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They were huge, slow, expensive, and often undependable.
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Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.
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AT&T's Bell Laboratories regulated current or voltage flow and act as a switch for electronic signals.
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Vaccum tubes purpose was to act like an amplifier and a switch.
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Vacuum tubes could take very weak signals and make the signal stronger (amplify it).
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The ENIAC gave off so much heat that they had to be cooled by gigantic air conditioners.
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Jack Kilby at Texas Instruments and Robert Noyce at Fairchild Semiconductor independently developed integrated circuits.
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Even with these huge coolers, vacuum tubes still overheated regularly.
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Transistor was faster, more reliable, smaller, and much cheaper to build than a vacuum tube.
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Computer manufactures developed operating systems that provided standardized routines for input, output, memory management, storage, and other resource management actiites.
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Transistors were made of solid material, some of which is silicon, an abundant element (second only to oxygen) found in beach sand and glass.
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Ran programming language compilers that allowed programmers to write instructions using English-like commands rather thanmachine language 1s and 0s.
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Early proprietary operating systems developed by IBM and other computer manufacturers were designed tow ork only on a particular compuer model.
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After programmers found themselves writing print routines over and over again, they began to look for a more efficient method to standardize such routines.
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Integrated circuit, or as it is sometimes referred to as semiconductor chip.
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Two of the first computers to incorporate itegrated circuits were the RCA Spectra 70 and the widly computers were filled.
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Intergrated circuit packs a huge number of transistors onto a single wafer of silicon.
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They could carry out instructions in billionths of a second.
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The size of these machines dropped to the size of small file cabinets.
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DEC introduced a succession of minicomputers that stole a share of the mainframe market.
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Ted Hoff developed the first general-purpose microprocessor.
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The Intel 4004 was a microprocessor that dramatically changed the computer industry.
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Motorola released the 6800 8-bit microprocessor.
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Zilog introduced the Z80 microprocessor.
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Apple II was sold to the public.
