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Things you may want to know but you don’t have to know

Things you may want to know but you don’t have to know. Stories of Two Companies. AT&T Digital Equipment Corporation. AT&T. Alexander Graham Bell Invented the telephone system. Founded the American Telephone and Telegraph Company (AT&T) in 1885. AT&T.

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Things you may want to know but you don’t have to know

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  1. Things you may want to know but you don’t have to know

  2. Stories of Two Companies • AT&T • Digital Equipment Corporation

  3. AT&T • Alexander Graham Bell • Invented the telephone system. • Founded the American Telephone and Telegraph Company (AT&T) in 1885.

  4. AT&T • AT&T became the world’s largest telephone company. • It employed one million people and its revenue was $3 billion annually. • In 1984, US government divided AT&T into 8 companies including original AT&T. • AT&T – long distance services • 7 Baby Bells – local services

  5. 7 Baby Bells • Bell Atlantic • NYNEX • Southwestern Bell • Ameritech • BellSouth • Pacific Telesis • US West

  6. 7 Baby Bells • Bell Atlantic => Verizon • NYNEX • Southwestern Bell => SBC • Ameritech • BellSouth • Pacific Telesis • US West

  7. 7 Baby Bells • Bell Atlantic => Verizon • NYNEX • Southwestern Bell => SBC => AT&T • Ameritech • BellSouth • Pacific Telesis • US West => Qwest => CenturyLink

  8. Digital Equipment Corporation (DEC) • Leading Computer Vendor from 1950s to 1990s. • PDP-11, VAX-11 minicomputers, etc.

  9. DEC was acquired by Compaq in 1998. Compaq was merged with HP.

  10. Why do we talk about these companies? • The UNIX operating system was developed by Ken Thompson and Dennis Ritchie in Bell Labs research center. • It was implemented on DEC PDP-7. • The code was written in Assembly language and C.

  11. What is an Operating System? Application Operating System Compiler Firmware Instr. Set Proc. I/O system Datapath & Control Digital Design Circuit Design Layout

  12. What is an Operating System? • It controls all the computer’s resources (processor(s), memory, input, output, etc.) • It provides the base upon which application programs can be written. • Without an OS, a computer cannot perform nothing. • Unix, Linux, Windows, MacOS, iOS, Android, …

  13. 2017 Top Programming Languages – IEEE Spectrum

  14. 2018 Top Programming Languages – IEEE Spectrum

  15. Terms • bit, byte, word • KB, MB, GB, TB, PB, EB, ZB, YB… • https://en.wikipedia.org/wiki/File_size • sec, ms, us, ns, ps

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