Transcript History of Computing

Computers in Society
History of Computing
Homework
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Futurism
Can we understand
the future of
computing?
What sort of
predictions have
been made?
Looking Back to Look Ahead
Perhaps the best way to look into the future of
computing is to look back.
Many predictions have been made – in books, in
movies, by academics, by entertainers, by
companies. Most of these predictions have
been very wrong!
What are some examples of “serious”
predictions about the future of computing?
Dubious Quotes
"Everything that can be invented has been invented."
— Charles H. Duell, Commissioner, U.S. Office of Patents, 1899.
"Computers in the future may weigh no more than 1.5 tons."
— Popular Mechanics, 1949
"I have traveled the length and breadth of this country and talked with the
best people, and I can assure you that data processing is a fad that won't
last out the year."
— The editor in charge of business books for Prentice Hall, 1957.
"There is no reason anyone would want a computer in their home."
— Ken Olson, president of Digital Equipment Corp., 1977.
"640K (of memory) ought to be enough for anybody."
— Bill Gates, 1981.
"If the automobile had followed the same development cycle as the
computer, a Rolls-Royce would today cost $100, get a million miles per
gallon, and explode once a year, killing everyone inside."
— Robert X. Cringely, InfoWorld
A Tour of The Computer
* Processing
* Memory
* Transmission
* Interfacing with the real world
It is important to understand how we assess
these things! What makes one device better
than another?
The Computing Element
The original computing element was the human brain. But
eventually mechanical devices were created to speed up the
calculation process.
The apex of mechanical computing was Babbage’s “analytical
engine”, a device too complex to ever work.
This early computing was mathematical – building tables of
numbers for navigation and engineering purposes.
John Von Neumann, one of the pioneers of
computing, used the word “Organ” to describe these
elements. The biological metaphors started from day
1…
Historical Computing Devices
Electronic Computing
The big innovation in computing was the
replacement of mechanical computing devices
by purely electronic ones.
A gear or relay is too big / slow / unreliable to
use in large quantities.
An electronic switch has no moving parts – it
operates by pushing electrons around.
The original electronic computers used vacuum
tubes – later transistors took over.
Electronic Gates
A gate is a device in which one signal controls
another. In a vacuum tube, the grid could
block or allow flow from input to output. So
this is just like a relay.
Transistors are very similar – just a lot smaller.
Silicon
The “computer revolution” came
about when VLSI technology
allowed a single chip to contain
LOTS of transistors. A Pentium has
about 50 million transistors. That
would have been a lot of vacuum
tubes. Manufacturing cost is
something like $0.000001 per
transistor. Note that computers
are built from a single part!
Timeline
• 2500BC – 300BC: Abacus
• 1617: Napier’s Bones
• 1820: First mass-produced mechanical
calculators
• 1822: Babbage’s difference engine
• 1930: motorized mechanical calculators able
to quickly add, subtract, multiply, divide
• 1940s: digital computers (vacuum tubes)
Timeline
• 1950s: computers are mass produced and
become common in the business world
• 1960s: transistors give way to integrated
circuits
• 1980s: personal computing arrives
• Now: a typical computer can do 5 – 10 million
numeric calculations per second (MFLOP)
Assessing Computation
How can we assess a computational technology?
This turns out to be REALLY HARD! Knowing how fast a
device can do one task doesn’t tell us a lot about
other tasks.
Approaches:
• Clock rate (not very accurate)
• MFLOP (only helps for numeric calculations)
• Specific benchmarks
Units: tasks / second