computer fund terms
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1. GENERATIONS OF COMPUTERS:
The tem generation indicates the type of technology used in thecomputer construction. As new technology was emerging, it wasbeing used in the making of computer. The new technology improved
the speed, accuracy and storage capacity of the computers.Different technologies have been used for computers in differenttimes.
Therefore, computers can be divided into five generationsdepending upon the technologies used. These are:
First Generation (1942 1955)Second Generation (1955 1964)Third Generation (1964 1975)Fourth Generation (Since 1975)Fifth Generation (Since 1980)
1. First Generation Computers (1942 1955):
The vacuum tube technology was used in first-generationcomputers. Mark-1m, ENIAC, EDSAC, EDVAC, UNIVAC-1 etc.machines belong to the first generation of computers. The machinelanguage only was used in first-generation computers.Principle:-
The vacuum tubes consisted of filaments inside it which on heatingemit electrons. These electrons were responsible for theamplification and deamplification of electrical signals.Input:-
Punched cardsOutput:-Print-outs
Advantages:
*These computers were the fastest of their time.
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*They were programmed using machine language.*The electronic digital computers were introduced due to thevacuum tube technology.
Disadvantages:
*Very large in size*Not reliable*Consumed large amount of energy*Constant maintenance required*More heat generated and air-conditioning was required*More costly*Very slow in speed (data processing)*It was difficult to programmed, because they used only machinelanguage*Non-portable*Limited commercial use
2. Second Generation Computers (1955 1964):
The transistor technology was used in second-generationcomputers. The electronic component transistor was invented in1948 at Bell Laboratories. The transistor is smaller in size andmore reliable than vacuum tube. Therefore, the transistortechnology was used in computer in place of vacuum tubetechnology. The programming assembly language was also introducedin second-generation of computers.The transistors consisted of BASE, COLLECTOR and EMITTER.
Their functions include:-BASE: input gate for the transistor.COLLECTOR: collect the amplified signalsEMITTER: output gate for emitting the amplified signals to theexternal environment.
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Advantages:
*Low in cost*Smaller in size*Fast in speed
*Less heat generated more reliable and accurate in calculations*Consume low power etc.*Used for commercial purposes*Portable*Assembly language was introduced. This language is easy to writeprogram than machine language
Disadvantages:
*Air-conditioning required*Commercial production was difficult and these were very costly*Constant (or frequent) maintenance required*Only used for special purposes
3. Third Generation Computers (1964 1975):
The IC (Integrated Circuits) technology was used in third-
generation computers. In a small IC chip (5 mm square size) acircuit is designed having large number of electronic componentslike transistors, capacitors, diodes, resistors etc. Initially, an ICcontained only about ten to twenty components. Thus the ICtechnology was named as Small Scale Integration (SSI). The third-generation was based on IC technology and the computers weredesigned using this technology.
Advantages:
*Smaller in size*Production cost was low*Very fast in computational power*More reliable
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*Low power consumption*Maintenance cost was low because failure rate of hardware wasvery low*Magnetic disk, used for external storage*More storage capacity*Easily portable*Easy to operate*Upgraded easily*Widely used for various commercial applications all over the world*Lower heat generated*High-level languages were commonly used
*Many input/output devices were introduced such as mouse andkeyboard etc.
Disadvantages:
*Air-conditioning required*Highly sophisticated technology required for the manufacturerchips
4. Fourth Generation Computers (1975 onwards):
The microchip technology was introduced in this generation ofcomputers. With the advancement in IC technology, LSI (LargeScale Integration) chips were developed. It was possible tointegrate over 30,000 or more components on to single LSI chip.After LSI, the VLSI (Very Large Scale Integration) was developedand the development of microprocessor possible. It is expected
that more than one million components will be integrated on a singlechip of VLSI. Using VLSI technology, the entire CPU is designed ona single silicon chip. The use of microprocessor as CPU introducedanother class of computers called the microcomputers. Thusfourth-generation may be called Microcomputer generation. IBMintroduced its personal computer for use in 1981.
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Advantages:
*Smaller in size*Production cost is very low
*Very reliable*Hardware failure is negligible*Easily portable because of their small size*Totally general purpose*Air conditioning is not compulsory*Very high processing speed*Very large internal and external storage capacity*Used advanced input & output devices such as optical readers,laser printers, CD-ROM/DVD-ROM drives etc.
Disadvantages:
*Highly sophisticated technology required for the manufacturer ofmicroprocessor chips
5. Fifth Generation Computers (In process):
The main drawback of first to fourth generation computers is thatthe computers have not their own thinking power. These are totallydepending upon the instructions given by the users.
Fifth generation computers are supposed to be the ideal computers,but do not exist. The scientists are working to design suchcomputers that will have the following features.*Having their own thinking power*Making decisions themselves*Having capabilities of learning*Having capabilities of reasoning*Having large capacity of internal storage*Having extra high processing speed
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*Having capabilities of parallel processing
Technologies used in fifth generation computers:
*ULSIC (Ultra Large Scale Integrated Circuits) technology*Artificial Intelligence (AI) technology also called the knowledgeProcessor. The AI means automatic programs that let the machinesto think and decide themselves. The programming languages LISP(List Processor) and PROLOG (Programming with Logic) are used forartificial intelligence. The scientists at ICOT in Japan use thePROLOG to develop the Artificial Intelligence software.
Advantages:
*Laptops, Pocket computers and PDA were developed.*Development of parallel processors*Development of centralized servers*Development of optical disc technology*Invention of internet and its advantages.
2. CLASSIFICATION OF COMPUTERS:
Computers can be classified based on the following criteria:
According to Technology:
$Analog Computers$Digital Computers$Hybrid Computers
According to Purpose:
$General purpose Computers$Special Computers
According to size:
$Supercomputers$Mainframe Computers$Minicomputers
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$Microcomputers, or Personal Computers
Based on operating principles and technology:
Analog computers:$These computers represent data in the form of continuouselectrical signals.$These are fast and multi-tasked.$Results displayed by these computers are less accurate.$Powerful in solving differential equations.$These computers use OP-AMP (Operational Amplifier).$The features of OP-AMP include:
*High voltage gain. The voltage gain is defined as the ratio ofoutput voltage to input voltage.
*Infinite input resistance. The input resistance is defined as theratio of change in input voltage to the change in input current.
*Zero output resistance. The output resistance is defined as thenominal resistance measured with nil loads.$The basic OP-AMP circuit is represented as:
Wherein, Rin is the input resistance, RF is the feedback resistanceA is the amplifier which is used to invert the incoming signals ofvoltage Vin to Vout.
Digital computers:
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$These are called the Digital information processing systems.$These systems store and process the data in digital form (stringsof 0's and 1's)$They are capable of processing analog signals but the analogsignals have to be converted into digital signals using an ADCbefore feeding into the digital computers.Hardware components:$Arithmetic Logical unit (ALU)$Control unit$Memory unit$Input unit
$I/O unitsHybrid computers:
$These are the combination of both Analog and Digital computersencompassing the best features of both the computers.$Fast, efficient and reliable computer systems.$The Data is measured and processed in the form of electricalsignals and stored with digital components.$The input is accepted in the form of varying electrical signals andis converted into discrete values for performing operations.$They are used in hospitals to measure heartbeat and haveengineering and scientific applications.
Based on Applications:
General purpose computers:
$Work in all environments
$Versatile computers$Store number of programs to perform distinct operations$More expensive$Not efficient and consume large time to generate results
Special purpose computers:
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magnetic tapes, floppy, CD, USB, etc,Peripheral devices:
$Input devices: They are used to transfer data into thecomputer. Examples: keyboard, mouse, etc,
$Output devices: Used to display the results processed by thecomputer. Examples: Monitor, printer, etc,System bus:
$It is also called the FRONTSIDE BUS, MEMORY BUS, LOCAL orHOST BUS.$It is used to connect microprocessor, memory and peripheraldevices into a unit.
SYSTEM BUS= ADDRESS BUS+DATA BUS+CONTROL
BUS
$Address bus: Unidirectional bus to identify the peripheral devicesand memory.$Data bus: Bi-directional bus used to transfer data among the
microprocessor, peripheral devices and memory.$Control bus: bus used by the microprocessor to send controlsignals to various devices.
Depending on size, Microcomputers are of three types:*Desktop computers:
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They are used in single location, cheap, and have good storage.Examples include: Apple, IBM.*Laptop computers:
Portable computers also called as the notebook computers or mobile
computers. They are smaller in size, more expensive and arerechargable.Examples include Apple, Acer, Hewlett Packard (HP)*Hand-held computers:
Also called as Personal Digital Assistants (PDA's), Palmtop orMobile device. They are smaller in size, have smaller display andinput device is generally an electronic stylus. Their storagecapacity is small. Examples include Apple Newton, Franklin eBookman.
Mini computers:
$These were introduced by Digital Equipment Corporation (DEC) in1960.$They can process more data and can support more I/O devicesThey are less powerful than mainframe computers but morepowerful than micro computers. Hence they are called MID-RANGECOMPUTERS.
They cater to the needs of 4-200 users at a time$They are used in business as a centralized computer or as aninternet server$They are less expensive than Mainframe computers. Examplesinclude PDP 11, IBM 8000 series, etc,
Mainframe computers:
$These are capable of handling millions of records a day.
$These are bigger and more expensive than mini-computers$They require a large space and closely monitored humidity andtemperature.Characteristics:
*A typical mainframe computer consists of 16 microprocessors andeven more than that.
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*RAM capacity is 128MB to 8GB*They can run multiple operating systems. Hence they are called-
VIRTUAL MACHINES*They handle a large amount of I/O devices which are arranged in
separate CABINETS or FREMES and hence the name.Applications:
*they are used in large financial transactions*Enterprise Resource Planning (ERP)*Industry and consumer statistics*Census
Supercomputers:
$These are the fastest and complex computers with very highspeed$First Supercomputer was presented by SEYMOUR CRAY in 1960 inControl Data Corporation (CDC)$Used exclusively in applications where large complex calculationshave to be performed to get the output$These are very expensive and designed to perform only smallnumber of programs at a time$The manufacturers of Supercomputers are: IBM, SILICONGRAPHICS, FUJSTU, INTEL, etc.These are the fastest as they employ 1000's of processors, 100sof GB of RAM, 1000s of GB of secondary storage$the principles used in these computers are:*Pipelining: This enables the processor to execute second
instruction even before the first is completed provided, it has the
required resources*Parallelism: Enables the processor to execute severalinstructions at a time$Examples include: CRAY 3, Cyber-205, PARAM, etc.
3. Characteristics of computers:
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Computers have distinguishing characters which make them idealmachines. But they do not certain characters which human possess.Some of the important characteristics of computers are:
(I)Automatic:#Computers are automatic machines which once started a job,carry it on until it is complete provided they are given the requiredinstructions by the users.
(II)Speed:
#The computers are capable of taking logical decissions,performing arithmetic and non-arithmetic operations on alphabets
and copying at an unbelievable speed#The units of speed for a computer are in microseconds (10 -6) oreven in nano and Pico second (10 -9 or 10 -12)
#A powerful computer can perform 3 to 4 million arithmeticoperations per second
#The speed of the computers is attributed to the fact that THECOMPUTERS ARE ELECTRONIC DEVICES WORKING ONELECTRICAL PULSES WHICH TRAVEL AT HIGH SPEED.
(III)Accuracy:
#The computer produces highly accurate and reliable results#The errors in the calculations may be due to the error in thelogic of the human but not due to the computer.
#The computers perform accurate calculations 'n' number of times
(IV)Versatility:
#A computer is capable of performing a wide variety of functions#It can accept data and produce results.#It can perform the basic arithmetic and logic operations#It can transfer data internally#Several applications can be run at a time. For example MS paintAdobe Photoshop and VLC media player can be run at a time.
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(V)Diligence:
#A computer is capable of performing the same task over and overagain with the same degree of accuracy and reliability as the first
one#This is because, unlike human beings, computers are free frommonotony, tiredness, lack of concentration, etc, and can workhours together without creating bugs.
(VI)Large and perfect memory:
#A computer can store and recall any amount of informationbecause of its secondary storage capability with perfect accuracy
unlike human beings.#The storage capacity of the computer is enormous and is perfect#A computer recalls a data with greater accuracy even afterseveral times and does not lose any information unless it isprompted to do so.
(VII)No I.Q and feelings:
#A computer is not intelligent on its own and cannot think on its
own#It can only perform the tasks specified by the human but thedifference is that it does this with greater accuracy and speed.
#It cannot decide on its own and only the user can determine whatthe computer must do
#A computer has no feelings but a human does.
4. Basic computer organization:
The organization of computers involves the interfacing of variouscomponents of the computer and the co-ordination of theoperations performed by them. The various functional units of acomputer include:(I)Input unit
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(II)Memory unit(III)Central processing unit(IV)Output unit
BASIC COMPUTER ORGANISATION
Input devices:
@These devices are used to feed the data inside the computer.
@The most commonly used input devices are:
*keyboard
*mouse
*light pen
*digitizer
*trackball
*joystick
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*OCR (Optical Character Recognizer)
*MICR (Magnetic Ink Character Recognizer)
*OMR (Optical Mark recognizer)
Keyboard:
@It is used to enter alphanumeric data into the computer and to
perform special functions:
@Alphanumeric keys: Used to enter alphabets and Numbers
@Function keys: Used to perform special functions. These include
F1 to F12.For example F5 is used for refreshing a page or desktop
@Modifier keys: SHIFT and CONTROL keys are called modifier
keys and they perform special functions. For example CTRL+X for
cut
@Spacebar key: Used to move by one space in a document orworksheet or DBMS.
@Enter key: Used to open something like a file or a web-page or
to move to the succeeding line in a document.
Mouse:
@It is an electronic device used for selecting and pointing
purposes. Hence it is called the POINTING DEVICE.
@Left mouse button: Used for selection purpose
@Right mouse button: Used to perform special functions like OPEN,
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EXPLORE, COMPRESS, etc.
@Ball at the bottom: The ball at the bottom of the mouse moves
and the cursor moves on the screen in whichever direction the ball
rotates
@Wheel at the top: To scroll a web-page or a document.
Scanner:
@Used to scan images and documents
@The scanned images are converted into the DIGITISED IMAGES
understandable by the computers.
@Color images can also be scanned using the scanner depending
upon the RED GREEN BLUE (RGB) PROPORTIONS
@The principle used in the BARCODE READER is similar to that of
a scanner.
Memory unit:
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MEMORY PYRAMID OF A COMPUTER
The memory unit is used to store data on a temporary or
permanent basis. The various types of memory can be depicted as:
0100090000032a0200000200a20100000000a20100002606
0f003a03574d464301000000000001007a8e000000000100
0000180300000000000018030000010000006c0000000000
0000000000001a000000370000000000000000000000b631
00006418000020454d460000010018030000120000000200
0000000000000000000000000000f6090000e40c0000d800
0000170100000000000000000000000000005c4b030068430400160000000c000000180000000a000000100000000000
0000000000000900000010000000de050000e10200002500
00000c0000000e000080250000000c0000000e0000801200
00000c00000001000000520000007001000001000000d2fff
fff0000000000000000000000009001000000000000044000
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MEMORY:
PRIMARY MEMORY
@Read only memory
*MASK PROM
*PROM
*EPROM
*EEPROM
@Read/Write memory
*Static RAM
*Dynamic RAM
*Cache memory
SECONDARY MEMORY
@Disk Drives
*Floppy
*Hard disk
*CD-ROM (Read only and Rewritable)
@Tape drives:
*Cartridge Drive
*Cassette drive
INTERNAL PROCESSOR MEMORY
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@Registers
*ACC
*PC*IR
*MAR
*MBR
*MDR
Primary memory:
@This memory is also called as MAIN MEMORY.
@The information stored in this memory that are needed by the
microprocessor during the time of processing are temporary and
the information in the ROM are permanent
Read Only Memory (ROM):
@It is a non-volatile memory
@The contents of this memory are permanent
@These are cost-effective
@They are available in high storage capacity
@Processing speed is very low
@Generally, the OS supporting programmes and the Basic Input
Output System (BIOS) programs are stored in this
@In this trigonometric and logarithmic functions are also stored
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@In PROM (Programmable Read Only Memory), The flexibility of
data alteration is also provided.
Random Access Memory (RAM):
@This is the part of computer's temporary storage where the ALL
THE DATA, INSTRUCTIONS NEEDED BY THE MICROPROCESSOR
AND THE RESULTS EXECUTED BY IT are stored.
@It is a volatile memory
@The contents are temporary
@Cost is very high
@They are available in small storage capacity
@processing speed is high
@User defined programmes can be stored at any time
Principle:-Each bit in a RAM stores information by means of
electric charge, where the presence of electrical signals indicate'1'
and the absence of electrical signals indicate'0'.
Types of RAM:
DYNAMIC RAM:
@The electric charges tend to be leak out in a few milliseconds, so
the information present in RAM is lost
@Hence, the set of data stored in Dynamic ram has to be
refreshed periodically before all the charges have leaked.
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STATIC RAM:
@Special refresh circuitry is provided
@They are not leaky and hence do not require any refreshing
Cache memory:
A small memory between the CPU and the main memory is called
the cache memory.
@It is faster than main memory and the access time of this
memory is close to the processing speed of the CPU
@It acts as a HIGH-SPEED BUFFER between the CPU and the
main memory
It is used to store temporary and active (most frequently used)
data during the time of processing
The other components of primary memory include:
@PROM (Programmable Read Only Memory)
@EPROM (Erasable PROM)
@EEPROM (Electrically Erasable PROM)
Secondary memory:
@The secondary memory is also called as the AUXILLARY
MEMORY
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@It may be in-built or may be introduced into the computer and is
used to store the data on a PERMANENT basis
@The various types of secondary memory include:
Magnetic storage device:
@Use magnetism property to store data
@The data stored in these devices can be stored, erased,
rewritten many number of times
@Examples include: Magnetic tapes, magnetic disks, floppy disk,
etc
Optical storage device:
@Uses the LASER BEAMS to store data
@The data stored in these devices can be erased and rewritten
many number of times
@Examples include: CD, CD-ROM-CD-RW, DVD, etc.
Magneto-Optical storage device:
@This uses both MAGNETISM and LASER BEAMS to store data
@These devices are generally used in the cases of BACKUP, DATA
RECOVERY, etc,
@The data stored in the can be erased and rewritten many times
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CONTROL UNIT) ALU (ARITHMETIC LOGICAL UNIT)
Universal Serial Bus (USB):
@These are commonly called as pen drives
@These are compact and store large data than the other storage
devices
@These are connected to the USB PORT in the CPU
Central processing unit:
The CPU is the main functional unit of the computer. The basic
functions of CPU include:
@fetch the data from the user
@Decode the data into a computer-understandable form
@Process the data or execute the operation
@Store the result
This sequence of functions is called the INSTRUCTION CYCLE and
is represented as:
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MAIN MEMORY
EXECUTE
FETCH
The various units of the CPU include:
ARITHMETIC LOGICAL UNIT (ALU):
@It is used to perform the various arithmetic and logical
operations.
@Arithmetic operations like +,-,*, / are performed by ALU
@Logical operations like >,
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example like, STATIONARY POINT OR FLOATING Pointed, etc
CONTROL UNIT (CU):
@The CU control the flow of information
@It is called THE BRAIN OF THE CPU
@It directs the tasks performed by the ALU and also the
functions carried out by the I/O DEVICES
REGISTERS:
@The CPU contains certain temporary storage units called as the
REGISRES.
@The various types of registers and their functions are:
@Program Counter (PC): Stores the next operation to be performed
@Information Counter(IC): Store the information or data to beprocessed by the CPU
@Memory Address Register (MAR): Stores the address of the next
location in the memory
@Memory Buffer Register: Stores the data received from or sent
to the CPU
@Memory Data Register (MDR): Stores Operands and Data
Output units:
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@These are electronic or electromechanical devices which give the
desired result or output to the user in the USER-
UNDERSTANDABLE format.
@The various output units include:
*Visual Display Unit (VDU) or Monitor
*Printer
*Computer Output Micro file
*Plotter
Monitor:
@The monitor is a visual display unit used to display the output to
the user and is often referred to as the ELECTRONIC MEDIA
Principle:-When the beams of electrons in the electrical signals
strike the inner side of the monitor containing RED, BLUE and
GREEN PHOSPHOROUS, the color and detail of the object is
visible depending on the PROPORTIONS OF THE COLOR and the
INTENSITY OF THE ELECTRON BEAMS
@The types of monitor include: Cathode Ray Tube (CRT) and Liquid
Crystal Display (LCD)
@Cathode ray is better at picture perception when compared to
LCD
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@The CRITICAL PARAMETERS of the monitor include:
*SIZE (length, breadth, thickness)
*RESOLUTIONS (pixels)
@Video card is to be installed for better graphical perception
Printer:
@printer is used to get a printed or PHOTOCOPY of the document
or image present in the system.
@The types of printers include:
@DOTMATRIX PRINTERS: High speed printers but the quality of
the image is poor
@INKJET PRINTERS: Slower than the Dot-Matrix printers but
have good picture quality
@LASER PRINTERS: Since these printers have their own ROM,
RAM and MICROPROCESSOR and hence produce HIGH QUALITY
IMAGES WITH GOOD SPEED.
Quality of printers is measured using the CRITICAL PARAMETERS:
*DOT PER INCHES (DPI)
*PAGES PER MINUTE (PPM)
Speaker:
@It is an electromechanical device that converts ELECTRICAL
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SIGNALS into SOUND WAVES
@AUDIO DEVICE DRIVER has to be installed for the speaker to
perform
@Speaker may be in-built or it may be separately attached to the
computer
@Quality of the speaker is dependent on the SOUND CARD
installed in the computer
@Sophisticated Speakers contain SUB-WOOFER SYSTEM to
increase the BASS OUTPUT
5. MEMORY UNIT OF THE COMPUTER AND VARIOUS TYPES
OF MEMORY(REFER MEMORY UNIT IN THE ORGANISATION
OF COMPUTERS)
6. EVOLUTION OF COMPUTERS:
In earlier years, people used fingers, stones, pebbles, andnotches in sticks and knots in ropes to perform simplearithmetic calculations.
SAND TABLE:(EARLIER PERIOD)
Used stones for calculations It contains three channels filled with sand and each
chamber can hold a maximum of 10 stones ABACUS:(2500 BC)
It was invented by ASIA MINOR in 2500 BC. It consisted of a wooden frame with strings and
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beads which were used for calculations. NAPIERS BONE:(1614)
This is a complicated manual device calculated byJOHN NAPIER in 1614
This device consisted of a board with nine rods The rod on the left corner consisted of digits from 1
to 9 The rod at the extreme right consisted of ZEROS
and was called the CONSTANT ROD It was exclusively used for multiplying or dividing two
numbers only if one of the numbers is a single digit
SLIDE RULE:(1620) It was devised by EDMUND GUNTER in 1620 It consisted of two graduated scales sliding over
each other It was used to perform not only simple arithmetics,
but also complex calculations like LOGARITHM andTRIGNOMETRIC ROOTS, etc.
PASCALINE:(1642)
It was devised by BLAISE PASCAL in 1642 It was also called as the ROTATING WHEEL
CALCULATOR or NUMERICAL WHEEL CALCULATOR It was designed to handle numbers up to
999,999.999 STEPPED RECKONER:(1694)
Pascaline was improved by a German mathematician,GOTFRIED WILHELM VON LEIBNIZ into a stepped
reckoner It performs multiplication, division and also SQUARE
ROOT of a number DIFFERENCE ENGINE:(1822)
It was devised by CHARLES BABBAGE in 1882 It used the features of the modern digital
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computers likeINPUT,OUTPUT,STORAGE,PROCESSOR andCONTROL UNITS
It was designed to perform mathematicalcalculations by getting two inputs from the user(a)aset of programs that contains the instructions to beexecuted(b)a list of variables on which the operationis to be performed
It was a digital automatic programmable generalpurpose computer
Its disadvantage was that it was a slow engine
taking 3 minutes to multiply 2 numbers of 20 digitseach 1883-The idea of analytical difference engine was given by
CHARLES BABBAGE 1889-The idea of punched cards as input was introduced by
HERMAN HOLERITH MARK-I(1994):
It was devised by Aiken,an American mathematician
in 1937 and completed in 1994 It is faster than difference engine. For example, it
can multiply two digits of 20 digits each within 6seconds
But it was slow in processing the results(RATE OFRESULT=ONE RESULT/SECOND)
It was noisy and large in size COLOSSUS(1994):
It was devised by ALAN MATHINSON, a Britishmathematician in 1994
It was a pure electronic digital programmablecomputer
It used VACUUM TUBE TECHNOLOGY It was designed to perform only specific operations
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ENIAC(1946): Electronic Numerical Integrator And Calculator
developed by John Eckert and John Mauchley in1946
Used Vacuum tube technology for basic circuits Consisted of 17468 vacuum tubes, 7200 crystal
diodes, 10000 capacitors, 1000 relays 1000 times faster than MARK-I Perform simple arithmetic and advanced operations Used DECIMAL SYSTEM for representing and
processing values
EDVAC(1949): Electronic Discrete Variable Automatic Computerdevised by Eckert and Mauchley in 1949
Worked on the principles of STOREDPROGRAMS(program and data are considered asstrings of BINARY DIGITS)
Units are: Magnetic tape, Control unit, Dispatcherunit, Processor, Timer, Dual memory, Three
temporary tanks to hold a single word EDSAC(1949):
Electrical Delay Storage Automatic Calculatordeveloped by Maurice Wilkes in 1949
Vacuum tube technology used for basic circuits andMERCURY DELAY LINES for memory construction
Input unit- Punched cards Output unit- Teleprinter
Able to carry out 650 instructions per second UNIVAC(1951):
Universal Automatic Computer developed byECKERT-MAUCHLEY corporation in 1951
5200 Vacuum tubes were used for basic logiccircuits and MERCURY DATA LINES for memory
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construction It can process numbers and alphabets Since it provided separate processors for handling
input, output and processing units, it was UNIQUEamong the early computers