Saturday, May 19, 2012

Class XI, INFORMATION TECHNOLOGY, "History of Computers"

History of Computers
At the early age people used pebbles, stones, sticks, scratches, symbols and finger tips to count, which were later replaced by numbers.
The history of computing is divided into three ages during which man invented and improved different types of calculating machines. These ages are,
  • Dark age – 300 BC to 1890
  • Middle age – 1890 AD to 1944
  • Modern age – since 1944 AD
Dark Age (3000 BC to 1890 AD
About 3000 years BC, Chinese developed the first calculating machine named Abacus or Soroban.
Abacus consists of a rectangular wooden frame having rods which carry round beads. Counting is done by shifting the beads from one side to another.
In 1632 AD William Oughtred, an English mathematician developed a slide rule. This device consists of two movable rules placed side by side on which number were marked.
Blasé Pascal (1623-1662), a French developed the first mechanical calculating machine in 1642. This machine consists of gears, wheels and dials. It was capable of adding and subtracting operations.
In 1671, a German, Gottfried Von Leibnitz (1646-1716) improved Pascal’s calculator to make it capable of performing all maths operations.
In 1801, a French, Joseph Marie Jacquard developed the first punch card machine.
Charles Babbage (1792-1871) an English mathematician also called Father of modern computer. As he gave the true concept of computer at Cambridge University, he developed Babbage Difference Engine in 1823 and Babbage Analytical Engine in 1833.
Lady Ada Augusta an assistant of Babbage is called the first programmer.
Middle Age (1890 AD TO 1944 AD)
In 1880s Herman Hollerith an American developed a machine which used punch card system. The machine could sense and punch holes, recognize the number and make required calculations. This machine was first used in 1890s by American Census Bureau.
In 1937, Professor Howard Aiken build the first electro-mechanical computer Mark-1, by trying to combine Babbage’s theory and Hollerith’s punching technologies. He completed his project in 1944 with the help of IBM Engineers.
Mark 1 could multiply two, twenty digit numbers in 5 seconds and made a lot of noise. It had a shape like a monster about 50 feet long, 8 feet high, having wiring of length equal to distance from Lahore to Gilgit or Karachi to Bahawalpur (800km) and had thousand ends of electro-magnetic relays.
ABC a special purpose computer was developed in 1938 by Dr. John Vincent Atanasoff and Clifford Berry at Iowa State College, USA.
Modern Ages (Since 1944 AD)
In 1945, Dr. John Von Neuman suggested the concept of Automatic Data Processing (ADP) according to the stored program and data. ENIAC
Electronic Numerical Integrator And Calculator (ENIAC) was the first electronic computer made in 1946 by John Presper Eckert and John Williams Mauchly, at the University of Pennsylvania, USA. This was based on decimal number system and it has no memory.
It could perform 5000 additions or 350 multiplications in one second. It contained 18000 vacuum tubes, 70,000 resistors, 10,000 capacitors and 60,000 switches and occupied a two room car garage. It consumed 150 kW of power. It weighed 27 tons.
Electronic Delay Storage Automatic Computer (EDSAC) was first computer based on stored program concept. It was completed by Mourice Wilkes at Cambridge University in 1949.
Electronic Discrete Variable Automatic Computer (EDVAC) was built by John Williams Mauchly, John Presper Eckert at Moore School, Pennsylvania in 1951.
UNIVersal Automatic Computer (UNIVAC) was the first commercially used computer made by John Presper Eckert and John Williams Mauchly in June 14, 1951.
Generations of Computer
First Generation of Computer (1946-1959)
Main Features
  • Major Innovation – Vacuum Tubes
  • Main Memory – Punched Cards
  • Input Output Devices – Punched cards and papers
  • Languages – Low level machine language
  • Operating System – No operating system, human operators to set
  • switches
  • Size – Main frame for example ENIAC, EDVAC, UNIVAC
The duration lasted from 1946-1959 was based on vacuum tubes. These vacuum tubes were about the size of 100 watt light bulb and used as the internal computer component. However because thousands of such bulbs were used, the computers were very large and generate a large amount of heat, causing many problems in temperature regulation and climate control.
In this generation input and out put device (punched card) that was used fro data storing purpose were very slow. The computers were operating manually and the language used was a low level machine language (symbolic language) with binary code that required a high programming skill. ENIAC, EDVAC, UNIVAC and Mark-1 were some of the major inventions of this generation.
Advantages of First Generation
1. Vacuum tubes were used as electronic component.
2. Electronic digital computers were developed for the first time.
3. These computers were the fastest calculating devices of their time.
4. Computations were performed in millisecond.
Disadvantages of First Generation
1. Too large in size.
2. They were unreliable.
3. Induce a large amount of heat due to the vacuum tubes.
5. Not portable.
6. Limited commercial use.
Second Generation of Computers (1959-1964)
Main Features
  • Major Innovation – Transistors as main component.
  • Main Memory – RAM and ROM.
  • External Storage – Magnetic tapes and Magnetic Disk.
  • Input Output Devices – Magnetic tapes and Magnetic Disk.
  • Languages – Assembly language, some high level languages for Example BASIC, COBOL, FORTRAN.
  • Operating System – Human handles punched card.
  • Size – Main frame for example IBM-1401, NCR-300, IBM-600 etc.
The period of this generation is from 1959 to 1964. During this period transistor were used for internal logic circuits of computers. These computers could execute 200000 instructions per second. The input/output devices became much faster by the use of magnetic table. During this period the low level programing language were used however the high level programming languages such as FORTRAN and COBOL were also used. The problem of heat maintenance was solved and size of computer reduced, while speed and reliability were increased. Many companies manufactured second generation computers and many of those for business applications. The most popular second generation computer was IBM-1401, introduced in 1960, while the following computers were used by many business organizations. IBM-1400 series, IBM-1600 series, UNIVAC-III, NCR-300 etc.
Advantages of Second Generation
1. Smaller in size as compares to 1st generation.
2. Much more reliable.
3. Less heat generated.
4. Computation was performing in micro second.
5. Less hardware and maintenance problem.
6. Could be used for commercial use.
Disadvantages of Second Generation
1. Very costly for commercial use.
2. It still required frequent maintenance.
3. Frequent cooling also required.
Third Generation of Computers (1965-1970)
Main Features
  • Major Innovation – Integrated circuit (ICs) as basic electronic component.
  • Main Memory – PROM and DRAM.
  • External Storage – Improve disk (Floppy Disk)
  • Input and Output Devices – Keyboard for input, monitor for output.
  • Languages – More high level languages.
  • Operating System – Complete operating systems were introduced.
  • Size – Mini, for example: IBM SYSTEM / 360, ICH-360, HONEY WELL-316 etc.
In this generation the integrated circuits (IC) were used. Integrated circuits contain many electronic components on a single chip. The disk oriented systems wee made at the end of this generation. The size of computer became very small with better performance and reliability. High level programming languages were extensively used. In 1969 the first microprocessor chip INTEL 4004 was developed but it was used only in calculators. The faster input/output devices made possible multi-processing and multi programming. Where by a number of input terminals could be run virtually at the same time on a single centrally located computer. The famous computer were IBM-360, IBM-370, UNIVAC 9000 series etc.
Advantages of Third Generation
1. Smaller in size as compared to second generation.
2. More reliable.
3. Portable
4. Less electricity consumption.
5. Heat generation was rare.
6. General purpose computer.
Disadvantages of Third Generation
1. Air conditioning was required in many cases due to ICs.
2. Very advance technology was required to make the ICs.
Fourth Generation of Computers (1971-1981)
Main Features
  • Major Innovation – LSIC and VLSIC (Micro Processor)
  • Main Memory – EPROM and SRAM.
  • External Storage – Floppy Disk and Hard Disk.
  • Input and Output Devices – Monitor for output.
  • Languages – Languages and application softwares.
  • Operating System – MS-DOS and PC-DOS
  • Size – Micro computer e.g. IBM-PC, Apple Macintosh etc.
The Integrated circuits were more developed and called Small scale integration (SSI), after some time the SSI were more developed and termed as Large scale integration (LSI). There was a great versatility of input/output devices. In 1971, a powerful microprocessor chip INTEL 8008 was introduced. The first microprocessor which is used in personal computers (PC) was INTEL 8080. The 8 inch floppy disk was also introduced in 1971, while hard disk was introduced in 1973. The 5.25 floppy disk was first time used in 1978. The optical disk was developed in 1980. First portable computer “Osborne I” was marketed in 1981. IBM-3033, IBM-370, IBM system 34, IBM system 36, Cray-I, CP/M etc were introduced in this generation.
Advantages of Fourth Generation
1. Smaller in size and much reliable.
2. No cooling system required in many cases.
3. Much faster computation.
4. Portable and cheap.
5. The heat generated was negligible.
6. Totally general purpose computer.
Disadvantages of Fourth Generation
1. Very advanced technology was required to fabricate to the ICs.
Fifth Generation (1981-Onward)
Main Features
  • Major Innovations – ULSIC (Ultra large scale integrated circuit)
  • Main Memory – EEPROM, SIMM and DIMM.
  • External Storage – Modified magnetic and Optical disks.
  • Input/output Devices – Keyboard, Pointing Device, Scanner as input and Monitor as main output.
  • Languages – AI (Artificial Intelligence) Expert systems.
  • Operating System – GUI based e.g. Windows 95, Windows NT.
  • Size – Very small in size example: Laptop, Note book, Digital Diary, Palm top and Pocket PC.
This generation is started from 1981 and still continued, new technologies are adopted to fabricate IC chips, such as electron beam, X-rays or laser rays. The Very Large Scale Integration
(VLSI) was developed, so the computer became much smaller than ever before. New memory storage device like bubble memory, optical or memory are being designed. the new computer will be controlled by using human voice and will work by giving command in our own language. Future computer will in some way to be intelligent and capable of making decision.
Advantages of Fifth Generation
1. Very large storage capacity.
2. Long bit processor builds.
3. Artificial Intelligence Language developed


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