The Modern Computer

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The Modern Computer
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The Microprocessor and the Microcomputer

• Microprocessor
• An entire CPU on a chip
• Designed by Marcian Hoff, Intel Corporation in
  1970
• Made it possible to build a microcomputer
  (desktop)
• First was the ALTAIR in 1975
• In 1977, Stephen Wozniak Steve Jobs designed
  and built the Apple computer.

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Computer Architecture

• Input Devices Tools computer accepts data from
  user (keyboard, scanner, mouse)
• Memory Electronic storage of instructions and
  data
• Central Processing Unit (CPU) Chip processes
  data and controls flow of data
• Output Devices Tools display data (monitors and
  printers)

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Memory

• ROM Read Only Memory
• Contains the most basic operating instructions
  for the computer
• Complete simple tasks (placing a character on the
  screen, keys pressed)
• RAM Random Access Memory
• Data and instructions temporarily stored
• Can be changed or erased

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CPU

• Central Processing Unit
• Directs all activities of the computer
• Brain of the computer
• Only executes tasks according to the instructions
  cannot think for itself

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ALU

• Arithmetic Logic Unit
• Intelligence of the computer
• Performs adding and comparing numbers
• Measured in nanoseconds (billionth of a sec)

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Number Systems
Called a bit (Binary digiT)

• Circuits on a chip have two states
• 0 for OFF / 1 for ON
• Binary System (base 2) ASCII Code
• Established to translate numbers, letters and
  characters into binary digits
• Letter ASCII Binary Code
• J 74 01001010
• I 73 01001001
• M 77 01001101

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Programming Languages

• Low-level programming
• Used 0s and 1s to represent status of switches
• Called machine language
• High-level programming
• Written in English-like instructions
• FORTRAN - 1956 by John Backus
• COBOL 1959 by Grace Hopper
• First person to apply term debug
• PASCAL 1971 by Niklaus Wirth
• C/C - 1978/1980 by Bell Laboratories