Very Large-Scale Integration" (VLSI). This could be said to start with This could be said to start with hundreds of thousands of transistors hundreds of thousands of transistors in the early 1980s, and continues in the early 1980s, and continues beyond several billion transistors as beyond several billion transistors as of 2007.of 2007.

COMPUTER GENERATIONSCOMPUTER GENERATIONS General purpose machine. Suitable for scientific & commercial uses.General purpose machine. Suitable for scientific & commercial uses. Cheaper and very powerful.Cheaper and very powerful. Much smaller and handy. (such as Laptop)Much smaller and handy. (such as Laptop) Consume less power Consume less power and less prone to hardware failure than and less prone to hardware failure than

3rd generation computers.3rd generation computers. More reliable.More reliable. Faster and larger storage.Faster and larger storage. More user friendly interface with multi media features.More user friendly interface with multi media features. Graphical user interface enables new user to quickly learn Graphical user interface enables new user to quickly learn

how to use computer. how to use computer. Easier to produce commercially.Easier to produce commercially. Secondary storage has also evolved at fantastic rates with storage Secondary storage has also evolved at fantastic rates with storage

devices holding gigabytes (1000Mb = 1 Gb) of data.devices holding gigabytes (1000Mb = 1 Gb) of data.

In short First

Generation Second Gen.

Third Gen.

Fourth Gen.

Technology Vacuum Tubes

Transistors Integrated Circuits (multiple transistors)

Microchips (millions of transistors)

Size Filled Whole Buildings

Filled half a room

Smaller Tiny - Palm Pilot is as powerful as old building sized computer

Types of Computer Types of Computer

SUPERCOMPUTERSUPERCOMPUTER MAINFRAMEMAINFRAME MINICOMPUTERMINICOMPUTER MICROCOMPUTERMICROCOMPUTER LAPTOPS & SMALLERLAPTOPS & SMALLER

SUPERCOMPUTERSUPERCOMPUTERTERAFLOP:TERAFLOP: TRILLION TRILLION

CALCULATIONS/SECONDCALCULATIONS/SECOND An extremely fast computer An extremely fast computer

that can perform hundreds of that can perform hundreds of millions of instructions per millions of instructions per second. second.

Supercomputers are very Supercomputers are very expensive and are employed expensive and are employed for specialized applications for specialized applications that require immense that require immense amounts of mathematical amounts of mathematical calculations. For example, calculations. For example, weather forecasting requires weather forecasting requires a supercomputer. Other uses a supercomputer. Other uses of supercomputers include of supercomputers include fluid dynamic calculations, fluid dynamic calculations, nuclear energy research, and nuclear energy research, and petroleum exploration. petroleum exploration.

**

SUPERCOMPUTERSUPERCOMPUTER

E.g.:- CRAY Research:- CRAY-1 & E.g.:- CRAY Research:- CRAY-1 & CRAY-2, CRAY-2,

Fujitsu (VP2000), Fujitsu (VP2000),

Hitachi (S820), Hitachi (S820),

NEC (SX20), NEC (SX20),

PARAM 10000 by C-DAC. PARAM 10000 by C-DAC.

General Use of Super ComputerGeneral Use of Super Computer Petroleum industryPetroleum industry - to analyze volumes of seismic data which - to analyze volumes of seismic data which

are gathered during oil seeking explorations to identify areas are gathered during oil seeking explorations to identify areas where there is possibility of getting petroleum products inside the where there is possibility of getting petroleum products inside the earth earth

Aerospace industryAerospace industry - to simulate airflow around an aircraft at - to simulate airflow around an aircraft at different speeds and altitude. This helps in producing an effective different speeds and altitude. This helps in producing an effective aerodynamic design for superior performance aerodynamic design for superior performance

Automobile industryAutomobile industry – to do crash simulation of the design of an – to do crash simulation of the design of an automobile before it is released for manufacturing – for better automobile before it is released for manufacturing – for better automobile design automobile design

Structural mechanicsStructural mechanics – to solve complex structural engineering – to solve complex structural engineering problems to ensure safety, reliability and cost effectiveness. Eg. problems to ensure safety, reliability and cost effectiveness. Eg. Designer of a large bridge has to ensure that the bridge must be Designer of a large bridge has to ensure that the bridge must be proper in various atmospheric conditions and pressures from wind, proper in various atmospheric conditions and pressures from wind, velocity etc and under load conditions. Meteorological centers velocity etc and under load conditions. Meteorological centers use super computers for weather forecasting use super computers for weather forecasting

Biomedical researchBiomedical research – atomic nuclear and plasma analysis – to – atomic nuclear and plasma analysis – to study the structure of viruses such as that causing AIDS study the structure of viruses such as that causing AIDS

Other Use: Other Use: For weapons research and development, sending For weapons research and development, sending rockets to space etc rockets to space etc

SUPERCOMPUTERSUPERCOMPUTER

Teraflop: Trillion calculations/secondTeraflop: Trillion calculations/second Highly sophisticatedHighly sophisticated CPU speed: 100 MIPS, Equivalent to CPU speed: 100 MIPS, Equivalent to

4000 computers4000 computers Complex computationsComplex computations Fastest CPUSFastest CPUS Large simulations & High precision Large simulations & High precision State-of-the-art componentsState-of-the-art components ExpensiveExpensive

MAINFRAMEMAINFRAME

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

mainframes are just below mainframes are just below supercomputers. supercomputers.

The chief difference between a The chief difference between a supercomputer and a mainframe supercomputer and a mainframe is that a supercomputer channels is that a supercomputer channels all its power into executing a few all its power into executing a few programs as fast as possible, programs as fast as possible, whereas a mainframe uses its whereas a mainframe uses its power to execute many programs power to execute many programs concurrently. concurrently.

E.g.E.g.:- :- IBM 3000 series, Burroughs IBM 3000 series, Burroughs B7900, Univac 1180, DEC B7900, Univac 1180, DEC

**

MIPS: Millions of Instructions per secondMIPS: Millions of Instructions per second

MAINFRAMEMAINFRAME

MAINFRAMEMAINFRAME

General Use of Mainframe General Use of Mainframe ComputerComputer

Used to process large amount of data at very Used to process large amount of data at very high speed such as in the case of Banks/ high speed such as in the case of Banks/ Insurance Companies/ Hospitals/ Railway Insurance Companies/ Hospitals/ Railway etc. which need online processing of large etc. which need online processing of large number of transactions and requires massive number of transactions and requires massive data storage and processing capabilities data storage and processing capabilities • Used as controlling nodes in WANs (Wide Used as controlling nodes in WANs (Wide

Area Networks) Area Networks) • Used to mange large centralized databases Used to mange large centralized databases

MAINFRAMEMAINFRAME MIPS: millions of instructions per secondMIPS: millions of instructions per second Largest enterprise computerLargest enterprise computer Able to process large amount of data at Able to process large amount of data at

very high speed very high speed Supports multi-user facility Supports multi-user facility Supports many I/O and auxiliary storage Supports many I/O and auxiliary storage

devices devices 5o megabytes to over one gigabyte ram5o megabytes to over one gigabyte ram Commercial, scientific, military Commercial, scientific, military

applicationsapplications Massive dataMassive data Complicated computationsComplicated computations

MINICOMPUTERMINICOMPUTERA multi-user computer capable of supporting from 10 A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.to hundreds of users simultaneously. E.g.:- Digital Equipments PDP 11/45 and VAX 11) E.g.:- Digital Equipments PDP 11/45 and VAX 11)

Middle-rangeMiddle-range 10 megabytes to over one gigabyte ram10 megabytes to over one gigabyte ram Universities, factories, labsUniversities, factories, labs Used as front-end processor for mainframe. Used as front-end processor for mainframe.

Can also communicate with main frames Can also communicate with main frames Perform better than micros Perform better than micros Designed to support more than one user at a Designed to support more than one user at a

timetime Posses large storage capacities and operates Posses large storage capacities and operates

at higher speed at higher speed **

A small, single-user computer based on a A small, single-user computer based on a microprocessor. In addition to the microprocessor. In addition to the microprocessor, a personal computer has a microprocessor, a personal computer has a keyboard for entering data, a monitor for keyboard for entering data, a monitor for displaying information, and a storage device displaying information, and a storage device for saving data. for saving data. E.g.:- IBM PC, PS/2 and Apple Macintosh E.g.:- IBM PC, PS/2 and Apple Macintosh Microcomputer is generally used in the field Microcomputer is generally used in the field of desktop publishing, accounting, statistical of desktop publishing, accounting, statistical analysis, graphic designing, investment analysis, graphic designing, investment analysis, project management, teaching, analysis, project management, teaching, entertainment etc entertainment etc

MICROCOMPUTERMICROCOMPUTER

MICROCOMPUTERMICROCOMPUTER Desktop or portableDesktop or portable They are designed to be used by only one They are designed to be used by only one

person at a timeperson at a time A microcomputer uses a microprocessor as A microcomputer uses a microprocessor as

its central processing unit. Microcomputers its central processing unit. Microcomputers are tiny computers that can vary in size are tiny computers that can vary in size from a single chip to the size of a desktop from a single chip to the size of a desktop model model

Personal or business computersPersonal or business computers AffordableAffordable Many available componentsMany available components Can be networkedCan be networked

LAPTOPS & SMALLERLAPTOPS & SMALLER PERSONAL COMPUTERS (PC): The name PC PERSONAL COMPUTERS (PC): The name PC

was given by the IBM for its microcomputers. was given by the IBM for its microcomputers. PCs are used for word processing, PCs are used for word processing, spreadsheet calculations, database spreadsheet calculations, database management etc. management etc.

LAPTOP (OR NOTEBOOK): Briefcase type LAPTOP (OR NOTEBOOK): Briefcase type package, very portable, can be inexpensive, package, very portable, can be inexpensive, can connect to other computers or networkscan connect to other computers or networks

HAND-HELD (OR PALMTOP): Sub-miniature, HAND-HELD (OR PALMTOP): Sub-miniature, wireless computer. Growing in sophistication wireless computer. Growing in sophistication and connectivityand connectivity