Transcript what are the three "core/key skills"?

COMP 1321
Digital Infrastructure
Richard Henson
University of Worcester
September 2012
What is a computer?
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In small groups…
 Four attributes of a computer…
 What is it?
 What does it do?
 10 minutes
Are these computers?
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Abacus
Bathroom scales
Thermostat
Pocket calculator
DVD player
Typewriter
Car speedometer
Stonehenge
Person
Microphone
History of Computing (Origins)
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3400 BC: counting in tens (Egypt)
2600 BC: Abacus (China)
1900-1600 BC: Stonehenge completed
260 BC: base-20 counting – including
zero (Maya – Central America)
Abacus
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Ref:
http://www.tased.edu.au/schools/rokebyh/curric/infotec
h/stage1/assign2/pre20th.htm
Stonehenge
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Ref: http://www.astro.virginia.edu/class/courses.html
History of Computing (Europe)
967 AD: Zero in the eastern hemisphere
(Muhammad Bin Ahmad)
 Around 1500: Design of mechanical
calculator (Leonardo da Vinci)
 1614: Logarithms (John Napier)
 1621: Slide rule (Edmund Gunter,
William Oughtred)
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Slide rules
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Ref: http://osaki.cool.ne.jp/other/other/sliderule/sliderule.html
History of Computing
(Europeans – continued)
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1642: Adding machine (Blaise Pascal)
1679: Binary arithmetic (Gottfried
Leibnitz)
1820s and 1830s: Charles Babbage’s
Difference Engine and Analytical Engine
1840s George Boole: Boolean Algebra
– algebra using just 0 and 1
Babbage
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Ref: http://w1.131.telia.com/~u13101111/merschwib.html
Boole: inventor of “digital”
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Ref: http://buttrysymicaela.blogspot.co.uk/2010/06/george-boole.html
European Domination
(mostly British)
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1843: The idea of Computer Programming
(Ada Lovelace (Byron))
1904: Vacuum tubes (“valves”) birth of
electronics
(John – not Alexander - Fleming)
The Second World War
 1936: Programmable computer (Konrad Zuse,
Germany)
 1943: Colossus – won the war?
Colossus – what’s that!
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Top secret code breaker … 9000 people worked at
Bletchley Park during ww2… here are two of them…
Post-war: US domination
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1947: Transistors (John Bardeen, Walter
Brattain & William Shockley)
1949: ENIAC First commercial computer
1960s: First minicomputer, the DEC PDP-1
(Program, Data, Processor)
1969: Internet begins with 4 mainframes
1971:Floppy disks (IBM: Alan Shugart et al.)
1981: IBM PC launched with Microsoft
Operating system, MS-DOS
Development of Infrastructure
Input-output extended through dumb
terminals (Wang, 1970s)
 Linked together
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Peer-peer networks (Internet…)
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Networks evolve into client-server
(1980s)
client-end usable by non-specialists
European Comeback?
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1988: ARM CPU chip (Acorn)
used in many mobile phones
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1991: World Wide Web founded at EU
research facility, CERN, under the
Swiss Alps (Sir Tim Berners-Lee)
Integration of Telephone and
Digital Infrastructures
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OSI model (1978)
 International Standard in 1984
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European (French) domination
 stubbornly analogue…
 digital data had to be converted before
transmission
 very slow…
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Gradual evolution to digital telecoms
(1990s/2000s)
 ADSL and fast broadband (not rural areas…)
More US domination
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Mobile phone
i-player, i-phone, i-pad
Smart phone
Mobile apps
Cloud computing
What next?…
This?
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The credit card sized Raspberry Pi…
 designed in UK, and now manufactured in UK!
 available for resale at less than £30
Digital?

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Based on approximation
Use “state” (on or off) to represent data
 presence/absence of an electric voltage
 low voltage or higher voltage
0-2 volts = off, 3-5 volts = on
 binary (off = 0, on = 1)
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numbers <-> electrical “square wave” pulses
 great for working with transistors…
Digits
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from
http://www.dribbleglass.com/Toes/uglyt
oes-2.htm
Digital multimeter
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Ref: http://www.universalradio.com/catalog/fm_txvrs/03850208.ht
ml
Analogue
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Uses physical entities to represent data
e.g. the size of an electric voltage, the
frequency of a signal, etc.
Analogue multimeter
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Ref: http://www.kpsec.freeuk.com/
multimtr.htm
Analogue and Digital
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The real world has always been
analogue…
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Digital World = post-war human
invention
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Discussion:
analogue or digital… which is best
Summary
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No fuzziness in digital: exact value
No fractions in digital: precision of value
limited to last digit
Electronics easier with digital
Precision of instruction is crucial:
“A computer will do what you tell it to do, but
that may be very different from what you had
in mind.” (Joseph Weizenbaum)
Computers don’t need tea-breaks (!)