**Chronology of Calculator and Computer
Technology**

1617 | John Napier discusses the Napier's bones calculating method in Rabdologia. |

1622 | William Oughtred invents the slide rule. |

1623 | Wilhelm Schickard builds his 6-digit "Calculating Clock'' that can add and subtract. |

1645 | Blaise Pascal completes his 5-digit "Pascaline'' that can add. |

1930 | Vannevar Bush builds a partly electronic computer capable of solving differential equations. |

1946 | Presper Eckert and John Mauchly announce ENIAC, the first practical entirely electronic computer. |

1948 | William Shockley, Walter Brattain, and John Bardeen invent the transistor. |

1950 | Alan Turing proposes the "Turing test'' criterion for an intelligent machine. |

1951 | Presper Eckert and John Mauchly finish UNIVAC I, the first mass-produced electronic computer. |

1971 | Texas Instruments releases the first easily portable electronic calculator. |

1977 | Apple Computer releases the Apple II personal computer. |