Transcript Ada Lovelace

History of Informatics:
Ada Lovelace
Women and computing?
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Manual computations
First computer programmers were women
Ideal programmers because
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patience
persistence
capacity for detail
Contributions traditionally been ignored
Augusta Ada Lovelace
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First computer programmer
in history
Mathematician and
musician
Creator of
"sets of instructions"
Wrote about Babbage's
"Analytical Engine"
Biography
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Born in London on December 10th, 1815
Family of high status
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father: famous poet
mother: mathematician and poet
Married Lord William King at age 20
Passed away at age 36
Upbringing
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Parents divorced
Brought up by mother
Focus on math and science
Tutored by de Morgan
Role model and best friend:
Mathematician Mary Sommerville
Plagued life
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age 14: Measles and invalid
age 29: Mental and physical breakdown
Gambling habit: looses family fortune
Drug addictions (alcohol, opium,
morphine)
age 36: Dies of cancer
Contributions
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Difference Engine
Analytical Engine
Notes
Programming instruction sets
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loops
subroutines
stored programs
Charles Babbage
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Differential Engine
''She seems to understand it better than I do, and is far,
far better at explaining it''
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Analytical Engine
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successive executions independently
algebraic specifications
read data from punched cards
store data
Notes
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Translation of Menabrea's paper
Added footnotes and explanations
Result 3 times as long as original
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Identity "A.A.L." unknown for 30 years
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The machine
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200 columns with circular discs
Discs labelled with decimal digits
5
3
1
2
represents: 5312
Types and Operators
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2 types of cards:
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Operation cards
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arrange machine parts to execute + - × ÷
Variable cards
represent results
 machine's memory
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Columns
V1
V2
V3
-
+
+
0
0
0
0
0
0
9
0
0
8
7
2
(a)
(n)
(x)
Columns
V1
V2
V3
V4
-
+
+
+
0
0
0
0
0
0
0
0
9
0
0
3
8
7
2
0
(a)
(n)
(x)
(axn)
Table representation
Op. nr.
1
...
6
7
Symbol
×
...
×
×
Input
V3 × V3
...
V3 × V4
V1 × V4
Output
V4
...
V4
V4
Calculating axn requires 7 multiplications
Progress
= x2
...
= xn
= axn
Ada's contribution
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Distinction between types and operators
Loop statements
Arrays
Subroutines
Stored programs
Loop Statements
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Unconditional looping:
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cards executed sequentially
loop instruction found
Engine sort back through cards
when proper card found
execution progresses normally
Conclusion
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Unconventional for women to be
interested in math and science
Ada's work not recognized until years after
her death
Women vital in computer development in
past and future!
Lovelace award