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Harvard Mark 1 The IBM Automatic Sequence Controlled Calculator after installation at Harvard University, 1944. It is 51 feet long, weighs 5 tons, and incorporates 750,000 parts, including 72 accumulators and 60 sets of rotary switches, each of which can be used as a constant register, plus card readers, a card punch, paper tape readers, and typewriters. Sequencing is controlled by a long rotating shaft. An addition takes 1/3 second, and a multiplication, 1 second. The dial switches are at the left, followed by the bays of storage counters. Partially obscured by the observers are the multiplying-dividing unit and the counters used in computing logarithmic and trigonometric functions. At the right are paper-tape units, typewriters, and card punch ENIAC America, with the success of Aiken's Harvard Mark-I as the first major American development in Back in America, with the success of Aiken's Harvard Mark-I as the first major American development in the computing race, work was proceeding on the next great breakthrough by the Americans. Their second contribution was the development of the giant ENIAC machine by John W. Mauchly and J. Presper Eckert at the University of Pennsylvania. ENIAC (Electrical Numerical Integrator and Computer) used a word of 10 decimal digits instead of binary ones like previous automated calculators/computers. ENIAC also was the first machine to use more than 2,000 vacuum tubes, using nearly 18,000 vacuum tubes. Storage of all those vacuum tubes and the machinery required to keep the cool took up over 167 square meters (1800 square feet) of floor space. Nonetheless, it had punched-card input and output and arithmetically had 1 multiplier, 1 divider-square rooter, and 20 adders employing decimal "ring counters," which served as adders and also as quick-access (0.0002 seconds) read-write register storage. the computing race, work was proceeding on the next great breakthrough by the Americans. Their second contribution was the development of the giant ENIAC machine by John W. Mauchly and J. Presper Eckert at the University of Pennsylvania. ENIAC (Electrical Numerical Integrator and Computer) used a word of 10 decimal digits instead of binary ones like previous automated calculators/computers. ENIAC also was the first machine to use more than 2,000 vacuum tubes, using nearly 18,000 vacuum tubes. Storage of all those vacuum tubes and the machinery required to keep the cool took up over 167 square meters (1800 square feet) of floor space. Nonetheless, it had punched-card input and output and arithmetically had 1 multiplier, 1 divider-square rooter, and 20 adders employing decimal "ring counters," which served as adders and also as quick-access (0.0002 seconds) read-write register storage. in America, with the success of Aiken's Harvard Mark-I as the first major American development in the computing race, work was proceeding on the next great breakthrough by the Americans. Their second contribution was the development of the giant ENIAC machine by John W. Mauchly and J. Presper Eckert at the University of Pennsylvania. ENIAC (Electrical Numerical Integrator and Computer) used a word of 10 decimal digits instead of binary ones like previous automated calculators/computers. ENIAC also was the first machine to use more than 2,000 vacuum tubes, using nearly 18,000 vacuum tubes. Storage of all those vacuum tubes and the machinery required to keep the cool took up over 167 square meters (1800 square feet) of floor space. Nonetheless, it had punched-card input and output and arithmetically had 1 multiplier, 1 divider-square rooter, and 20 adders employing decimal "ring counters," which served as adders and also as quick-access (0.0002 seconds) read-write register storage. TRANSISTOR A Three Terminal Device The transistor is a three terminal, solid state electronic device. In a three terminal device we can control electric current or voltage between two of the terminals by applying an electric current or voltage to the third terminal. This three terminal character of the transistor is what allows us to make an amplifier for electrical signals, like the one in our radio. With the three-terminal transistor we can also make an electric switch, which can be controlled by another electrical switch. By cascading these switches (switches that control switches that control switches, etc.) we can build up very complicated logic circuits. These logic circuits can be built very compact on a silicon chip with 1,000,000 transistors per square centimeter. We can turn them on and off very rapidly by switching every 0.000000001 seconds. Such logic chips are at the heart of your personal computer and many other gadgets you use today Light Bulbs and Vacuum Tubes The transistor was not the first three terminal device. The vacuum tube triode preceded the transistor by nearly 50 years. Vacuum tubes played an important role in the emergence of home electronics and in the scientific discoveries and technical innovations which are the foundation for our modern electronic technology. Thomas Edison's light bulb was one of the first uses of vacuum tubes for electrical applications. Soon after the discovery of the light bulb, a third electrode was placed in the vacuum tube to investigate the effect that this electrode would have on "cathode rays," which were observed around the filament of the light bulb. Joseph John Thomson developed a vacuum tube to carefully investigate the nature of cathode rays, which resulted in his discovery, published in 1897. He showed that the cathode rays were really made up of particles, or "corpuscles" as Thomson called them, that were contained in all material. Thomson had discovered the electron, for which he received the Nobel Prize in Physics 1906 |
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HARVARD MARK 1 , ENIAC & TRANSISTORS
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