Transcript Second Generation Software

Chapter 1
The Big Picture
Layers of a Computing System
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Early History of Computing
Abacus
An early device to record numeric values
Blaise Pascal
Mechanical device to perform
whole number addition and subtraction
Gottfried von Leibniz
Device to perform all four whole number
operations
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Early History of Computing
Joseph Jacquard
Jacquard’s Loom, the punched
card, not a computing device
Charles Babbage
Analytical Engine – 19th Century – never actually built
because of the technical limitations of the time, but design
includes important components of today’s computers –
memory, cpu, input device for both data and instructions)
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Early History of Computing
Ada Lovelace
Daughter of Lord Byron – Skilled
Mathematician -- First Programmer, the loop
William Burroughs
Mechanical adding machine
Herman Hollerith
Tabulator that read punched
cards – used for tabulating census
Company became IBM
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Early History of Computing
Alan Turing
Turing Machine – computing theory
Artificial Intelligence Testing (an
interrogator asks human and computer
questions to determine who is who)
Harvard Mark I, ENIAC, UNIVAC I
Early computers launch new era
in mathematics, physics, engineering
and economics
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First Generation Hardware
(1951-1959)
Vacuum Tubes
Large, not very reliable, generated a lot of heat
Magnetic Drum
Memory device that rotated
under a read/write head
Card Readers  Magnetic Tape Drives
Sequential auxiliary storage devices
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Second Generation Hardware
(1959-1965)
Transistor
Replaced vacuum tube, fast, small,
durable, cheap
Magnetic Cores
Replaced magnetic drums,
information available instantly
Magnetic Disks
Replaced magnetic tape, data can be
accessed directly
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Third Generation Hardware
(1965-1971)
Integrated Circuits
Replaced circuit boards, smaller, cheaper,
faster, more reliable (Moore’s Law – no.
of IC on a chip was doubling each year)
Transistors
Now used for memory construction
Terminal
An input/output device with a
keyboard and screen
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Fourth Generation Hardware (1971-?)
Large-scale Integration
Great advances in chip technology
Moore’s Law – chip density is
doubling every 18 months
PCs, the Commercial Market, Workstations
Personal Computers and Workstations emerge
New companies emerge: Apple, Sun, Dell …
Moore’s Law Today
‘Computers will either double in power at the same price
or halve in cost for the same power every 18 months’
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Parallel Computing and Networking
Parallel Computing
Computers rely on interconnected
central processing and/or memory
units that increase processing
speed
Networking
Ethernet connects small
computers to share resources
File servers connect PCs in
the late 1980s
ARPANET and LANs  Internet
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ARPANET
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First Generation Software
(1951-1959)
Systems programmers
write the assembler
(translator)
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Applications programmers
use assembly language to
solve problems
Second Generation Software
(1959-1965)
High-level Languages
English-like statements made programming easier:
Fortran, COBOL, Lisp
Systems
programmers
write translators for
high-level languages
Application
programmers
use high-level
languages to
solve problems
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Third Generation Software
(1965-1971)
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Fourth Generation Software
(1971-1989)
Structured Programming
Pascal
C
C++
GUIs
New Application Software for Users
Spreadsheets
Word processors
Database management systems
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Fifth Generation Software
(1990- present)
What do you think?
courtesy, www.opte.org
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Computing as a Tool
Programmer / User
Systems Programmer
(builds tools)
Applications Programmer
(uses tools)
Domain-Specific Programs
User with No
Computer Background
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What are your thoughts?
As our society has become more
automated, it has become easier for
governments to monitor the activities of
their citizens.
Is this a good thing or a bad thing?
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Problem Solving
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The arrangement of the numbers represents a pattern.
This pattern is a mathematical relationship between the
numbers in each square.
Can you identify the pattern and replace the question
mark?
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