 Welcome to the session on State of Computing. At the end of the session, students will be able to express the different forms and types of computers that emerge throughout history. So before we go further with design and organization issue of parallel computer architecture, it is necessary to understand how computers had evolved. Initially, man used simple mechanical devices like a bag of about 500 BC, knotted string and the slide rule for computation. Early computing was entirely mechanical like mechanical adder substractor under Pascal from since 1642. Different engine design baggage like since it is from 1827, then binary mechanical computer used since 1941, electromechanical decimals machines icon since 1944. So here mechanical and electromechanical machines have limited speed and reliability. So because of the many moving parts, fine. So modern machines use electronic for most information transmission. So in computing generation, computing is normally thought of as being divided into different generations. So there we can able to check the different generations from generation one, then from one to two, two to three, three to four and four to five. So in each generation, the space and speed both we are trying to improve. And each successive generation is marked by sharp changes in hardware and software technologies. With some exceptions, most of the advances introduced in one generation are carried through the later generations. So we are currently in the fifth generations. So as we discussed in previous slide, here in the generations, what are the sharp changes you just observe through the pictures. So in the first generation, the space is consumed huge. Then in the latter, the computer size get reduced on a big table. Again in the third generation, the size of the computer gets reduced is available in the like a server machine like mainframe machine. The next again, if you are observing in the next generation, that is in the fourth generation, there we are introduced with the ICs and all. So again the space, here it is highly reduced. And thereafter in the fifth generation, the machine itself is called like a personal computer. Now in the first generation, since 1945 to 54, here the first generation computer were based on vacuum technology, vacuum tube technology. The first large electronic computer was ENIAC that is Electronic Numerical Integer and Calculator, which used high speed vacuum tube technology and were designed primarily to calculate the trajectories of missiles. They used separate memory block for program and data. Later in 1946, Van Neumann introduced a concept of stored program in which data and program were stored in same memory block. So this is about the first generation and the advantage part, it made use of vacuum tubes which are the only electronic components available during those days. So those computers could calculate in milliseconds. We can also parallely check the different disadvantages, there were very big in size weight was about 30 tons. Then these computers were based on vacuum tubes. So the heating issue you can able to check the order. Then these computers were very costly. It could store only small amount of information due to the presence of magnetic drums. About the second generation, since 1955 to 64, the transistor were invented by Bardin, and Shockley in 1947 at Bell Labs. And by the 1950s, these transistors made an electronic revolution in the transistors is small or cheaper and dissipate less heat as compared to vacuum tubes. Now the transistors were used instead of a vacuum tube to construct computer. The major invention was invention of magnetic cores for storage. These cores were used to large random access memories. These generation computers has better processing speed and larger memory capacity. And the smaller size as compared to previous generation computer. So here you can check again some advantages part, the result is the result is reducing the size of computer as compared to first generation, less energy and not produce as much heat as the first generation, assembly language and punch cards used for input. So disadvantage you can check a cooling system was required, consistent maintenance was required, used only for specific purpose, got it. Now we are here at the third generation since 1965 to 74. In 1950 to 60, the discrete components like transistors, resistors, capacitors were manufactured packaged in a separate container. So to design a computer these discrete units were soldered and wired together on a circuit board. The revolution in computer design come when 1960s, the Apollo guidance computer and Mitman missile were able to develop an integrated circuit that is called ICs. So made the circuit design more economical and practical. So the IC based computers are called third generation computers. So as integrated circuit consist of transistors, resistors, capacitors on a single chip eliminating wired interconnections, the space required for the component was greatly reduced. So this is about the third generation advantage. These computers were cheap as compared to the second generation. They were fast and reliable. The use of IC in the computers provides the small size of the computer. Regarding the disadvantages, IC chips are difficult to maintain. The highly sophisticated technology required for the manufacturing of IC chips, fine. So here we have a question, which generation of computer started with using vacuum tubes of the basic components? So here you need to mention which generation of computers. So you have your answer. Your answer is A, that is first generation computer started with using vacuum tubes as the basic components of memory and circuitry for the CPU. Now we are here in the fourth generation since 75 to 90. The microprocessors was invented as single VLSI, that is main memory chips of 1MB plus memory address were introduced as single. So VLSI chip, the cache were invented and placed within the main memory and microprocessor. The VLSI and VAB SLI greatly reduced the space required in a computer and increased significantly the computational speed. Here you can also check different advantages, fastest in computational and size get reduced than previous. Heat generated is negligible, small in size as compared to the previous, less maintenance. And about the disadvantage, the microprocessor design and fabrications are very complex. Computer conditioning is required, then advances in technology is required to make the ICs. At the end we are moving our last slide that is of the last generation, fifth generation after 1990 to till date. So in the mid to late 1980s, in order to further improve the performance of the system, the designers start using a technique known as instruction pipelining. So the idea is to break the program into small instructions and process works on these instructions in different stages of completion. For example, the processor while calculate the result of the current instructions also retrieve the operands for the next instruction based on this. Computer superscalar processors were designed here to execute multiple instruction. In parallel we have multiple execution in it like separate arithmetic and logic units. And we are also here check different advantages it is more reliable and works faster. It is available in different sizes and unique features. They need some disadvantages is also there they need very low level languages. Then they may make the human brains dull and doomed. So here I have my references, thank you.