GENERATION OF COMPUTERS




Generation in the computer era provides a framework for the growth of the computer industry and generally characterizes the major developments in the computer industry. The modern computer era can be divided into Five generations distinguished by the basic electronic component within the computer. Each new logic unit let the computers faster in speed, smaller in size, more reliable and less expensive than their predecessors. Modern computers came in a variety of shapes, sizes and costs.

Computers were developed in Five different phases known as the Generation of Computers.
Let’s discuss one by one in a little detail :

First Generation (1942-1955)



The computers of this generation used Electronic Valves (an array of Vacuum Tubes) as the basic component for memory and circuitry for the central processing unit. These vacuum tubes were a fragile glass device like an electric bulb, that could control and amplify electronic signals. They produced a lot of heat and were prone to frequent fusing/ damaging of the installations. Therefore, they were used very expensive and could be afforded only by very large organizations.
Advantages :
i)    these computers were the fastest calculating device of their time. They could perform computations in milliseconds.
ii)    vacuum tube technology made possible the advent of electronic digital computers.
Disadvantages :
i)    Too bulky in size
ii)    Air conditioning required to control the temperature
iii)    Prone to frequent hardware failure.
iv)    Commercial production was difficult and costly.
v)    Slow input and output operations.

USEFUL POINTS :

    Period: 1942-1955
    The component used: Vacuum tubes
    Speed: milliseconds
    Maximum memory capacity: 2000 inch
    Mean time before failure: minutes
    Peripherals :
o    I/O : Punched cards, Paper tape, Magnetic tape, Printer (online)

o    Secondary Storage: Punched Cards, Paper Tape, Magnetic Drum, Magnetic Disk etc
    Operating System : Mainly Batch Processing
    Languages : Machine Code and Electric Wired board
    Application Areas : Payroll Processing, Record Keeping etc.

    Example : ENIAC, EDVAC, EDSAC and IBM 650 ( the first modern digital computer produced on mass scale)

Second Generation (1955-1964)



 The second generation computer used Semi-conductor transistor instead of vacuum tubes after the invention of transistor by a team led by William Shockley.

This generation computers used transistors which were cheaper, consumed less power, more compact in size, more reliable and faster than the vacuum tubes used in first generation computers.

Advantages :
i)    Smaller in size as compared to first generation computers
ii)    More reliable
iii)    Less heat generated.
iv)    Less prone to hardware failure
v)    Wider commercial use

Disadvantages :
i)    Air conditioning required
ii)    Manual assembly of individual components into a functioning unit was a cumbersome task.

USEFUL POINTS :
    Period: 1955-1964
    The component used: Transistors
    Speed: microseconds
    Maximum memory capacity: 128000 inch
    Mean time before failure: days
    Peripherals :
o    I/O : Paper tape, Magnetic tape, Visual Display Unit
o    Secondary Storage : Paper Tape, Magnetic Drum, Magnetic Disk etc
    Operating System: Multiprogramming, Time-Sharing and Real-Time processing
    Languages: Assembly Language, High-Level Languages like FORTRON, COBOL etc
    Application Areas: Batch –oriented application like Billing, Payroll processing, Updating Inventory etc.
    Example : IBM 1401, IBM 7090, IBM 1620, IBM 7094, IBM 700 series, CDC 1604, CDC 3600, UNIVAC 1108

Third Generation (1964-1975)



 The third generation computers used Integrated Circuits (or IC Chips) in which many transistors, resistors, capacitors and other
components (circuit elements) are fabricated or integrated and packaged together into a very small surface of silicon known as Chips.
This new microelectronic technology was called Integrated Circuits. The IC was invented by Jack Kilby in 1958
Advantages :
i)    Smaller in size as compared to the previous generation
ii)    More reliable than second generation computers
iii)    Low maintenance cost
iv)    Easily portable
v)    Commercial production was easier and cheaper.

Disadvantages :
i)    Air conditioning required in any case
ii)    Highly sophisticated technology required for the manufacture of IC chips.

USEFUL POINTS :
    Period : 1964-1975
    Component used : Integrated Circuits (IC)
    Speed : nanoseconds
    Maximum memory capacity : 4 million inch
    Mean-time before failure : weeks to months
    Peripherals :
o    I/O : Typewriter terminal, Visual Display Unit, Optical Character Reader etc

o    Secondary Storage : Magnetic Disk, Extended Core Storage, Mass Storage devices
    Operating System : Multiprogramming, Time-Sharing, Real Time processing and Remote processing
    Languages : High Level Languages like FORTRON-II to IV , COBOL , BASIC, ALGOL-68,
    Application Areas : Airline System, Market forecasting, Credit Card billing etc
    Example : IBM 360/370 series, ICL 1900 series, PDP 11, RCA Spectra 70 etc.

Fourth Generation (1975 onwards)



 Initially, the Integrated Circuits contained only about 10 to 20 components called Small Scale Integration (SSI). Later on with the advancement in technology for manufacturing Integrated Circuit Silicon Chips (ICS), it became possible to integrate up to a hundred components on a single chip called Medium Scale Integration (MSI).
Now the manufacture of integrated circuits became so advanced as to incorporate hundreds of thousands of active components in a volume of a fraction of inch, leading to Large Scale or Very Large Scale Integration (VLSI).
Integrated Circuits which have the entire computer circuit on a single silicon chip are called Microprocessors. The development of microprocessors made it possible to place the complete CPU of a computer on a single chip.
The first Microprocessor Intel 4004 consisted of 2250 transistors on a microprocessor was designed by Intel Corporation engineer Ted Hoff in 1971. It was 4-bit microprocessor.
Advantages :
i)    Smaller in size because of high component density
ii)    Heat generated is negligible
iii)    Much faster in computation then previous generations
iv)    Less power consumption
v)    No air conditioning is required in most cases

Disadvantages :
i)    Highly sophisticated technology is required for the manufacturing of VLSI chips
ii)    Highly skilled people are required in its manufacturing

USEFUL POINTS :
    Period : 1975 onward
    Component used : Very Large Scale Integrated Circuits (IC)
    Speed : picoseconds
    Maximum memory capacity : 200 million inch
    Mean-time before failure : months
    Peripherals :

o    I/O : Visual Display Unit, Optical Character Reader, Magnetic Ink Character Reader,

o    Secondary Storage : Floppy disk , Hard Disk, CD-ROM, DVD etc

    Operating System : Time-Sharing, Real Time processing and Network Distribution
    Languages : All High Level Languages like C, C++, Java and other 4th generation languages (declarative languages used in Database )
    Application Areas : Mathematical Modelling, Simuation, Electronic Fund Transfer, Computer Aided Manufacturing and Design etc
    Example : CRAY-1, CRAY-2, IBM 3090/600, IBM AS/400 HP 9000, IBM ES/9000, VAX etc

Fifth Generation (Future Generation: 1991 onwards ) :



 the fifth generation computers are under development stage. These computers will use Ultra Large Scale Integration (ULSI) chips instead of VLSI. These will be employing two or more processors which compute in parallel.
The fifth generation machine are proposed to be based on Parallel Processing hardware and Artificial Intelligence software with genuine I.Q. (Intelligence Quotient). That provide the ability to reason logically and with real knowledge of the world like human do.

Characteristics of future generation computers :
i)    Decreasing cost of hardware and software
ii)    High speed processing
iii)    Knowledge based processing system
iv)    Development of natural language processing
v)    Advancement in supercomputer technology
vi)    Artificial Intelligence , think and behave like human (humanoid).



THANK YOU!












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