History of Computers

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History of Computers
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Counting

• Man started off by counting on his digits
• Needed ways to measure months and seasons in
  order to perform festivals and ceremonies

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Primitive Calendar

• Stonehenge
• Home for thousands of years to ceremonial and
  religious events involving the summer solstice

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The Abacus

• The First Automatic Computer
• The abacus
• first attempt at automating the counting process.
  
• The abacus is not really an automatic machine it
  is more a machine which allows the user to
  remember his current state of calculations while
  performing more complex mathematical operation.

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Forefathers of Computing

• Forefathers of Modern Computers

Charles Babbage
Gottfried Wilhelm
Blaise Pascal
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The First MechanicalCalculator

• Pascals Gear System
• A one tooth gear engages its single tooth with a
  ten-teeth gear once every time it revolves the
  result will be that it must make ten revolutions
  in order to rotate then ten-teeth gear once.
• This is the way that an odometer works for
  counting kilometers. The one tooth gear is large
  enough so that it only engages the next size gear
  after 1km has passed.

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The Difference Engine

• Never built
• Steam-driven
• Fully automatic
• Next idea was the Analytical Engine

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The Conditional

• Babbages Conditional
• The conditional point allows us to check to see
  what the current value of S is. If s is
  greater than 3, then we want the computer to
  output the value of s (4 in this case.) If s
  is less than or equal to 3, then we want the
  computer to output the value 0

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Hermann Holleriths Tabulating Machine

• This machine was so successful that Hollerith
  started a firm to market it which later became
  known as IBM

10
Binary Representations

• Numbers can be converted to decimal to adding
  together the values of the holes, given that the
  first hole 1 and the second 2, etc.
• For example, 2625232120
• Holes represent an on signal.
• With 6 holes permissible, 26 numbers possible.

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Harvard Mark I

• Grace M. Hopper working on the Harvard Mark-I,
  developed by IBM and Howard Aiken. The Mark-I
  remained in use at Harvard until 1959, even
  though other machines had surpassed it in
  performance, providing vital calculations for the
  navy in World War II.

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Alan Turing

• Sample Turing Machine
• Problem Output a 1 if 3 or more ones in a row
  encountered otherwise )

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ENIAC
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John Von Neumann

• The Von Neumann Machine
• Data and program can be stored in the same space.
  Thus, the machine itself can alter either its
  program or its internal data.
• Conditional gotos to other points in the code
• Von Neumann worked with Mauchly and Eckert on the
  design for EDVAC
• Also a contributor to the fields of game theory
  and cellular automata

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John Von Neumann
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EDVAC
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Advances in the 1950s

• Transistors
• Freedom from vacuum tubes, which were extremely
  bulky
• Integrated Circuits
• Allowed the placement of many transistors into a
  small area.
• Both these advances enables machines to become
  smaller and more economical to build and maintain

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The Altair

• Bill Gates and Paul Allen in 1975 approached Ed
  Roberts if MITS, the company who developed the
  Altair, and promised to deliver the BASIC
  complier.
• They did so and from the
  sale Microsoft was born

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Creation of Microsoft

• BASIC- Beginners All-Purpose Symbolic
  Instruction Code
• Developed by Kemeny and Kurtz in 1964. two
  mathematicians at Dartmouth
• Simple, easy-to-understand syntax allowed
  students to quickly learn it.
• Provided ease of programming and easier debugging
  than machine code or assembly

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Other Languages

• FORTRAN
• FORmula Translator
• Used for science, math, engineering
• PASCAL
• Developed by Niklaus Wirth in the 60s
• Disciplined approach to structure and data
  description
• COBOL
• Common Business Oriented Language
• Data description stored separately from the
  pgram.
• C
• Derivative of ALGOL
• It and its decendants very popular today for
  system programming

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The PC Explosion

• IBM
• Acorn released under the unassuming name PC in
  1981
• 1984, 286-AT
• Whole Host of clones introduced Compaq releases
  a portable
• Apple
• Apple II, 1977
• Apple III, 1980
• Lisa, 1983 first machine with a mouse and
  graphical user interface
• Macintosh introducted in 1984
• Other
• TRS-80 from Radio Shack 1977
• Commodore PET 1980s
• 1981, journalist Adam Osborn commissions design
  of Osborne I which used CP/M

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Bill Steve Before Microsoft
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PCs Today

• Fast
• Graphical User Interfaces (GUI)
• Allows you to use a mouse to control the computer
• Can run thousands of different sets of
  instructions (programs)

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The Web

• The Web can be used for
• Looking up information on publications
• Shopping for books, computers, or CDs
• Investigating staff or research at universities
• Downloading pictures, games, or other files/
• The Web (World Wide Web) was developed at CERN
  lab in Zurich, Switzerland

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Internet

• New form of communicating
• 2 things needed to view the internet
• Internet connection
• Browser