Transcript PowerPoint - University of Virginia, Department of Computer Science

Computer History
CS 110
Fall 2005
Homework
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TA Office hours
• Sunday, Sept 4th from 3-5
• Thornton Hall Stacks Computer Lab
Review of HTML / Homedir
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Connect using Homedir
Explain the parallel between public_html on Homedir (as observed using
Windows Explorer) and www.people.virginia.edu (as observed using
Internet Explorer)
Visit http://www.people.virginia.edu/~dcb8j
• This page is found in my public_html folder
• Note the default is to display index.htm
Demonstrate IP/URL parallels
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• To find IP address, use http://www.dnsstuff.com/
Demonstrate subdirectories
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http://128.143.22.98/~dcb8j
http://www.people.virginia.edu/~dcb8j/Daughter
Note the link to an image (Rotunda) on the web
Demonstrate access to specific web page (not default index.htm)
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http://www.people.virginia.edu/~dcb8j/Daughter/keene2.htm
Note the reference to an image stored in a folder other than the folder in which
the web page is found (“..” indicates the image is found in the parent folder)
http://128.143.22.98/
What is a computer?
Babbage’s “Difference Engine” for computing polynomials (1822)
http://en.wikipedia.org/wiki/Difference_engine
Mechanical Calculators
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1623 – first mechanical calculators
• Add, subtract, multiply, divide
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1800s – computers that are powered
by steam and programmed by punch
cards
• Babbage and Ada Lovelace (Lord
Byron’s daughter)
• IBM’s roots in 1890 census
Analog Computers
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1900s - use a
continuously
variable physical
quantity to store
values
Require “plumbing”
The Soviet Water Integrator (1936)
to be adapted to
new problems
http://en.wikipedia.org/wiki/
Digital Computers
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1940s – WW II
• Electronic circuits, vacuum tubes, etc.
• Mercury tube and TV tube memory
• Computer control over telephone lines
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Parallel developments in Germany,
England, and the US
The British War Effort
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Colossus
• Crack German
encryption codes
• Made Normandy
a success
(18,000 messages
per day)
Colossus (1944)
• Churchill ordered it to be destroyed
“in pieces no larger than a man’s hand”
http://en.wikipedia.org/wiki/Image:Colossus.jpg
Alan Turing
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The creator of Colossus
The father of modern computer science
The inventor of the Turing Test
The discoverer of computability
through the Turing Machine
“Outed” as a homosexual in 1952 and
forced to undergo hormone therapy
Committed suicide in 1954
The US War Effort
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ENIAC
• Used for Army ballistics
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The first computer known to be
completely
generalizable
(Turing Complete)
The German War Effort
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Zuse
• Turing-Complete computer
• Switched numeric representation from
decimal system to binary
• Utilized Von Neumann architecture
where program is stored in same place
as data
• First high-level programming language
Transistors
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1947 – Bell Labs
Electronic switches
On the same order as printing press
and the telephone
Present in nearly
*all* electronic
devices
Desktop computers
were possible
Integrated Circuits
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1956 –Texas Instruments and
Fairchild Semiconductor
Layers of semiconductors
permit complex lattices of
digital switches
Semiconductors change
conductivity in response
to light (CCDs) or
electricity (ICs)
1960 - 1980
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Things moved quickly
Mainframe computer designs were
adapted to the new hardware
New uses for computers were
discovered (supercomputers)
Simplicity and affordability made
computing available for home use
Home Computers
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1974
1975
1977
1981
1982
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Intel 8080 IC
Altair is first mass-produced
Apple II
IBM PC
Commodore 64
Commodore 64 (1944)
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Specs: 64,000 bytes of RAM (vs 1 trillion)
5,000 Hz (vs 4,000,000 Hz)
Home Computers
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Critical features
• Operating Systems
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CP/M  Microsoft copied to create MS-DOS
• Kill Apps
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MacWrite and MacPaint
People started to need computers
Home Computers
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Graphical User Interface (GUI)
• Apple Lisa (1983)
• Apple Macintosh (1984 Superbowl)
• Microsoft Windows (1985)
The Future
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The number of
transistors
incorporated in a
chip will
approximately
double every 24
months
Gordan Moore’s Law, 1965
ftp://download.intel.com/museum/Moores_Law/Printed_Materials/Moores_Law_Poster_Ltr.pdfs.jpg
The Future
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Graphics Cards
• Surpassing Moore’s Law
• Much faster than CPUs (Why?)
• Frequently the most expensive part on a
computer (Why?)
• What are game consoles?