Archive for November 2014

Words of Arthur.C.Clarke

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"Any sufficiently advanced technology is indistinguishable from magic."
                                           Arthur.C.Clarke

Words of Albert Einstein

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Most people say that it is the intellect which makes a great scientist. They are wrong: it is character.
                                                                                                                    Albert Einstein

Some words from Albert Einstein

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Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.
                                                                                                                       Albert Einstein

Article on Computer Generations

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           Computer Generations

There are five computer generations in which computer development proceeded and they are following:
                I.            1st   Generation  (1940-1956)
              II.            2nd  Generation  (1956-1963)
           III.            3rd   Generation  (1963-1971)
          IV.            4th   Generation  (1971-1989)
             V.            5th   Generation  (1989-onward)
Generation after generation the performance, efficiency and reliability of computer increased and size, cost and power usage decreased rapidly.   

         First Generation (1940-56)

First electronic computer was designed and built at the University of Pennsylvania based on vacuum tube technology. It was named Mark-1 and was introduced on 14-February, 1946. Some features about this computer is:
1.    It weighed about 27 tons.
2.    It used machine language only which is considered to be the lowest level programming language.
3.  It contained about 18000 vacuum tubes. Some details of vacuum tubes are:
             i.      Vacuum tube was discovered by Lee De Forest in 1906 .
             ii.   Vacuum tubes were used to perform logic operations and to store data.
             iii.Basically Vacuum tubes were used as switches, amplifiers, rectifiers,                    electronic controlled switches and oscillators.
4.    Circuitry and Magnetic drum memories were used. Data was written on magnetic drum by read and write heads. Magnetic drums were rotating cylinders with magnetic iron coating and circled with read and write heads.               
5.    Punch cards and paper tapes were used as input devices. Punch cards consisted of digits from 0-9 on it. 
6.   Output was in the form of printout.
Disadvantages in 1st generation computers:
Some disadvantages of 1st generation computer were:
1.   Vacuum tubes could perform only basic arithmetic operations. They heated up very quickly and needed to be replaced soon.
2.   Occupied very large space.
3.   Consumed a large amount of power and gave only limited performance.
4.   A lot of heat was generated which caused system malfunctioning.
5.   Air-conditioning was required.
6.    Was unreliable and very costly.
7.   Input and Output devices were very slow.
8.   One Task could be done at a time.
9.   Continuous maintenance was required.
10.               Errors couldn’t be predicted.
Some Representative Systems in 1st generation:
Some important computers of 1st generation computers are:
1.   ENIAC (Electronic Numerical Integrator and Calculator).
2.   EDSAC (Electronic Delay Storage Automatic Computer).
3.   EDVAC (Electronic Discrete Variable Automatic Computer).
4.   UNIVAC (Universal Automatic Computer).
5.   IBM 701.
                                     
‘‘UNIVAC was the most commercially used computer in 1st generation and was mainly used for scientific purpose.’’

    Second Generation (1956-1963):

The invention of transistors brought revolution in computer development process. Transistor was discovered in 1947 by two engineers John Bardeen and Walter Brattin in Bell Laboratory, but it use in computer production was started in late 1950’s. Transistors replaced vacuum tubes in 2nd generation computers. Transistors were far superior than vacuum tubes, allowing computers to become smaller, faster, cheaper, more energy saving, more efficient and reliable than 1st generation computers. Although transistors also generated heat but it was a great improvement over vacuum tubes. 2nd generation computers used:
1.   Punched cards were still used as input device.
2.   Magnetic core memories were used as main memories.
3.   Magnetic tapes and disks were used as secondary memory.
4.   Symbolic or Assembly language was used instead of machine language which was High-Level Programming Language and allowed the programmers to specify instructions in form of simple words. Other languages used were COBOL and FORTAN.
5.   Output was still in form of printouts.
Basic advantages in 2nd generation computers:
1.   Size of computers reduced significantly with the use of transistors.
2.   It was low cost generation than 1st generation computers.
3.   Used less power than 1st generation computers.
4.   Supported assembly language.
5.   Use was increased in business and industry.
6.   Transistor was 40 times faster than vacuum tube.
Disadvantages in 2nd generation computers:  
They were still costly but less than 1st generation computers.  Still required proper air-conditioning.
Some Representative Systems in 2nd generation:
1.IBM 1620.
2.   IBM 709 
3. CDC 1604.
4.  CDC 3600
5.   UNIVAC 1108.
  Third Generation (1963-71): 
Transistors were miniaturized and placed on silicon chips called semiconductors, which drastically increased the speed and efficiency of computers. When semi-conductor chip was assisted with capacitors and resistors, the whole assembly was name as Integrated Circuit (I.C). I.C was invented by Jack Kilbey and shown in adjoining figure. Some new components and features about 3rd generation computers are:
1.   Instead of punched cards keyboard was used for the first time in computer history.
2.   Output in form of printout was replaced by Monitor.
3.   Use of integrated circuits made the computer much smaller in size.
4.   3rd generation computers became more reliable and efficient.
5.   It used High-Level Programming language like FORTAN (II-IV), COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc, which made it able of Multi-Programming.
6.   It was fast in speed and processing than its predecessors.
7.   Micro-programming was used to program micro-processors. Microprogramming, parallel processing (pipelining, multiprocessor system etc), multiprogramming, multi-user system (time shared system) etc were introduced.
8.   Operating system softwares were introduced (efficient sharing of a computer system by several user programs).
9.   In beginning it used magnetic core memories which later on were replaced Semi-conductor Memories RAM (Random Access Memory) and ROM (Read Only Memory).
10.   These computers consumed much less power than previous generations and generated less heat.
11.They were cheap than previous generations.
12.Cache and virtual memories were introduced (Cache memory makes the main memory appear faster than it really is. Virtual memory makes it appear larger)
Disadvantages in 3rd  generation computers:
Still air-conditioning was required.
Some Representative Systems in 3rd  generation:
1.   IBM 360 series.
2.   Honeywell-6000 series etc.
3.   PDP (Personal Data Processor).
4.   IBM-370/168.
5.   TDC-316.
     

     Fourth Generation (1971-1989):
The micro-processors bought fourth generation of computers and thousands of integrated circuits were built into a single silicon chip. It reduced the size of the computer so small that it only occupied the space of a palm.  Main features of 4th generation computers are:
1.   It used VLSI (Very Large Scale Integrated Circuits) which consists of 10,000 of transistors on a single silicon chip.
2.   These computers were more powerful, compact, reliable and affordable (which gave rise to use of personal computers).
3.   Used CRT (Cathode Ray Tube) Screens as output devices.
4.   Also used laser-jet printers. Scanner was also introduced.
5.   Mouse was used for the first time as pointing device.
6.   Semiconductor memory chips (RAM & ROM) were used as primary memory.
7.    Secondary memory disks involved Hard Disks, Floppy Disks and Magnetic Tapes.
8.   LAN (Local Area Network) and WAN (Wide Area Network) was introduced.
9.   Introduced High-Level languages like C language and Unix OS.
10.   Introduced GUI (Graphical User Interface) which allowed user to interact with the computer easily.
11.   Less power was consumed by it and had high performance. Speed was enhanced to a great extent.
12.    Parallelism, Pipelining Cache memory and virtual memory were introduced.
13.   Some Super-computers based on Parallel Vector Processing and Symmetric Multi-programming were also introduced.
14.   They were easy to manufacture and software development in it was also easy.
Some Representative Systems in 4th generation:
1.   Intel Series (8088,80286,80386 etc).
2.   Apple II.
3.   CRAY 1/2/X/MP etc.
4.   IBM PC’s.
Fifth Generation (1989-Present and Beyond):
5th generation computers emerged from 1989 and are till date and will be beyond date. In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc., are used in this generation.

Artificial Intelligence includes:
             I.            Robotics.
           II.            Neural Networks.
        III.            Game Playing.
       IV.            Development of expert systems to make decisions in real life situations.
          V.            Natural language understanding and generation.

Also Quantum Computation, Molecular and Nanotechnology will radically change the phase of the computers in coming years. The goal of fifth generation computing is to develop devices that respond to natural language input and are capable of learning and self-organizing. Some important features of 5th generation computers are:
1.   Introduced ULSI (Ultra Large Scale Integration) technology – Intel’s Pentium 4 microprocessor contains 55 million transistors millions of components on a single IC chip.
2.   Computers became much faster, cheaper, reliable and efficient. Computers also become portable and now require very less power for their operation.
3.   Computers based on artificial intelligence are available.
4.   Computers use extensive parallel processing, multiple pipelines, multiple processors etc
5.   Massive parallel machines and extensively distributed system connected by communication networks fall in this category.
6.   Superscalar processors, Vector processors, SIMD processors, 32 bit and 64 bit micro controllers and embedded processors, Digital Signal Processors (DSP) etc have been developed.
7.   Memory chips up to 16 GB, hard disk drives up to 1 TB and USB’s up to 120 GB are available (still the capacity is increasing).
8.   Introduced World Wide Web (WWW).
9.   Object oriented language like JAVA suitable for internet programming has been developed.
10. Portable note book computers introduced.
11.New operating systems developed – Windows      95/98/XP/7/8/LINUX, etc.
12. Multimedia and Internet use was enhanced. Many new applications were developed to make the use of computer much easier and human friendly.
Some Representative Systems in 5th generation:
1.   IBM notebooks
2.   Pentium PCs-Pentium 1/2/3/4/Dual core/Quad core.
3.    Origin 2000.
4.   PARAM 10000.
5.   IBM SP/2.
Moreover computer is present in following forms:
            I.            Desktop.
         II.            Laptop.
      III.            Notebook.
     IV.            Ultra-book.
        V.            Chrome-book.
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