UNIT 1-new

Wednesday, May 3, 2023Wednesday, May 3, 2023 11

UNIT 1UNIT 1

INTRODUCTION TO INTRODUCTION TO

COMPUTERSCOMPUTERS


TOPICS TO BE COVEREDTOPICS TO BE COVERED

DEFINITIONDEFINITION A SIMPLE MODEL OF COMPUTERA SIMPLE MODEL OF COMPUTER CLASSIFICATION OF COMPUTERCLASSIFICATION OF COMPUTER CHARACTERSTICS OF COMPUTER CHARACTERSTICS OF COMPUTER

SYSTEMSYSTEM


DEFINITION--- a computer is an DEFINITION--- a computer is an automatic electronic apparatus use to automatic electronic apparatus use to perform calculation or controlling perform calculation or controlling operations that are expressible in operations that are expressible in numerical or logical terminology numerical or logical terminology

In other word a computer is defined In other word a computer is defined as an electronic device used to carry as an electronic device used to carry out mathematical and non out mathematical and non mathematical operation with the help mathematical operation with the help of programsof programs


Program--: a program is a sequence Program--: a program is a sequence of instructions written in specific of instructions written in specific computer language, which operates , computer language, which operates , on data to perform certain task.on data to perform certain task.


Characteristics of computerCharacteristics of computer SPEEDSPEED STORAGESTORAGE DILIGENCEDILIGENCE VERSATILITYVERSATILITY ACCURACYACCURACY NO/INTELLIGENCE/I.QNO/INTELLIGENCE/I.Q


No human emotionsNo human emotions Reduce redundancyReduce redundancy AutomationAutomation CostCost ProgrammabilityProgrammability No heuristicsNo heuristics No decision making powerNo decision making power


TYPES OF COMPUTERTYPES OF COMPUTER Computer can be classified based on Computer can be classified based on

two different parameters two different parameters According to data processing According to data processing

mode/logic/ manufacturing principlemode/logic/ manufacturing principle According to size/ function/costAccording to size/ function/cost


According to data processingAccording to data processing 1) Analog1) Analog 2) Digital2) Digital 3) Hybrid3) Hybrid

Digital are further divided in two typesDigital are further divided in two types general purposegeneral purpose special purposespecial purpose


According to size/function/costAccording to size/function/cost 1) Micro computer1) Micro computer 2) Mini computer2) Mini computer 3) Main frame computer3) Main frame computer 4) Super computer4) Super computer


ANALOG COMPUTERANALOG COMPUTER These computers are used for These computers are used for

measuring purpose rather than countingmeasuring purpose rather than counting They are used for measurement of They are used for measurement of

physical quantity and output are physical quantity and output are generally displayed on graphsgenerally displayed on graphs

Physical process is converted into Physical process is converted into mathematical equation than these eq. mathematical equation than these eq. are converted into mathematical formare converted into mathematical form


And finally this output is converted And finally this output is converted into mathematical forminto mathematical form

Example of quantity that can be Example of quantity that can be measuredmeasured

by analog computer are pressure, by analog computer are pressure, voltage, temperature and speedvoltage, temperature and speed


DIGITAL COMPUTERDIGITAL COMPUTER Digital computer represent Digital computer represent

information discretely (non- information discretely (non- continuous)continuous)

They use a binary system that They use a binary system that represent each piece of information represent each piece of information as a series of zeros and onesas a series of zeros and ones

Digital values are countable instead Digital values are countable instead of measurable of measurable


Digital computer are high-speed Digital computer are high-speed programmable electronic devices programmable electronic devices that perform arithmetical, logical that perform arithmetical, logical operations and store the result.operations and store the result.

General purpose digital computer --: General purpose digital computer --: digital computer can be used for digital computer can be used for general- purpose applications such general- purpose applications such as accounting, banking, payroll. as accounting, banking, payroll.


Special purpose digital computer--: Special purpose digital computer--: use for special scientific purposes use for special scientific purposes such as special purpose processor such as special purpose processor designed to store complex designed to store complex navigational problems navigational problems


HYBRID COMPUTERHYBRID COMPUTER Hybrid computer combine feature of Hybrid computer combine feature of

digital and analog computerdigital and analog computer Digital computer give better Digital computer give better

accuracy and analog computer give accuracy and analog computer give better speed ,so hybrid computer better speed ,so hybrid computer include both the feature of speed and include both the feature of speed and accuracyaccuracy


Hybrid computer are usually used for Hybrid computer are usually used for those types special problem in which those types special problem in which input data derived from measurement input data derived from measurement is converted into digital form and is converted into digital form and processed by the computerprocessed by the computer

for example ICU, of the for example ICU, of the hospital ,analog devices are used to hospital ,analog devices are used to measure the heart function, measure the heart function, temperature and other vital signs temperature and other vital signs


Than these measurement are Than these measurement are converted into number and supplied converted into number and supplied to a digital device to a digital device

This digital device is used to monitor This digital device is used to monitor the patient vital signal and to send the patient vital signal and to send an immediate signal to the doctor’s an immediate signal to the doctor’s room ,if any abnormal reading is room ,if any abnormal reading is detecteddetected


MICRO COMPUTERMICRO COMPUTER

a)a) Cheapest and smallest computerCheapest and smallest computerb)b) Micro refers to size of computer and Micro refers to size of computer and

its circuitry its circuitry c)c) Microcomputer has a microprocessor Microcomputer has a microprocessor

chip as its CPUchip as its CPUd)d) Microprocessor is digital electronic Microprocessor is digital electronic

device ,which has million of logical device ,which has million of logical circuits fabricated according to a plancircuits fabricated according to a plan


First micro computer was invented in First micro computer was invented in 19701970

It was built with 8- bit microprocessor It was built with 8- bit microprocessor chipchip

E.g. MOS 6502, intel8080E.g. MOS 6502, intel8080 Now 16 bit, 32 bit,64 bit microprocessor Now 16 bit, 32 bit,64 bit microprocessor

are availableare available Speed of 16 bit and 32 bit Speed of 16 bit and 32 bit

microcomputer is 100 KIPS microcomputer is 100 KIPS


Main feature of micro computerMain feature of micro computer portableportable affordable costaffordable cost easily upgradeableeasily upgradeable easily transportableeasily transportable easy to installeasy to install


MINI COMPUTERMINI COMPUTER Introduced in 1960Introduced in 1960 Storage capacity is more than that of Storage capacity is more than that of

microcomputermicrocomputer Size larger than microcomputer but Size larger than microcomputer but

smaller than main frame computersmaller than main frame computer Generally used where large n.o of Generally used where large n.o of

people have to work on different people have to work on different terminals having same job such as terminals having same job such as telephone or electricity billingtelephone or electricity billing


Mini computer were used for both the Mini computer were used for both the single and multipurpose single and multipurpose

Mini computer are compatible speed Mini computer are compatible speed wise with microcomputer and storage wise with microcomputer and storage capacity is larger than microcomputercapacity is larger than microcomputer

Most suitable for network environment Most suitable for network environment such as railways, air line reservationsuch as railways, air line reservation


MAIN FRAME COMPUTERMAIN FRAME COMPUTER Also known as midi computerAlso known as midi computer Very large computers in sizeVery large computers in size Memory size of these vary from 1 MB to Memory size of these vary from 1 MB to

16 GB16 GB CPU speed vary in range from 32 to CPU speed vary in range from 32 to

100 millions instructions per second100 millions instructions per second Main frame computer can support more Main frame computer can support more

than 100 user in time sharing modethan 100 user in time sharing mode


Cost of main frame computers range Cost of main frame computers range from 10 lakhs to crorefrom 10 lakhs to crore

Extensively used in large Extensively used in large organizations such as university organizations such as university banks etcbanks etc


SUPER-COMPUTERSUPER-COMPUTER Also called as maxi computersAlso called as maxi computers Most sophisticated machines used for Most sophisticated machines used for

special purpose application such as special purpose application such as weather forecasting ,missile launching, weather forecasting ,missile launching, remote sensing and image processingremote sensing and image processing

Super computer contains a n.o of CPU Super computer contains a n.o of CPU which operates in parallel to make it which operates in parallel to make it fasterfaster

The memory and hard disk capacity are The memory and hard disk capacity are 256 MB or even more than 1000 GB 256 MB or even more than 1000 GB


Super computer is based on the Super computer is based on the principle of parallel processing a single principle of parallel processing a single job is broken into no of module and job is broken into no of module and each module is performed by different each module is performed by different CPUs simultaneouslyCPUs simultaneously

Price of super computer is in millions of Price of super computer is in millions of dollardollar

E.g PARAM -10,000 , ANURAG, cyber -E.g PARAM -10,000 , ANURAG, cyber -205205


Speed of super computer has been Speed of super computer has been extended upto BIPSextended upto BIPS

Memory capacities are several giga Memory capacities are several giga bytesbytes


Computer generationsComputer generations First developed computer was First developed computer was

abacus , developed in china in 600 abacus , developed in china in 600 B.C and was based on the principle B.C and was based on the principle of positional weights of beads on a of positional weights of beads on a rockrock

Computer generation is basically Computer generation is basically divided in 5 parts divided in 5 parts


FIRST GENERATION(1951-FIRST GENERATION(1951-1959)1959)

in this generation in this generation ENIAC,EDVAC,EDSAC,IBM-650 ENIAC,EDVAC,EDSAC,IBM-650 computers were developedcomputers were developed

These generation was started in 1946These generation was started in 1946 Vacuum tubes were used in this Vacuum tubes were used in this

generationgeneration Punched card were used for I/O Punched card were used for I/O

operationsoperations


Machine language and assembly Machine language and assembly language were used this generationlanguage were used this generation

Magnetic tapes were used as Magnetic tapes were used as secondary storage devicesecondary storage device

DRAW BACKSDRAW BACKS UnreliableUnreliable air conditioning were require for air conditioning were require for

cooling the vacuum tubescooling the vacuum tubes


Huge in size, costly , limited use Huge in size, costly , limited use


SECOND GENERATION (1959-1965)SECOND GENERATION (1959-1965)

Transistor were used as brain of Transistor were used as brain of computer in place of vacuum tubescomputer in place of vacuum tubes

1.1. Punched card and magnetic tapes Punched card and magnetic tapes were used for i/p and o/p operationwere used for i/p and o/p operation

2.2. High level language such as fortan, High level language such as fortan, cobol, basic were introduced cobol, basic were introduced


Smaller more reliable ,less heat Smaller more reliable ,less heat generatinggenerating

High speed than first generation High speed than first generation computercomputer

E.g IBM 1401 series, ATLAS E.g IBM 1401 series, ATLAS


THIRD GENERATION (1965-1971)THIRD GENERATION (1965-1971)

Integrated circuit technology was Integrated circuit technology was introducedintroduced

Smaller in sizeSmaller in size Monitor and keyboard were Monitor and keyboard were

introduced for i/p and o/p operationsintroduced for i/p and o/p operations Magnetic disk were still used for Magnetic disk were still used for

external storageexternal storage


Time sharing and multi programming Time sharing and multi programming os were introduced os were introduced

Speed was maintenance cost and Speed was maintenance cost and hardware failure was reducedhardware failure was reduced

In this generation manual assembly of In this generation manual assembly of component was replaced by machine component was replaced by machine assembly, therefore the commercial assembly, therefore the commercial production become cheaper and fasterproduction become cheaper and faster


Fourth generation(1971-presentFourth generation(1971-present)) Fourth generation of computers Fourth generation of computers

emerged with a large scale integrated emerged with a large scale integrated circuit and very large scale integrated circuit and very large scale integrated circuit, which fabricated lakh of circuit, which fabricated lakh of transistor on a tiny silicon chip, these transistor on a tiny silicon chip, these development were followed by development were followed by creation of microprocessorcreation of microprocessor

It was capable of performing It was capable of performing arithmetic, logic and control operation arithmetic, logic and control operation with very fast speedwith very fast speed


The single microprocessor was called The single microprocessor was called CPUCPU

Compact size, faster speed and high Compact size, faster speed and high reliabilityreliability

High portability low maintenance High portability low maintenance cost, semi conductor main memory cost, semi conductor main memory was introducedwas introduced


Use of application software , DBMS, Use of application software , DBMS, and spread sheetand spread sheet


Fifth generation computerFifth generation computer Future generation yet to comeFuture generation yet to come Computer which can think like Computer which can think like

human beinghuman being Main emphasis is on development of Main emphasis is on development of

artificial intelligenceartificial intelligence Knowledge processing in place of Knowledge processing in place of

data processingdata processing



COMPUTER HARDWARECOMPUTER HARDWARE Hard ware is a physical equipment Hard ware is a physical equipment

which can be seen touch and feel in which can be seen touch and feel in the computer systemthe computer system

Basic component or building block of Basic component or building block of computer systemcomputer system

CPUCPU MemoryMemory Input device and output deviceInput device and output device


Central processing unitCentral processing unit Also known as brain of system ,it is part of Also known as brain of system ,it is part of

computer that contain the electronic computer that contain the electronic circuitry that actually process the datacircuitry that actually process the data

Acting on the instructions it receive ,CPU Acting on the instructions it receive ,CPU perform operation on the dataperform operation on the data

CPU controls the flow of data through the CPU controls the flow of data through the system directing the data to enter the system directing the data to enter the system placing data in memory and system placing data in memory and retrieving them when needed ,and retrieving them when needed ,and directing o/p of informationdirecting o/p of information


CPU consist ofCPU consist of (1) ALU(1) ALU (2) control unit(2) control unit


Arithmetic logic unit –(1) perform Arithmetic logic unit –(1) perform arithmetic calculation and take arithmetic calculation and take logical decisionlogical decision

(2) can do addition subtraction as a (2) can do addition subtraction as a calculator and can also perform calculator and can also perform some logical function some logical function


REGISTERSREGISTERS A register is a digital circuit use for A register is a digital circuit use for

holding binary information in a holding binary information in a computer. Registers are made up of computer. Registers are made up of flip-flop flip-flop

To perform any arithmetic and or logic To perform any arithmetic and or logic operation an ALU require certain operation an ALU require certain temporary locations where data or temporary locations where data or information can be stored ,such information can be stored ,such memory location built in the ALU are memory location built in the ALU are called it’s register called it’s register


General purpose register-: are known General purpose register-: are known as programmable register ,as the user as programmable register ,as the user with the help of instructions may with the help of instructions may program themprogram them

Accumulator-: storing data and Accumulator-: storing data and performing operationsperforming operations

Flag registers -: condition code or Flag registers -: condition code or status register ,carry ,parity, zero,signstatus register ,carry ,parity, zero,sign


Fetch and execution cycleFetch and execution cycle Fetch cycle -: program register is Fetch cycle -: program register is

loaded with address of the instruction to loaded with address of the instruction to be fetched from the memorybe fetched from the memory

Op code part of the instruction is loaded Op code part of the instruction is loaded in the op register and the address part in the op register and the address part in the memory address registerin the memory address register

The op-code is decoded to perform The op-code is decoded to perform which of the operation are to be which of the operation are to be performedperformed


Execution of each operation need a set Execution of each operation need a set of control signals, which are initiated of control signals, which are initiated after decodingafter decoding

Program counter is incremented by 1 Program counter is incremented by 1 to get the address of the next to get the address of the next instruction in the memoryinstruction in the memory


EXECUTION CYCLEEXECUTION CYCLE Operand is fetched from the memory Operand is fetched from the memory

by using the address available in the by using the address available in the memory address registermemory address register

Using this operand and the second Using this operand and the second operand available in one of the operand available in one of the general-purpose register ,the basic general-purpose register ,the basic operation as per the decoded op code operation as per the decoded op code is performed in the processing unitis performed in the processing unit


At the end of execution the next At the end of execution the next instruction begin ,thus the fetch and instruction begin ,thus the fetch and execution cycle are performed execution cycle are performed alternate until the machine comes to alternate until the machine comes to halt stagehalt stage


CONTROL UNITCONTROL UNIT Control and co ordinate activities of all Control and co ordinate activities of all

other unit of a computer system in other unit of a computer system in following wayfollowing way

1) get instruction out of the memory unit1) get instruction out of the memory unit2) can de code the instruction2) can de code the instruction3) sets up routing through the internal 3) sets up routing through the internal

wiring of data to the correct places at wiring of data to the correct places at the correct time the correct time


4) Determine the storage from where it is to 4) Determine the storage from where it is to get next instruction after the previous get next instruction after the previous instruction has been executedinstruction has been executed

5) It fetches the required instruction from 5) It fetches the required instruction from the main storage via memory data register the main storage via memory data register and places it in control instruction register, and places it in control instruction register, than it interprets the instructions in CIR than it interprets the instructions in CIR and gets it executed by sending a and gets it executed by sending a command signal to the concerned command signal to the concerned hardware devicehardware device


Memory data register is a special Memory data register is a special register that holds all data and data register that holds all data and data instruction temporarily ,as they pass instruction temporarily ,as they pass in and out of the main memoryin and out of the main memory

Control instruction register is also a Control instruction register is also a special register ,which holds machine special register ,which holds machine instructions currently being instructions currently being interpreted by control unitinterpreted by control unit


MEMORY UNITMEMORY UNIT Memory can be of three typesMemory can be of three types Main memoryMain memory Secondary memorySecondary memory Cache memoryCache memory


Main memoryMain memory Memory unit that communicate Memory unit that communicate

directly with CPU ,CPU takes directly with CPU ,CPU takes instruction from main instruction from main

memorymemory Program and data currently being Program and data currently being

used are kept in main memoryused are kept in main memory


So main memory So main memory Store data or information or program Store data or information or program

before processingbefore processing Store intermediate resultStore intermediate result Store final result before printing or Store final result before printing or

sending for permanent storage sending for permanent storage


Main memory is divided into two Main memory is divided into two partsparts

RAMRAM ROMROM


INPUT OUTPUT DEVICESINPUT OUTPUT DEVICES OPTICAL CHARACTER RECOGNITIONOPTICAL CHARACTER RECOGNITION KEY BOARDKEY BOARD MOUSEMOUSE SCANNERSCANNER OPTICAL MARK READEROPTICAL MARK READER MAGNETIC INK CHARACTER READERMAGNETIC INK CHARACTER READER JOYSTICKJOYSTICK


LIGHT PENLIGHT PEN TOUCH SCREENTOUCH SCREEN VOICE/SPEECH INPUTVOICE/SPEECH INPUT


SECONDARY STORAGE DEVICESECONDARY STORAGE DEVICE FLOPPY DISKFLOPPY DISK CD ROMSCD ROMS DIGITAL VERSATILE DISKDIGITAL VERSATILE DISK HARD DISKHARD DISK


OUTPUT DEVICESOUTPUT DEVICES DOT MATRIX PRINTERDOT MATRIX PRINTER LASER PRINTERLASER PRINTER INK JET PRINTERINK JET PRINTER DIGITAL PLOTTERDIGITAL PLOTTER

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UNIT 1-new