Generations of Computers

The word generation refers to the different advancements of new computer technology. Each generation of computers is characterized by a major technological development that has drastically changes the way in which computers operate. Consequently, these computing devices have become smaller, cheaper, powerful, efficient and more reliable.

First Generation (1940–1956) : Vacuum Tubes.

Drums for memory. These computers were so big in size that they often required an entire room to be installed. The first generation computers were very expensive and were hence mainly used for scientific purpose. In addition to a large amount of space, they also needed a lot of electricity, and thus generated enormous heat, first-generation computers could be programmed using machine language, which is the lowest–level programming language, consisting of only 1s and 0s. These computers could solve only one problem at a time. While input to the computer was fed using punched cards and paper tape, the output was generated on printouts.

Advantage They were the fastest calculating devices of their time.

Disadvantages

·    They generated a lot of heat. ·    They consumed a lot of electricity. ·    They were very bulky in size. ·  Vacuum tubes used filaments that had limited life. Since every computer used thousands of vaccum tubes, these computers were frequently down due to hardware failures. ·    These computers had limited commercial use because they were difficult to program. ·     They were very expensive.

Second Generation (1956–1963) : Transistors

Secondary-generation computers were manufactured using transistors (as shown in figure), rather than vacuum tube. Computers manufactured using transistors were smaller, faster, cheaper, and more energy-efficient and reliable than their first-generation predecessors.

Input was fed to the second-generation computers using punched cards and output was generated as printouts. The second-generation computers moved towards symbolic or assembly languages, which allowed programmers to specify instructions in words. At this time, high-level programming languages such as COBOL, FORTRAN, ALGOL and SNOBOL were also being developed. Second-generation computers were the first to store instructions in memory, which moved from magnetic drum to magnetic core technology. Advantages : ·    They consumed less electricity and thus generated less heat as compared to the first-generation computers. ·  They were faster, cheaper, smaller, and more reliable than their first-generation counterparts. ·     They could be programmed using assembly language and high-level languages. ·     These computers had faster primary memory and a larger secondary memory. Disadvantage : Second-generation computers were manufactured using transistors, which had to be assembled manually. This made commercial production of computers difficult and expensive.

Third Generation (1964–1971) : Integrated Circuits :

The development of the integrated circuit (IC), shown in figure, was the hallmark of the third-generation computers. Several electronic components such as transistors, resistors, and capacitors were miniaturized and placed on silicon chips, called integrated chips, which drastically increased the speed and efficiency of computers. Integrated chips were smaller, less expensive, more reliable and faster in operation, consumed less power, and generated less heat than the components used earlier. Input to these computers could now be provided using the keyboard and the mouse. In the 1960s, the trend was moving towards small mini-computers that could fit in the corner of a room and be used for business applications. It was during this time that soft-ware houses emerged. Advantages : ·   They were faster than second-generation computers and could perform one million transactions per second. ·    They were smaller, cheaper, and more reliable than their predecessors. ·   These computers had faster and larger primary memory and secondary storage. · Third-generation computers were widely used for scientific as well as business applications. ·   During this generation of computers, standardization of existing high-level languages and invention of new high-level languages happened. ·  Third-generation computers could run time sharing operating system, which allowed interactive use of a computer ating systems, which allowed interactive use to a computer by one or more users simultaneously, thereby improving the productivity of the users. Disadvantages : ·      These computers were difficult to maintain. ·      They got heated very quickly.

Fourth Generation (1971–1989) : Microprocessors

The microprocessor launched the fourth generation of computers, with thousands of integrated circuits built onto a single silicon chip. Fourth-generation computers could fit in the palm of the hand.  During the fourth generation, semiconductor memories that were very fast were used and HDDs also became cheaper, smaller in size, and larger in capacity. For input, floppy disks (in addition to magnetic tapes) were used to port data and programs from one computer to another. During this period, many new operating systems were developed, including MS–DOS, Microsoft Windows, UNIX, and Apple’s proprietary operating system. Fourth-generation computers also saw the development of graphical user interfaces (GUIs), the mouse, and handheld devices. GUIs made computers more user-friendly, so that even a non-computer professional could work easily on it. In this period, several word processing packages to allow easy development of documents, spreadsheet packages to allow easy manipulation and analysis of data organized in rows and columns, and graphics packages to easily draw and edit images were introduced, thereby making computers a powerful tool for everyone. Advantages : ·  These computers were smaller, cheaper, faster, and more reliable than their predecessors. ·      They consumed less electricity and generated less heat. ·      They had faster and larger primary memory and secondary storage. ·      They could be used as general-purpose computers. ·      GUIs enabled people to learn to work with computers very easily. Hence, the use of computers both in offices and at homes became widespread. ·  Networks allowed sharing of resources, thereby enabling efficient utilization of computer hardware and software.

Fifth Generation (Present and Beyond) : Artificial Intelligence.

Fifth-generation computers are completely based on the new concept of artificial intelligence (AI). Although such computers are still in development, there are certain applications such as voice recognition that are widely being used today. Parallel processing and superconductor technology have made AI a reality. AI touches the following areas, among others : Gaming : Computers are programmed to play games such as chess and checkers. Expert Systems : Computers are programmed to take decisions in real-world situations. Natural languages : Computers are programmed to understand and respond to natural human languages. Neural networks : Systems are programmed to simulate intelligence by reproducing the physical connections that take place in animal brains. Robotics : Computers are programmed to look, listen, and react to other sensory stimuli.