Generations of Computers (1st To 5th)

First Generation of Computers (1940s-1950s)

The main features of the first generation are:

• Main electronic component – vacuum tube
• Main memory – magnetic drums and magnetic tapes
• Programming language – machine language
• Power – consume a lot of electricity and generate a lot of heat.
• Speed and size – very slow and very large in size (often taking up entire room).
• Input/output devices – punched cards and paper tape.
• Examples – ENIAC, UNIVAC1, IBM 650, IBM 701,IBM 750 etc.
• Quantity – there were about 100 different vacuum tube computers produced between 1942 and1963.

Second Generation of Computers (1950s-1960s)

The main features of the second generation are : 

• Main electronic component – transistor
• Memory – magnetic core and magnetic tape / disk
• Programming language – assembly language
• Power and size – low power consumption, generated less heat, and smaller in size (in comparison with the first generation computers).
• Speed – improvement of speed and reliability (in comparison with the first generation computers).
• Input/output devices – punched cards and magnetic tape.
• Examples – IBM 1401, IBM 7090 and 7094, UNIVAC 1107,CDC 1604, CDC 3600 etc.

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Third Generation of Computers (1960s-1970s)

The main features of the third generation are :

• Main electronic component – integrated circuits (ICs)
• Memory – large magnetic core, magnetic tape / disk
• Programming language – high level language (FORTRAN, BASIC, Pascal, COBOL, C, etc.)
• Size – smaller, cheaper, and more efficient than second generation computers (they were called minicomputers).
• Speed – improvement of speed and reliability (in comparison with the second generation computers).
• Input / output devices – magnetic tape, keyboard, monitor, printer, etc.
• Examples – IBM 360, IBM 370, PDP-11, UNIVAC 1108,Honeywell-6000 series,TDC-316 etc.

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Fourth Generation of Computers (1970s-1980s)

The main features of the fourth generation are :

• Main electronic component – very large-scale integration (VLSI) and microprocessor.

• VLSI– thousands of transistors on a single microchip.

• Memory – semiconductor memory (such as RAM, ROM, etc.)
  • RAM (random-access memory) – a type of data storage (memory element) used in computers that temporary stores of programs and data (volatile: its contents are lost when the computer is turned off).
  • ROM (read-only memory) – a type of data storage used in computers that permanently stores data and programs (non-volatile: its contents are retained even when the computer is turned off).
• Programming language – high level language (Python, C#, Java, JavaScript, Rust etc.).
  • A mix of both third- and fourth-generation languages
• Size – smaller, cheaper and more efficient than third generation computers.
• Speed – improvement of speed, accuracy, and reliability (in comparison with the third generation computers).
• Input / output devices – keyboard, pointing devices, optical scanning, monitor, printer, etc.

• Network – a group of two or more computer systems linked together.
• Examples – IBM PC, STAR 1000, APPLE II, Apple Macintosh, etc.

Fifth Generation of Computers (1980s-Present)

The main features of the fifth generation are :

• Main electronic component: based on artificial intelligence (AI), uses the Ultra Large-Scale Integration (ULSI) technology and parallel processing method.
  • ULSI – millions of transistors on a single microchip
  • Parallel processing method – use two or more microprocessors to run tasks simultaneously.
• Language – understand natural language (human language).
• Power – consume less power and generate less heat.
• Speed – remarkable improvement of speed, accuracy and reliability (in comparison with the fourth generation computers).
• Size – portable and small in size, and have a huge storage capacity.
• Input / output device – keyboard, monitor, mouse, trackpad (or touchpad), touchscreen, pen, speech input (recognize voice / speech), light scanner, printer, etc.
• Example – desktops, laptops, tablets, smartphones, etc.

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History of computer

The first counting device was used by the primitive people. They used sticks, stones and bones as counting tools. As human mind and technology improved with time more computing devices were developed. Some of the popular computing devices starting with the first to recent ones are described below.

Abacus

The history of computer begins with the birth of abacus which is believed to be the first computer. It is said that Chinese invented Abacus around 4,000 years ago.

It was a wooden rack which has metal rods with beads mounted on them. The beads were moved by the abacus operator according to some rules to perform arithmetic calculations. Abacus is still used in some countries like China, Russia and Japan. An image of this tool is shown below;

Napier’s Bones

It was a manually-operated calculating device which was invented by John Napier (1550-1617) of Merchiston. In this calculating tool, he used 9 different ivory strips or bones marked with numbers to multiply and divide. So, the tool became known as “Napier’s Bones. It was also the first machine to use the decimal point.

Pascaline

Pascaline is also known as Arithmetic Machine or Adding Machine. It was invented between 1642 and 1644 by a French mathematician-philosopher Biaise Pascal. It is believed that it was the first mechanical and automatic calculator.

Pascal invented this machine to help his father, a tax accountant. It could only perform addition and subtraction. It was a wooden box with a series of gears and wheels. When a wheel is rotated one revolution, it rotates the neighboring wheel. A series of windows is given on the top of the wheels to read the totals. An image of this tool is shown below-

Stepped Reckoner or Leibnitz wheel

It was developed by a German mathematician-philosopher Gottfried Wilhelm Leibnitz in 1673. He improved Pascal’s invention to develop this machine. It was a digital mechanical calculator which was called the stepped reckoner as instead of gears it was made of fluted drums. See the following image –

Difference Engine

In the early 1820s, it was designed by Charles Babbage who is known as “Father of Modern Computer”. It was a mechanical computer which could perform simple calculations. It was a steam driven calculating machine designed to solve tables of numbers like logarithm tables.

Analytical Engine

This calculating machine was also developed by Charles Babbage in 1830. It was a mechanical computer that used punch-cards as input. It was capable of solving any mathematical problem and storing information as a permanent memory.

Tabulating Machine

It was invented in 1890, by Herman Hollerith, an American statistician. It was a mechanical tabulator based on punch cards. It could tabulate statistics and record or sort data or information. This machine was used in the 1890 U.S. Census. Hollerith also started the Hollerith?s Tabulating Machine Company which later became International Business Machine (IBM) in 1924.

Differential Analyzer

It was the first electronic computer introduced in the United States in 1930. It was an analog device invented by Vannevar Bush. This machine has vacuum tubes to switch electrical signals to perform calculations. It could do 25 calculations in few minutes.

Harvard Mark I

The Automatic Sequence Controlled Calculator (Harvard Mark I) .The next major changes in the history of computer began in 1937 when Howard Aiken planned to develop a machine that could perform calculations involving large numbers. In 1944, Mark I computer was built as a partnership between IBM and Harvard. It was the first programmable digital computer.