Transcript Hardware: What`s Inside the Box

History of Computing
Define a computer before 1935?
What is the definition after 1945?
History of Computing
Define a computer before 1935?
– A person that computes or performs arithmetic
calculations
What is the definition after 1945?
– An electronic device for performing arithmetic
calculations
History of Computing
What motivated the need for computing machines?
History of Computing
What motivated the need for computing machines?
– Complex and tedious arithmetic calculations
History of Computing
What are some example tedious calculations that
were performed that motivated the need for
computing machines?
History of Computing
What are some example tedious calculations that
were performed that motivated the need for
computing machines?
–
–
–
–
–
Basic arithmetic (abacus)
Navigation and Mathematical tables (Babbage)
Flight trajectory tables (WWII)
Census (Eckert and Mauchley, UNIVAC)
Inventory and budget (J. Lyons)
History of Computing
What are some examples of early computing
machines (mechanical computers)?
History of Computing
What are some examples of early computing
machines (mechanical computers)?
–
–
–
–
–
Abacus (~5000 yrs ago)
Slide rule (Outred, 1600s)
Pascaline (Blaise Pascal, 1600s)
Difference engine (Charles Babbage, 1822)
Tabulating machine (Herman Hollerith, 1890)
History of Computing
What was the purpose of Babbage’s Difference
Engine?
History of Computing
What was the purpose of Babbage’s Difference
Engine?
Calculation of mathematical tables: evaluating mathematical
functions for sequences of values using the method of finite
differences
History of Computing
What was the purpose of Babbage’s Difference
Engine?
Calculation of mathematical tables: evaluating mathematical
functions for sequences of values using the method of finite
differences
History of Computing
Why did Babbage want to create the Analytical
Engine even after having increasing demand for
his Difference Engine?
History of Computing
Why did Babbage want to create the Analytical
Engine even after having increasing demand for
his Difference Engine?
The Difference Engine was still fixed in purpose. He wanted
to design a programmable machine.
History of Computing
What was a major significance of the Analytical
Engine towards the progress of computing?
History of Computing
What was a major significance of the Analytical
Engine towards the progress of computing?
• First time someone designed a machine independent of its
ultimate purpose.
• Birth of distinction between software and hardware
History of Computing
Who worked closely with Babbage during the
development of the Analytical Engine and is
credited as the first computer programmer?
History of Computing
Who worked closely with Babbage during the
development of the Analytical Engine and is
credited as the first computer programmer?
Ada Lovelace, daughter of the poet Lord Byron
Programming language Ada is named after her.
History of Computing
How were numbers represented and stored in the
mechanical computers?
History of Computing
How were numbers represented and stored in the
mechanical computers?
Positions of beads: abacus (~5000 years ago)
History of Computing
How were numbers represented and stored in the
mechanical computers?
Orientation of number wheels: Pascal’s Pascaline (1600s)
History of Computing
How were numbers represented and stored in the
mechanical computers?
Orientation of gears:
Babbage’s difference engine
(1822)
History of Computing
How were numbers represented and stored in the
mechanical computers?
Arrangements of holes in a punch card: Herman Hollerith
(1890)
History of Computing
How were numbers represented in modern
computers?
History of Computing
How were numbers represented in modern
computers?
• A series of 2-way switch settings
• Binary representation, streams of 0s and 1s
History of Computing
How were numbers represented in modern
computers?
• A series of 2-way switch settings
• Binary representation, streams of 0s and 1s
Why binary?
History of Computing
How were numbers represented in modern
computers?
• A series of 2-way switch settings
• Binary representation, streams of 0s and 1s
Why binary?
• Because binary digit (bit) easier to represent:
– Only 2 states: On/off, high/low, in/out, up/down,…
History of Computing
Why were binary digits fundamental to electronic
computers?
History of Computing
Why were binary digits fundamental to electronic
computers?
Engineering simplicity!
Used on/off switches to represent binary digits (bits):
– Relays, vacuum tubes, transistors, integrated circuits
History of Computing
Why didn’t mechanical computers need binary
numbers?
History of Computing
Why didn’t mechanical computers need binary
numbers?
• Unnecessary to perform number conversion
• They were able to easily distinguish more than 2 states
per digit
History of Computing
Why was the vacuum tube so important to computer
development?
History of Computing
Why was the vacuum tube so important to computer
development?
• SPEED!
• Fast switching between binary states
• 1000 times faster than relay (Colossus)
For what tradeoffs?
History of Computing
Why was the vacuum tube so important to computer
development?
• SPEED!
• Fast switching between binary states
• 1000 times faster than a relay (Colossus)
For what tradeoffs?
• Reliability and cost!
History of Computing
What replaced the vacuum tube and completely
revolutionized computers in 10 years?
History of Computing
What replaced the vacuum tube and completely
revolutionized computers in 10 years?
Transistors
History of Computing
What eventually replaced transistors?
Integrated circuits (ICs)
History of Computing
What did relays, vacuum tubes, transistors, and
integrated circuits all have in common for their use
in computers?
History of Computing
What did relays, vacuum tubes, transistors, and
integrated circuits all have in common for their use
in computers?
All acted as a 2-way switch that represented a single bit
of information
History of Computing
Most early computers were constructed only to
perform tedious arithmetic calculations. What was
special about the machine Colossus that Alan
Turing helped design? What was its purpose?
History of Computing
Most early computers were constructed only to
perform tedious arithmetic calculations. What was
special about the machine Colossus that Alan
Turing helped design? What was its purpose?
• Manipulated language symbols not just numbers
• Breaking German codes (U-boat attacks on British)
History of Computing
Describe Turing’s vision of what a computer is or
should be?
History of Computing
Describe Turing’s vision of what a computer is or
should be?
• Symbol manipulator not just numerical machine
• A learning machine
• A machine that exhibits some intelligence
History of Computing
What is the Turing test?
History of Computing
What is the Turing test?
A test devised by Alan Turing to determine if a machine
could be considered to possess some intelligence.
After 5 minutes, if a person asking a remote entity questions
was not sure if the entity was human or machine, then the
computer could be said to possess some intelligence.
History of Computing
Your thoughts…
Do you think this test was sufficient?
What would make you believe that a machine had
intelligence?
Do you consider this to be a danger? Why?
History of Computing
What were computers intended to replace?
History of Computing
What were computers intended to replace?
Large groups of people performing tedious, repetitive tasks such as
arithmetic calculations and various bookkeeping.
Your thoughts… Was this really a bad thing? Were people’s
fears justified? Will this replacement of humans by
machines continue?
History of Computing
Your thoughts…
How were computers portrayed in the early years of
computing (think UNIVAC times)?
How are they portrayed now?
Are there as many misconceptions and fears today? Why or
why not?