Few%20things%20happen%20at%20the%20right%20time,%20and%20the%20rest%20do%20not%20happen%20at%20all.%20The%20conscientious%20historian%20will%20correct%20these%20defects. - PowerPoint PPT Presentation

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Few%20things%20happen%20at%20the%20right%20time,%20and%20the%20rest%20do%20not%20happen%20at%20all.%20The%20conscientious%20historian%20will%20correct%20these%20defects.

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Few things happen at the right time, and the rest do not happen at all. The conscientious historian will correct these defects. Mark Twain The evolutionary path of ... – PowerPoint PPT presentation

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Title: Few%20things%20happen%20at%20the%20right%20time,%20and%20the%20rest%20do%20not%20happen%20at%20all.%20The%20conscientious%20historian%20will%20correct%20these%20defects.


1
Few things happen at the right time, and the rest
do not happen at all. The conscientious historian
will correct these defects.
Mark Twain
2
The evolutionary path of operating systems
3
Time Sharing
  • Each user has the feeling that he owns his
    portion of the machine.

4
DEC introduced TOPS-10 in 1972
  • ? files - blocks of data could be created,
    modified, stored, recalled from a terminal
  • ? file names 1 to 6 characters followed by a
    period, then a 3-character extension
  • ? small portion of TOPS-10 always present in
    core memory

5
Tops-10
  • ? other programs stored on the disk and called up
    as needed
  • ? user could move files to and from i/o equipment
  • ? text editor
  • ? dynamic debugging tool

6
Time Sharing
  • Since computers were expensive, some companies
    tried to sell time on their machines.
  • It did not work
  • Most people wanted to use the machine at the
    same time

7
Gordon Bell
  • The semiconductor density has really been the
    driving force of development. As you reach
    different density levels, different machines pop
    out of that in time.

8
The Microprocessor
  • Late 1960s metal oxide semiconductor (MOS) put
    more logic elements on a chip
  • Intel marketed the first in 1972
  • Made hand held calculators possible

Intel 8008
9
Computer on a chip
10
Hand-Held Calculators
  • It could
  • Execute short programs
  • Compute logarithms
  • Compute trigonometric functions
  • Use floating-point arithmetic to 10 digits of
    precision

Few mainframes could do this without
custom-written software.
Hewlett-Packard 65
11
The Personal Computer Changes the World as We
Know It
  • 1972-1977

12
The MICRALRealisations Etudes Electroniques
Thi T. Truong
  • The first general-purpose computer based on a
    microprocessor, the Intel 8008

13
Altair 88001974
  • Lost its data when the power was shut off
  • Data transformed into audio tones and stored on
    magnetic tape

14
Software Basic
  • The eight design principles of BASIC were
  • Be easy for beginners to use.
  • Be a general-purpose programming language.
  • Allow advanced features to be added for experts
    (while keeping the language simple for
    beginners).
  • Be interactive.
  • Provide clear and friendly error messages.
  • Respond fast for small programs.
  • Not require an understanding of computer
    hardware.
  • Shield the user from the operating system.

15
System Softwarethe final piece of the puzzle
  • Paul Allen showed the magazine to Bill Gates
  • They wrote a 4K, 8K, and an extended version of
    BASIC

Microsoft team 1978
16
The solution to the storage problem
The floppy disk drive
1942-1994
Gary Kildall
Big Advantage Random Access
17
(No Transcript)
18
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